Alternating Flow Column Chromatography Apparatus and Method of Use

Abstract

An alternating flow column chromatography apparatus comprising a U shaped or T shaped separation column including at least one loading port for loading of components for separation, a first purification column in fluid communication with one end of the separation column and a second purification column in fluid communication with another end of the separation column, at least one eluent input port, an eluate output port and an alternating flow valve in fluid communication with the primary eluent input port, the eluate output port, the first purification column and the second purification column wherein, when operated, the alternating flow valve reverses the flow of eluent through the purification columns and the separation column. Also a method of using the apparatus. A benefit of the apparatus and method is more efficient operation compared to existing direct flow column chromatography apparatuses.

Claims

1. An alternating flow column chromatography apparatus for chromatographic separation and chromatographic purification of ionic radionuclide components and chemical components soluble in a solution comprising: a chromatographic separation column of U shape or modified I shape, including at least one loading port for loading of components for separation; a first purification column in fluid communication with one end of the separation column and a second purification column in fluid communication with another end of the separation column; at least one eluent input port; an eluate output port; and an alternating flow valve in fluid communication with the at least one eluent input port, the eluate output port, the first purification column and the second purification column wherein, when operated, the alternating flow valve reverses the flow of eluent through the purification columns and the separation column.

2. The apparatus of claim 1 wherein one of the at least one eluent input port is a primary eluent input port and there are one or more specific eluent input ports.

3. The apparatus of claim 1 wherein at least one of the at least one loading port is disposed at the center of the chromatographic separation column or at an end of the separation column.

4. (canceled)

5. (canceled)

6. The apparatus of claim 1 further comprising an eluent selection valve for selecting between the at least one eluent input ports.

7. The apparatus of claim 1 further comprising a vacuum source that supplies a driving force for eluent/eluate liquid flow communication.

8. The apparatus of claim 1 wherein the separation column is pre-packed with sorbent powders of particle size from 50 m to 200 m and components for separation are loaded via one of the at least one loading ports.

9. The apparatus of claim 1 wherein the separation column is loaded with slurry of solid substrate powders of particle size from 50 m to 200 m containing components for separation through the loading port.

10. (canceled)

11. The apparatus of claim 1 wherein the purification columns are pre-packed with sorbent powders of particle size from 30 m to 150 m.

12. The apparatus of claim 1 wherein the columns are packed with inorganic or organic solid sorbent or inorganic or organic solid substrate having an affinity for at least one component of the components for separation and very little or no affinity for at least another component of the components for separation.

13. The apparatus of claim 1 comprising more than one purification column at each side of the separation column.

14. The apparatus of claim 1 wherein the alternating flow valve is a manually operated valve or an electrically operated valve or a pneumatically operated valve or an hydraulically operated valve.

15. The apparatus of claim 1 comprising a processor that operates the alternating flow valve according to a predetermined program.

16. A method of alternating flow column chromatography in an alternating flow column chromatography apparatus comprising: a separation column including at least one loading port for loading of components for separation; a first purification column in fluid communication with one end of the separation column and a second purification column in fluid communication with another end of the separation column; at least one eluent input port; an eluate output port; and an alternating flow valve in fluid communication with the at least one eluent input port, the eluate output port, the first purification column and the second purification column including the steps of: loading the separation column with sorbent powder and components for separation; delivering eluent through the alternating flow valve and the purification columns to the separation column; eluting eluate of a desired component from the separation column; collecting the eluate of desired component; and periodically operating the alternating flow valve to reverse the direction of the flow of eluent through the purification columns and the separation column.

17. The method of claim 16 including the steps of repeatedly reversing the flow of eluent for each elution.

18. The method of claim 16 wherein the ionic product-generating component or one of the components to be separated is immobilized in the separation column at the loading step and then at the separation elution step.

19. The method of claim 16 wherein step of loading the separation column is by solution loading or slurry loading.

20. (canceled)

21. The method of claim 16 wherein the separation column is first loaded with sorbent powder and then fully or at least almost fully loaded with components for separation separately.

22. The method of claim 16 wherein the step of delivering eluent includes delivering primary eluent and/or specific eluent.

23. The alternating flow column chromatography apparatus of claim 1 configured as a radionuclide generator wherein the chromatographic separation column is a generator column and wherein the components are radioisotopes.

24. (canceled)

25. (canceled)

26. A method of radionuclide generation in an alternating flow column chromatography apparatus of claim 23 including the steps of: loading the generator column with sorbent powder; immobilizing the ionic parent radionuclide (a product-generating component) in the generator column; delivering eluent through the alternating flow valve to the purification columns and generator column; eluting eluate of daughter radionuclide (product component) from the generator column and purification columns; collecting the eluate of daughter radionuclide; and periodically operating the alternating flow valve to reverse the direction of flow of eluent through the purification columns and the generator column for a consecutive elution-purification process and repeating the elution steps of eluting eluate for collecting the eluate of daughter radionuclide (without repeating the step of immobilizing the ionic parent radionuclide,) for the whole life time of the parent radionuclide and/or for whole the life time of a medically useful radionuclide generator.

27. (canceled)

28. (canceled)

29. The method of claim 26 wherein the step of loading the generator column is by loading sorbent powder and components for separation together or by first loading sorbent powder and then fully or at least almost fully loading components for separation separately or loading slurry of solid substrate powders containing a mixture of parent radionuclides (product daughter radionuclide generating component) and daughter radionuclide.

30. The method of claim 26 wherein the step of delivering eluent includes delivering primary eluent and/or specific eluent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings in which:

[0059] FIG. 1 shows a schematic representation illustrating a prior art system setup of conventional direct flow column chromatography (DFCC);

[0060] FIG. 2 shows a schematic representation illustrating a prior art setup of improved direct flow column chromatography (IDFCC);

[0061] FIG. 3 shows a schematic representation illustrating a first embodiment of an alternating flow column chromatography (AFCC) setup according to the present invention;

[0062] FIG. 4 shows a schematic representation illustrating a second embodiment of an alternating flow column chromatography (AFCC) setup according to the present invention;

[0063] FIG. 5 shows a schematic representation illustrating greater detail of the second embodiment of an alternating flow column chromatography (AFCC) of FIG. 4;

[0064] FIG. 6 shows a schematic representation illustrating a cross-sectional view of a radionuclide generator using the alternating flow column chromatography apparatus of FIG. 5;

[0065] FIG. 7 shows a photo of a radionuclide generator composed of a generator cartridge disposed in the internal volume of the generator body according to the schematic of FIG. 6;

[0066] FIG. 8 is a photograph of the generator cartridge of FIG. 7;

[0067] FIG. 9 shows a schematic of a first embodiment of an alternating flow valve;

[0068] FIG. 10 shows a schematic of a second embodiment of an alternating flow valve;

[0069] FIG. 11 shows a schematic of a third embodiment of an alternating flow valve;

[0070] FIG. 12 depicts various configurations of an alternating flow column chromatography apparatus;

[0071] FIG. 13 shows schematics depicting three operations of the AFCC apparatus. FIG. 13a depicts operational function 1 of a standard elution of a desired product (component). FIG. 13b depicts operational function 2 of a selective elution of a purified product (component). FIG. 13c depicts operational function 3 of a further purification and selective elution of purified product (component); and

[0072] FIG. 14 shows a graph demonstrating the effectiveness of the AFCC apparatus.

DETAILED DESCRIPTION

[0073] Referring to FIG. 1, there is shown a prior art Direct Flow Chromatography Column (DFCC). As is known in the art, the DFCC flow of eluting fluid (liquid or gas) runs in one direction all the time. FIG. 2 shows a known improved direct flow column chromatography (IDFCC) that separates the separation column from a following purification column and allows for independent loading of the separation column. However, the IDFCC still has flow of eluting liquid or gas running in one direction all the time.

[0074] In FIG. 1 there is shown a separation column (SC) for capturing and retaining a mixture of species needed to be separated. The eluent enters at the top of FIG. 1 and flows through a loading zone (LZ) to a separation/purifying zone (PZ) and hence exits as eluate, as described above in the background section. In FIG. 2 there is shown a separation column (SC) loaded with the solid substrate powders containing the parent radionuclide and daughter radionuclide components and a following purification column (PC). As with the prior art embodiment of FIG. 1, the eluent enters at the top of FIG. 2 and flows through the separation column (SC) before flowing through the purification column (PC). The embodiment of FIG. 2 also permits separate loading of the separation column (SC).

[0075] A first embodiment of an alternating flow column chromatography (AFCC) apparatus for the chromatographic separation and chromatographic purification of the ionic radionuclide components and chemical components of size <2.5 nm (<25 ) soluble in an aqueous solution is depicted schematically in FIG. 3.

[0076] The composition to be separated is a mixture of ionic desired (target or product) components, ionic product-generating components and ionic contaminant components (including the breakthrough of ionic product-generating components leachable from the separation and purification columns into eluate flow). The components (species) of the composition to be separated are ionic and/or non-ionic molecules of size <2.5 nm soluble in an aqueous solution. The product component may be generated from a product-generating component as a result of chemical, biochemical and nuclear (radiochemical) decomposition processes. The decomposition process may be an in-situ process occurring inside of the separation column loaded with ionic product-generating component or a process occurring outside of the separation column. The decomposition process may be a spontaneous radioactive decay of a parent radionuclide (an ionic product-generating component) to generate a daughter radionuclide (an ionic product component).

[0077] In broad terms the apparatus 1 consists of a separation column 2, a pair of purification columns 3a, 3b, and an alternating flow valve 4. The alternating flow valve 4 is operated to reverse the direction of eluent flow from feed eluent port 5 to eluate collection port 6 through the columns 2, 3a, 3b. A mixture of components to be separated may be loaded through a separation column loading port 7, as described in greater detail below.

[0078] The alternating flow valve 4 may take any appropriate form to achieve the reversible flow as described. Various options are described below. The alternating flow valve 4 operates in a first position to direct eluent (liquid or gas) from feed eluent port 5 to purification column 3a, through the separation column 2 and purification column 3b to eluate collection port 6 following the path indicated by the dotted arrow 9a and solid arrow 9b. In a second position the alternating flow valve 4 operates to direct eluent from feed eluent port 5 to purification column 3b, through the separation column 2 and purification column 3a to eluate collection port 6 following the path indicated by the solid arrow 9c and dotted arrow 9d. It will be appreciated that changing the alternating flow valve 4 between the first position and the second position reverses the direction of flow of eluent through the apparatus that achieves the various advantages outlined below.

[0079] The separation column is loaded with a composition to be separated. One or more component(s) of the composition is preferentially retained by the separation column, as is known. The desired component is washed through by the eluent and collected at the eluate port. The purification columns preferentially retain any of the first component(s) that break through from the separation column. The alternating flow valve reverses the direction of flow of eluent so that with each flow reversal the upstream purification column is regenerated and the everclean purification columns together with a larger volume of fully component-loaded separation column are actively used for a larger separation capacity.

[0080] FIG. 4 shows a second embodiment of an alternating flow column chromatography (AFCC) apparatus which is essentially equivalent to the first embodiment of FIG. 3 except that the separation column 2 is configured in a U shape instead of the I shape of FIG. 3. In other respects the components and operation are the same.

[0081] In order to better describe the invention a more detailed illustration of a third embodiment of an alternating flow column chromatography (AFCC) apparatus is shown in FIG. 5. Suitably the AFCC apparatus is setup in the format of an integrated device, preferably in a format of benchtop device operated by a limited vacuum driving force for eluent/eluate liquid flow communication without using differential pressure controllers.

[0082] As with the first and second embodiments, the apparatus 1 consists of a separation column 2, a pair of purification columns 3a, 3b, and an alternating flow valve 4. In the third embodiment, the separation column 2 has a U shape, although it could also be configured with an I shape. The alternating flow valve 4 is operated to reverse the direction of the eluent flow from feed eluent port 5 to eluate collection port 6 through the columns 2, 3a, 3b. A mixture of species to be separated may be loaded through a central separation column loading port 7a or through loading ports 7b at either end of the separation column. Depending on the favourable adsorption properties of the components to be separated, especially the product-generating component, for the sorbent packed in the column body, the loading ports 7b disposed at the two ends of the sorbent/substrate bed may be preferred over the centre inlet loading port 7a disposed at the centre of the body for loading solid substrate powders containing components to be separated. Typically sorbent or substrate powders of particle size from 50 m to 200 m are disposed in the column body. There may also be liquid permeable restrictors 2a disposed at both ends of the sorbent or substrate powder bed of the separation column 2 for preventing exit of the sorbent or substrate powders from the column body. Restrictors 3c may also be provided for the purification columns. The restrictors may be sintered glass frits, plastic frits or some other type of frit.

[0083] The chromatographic separation column is packed with the sorbent powders or solid substrate powders for chemically immobilizing ionic product-generating molecules or one of the components and other ionic contaminant components. The chromatographic separation column has low affinity (preferably no affinity) of retaining the ionic desired (product) component.

[0084] In the third embodiment of FIG. 5 there is provided a primary eluent port 5a and a specific eluent port 5b. Providing two (or more) eluent ports allows for more than one eluent to be used in operation of the AFCC. For instance, a primary eluent may be used for elution through the separation column and purification columns or a specific eluent may be used for just purification. The primary eluent is held in reservoir 5e and the specific eluent is held in vial 5c. An eluent selective valve 5d allows for selection of the desired eluent and directs the selected eluent to either purification column 3a, 3b or directly to the separation column 2, as desired. The eluent selective valve 5d is suitably a 2-way triple-port pinch valve.

[0085] FIG. 5 also shows eluate collection vials 6a, 6b which can be removed from the eluate collection port 6.

[0086] The separation column may be loaded according to a sorbent packing approach or a substrate loading approach. The sorbent packing approach means the separation column is pre-packed with sorbent powders but the composition to be separated is not loaded till a subsequent step, preferably just before separation. In this approach the composition for separation is delivered through the loading port 7a, which is at the centre of the column, and excess flows out through loading ports 7b. This approach may be referred to as solution loading (SOLP) as only the composition to be separated is loaded as a solution. The substrate loading approach means the empty separation column is loaded with substrate powders containing immobilized composition to be separated. To facilitate filling the empty separation column with solid powder, slurry with water is formed. The slurry of water and substrate powders containing immobilized composition to be separated is sucked into the separation column through loading ports 7b by a limited vacuum applied to the port 7a and excess flows from port 7a. This approach may be referred to as slurry loading (SULP) as the composition immobilized in substrate powders are loaded as slurry. The dry substrate powders can be loaded into the separation column (SC) using a limited vacuum applied to the outlet of loading port 7a.

[0087] In one embodiment, the chromatographic separation column according to the invention is fully loaded with the mixture of components to be separated and has a sharp loading zone (band) to minimize the column volume (loading effective zone) where the mixture of components is present. The small loading zone applicable in the AFCC method offers a reduction in the eluent volume needed to remove/separate the target species from the mixture of components. A small loading zone is hard to achieve in the conventional prior art DFCC procedure.

[0088] The chromatographic purification columns may be purposely designed to enable and to be effectively used for reverse-forward alternating the direction of eluent flow in the column. For instance, the sorbent powders may be chosen with particle size from 30 m to 150 m disposed in the column body for specific purpose. The chromatographic purification columns are packed with sorbent powders to immobilizes and/or retains the ionic contaminant components including a small amount of breakthrough of product-generating component leachable from the separation column. The chromatographic purification column has low affinity (preferably no affinity) of retaining the ionic desired (product) component.

[0089] In the AFCC method two purification columns of small diameter and reasonably long length, loaded with a relatively small weight of sorbent of small size and connected to both ends of the separation column, play a role of further purification of the desired (product) component separated by the separation column, and are regenerated (cleaned up) by the fresh feed primary eluent each time the eluent flow is reversed by operation of the alternating flow valve. The finer particle size sorbent powders packed in the purification column offers more effective retaining of contaminant components from the eluate flow. A longer length of the purification columns packed with reasonable small weight of sorbent powders of smaller particle size offers an elution with smaller eluent volume and a longer traveling time of contaminant components along the column giving higher probability of contacting with sorbent powders for retaining the contaminant components in a trace quantity from the eluate flow.

[0090] The embodiment of FIG. 5 shows the separation column 2 communicating with the purification columns 3a, 3b via tithes or pipes. The columns could be directly connected as per the example in FIG. 12g and FIG. 12h, discussed later.

[0091] As with the first embodiment (as shown in FIG. 3), the alternating flow valve 4 operates in a first position to direct eluent (liquid or gas) from feed primary eluent port 5a to purification column 3a, through the separation column 2 and purification column 3b to eluate collection port 6 following the path indicated by the dotted arrows 9a. In a second position the alternating flow valve 4 operates to direct eluent from feed primary eluent port 5a to purification column 3b, through the separation column 2 and purification column 3a to eluate collection port 6 following the path indicated by the solid arrows 9b. In operation, the alternating flow valve 4 is repetitively switched between the first position and the second position to repeatedly reverse the direction of flow of eluent through the apparatus to achieve the various advantages discussed herein.

[0092] The eluent-selective valve 5d connects to the primary eluent port 5a and the specific eluent port 5b to the alternating flow valve and to the loading ports 7b. The valve is being functioned in the operation of the multiple further purifications with several specific eluents and/or the elution of the product component from a purification column with a specific eluent for increasing the concentration of the product component. The inclusion of the specific eluent port 5b and the eluent selective valve 5d in the apparatus offers a capability of eluent variation and increasing the operation functions of AFCC apparatus resulting in advantageous features such as separation of desired (product) component of improved purity and higher concentration.

[0093] An example of the use of the additional eluent port and selective valve is shown in FIG. 13. The following items are shown in the figures:

TABLE-US-00001 ST-1 Operation step 1 ST-2 Operation step 2 ST-3 Operation step 3 SC Separation Column PC-1 Purification Column 1 PC-2 Purification Column 2 PE Primary Eluent SE-1 Specific Eluent 1 SE-2 Specific Eluent 2 W Waste DE Daughter radionuclide product Eluate Pb Lead radiation shielding

[0094] There are three steps depicted, they are:

a) Standard elution of desired (product) component as shown in FIG. 13a. This process involves eluting the desired component with a primary eluent from the separation column through one of the purification columns to an eluate output port while retaining the contaminant components in the purification column;
b) Selective elution of purified product component from as shown in FIG. 13b. This process is performed when both the product component (e.g. daughter radionuclide in a radionuclide generator) and contaminant components (including the breakthrough of product-generating component) separated by a primary eluent from the separation column (e.g. a radionuclide generator column loaded with parent radionuclide) are retained on the purification column, as depicted in Step 1. In step 2, a specific eluent is put to use in replacing the primary eluent by actuating the eluent selective valve 5d for selectively eluting the specific eluate of desired (product) component from the purification column into a specific eluate receptacle. The contaminants including the breakthrough of product-generating component are kept retained on the purification column. The product-generating component is immobilized in the separation column.
c) Further purification of the product component with specific eluents and selective elution of purified product component from purification column with purposely used specific eluent is shown in FIG. 3c. This process is performed when both the product component (e.g. daughter radionuclide in a radionuclide generator) and contaminant components (including the breakthrough of product-generating component) separated by a primary eluent from the separation column (e.g. a radionuclide generator column loaded with parent radionuclide) are retained on the purification column during elution in Step 1. In step 2 a further purification is performed with a specific eluent put into use in replacing the primary eluent by actuating the eluent selective valve 5d. By this operation the specific eluent passes through the purification column to remove the contaminants from the purification column into an evacuated waste container located at the eluate port while keeping the desired (product) component further retained on the purification column. In step 3 a specific eluent is used for eluting the specific eluate of desired (product) component from the purification column into a specific eluate receptacle. The product-generating component is immobilized in the separation column and a possible breakthrough of product-generating component is not retained by the purification column.

[0095] As will be appreciated, the steps are essential the same with reversal of the flow.

[0096] By way of summary, the functions shown in FIG. 13a, FIG. 13b and FIG. 13c are:

Function 1: Eluting the desired component with a primary eluent from the separation column through one of the purification columns to an eluate output port while retaining the contaminant components in the purification column;
Function 2: Eluting the desired component with a primary eluent from the separation column to move the desired component to be retained on a purification column, then recovering the eluate with a specific eluent from the purification column;
Function 3: Eluting the desired component with a primary eluent from the separation column to move the desired component to be retained on a purification column, then further purifying the desired component with a specific eluent and eluting the eluate of desired component from the purification column with another specific eluents.

[0097] The AFCC apparatus and method has a number of advantages compared to the DFCC and IDFCC techniques described above. These include that the regeneration of the purifying/separating zone by reversal of flow, non-spread sharp-cut analytic species loading zone, reduced eluent volume requirement and more effective separation.

[0098] The invention may be applied to various chemical, nuclear/radiochemical and biochemical separations such as preparative chromatographic separation, solid phase catalysis or solid-supported reagents based organic synthesis, analytical chemistry separation, biochemical separation of bioproducts generated from the enzymatic reaction of enzyme coated on solid particle surface enzyme, and particularly radioisotope separation in radionuclide generator production technology. FIG. 6 shows an embodiment of the alternating flow column chromatography apparatus that is particularly suited to radionuclide generation.

[0099] Referring to FIG. 6, there is provided a radionuclide generator 10 for generating a solution of an ionic radioactive isotope product component (daughter radionuclide). The generator design is based on the AFCC apparatus described according to the third aspect of the invention. It comprises a separation (generator) column 30 (GC), the generator having an ionic product-generating radioactive isotope component (parent radionuclide) retained on the column packing material thereof. The parent radionuclide is such that it decays to produce a daughter radionuclide and the parent radionuclide has a greater affinity for the column packing material than the daughter radionuclide does. The radionuclide generator further comprises two purification columns 40 (PC) which are packed with a sorbent adapted for selectively retaining the parent radionuclide and other contaminant component. The radionuclide generator further comprises an alternating flow valve 201 (AFV) for reversing the flow of eluent when a consecutive elution is performed. The radionuclide generator may also comprises a specific eluent input port and an eluent selective valve as shown in FIG. 5.

[0100] The alternating flow column chromatography based radionuclide generator is setup in the format of integrated device, preferably in a format of benchtop device by a limited vacuum driving force for eluent/eluate liquid flow communication without using differential pressure controllers.

[0101] Further detailed elements of the radionuclide generator are set out in the following table. In particular, the generator column 30 is embodied as a generator cartridge 20 so that it may be easily removed and reinserted in the generator 10. The cartridge 20 is held in a cartridge chassis 205 which has lead shielding 206. The loading port 704 is configured for either solution loading or slurry loading. The generator is constructed in a convenient package which may be transported with carry handle 905. Other elements are discussed below.

TABLE-US-00002 Numbers Assignment 10 Radionuclide generator 20 (C) Generator cartridge 201(AFV) Alternating Flow Valve 202 (VA) Valve actuating means 203 T connector of the Alternating Flow Valve 204 T connector of the Alternating Flow Valve 205 (CH) Cartridge chassis 206 (LS1) Local lead shielding of the generator cartridge 30 (GC) Generator column 301 Frit of the generator column 302 Aluminium-capped septum stopper of the generator column 303 Connector of the loading port (optional) used as an inlet for loading a generating (parent) radionuclide solution and as an outlet for loading a generating (parent) radionuclide-substrate material. 304 Connector of the loading port used as an inlet for loading the generating (parent) radionuclide-substrate material, in case. 305 Connector end of the Generator column 40 (PC) Purification column 401 Frits of the purification columns 402 Aluminium-capped septum stopper of the purification column 403 Connector end of the purification column 404 T- connector end of the purification column 501 (TB) Tubes connecting the purification column and generator column 60 (E) Feed eluent port 601 Vented spike of the Feed eluent port 602 Guide hole for eluent vial 603 Millipore filter of the Vented spike 70 (EL) Eluate collection port 701 Needle of the eluate collection port 702 Guide hole for eluate vial 703 Millipore filter of the eluate collection port 704(SOLP/SULP) Loading port for the generating (parent) radionuclide solution (SOLP) and/or for the generating radionuclide-substrate material (SULP). 705 Tubing for loading the generating radionuclide-substrate material, in case. 80 (S) Radiation shielding means of the generator body 801 Internal volume of the generator body 802 (LS2) Local radiation shielding means 901 Guide cover for the ports 902 Support of the ports 903 Support of the radiation shielding means of generator body 904 Can of the generator 905 Means of carrying

[0102] A wet or dry elution technique may be applied to elute daughter radionuclide from the generator. Preferably, dry elution technique is applied to avoid diluting the eluate with the residual eluent present in the tubing connection.

[0103] To assist with understanding the nature of the radionuclide generator embodiment two photographs are provided as FIG. 7 and FIG. 8. Similar elements carry the same indicia as shown in FIG. 5, FIG. 6 and listed in the table above. As shown in FIG. 7 a radionuclide generator includes a generator cartridge which is shown in FIG. 8.

[0104] In use, auto-regeneration of the purification columns is performed by reversing the eluent flow in consecutive elution resulting in a longer life-time of the radionuclide generator.

[0105] The packing material of coarse particle size for the generator column and the sorbent of fine particle size for the purification columns are used for benefiting a good flow dynamics and highest purification/elution performance giving a small volume of daughter radionuclide eluate (higher concentration of daughter radionuclide) of high purity.

[0106] Advantageously, the generator column is packed with a sorbent adapted for being fully loaded with the parent radionuclide as a product-generating radionuclide source. The sorbent is adapted for selectively retaining the parent radionuclide as a product-generating radionuclide source, or being packed with a parent-radionuclide-substrate material having selectively immobilized product-generating radionuclide ion in the substrate. The column packing material comprises an inorganic or organic solid sorbent or inorganic or organic solid substrate containing parent radionuclide immobilized in the solid material matrix. Preferably, the inorganic sorbent or inorganic solid substrate has no (or very little) affinity to retarding the daughter radionuclide of the parent radionuclide in use. Preferably, the inorganic sorbent or inorganic solid parent-nuclide-substrate is in powder form of particle size from 50 m to 200 m or of mean particle size from 60 m to 100 m.

[0107] The generator column 30 is usefully in the form of U tube but an I tube is also effective. As with the earlier embodiment the parent nuclide loading ports are located at both ends of the generator column and/or at the middle of the generator column. Two ends of the generator column are connected in series to two purification columns (which may be identical). The arrangement provides for flexibility in the nature of radionuclide parent loading of the column 30. The generator column may be suitable for separation of radioactive ions. The housing, the body, the restrictors, the loading port and the bifunctional outlet-inlet connectors may all be constructed from materials that are not degraded by radiation of parent radionuclide and daughter radionuclides and by the gamma-radiation and autoclaving steam-temperature applied for sterilization of the generator columns.

[0108] The purification columns 40 are packed with a sorbent adapted for selectively retaining the parent radionuclide and other contaminant components.

[0109] The purification columns comprise a column packing material for selectively retaining the parent radionuclide from the eluate of the daughter radionuclide of the parent radionuclide in use. Suitably the column packing material comprises an inorganic or organic solid sorbent which has no (or very little) affinity to retard the daughter radionuclide of the parent radionuclide in use. Preferably, the inorganic or organic solid sorbent used in the purification columns is in powder form of particle size from 30 m to 150 m or of mean particle size from 40 m to 70 m. The purification column may be suitable for purification of radioactive ions. The housing, the body, the restrictors, the bifunctional outlet-inlet connectors may all be constructed from materials that are not degraded by radiation of parent radionuclide and daughter radionuclides and by the gamma-radiation and autoclaving steam-temperature applied for the sterilization of the purification columns.

[0110] In one embodiment, the chromatographic separation column (generator column) of AFCC-based radionuclide generator according to the invention is fully loaded with the parent radionuclide and has a sharp loading zone (band) to minimize the column volume (loading zone) where the mixture of parent radionuclides and daughter radionuclides is present. The small loading zone applicable in the generator column offers a reduction in the eluent volume needed to remove/separate, the daughter radionuclides from the mixture of parent radionuclides and daughter radionuclides. A small loading zone is hard to achieve in the conventional prior art DFCC-based radionuclide generator.

[0111] In the AFCC-based radionuclide generator two purification columns of small diameter and reasonably long length, loaded with a relatively small weight of sorbent of small size and connected to both ends of the generator column, play a role of further purification of the daughter radionuclide separated by the generator column, and are regenerated (cleaned up) by the fresh feed eluent each time the eluent flow is reversed by operation of alternating flow valve. The finer particle size sorbent powders packed in the purification columns offers more effective retaining of contaminant components (including a breakthrough of parent radionuclide considered as main contaminant) from the eluate flow. A longer length of the purification columns packed with reasonable small weight of sorbent powders of smaller particle size offers an elution with smaller eluent volume and a longer traveling time of contaminant species along the column giving higher probability of contacting with sorbent powders for retaining the contaminant species in a trace quantity from the eluate flow.

[0112] Suitable sorbents are discussed later with respect to specific examples.

[0113] The generator column and purification columns are provided with support frits 301 and 401 of pore size between 20 m to 50 m at both ends of the column. Each end of generator column 30 is connected to one end of each purification column 40 using lead tubing 501(TB). In the alternative each end of generator column 30 may be connected directly to the one end of each purification column 40 without lead tubing.

[0114] The generator column 30 is provided with one feed eluent port 60(E) which is provided with a 0.22 m Millipore filter 703 and a needle 701. The generator column 30 is also provided with one eluate collection port 70(EL) with a pin vented by a 0.22 m Millipore filter 603.

[0115] Each purification column is connected to the alternating flow valve 201 which operates with two open-close channels. Each channel accommodates one upper line and one lower line for fluid (liquid or gas) flow. On one side of the valve two upper lines of the channels are connected via a T connector 203 which is itself connected to the feed eluent port 60 and two lower lines of the channels are connected via a T connector 203 which is connected to the eluate collection port 70. On the other side of the valve the upper line and lower line of the channels are connected via a T connector 204 which is connected to one end of each purification column. Another end of each purification column is connected to the end of the generator column via a T connector 204 which is connected to the loading port.

[0116] The whole apparatus 10, or at least the generator column 30 and purification columns 40, when prepacked with sorbent materials, is sterilized by gamma ray radiation. A pre-assembled sterile generator cartridge may be produced offering the sterile inline loading of parent nuclide into the generator thereby achieving a highly standardized production process. If not pre-packed and sterilized, the columns are loaded with sterile compositions.

[0117] As shown, the radionuclide generator device comprises a body 80 having an internal volume 801, the generator cartridge 20 being located substantially within the internal volume of the body in use. The body comprises shielding means for shielding at least the generator cartridge during use. The shielding means reduces the risk of possible exposure to the radionuclides. The radiation shielding material may be lead or tungsten or depleted uranium metal. The body comprises support means 902 for supporting the parent-nuclide loading port, eluate collection port, and feed eluent port on the upper part of the body in use.

[0118] In the particular embodiment shown, the alternating flow valve 201 includes a valve actuating means 202(VA) being configurable between a first position corresponding to the at least one valve being in the first open configuration and a second position corresponding to the at least one valve being in the second open configuration. Rotation of the valve actuating means 202 effects reversal of the flow direction.

[0119] It is preferable for the valve actuating means to be located externally of the body so that a user can manually transition the at least one valve between the first open configuration and the second open configuration by virtue of the valve actuating means. However, an alternate arrangement is to use hydraulic, pneumatic or electric actuation. It is also useful to automate the actuation for unsupervised operation of the radionuclide generator. For automatic operation of the alternating flow valve the times for reversal of the flow may be according to a programmed schedule determined for the specific elution.

[0120] Optional designs of the alternating flow valve are shown in FIGS. 9-11. Referring to FIG. 9, there is shown an alternating flow valve 70 incorporating an oval drive 71 with oval driven pinch means 72 in a body 73. The oval drive 71 is actuated by actuating means 74 to move the pinch means 72 into either a first channel 75 or a second channel 76. Only an upper pair of channels is visible in FIG. 9, but there are a second pair of lower channels that are actuated in the same manner.

[0121] FIG. 10 shows a second design of an alternating flow valve 90 in the form of a thread drive 91 with a thread-driven pinch means 92 in a body 93. The thread drive 91 is actuated by actuating means 94 to move the pinch means 92 to pinch either a first channel 95 or a second channel 96. The sketch of FIG. 10 also shows the corresponding channels 97, 98 that are not visible in FIG. 9.

[0122] FIG. 11 shows a third design of an alternating flow valve 110 in the form of a shaft drive with a peristaltic pinch shaft 111 in a valve body 112. The shaft drive 111 is actuated by actuating means 113 to turn the peristaltic pinch shaft 111 into either a first channel 114 or a second channel 115. A first pair of channel is visible with clamped tubes 116, but there is a second pair of channel that are actuated with the open tubes 117. The alternating flow valve 110 of FIG. 11 operates in similar manner to the first and second designs.

[0123] Referring generally to all designs, the alternating flow valve consists of two open-close channels. Each channel accommodates one upper line and one lower line for liquid or gas flow. On one side of the valve, two upper lines of the channels are connected via a T connector which is connected to the feed eluent port and two lower lines of the channels are connected via a T connector which is connected to the eluate collection port. On the other side of the valve, the upper line and lower line of the channels are connected via a T connector which is connected to one end of each purification column. Another end of each purification column is connected to the end of the separation column via a T connector which is connected to the loading port.

[0124] Although not shown in the figures, the eluent flow passing through the system may be driven by a limited vacuum generating device such as evacuated vials or vacuum chambers of limited volume, or similar means. Pumping may also be used as an alternative.

[0125] As described above, with each elution, the contaminants from the proceeding elution including breakthrough of unwanted species retarded by purification column located on the upstream end of the source chromatographic column will go back, at least to some extent, to the separation column. Also, in each elution the purification column located on the upstream end of the generator column will be regenerated, at least to some extent, by fresh feed primary eluent. Thus, the AFCC method is characterized by the capability of auto-regeneration of the purification columns by reversing the fresh feed primary eluent flow in the consecutive elution, hence resulting in longer life-time of the separation system. Advantageously, the AFCC method is characterized by using smaller separation and purification columns to ensure a more effective repeated separation resulting in high purity and higher concentration (or smaller eluate volume) of the separated product component.

[0126] The components of the alternating flow column chromatography apparatus may take different forms depending on specific design requirements. A variety of different forms are depicted in FIG. 12. In each case the apparatus shows the core elements of a separation (generator) column, two purification columns, an alternating flow valve, an eluent input port and an eluate output port. The variation from version to version resides in the shape of the separation column and the manner of loading.

[0127] FIG. 12a shows a standard I shaped separation column 121 with solution loading of the composition to be separated. Solution loading occurs through T connectors between the purification columns and the separation column. The composition to be separated may flow through the separation column from either direction.

[0128] FIG. 12b shows an improved I shaped separation column 122 with solution loading of the composition to be separated. Solution loading occurs through a central loading port 122a. The composition to be separated may flow through the separation column from the centre in either direction to T connectors between the purification columns and the separation column. The embodiment of FIG. 12b could also be loaded in the same manner as the embodiment of FIG. 12a.

[0129] FIG. 12c shows a standard I shaped separation column 123 similar to the embodiment of FIG. 12a but with an additional port 123a that facilitates slurry loading or solution loading. The loading port 123a is configured to permit loading of the slurry bypassing the T connector.

[0130] FIG. 12d shows a U shape separation column 124 for solution loading in the same manner as described by reference to FIG. 12a.

[0131] FIG. 12e shows an improved U shape separation column 125 with a central loading port 125a for solution loading in the same manner as described by reference to FIG. 12b.

[0132] FIG. 12f shows an improved U shape separation column 126 with a central loading port 126a and loading ports 126b that facilitate slurry loading. The configuration of FIG. 12f can be used for solution loading or slurry loading.

[0133] FIG. 12g shows a segmental I shaped separation-purification column 127 with the purification columns connected directly to the separation column. Loading ports 127a facilitate slurry loading but may also be used for solution loading.

[0134] FIG. 12h shows a segmental U shape separation-purification column 128 which is identical to the embodiment of FIG. 12f but with the purification columns connected directly to the separation column.

Implementation

[0135] Separation columns packed as sorbent and substrate columns used in the radionuclide generator designs are preferably divided into 2 groups based on the available specific radioactivity of the generating radionuclide sources loaded in the generator columns.

Group 1AFCC-Based Radionuclide Generator Columns Loaded with Generating Radionuclide Sources of High Specific Activity

[0136] The generating parent radionuclide source of high specific activity is specified as a no-carrier-added radionuclide source. As examples .sup.68Ga-generator and .sup.99mTc-generator use the high specific activity .sup.68Ge- and .sup.99Mo-radionuclide sources produced by .sup.69Ga (p, 2n) .sup.68Ge reaction on particle accelerators and by nuclear fission reaction of .sup.235U nuclide, respectively. The theoretical specific activity value of the no-carrier-added .sup.99Mo radionuclide source is 17555.0 GBq (474.46 Ci) per mg Mo in carrier-free state of .sup.99Mo nuclide. The high specific activity .sup.99Mo source of specific activity >10.0 Ci .sup.99Mo/mg Mo is currently available from different producers in the world today. This figure means that a small generator column packed with 100.0 milligram weight of sorbent of adsorption capacity 10-20 mg Mo per 1000 mg alumina sorbent and correspondingly small purification columns can be used. A generator column of 100 mg weight alumina and two purification columns of 500 mg weight are preferably used for an AFCC-based .sup.99mTc-generator production described in this invention.

[0137] This progress offers the use of an even smaller generator column packed with a newly developed sorbent of adsorption capacity 300 mg Mo per 1000 mg sorbent as specified in the patent applications WO 2011/106847 A1 and/or WO 2015/039170A1 and correspondingly small purification columns can be used for an improved chromatographic .sup.99mTc-generator production. Practically, a generator column of 10 mg weight sorbent and two purification columns of around 0.5 g weight is preferably used for an AFCC-based .sup.99mTc-generator production described in this invention. The performance of this AFCC-based generator using these high adsorption capacity sorbents is superior compared to a currently used DFCC-based generator which composes of the generator column loaded 2000.0 mg weight of the same alumina sorbent typically described in different .sup.99mTc-generator production facilities.

[0138] In the case of no-carrier-added .sup.68Ge radionuclide source of high specific activity currently used in a column-chromatographic .sup.68Ga-generator production, the theoretical specific activity is 247.5 MBq (6.689 mCi) perm Ge. Practically the .sup.68Ge source of 58 MBq (1.6 mCi).sup.68Ge/g Ge element is available for use in the .sup.68Ga-generator production. A small generator column packed with 80.0 milligram weight of the sorbent of adsorption capacity 1.30 mg Ge per gram (or 1.30 g/mg) sorbent as specified in the patent application WO 2011/106847 A1 and correspondingly small purification columns can be used for the production of .sup.68Ga-generator of 150 mCi activity available for nuclear medicine use.

[0139] Practically, a generator column of 30-100 mg weight sorbent and of two purification columns of 500-1000 mg weight are preferably used for an AFCC-based .sup.68Ga-generator production described in this invention. The performance of this AFCC-based generator is superior compared to a currently used DFCC-based generator which composes of the generator column loaded 1000.0-3000 mg weight of the same sorbent as shown in the prior of the art patent application WO 2011/106847 A1.

[0140] The alternating flow column chromatography (AFCC) method doesn't limit the size of columns used in the separation system. The size of the generator column and purification columns is a subject of optimization for the separation system design based on total required radioactivity and concentration of daughter (target) radionuclide and on the porosity, particle size, and the capacity and affinity of the packing material for the separating species. However for the production of a useful radionuclide generator used in nuclear medicine application, the following parameters are preferable for a radionuclide generator design.

[0141] It is generally stated that the AFCC-based radionuclide generator using a generating parent radionuclide source of high specific activity consists of:

Generator Column

[0142] Column packing material weight: from 30 mg to 100 mg [0143] The weight of the column packing material is in the range from 30 mg to 100 mg. These columns are useful for the elution of the generator using evacuated vial. If the elution is performed using any type of liquid pump or a vial connected to a vacuum machine or to a vacuum chamber of large volume, then the weight of the column packing material and correspondingly the activity of the generators can be increased much more accordingly.

[0144] Particle size: from 50 m to 100 m,

[0145] Column size: ID (inner diameter): from 3 mm to 4 mm [0146] Length: from 5 mm to 10 mm

Purification Columns

[0147] The weight of the sorbent is in the range from 500 mg to 1000 mg. [0148] These are preferable for the elution of the generator using evacuated vial. If the elution is performed using any type of liquid pump or a vial connected to a vacuum machine or to a vacuum chamber of large volume, then the weight of the column packing material can be increased correspondingly with the increased size of the generator column.

[0149] Particle size: From 30 m to 75 m

[0150] Column size: ID (inner diameter): from 4 mm to 6 mm [0151] Length: from 10 mm to 20 mm
Group 2AFCC-Based Radionuclide Generator Columns Loaded with Generating Radionuclide Sources of Low Specific Activity

[0152] Examples of generator columns applied in the AFCC method based .sup.99mTc-generators and .sup.188Re-generators using low specific activity parent .sup.188W- and .sup.99Mo-radionuclide sources, respectively, are described in the present invention as follows.

[0153] Low specific activity .sup.99Mo production based on reactor neutron capture is a viable and proven technology. The neutron capture-based .sup.99Mo production evaluated at EOB of an 8-day irradiation process in a reactor of 2.010.sup.13-1.010.sup.14 n.Math.cm.sup.2.Math.sec.sup.1 thermal neutron flux gives a .sup.99Mo product of SA value around 0.3 to 1.6 mCi .sup.99Mo per mg of natural isotopic abundance molybdenum and up to 6.0 mCi .sup.99Mo per mg of 98%-enriched .sup.98Mo target. While the specific activity of .sup.99Mo produced using accelerators (ranging up to 10 mCi/mg at EOB) is not significantly higher than that of .sup.99Mo produced by neutron capture using nuclear reactor. To produce the .sup.99mTc generators of the same activity size (1-5 Ci) as in the case of using high SA .sup.99Mo mentioned above, new .sup.99mTc-generator system should be developed for of processing several grams of molybdenum existing in low specific activity .sup.99Mo source.

[0154] Based on the adsorption capacity of the sorbents available today and on the specific radioactivity values of the generating parent radionuclide sources available from nuclear facilities around the world, the AFCC method advantageously uses the generator columns containing large amount of the sorbent for loading a sufficient activity of parent radionuclide solution or the generator columns containing a large amount of the substrate of sufficient parent radionuclide activity (such as the gel-type substrate synthesized from parent radionuclide solution and the pre-formulated powder substrate out-column-adsorbed with parent radionuclide solution) for the clinically useful .sup.99mTc-generator production.

[0155] The sorbent and substrate columns used in the designs of AFCC method based radionuclide generators useful for nuclear medicine application are preferably described herein comprising: [0156] .sup.99Mo-radionuclide sources of specific activity higher than 0.20-10.0 mCi .sup.99Mo/mg, such as in the case of .sup.99Mo radionuclide produced by thermal neutron capture reaction of stable .sup.98Mo isotope target or by different nuclear reaction using particle accelerators and .sup.100Mo isotope target; [0157] Column packing sorbent of adsorption capacity higher than 2.010.sup.3 mole of Molybdenum element (equivalent to 191.9 mg Mo) per 1000 mg of column packing sorbent; [0158] Column packing substrate of Mo-content (molal concentration) higher than 2.010.sup.3 mole of Molybdenum element per 1000 mg of column packing substrate.

[0159] These figures mean that a large generator column packed with >300.0 mg weight of the sorbent with adsorption capacity higher than 2.010.sup.3 mole of molybdenum element per 1000 mg of column packing sorbent are preferably used for an AFCC-based .sup.99mTc-generator production as described in this invention. The performance of this AFCC-based generator is much better in comparison to a currently used DFCC-based generator which consists of the generator column loaded with much larger weight of alumina sorbent typically described in different .sup.99mTc-generator production facilities.

[0160] Moreover, as a result of the development of high capacity sorbents the use of an even smaller generator column packed with a newly developed sorbent of the adsorption capacity of >300 mg Mo per 1000 mg sorbent as specified in the patent applications WO 2011/106847 A1 and/or WO 2015/039170A1 and correspondingly small purification columns can be advantageously used for the production of high performance .sup.99mTc-generators based on AFCC method.

[0161] For the production of a useful radionuclide generator used in nuclear medicine application, the following detailed parameters are preferable for radionuclide generator design. Practically, the generator columns of 0.3-50 g weight sorbent or substrate (Loading of 100-15000 mg Mo) and two purification columns of around 0.5-2.5 g weight are preferably used for production of AFCC-based .sup.99mTc-generator of radioactivity from 500 mCi to 15010.sup.3 mCi are preferably described, as examples, in this invention. The performance of these AFCC-based generators is superior compared to a currently used DFCC-based generator which composes of the generator column of much larger sorbent and/or substrate weight described by different radionuclide generator producers.

[0162] Although the maximal specific activity value of the no-carrier-added .sup.188W radionuclide source is 3.7210.sup.5MBq (10.06 Ci)/mg Tungsten. Practically .sup.188W source of low specific activity 5-10 mCi .sup.188W per mg W is currently available for .sup.188Re-generator production using high neutron flux (>10.sup.15 n.Math.cm.sup.2.Math.s.sup.1) reactor. Today the alumina based .sup.188Re generators are based on the conventional DFCC method. This type of .sup.188Re generator has a low .sup.188W radioactivity (from 250 mCi to 1.0 Ci .sup.188W for each generator unit). The .sup.188W/.sup.188Re generator production from lower specific radioactivity .sup.188W solution producible in the medium neutron flux (>2.10.sup.14 n.Math.cm.sup.2.Math.s.sup.1) reactors operated in many countries is promoted. For this purpose, the alternative .sup.188Re generator production method and compact generator system should be anticipated to increase .sup.188Re-concentration of the .sup.88Re-eluate to meet the requirement of targeting radiopharmaceutical preparation. As a predictable example of up-scale of the AFCC method based .sup.188Re-generator systems of >1.5 Ci .sup.188W activity could be prepared using low specific radioactivity .sup.188W (0.5 Ci/g W to 0.8 Ci/g W).

[0163] Based on the adsorption capacity of the sorbents available today and on the specific radioactivity values of the generating parent radionuclide sources available from nuclear facilities around the world, the AFCC method advantageously uses the generator columns containing large amount of the sorbent for loading a sufficient activity of parent radionuclide solution or the generator columns containing a large amount of the substrate of sufficient parent radionuclide activity (such as the gel-type substrate synthesized from parent radionuclide solution and the pre-formulated powder substrate out-column-adsorbed with parent radionuclide solution) for the clinically useful .sup.188Re-generator production.

[0164] The sorbent and substrate columns used in the designs of AFCC method based radionuclide generators useful for nuclear medicine application are preferably described herein comprising: [0165] .sup.188W-radionuclide sources of a specific activity 0.20-10.0 mCi .sup.188W/mg such as in the case of .sup.188W radionuclide produced by thermal neutron capture reaction of stable .sup.186W isotope target, [0166] Column packing sorbent of a adsorption capacity higher than 2.010.sup.3 mole of Tungsten element (equivalent to 367.7 mg W) per 1000 mg of column packing sorbent, [0167] Column packing substrate of W-content (molal concentration) higher than 2.010.sup.3 mole of Tungsten element per 1000 mg of column packing substrate.

[0168] These figures mean that a large generator column packed with >300.0 mg weight of the sorbent with adsorption capacity higher than 2.010.sup.3 mole of tungsten element per 1000 mg of column packing sorbent are preferably used for an AFCC-based .sup.188Re-generator production as described in this invention. The performance of this AFCC-based generator is much better compared to a currently used DFCC-based generator which composes of the generator column loaded with much larger weight of the alumina sorbent typically described in different .sup.188Re-generator production facilities.

[0169] Moreover, as a result of the development of high capacity sorbents, the use of an even smaller generator column packed with a newly developed sorbent of adsorption capacity >500 mg W per 1000 mg sorbent as specified in the patent applications WO 2011/106847 A1 and/or WO 2015/039170A1 and correspondingly small purification columns can be advantageously used for the production of high performance .sup.188Re-generators based on AFCC method.

[0170] For the production of a useful radionuclide generator used in nuclear medicine application, the following detailed parameters are preferable for radionuclide generator design. Practically, the generator columns of 0.3-50.0 g weight sorbent or substrate (Loading of 150.0-25000.0 mg W) and two purification columns of around 0.5-2.5 g weight are preferably used for production of AFCC-based .sup.188Re-generators of radioactivity from 500 mCi to 25010.sup.3 mCi are preferably described, as examples, in this invention. The performance of these AFCC-based generators is superior compared to a currently used DFCC-based generator which composes of the generator column of much larger sorbent and/or substrate weight described by different radionuclide generator producers.

[0171] The alternating flow column chromatography (AFCC) method doesn't limit the size of columns used in the separation system. The size of the generator column and purification columns is a subject of optimization for the separation system design based on total required radioactivity and concentration of daughter (target) radionuclide and on the porosity, particle size, and the capacity and affinity of the packing material for the separating species. However for the production of a useful radionuclide generator used in nuclear medicine application, the following parameters are preferable for a radionuclide generator design.

[0172] Generally it is stated that the AFCC-based radionuclide generator using a generating parent radionuclide source of low specific activity composes of:

Generator Column

[0173] Column packing material weight: from 0.3 g to 100 g [0174] The weight of the column packing material is in the range from 0.3 g to 50 g. This limit is preferable for the elution of the generator using evacuated vial. If the elution is performed using any type of liquid pump or a vial connected to a vacuum machine or to a vacuum chamber of large volume, then the weight of the column packing material can be increased to 100 g or much more. [0175] Particle size: from 50 m to 200 m, or mean particle size from 70 m to 100 m [0176] Column size: ID (inner diameter): from 5 mm to 25 mm [0177] Length: from 20 mm to 200 mm

Purification Columns

[0178] The weight of the sorbent is in the range from 0.5 g to 2.0 g. [0179] This limit is preferable for the elution of the generator using evacuated vial. If the elution is performed using any type of liquid pump or a vial connected to a vacuum machine or to a vacuum chamber of large volume, then the weight of the column packing material can be increased correspondingly with the increased size of the generator column. [0180] Particle size: From 30 m to 100 m, or mean particle size from 50 m to 70 m [0181] Column size: ID (inner diameter): from 5 mm to 10 mm [0182] Length: from 10 mm to 50 mm

Example 1: AFCC Method Based .SUP.68.Ga-Generator Using High Specific Activity .SUP.68.Ge-Source (Operation Per FIG. 13a)

[0183] This example of the present invention relates to the .sup.68Ga generators produced based on the nano-crystalline sorbent ZT-11 (Adsorption capacity: 1.3 mg Ge/g sorbent) and the multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 3.0 mg Ge/g), which are specified in the patent applications WO 2011/106847 A1 and WO 2015/039170A1, respectively. .sup.68Ge-source of high specific activity 1.6 mCi .sup.68Ge/g Ge was used for loading the generator column.

[0184] These sorbents are in solid particulate form, so that the generator columns contain a packed bed of the particulate sorbent. Both sorbents have a much higher affinity for .sup.68Ge than for .sup.68Ga so that .sup.68Ga is preferentially eluted from the sorbent while the majority, preferably substantially all, of the .sup.68Ge is retained on the sorbent. Typically both sorbents ZT-11 and ISOSORB-MOX-HP are such that the breakthrough percentage of .sup.68Ge is less than 10.sup.5% or 10.sup.6%. The sorbents are resistant to radiation. This feature is important since the .sup.68Ge typically resides on the generator column for a period longer than 2 years. The Ge adsorption capacity of the sorbents ZT-11 and ISOSORB-MOX-HP is sufficiently high (as shown in Table 1), so as a high .sup.68Ga radioactivity generator may be prepared based on these sorbents. Typically a generator column of several hundreds mCi .sup.68Ga may be prepared from. The sorbents are chemically stable in HCl solution eluents having a wide range of concentrations. Typically these sorbents are stable in HCl solution of up to 3 M HCl. Typical generator column contains from 0.03 g to 1.0 g sorbent as shown in Table 1.

[0185] As shown in Table 1, First .sup.68Ga-generator is an AFCC-based .sup.68Ga-generator and second one is a comparative conventional DFCC-based .sup.68Ga-generator. These generators being of the same parent nuclide activity and using the same sorbent ZT-11 (as shown in Table 1) were manufactured and their performance was tested for justification on the superior advantage of AFCC-based .sup.68Ga-generator compared to conventional DFCC-based .sup.68Ga-generator. Third .sup.68Ga-generator, using a multifunctional sorbent ISOSORB-MOX-HP of higher .sup.68Ge-adsorption capacity (3.0 mg Ge/g) which was specified in the patent application WO 2015/039170A1 and being loaded with of much higher parent activity, was manufactured and its performance was tested for justification on the superior advantage of AFCC-based .sup.68Ga-generator in the production of the eluate solution of super high concentration of target (daughter) radionuclide .sup.68Ga.

[0186] A suitable generator design for separating target radionuclide .sup.68Ga from mixtures of generating parent nuclide .sup.68Ge ions and .sup.68Ga ions, is described above. The generator column is made from glass or stainless steel or thermoplastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and is provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both ends. The ends are closed by septa together with silicone rubber gaskets. The generator column ends are capped by aluminium clamping lids. The generator column is from 5 mm to 10 mm in length and from 3 mm to 4 mm inner diameter. The fritted filter disks are of 20 m porosity. The generator column is packed with a sorbent which is detailed in Table 1 and both its ends are connected to two purification columns loaded with the same sorbent of weight detailed in Table 1. Purification columns are made from glass or stainless steel or plastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and are provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both ends. The ends are closed by septa together with silicone rubber gaskets. The purification column ends are capped by aluminium clamping lids. The purification column is from 10 mm to 20 mm in length and from 4 mm to 6 mm in inner diameter. The fritted filter disks are of 20 m porosity. The generator column and purification columns are connected to the alternating flow acting valve and assembled into a cartridge chassis of generator cartridge. Feed eluent port, Eluate collection port and Loading port for the generating .sup.68Ge-radionuclide solution are assembled as described previously. The assembled cartridge is housed in a radiation protection shielding lead container.

[0187] In operation of the generator, 0.1 M HCl solution is used as an eluent of .sup.68Ga. Thus eluent supply is a sterile vial loaded with this eluent solution. This eluent vial is applied to vented spike of the feed eluent port. The sorbent in the generator column is loaded with .sup.68Ge. On the sorbent, this gradually decays to form .sup.68Ga.

[0188] In one of the elution of the generator when a solution of .sup.68Ga is required, first channel of the dual channel alternating flow acting valve is opened (the second channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the pathway of the First purification column.fwdarw.Generator column.fwdarw.Second purification column connection, so as to elute .sup.68Ga into evacuated vial used as .sup.68Ga product container. Because the affinity of the sorbent in generator column and purification columns for .sup.68Ge is high, negligible or zero amounts of .sup.68Ge are eluted from the sorbent. However, as the affinity of the sorbent in all columns for .sup.68Ga is quite low, this species is readily eluted, resulting in an eluent collected in evacuated vial used as .sup.68Ga product container which comprises a solution of .sup.68Ga substantially free of .sup.68Ge.

[0189] In the elution following the preceding elution of the generator when a solution of .sup.68Ga is required, second channel of the dual channel alternating flow acting valve is opened (the first channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the reverse pathway of the Second purification column.fwdarw.Generator column.fwdarw.First purification column connection, so as to elute .sup.68Ga into evacuated vial used as .sup.68Ga product container. By this way the small amount of .sup.68Ge broken through from generator column and trapped on second purification column will be washed back to the generator column and this second purification column is cleaned up and regenerated.

Loading of Stock Acidic .SUP.68.Ge Solution on Generator Column

[0190] Before loading with .sup.68Ge solution, the sorbent column was washed with about 5 mL 1M HCl solution. The stock acidic .sup.68Ge solution was a 0.1 M HCl .sup.68Ge solution. .sup.68Ge concentration was about 1-12 mCi/mL, e.g. about 10.0 mCi .sup.68Ge/mL. The .sup.68Ge solution volume applied to each generator column was about 5-15 mL. The stock acidic .sup.68Ge solution was loaded onto a generator column through loading port using an evacuated vial for sucking the .sup.68Ge solution through the generator column with a flow rate of 0.15 mL/minute. Following the loading, the column was washed with 10 mL 0.1 M HCl solution. The column was then ready for regular eluting (separating).sup.68Ga daughter radioisotope solutions for daily use.

Eluting .SUP.68.Ga

[0191] The generator was eluted with 2 mL or 6 mL or 3 mL 0.1 M HCl solution and the elution profile of the .sup.68Ga was recorded. The graphic radioactivity recording system (which is not a part of the .sup.68Ga generator system described in this invention) indicated the effective elution volume used for the elution of .sup.68Ga. Table 1 shows the performance of the AFCC-based .sup.68Ga generator of this invention compared with a conventional DFCC-based .sup.68Ga generator. The present invention provides improved elution volume (smaller volume of .sup.68Ga eluate) giving higher .sup.68Ga-concentration and longer useful life without any additional action during operation.

Example 2: AFCC Method Based .SUP.99m.Tc-Generator Using Low Specific Activity

[0192] .sup.99Mo-source (Operation per FIG. 13a)

[0193] This example of the present invention relates to the .sup.99mTc generators produced based on the PZC sorbent (Adsorption capacity: 250 mg W per gram Sorbent) and Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 300 mg Mo/g; Patent Application Publication WO 2015/039170A1). .sup.99Mo source of low specific activity 1.0 mCi .sup.99Mo/mg Mo was used for loading the generator column.

[0194] These sorbents are in solid particulate form, so that the generator columns contain a packed bed of the particulate sorbent. Both sorbents have a much higher affinity for .sup.99Mo than for .sup.99mTc so that .sup.99mTc is preferentially eluted from the sorbent while the majority, preferably substantially all, of the .sup.99Mo is retained on the sorbent. Typically both sorbents PZC sorbent and Multifunctional sorbent ISOSORB-MOX-HP are such that the breakthrough percentage of .sup.99Mo is less than 10.sup.3% or 10.sup.4%. The sorbents are resistant to radiation. This feature is important since the .sup.99Mo typically resides on the generator column for a period longer than two months. The Mo adsorption capacity of these sorbents is sufficiently high (as shown in Table 2), so as a high .sup.99mTc radioactivity generator may be prepared based on these sorbents. Typically a generator column of several Ci .sup.99mTc may be prepared from a generator column containing from 0.3 g to 100.0 g sorbent as shown in Table 2.

[0195] As shown in Table 2, First .sup.99mTc-generator is an AFCC-based .sup.99mTc-generator and second one is a comparative conventional DFCC-based .sup.99mTc-generator. These generators being of the same parent nuclide activity using the same PZC sorbent were manufactured and their performance was tested for justification on the superior advantage of AFCC-based .sup.99mTc-generator compared to conventional DFCC-based .sup.99mTc-generator. Third .sup.99mTc-generator, using a multifunctional sorbent ISOSORB-MOX-HP of higher .sup.99Mo-adsorption capacity (300.0 mg Mo/g) which was specified in the patent application WO 2015/039170A1 and being loaded with much higher parent nuclide activity, was manufactured and its performance was tested for justification on the superior advantage of AFCC-based .sup.99mTc-generator in the production of the eluate solution of super high concentration of target (daughter) radionuclide .sup.99mTc.

[0196] A suitable generator design for separating target radionuclide .sup.99mTc from mixtures of generating parent nuclide .sup.99Mo ions and .sup.99mTc ions, is described previously. The generator column is made from glass or stainless steel or thermoplastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and is provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both its ends. The ends are closed by septa together with silicon rubber gaskets. The generator column ends are capped by aluminium clamping. The generator column is from 20 mm to 200 mm in length and from 5 mm to 25 mm inner diameter. The fitted filter disks are of 50 m porosity. The generator column is packed with a sorbent which is detailed in Table 2 herein and both its ends are connected to two purification columns loaded with the same sorbent of weight detailed in Table 2. The purification column is made from glass or stainless steel or plastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and is provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both the ends. The ends are closed by septa together with silicon rubber gaskets. The purification column ends are capped by aluminium clamping lids. The purification column is from 10 mm to 50 mm in length and from 5 mm to 10 mm in inner diameter. The fritted filter disks are of 20 m porosity.

[0197] The generator column and purification columns are connected to the alternating flow acting valve and assembled into a cartridge chassis of generator cartridge. Feed eluent port, eluate collection port and loading port for the generating .sup.99Mo-radionuclide solution are assembled as shown previously. The assembled cartridge is housed in a radiation protection shielding lead container.

[0198] The details of the columns and sorbents in use are shown in Table 2.

[0199] In operation of the generator, 0.9% NaCl solution is used as an eluent of .sup.99mTc. Thus eluent supply is a sterile vial loaded with this eluent solution. This eluent vial is applied to vented spike of the feed eluent port. The sorbent in generator column is loaded with .sup.99Mo. On the sorbent, this gradually decays to form .sup.99mTc.

[0200] In one of the elution of the generator when a solution of .sup.99mTc is required, first channel of the dual channel alternating flow acting valve is opened (the second channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the pathway of the First purification column.fwdarw.Generator column.fwdarw.Second purification column connection, so as to elute .sup.99mTc into evacuated vial used as .sup.99mTc product container. Because the affinity of the sorbent in generator column and purification columns for .sup.99Mo is high, negligible or zero amounts of .sup.99Mo are eluted from the sorbent. However, as the affinity of the sorbent in all columns for .sup.99mTc is quite low, this species is readily eluted, resulting in an eluent collected in evacuated vial used as .sup.99mTc product container which comprises a solution of .sup.99mTc substantially free of .sup.99Mo.

[0201] In the elution following the preceding elution of the generator when a solution of .sup.99mTc is required, second channel of the dual channel alternating flow acting valve (201(AFV) is opened (its first channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the reverse pathway of the Second purification column.fwdarw.Generator column.fwdarw.First purification column connection, so as to elute .sup.99mTc into evacuated vial used as .sup.99mTc product container. By this way the small amount of .sup.99Mo broken through from generator column and trapped on second purification column will be washed back to the generator column and this second purification column is cleaned up and regenerated.

Loading of Stock .SUP.99.Mo Solution on Generator Column

[0202] Before loading with .sup.99Mo solution, the sorbent column was washed with about 30 mL 0.1M HNO.sub.3 solution. The stock .sup.99Mo solution was a .sup.99Mo solution of pH=3. Mo element concentration was about 10-15 mg Mo/mL. .sup.99Mo concentration was about 10-20 mCi/mL, e.g. about 12.5 mCi .sup.99Mo/mL. The .sup.99Mo solution volume applied to each generator column was about 200-500 mL. The stock .sup.99Mo solution was loaded onto a generator column through loading port using an evacuated vial for sucking the .sup.99Mo solution through the generator column with a flow rate of 1.5 mL/minute. Following the loading, the column was washed with 100 mL 0.1 M HNO.sub.3 solution followed by a 50 ml 0.9% NaCl solution wash. The column was then ready for regular eluting (separating).sup.99mTc daughter radioisotope solutions for daily use.

Eluting .SUP.99m.Tc

[0203] The generator was eluted with 22 mL or 65 mL or 40 mL 0.9% NaCl solution and the elution profile of the .sup.99mTc was recorded. The graphic radioactivity recording system (which is not a part of the .sup.99mTc generator system described in this invention) indicated the effective elution volume used for the elution of .sup.99mTc. Table 2 shows the performance of the AFCC-based .sup.99mTc generator of this invention compared with a conventional DFCC-based .sup.99mTc generator. The present invention provides improved elution volume (smaller volume of .sup.99mTc eluate) giving higher .sup.99mTc-concentration and longer useful life without any additional action during operation.

Example 3: AFCC Method Based .SUP.188.Re-Generator Using Low Specific Activity .SUP.188.W-Source (Operation Per FIG. 13a)

[0204] This example of the present invention relates to the .sup.188Re generators produced based on the Alumina (Adsorption capacity: 100-120 mg W per gram Sorbent) and Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 500 mg W/g Patent Application Publication WO 2015/039170A1). .sup.188W-source of low specific activity 5.0 mCi .sup.188W/mg W was used for loading the generator column.

[0205] These sorbents are in solid particulate form, so that the generator columns contain a packed bed of the particulate sorbent. Both sorbents have a much higher affinity for .sup.188W than for .sup.188Re so that .sup.188Re is preferentially eluted from the sorbent while the majority, preferably substantially all, of the .sup.188W is retained on the sorbent. Typically both sorbents Alumina and Multifunctional sorbent ISOSORB-MOX-HP are such that the breakthrough percentage of .sup.188W is less than 10.sup.4% or 10.sup.5%. The sorbents are resistant to radiation. This feature is important since the .sup.188W typically resides on the generator column for a period longer than 500 days. The W adsorption capacity of these sorbents is sufficiently high (as shown in Table 3), so as a high .sup.188Re radioactivity generator may be prepared based on these sorbents. Typically a generator column of several Ci .sup.188Re may be prepared from a generator column containing from 0.3 g to 100.0 g sorbent as shown in Table 3.

[0206] As shown in Table 3, First .sup.188Re-generator is an AFCC-based .sup.188Re-generator and second one is a comparative conventional DFCC-based .sup.188Re-generator. These generators being of the same parent nuclide activity using the same Alumina sorbent were manufactured and their performance was tested for justification on the superior advantage of AFCC-based .sup.188Re-generator compared to conventional DFCC-based .sup.188Re-generator. Third .sup.188Re-generator, using a multifunctional sorbent ISOSORB-MOX-HP of higher .sup.188W-adsorption capacity (500.0 mg W/g) which was specified in the patent application WO 2015/039170A1 and being loaded with much higher parent nuclide activity, was manufactured and its performance was tested for justification on the superior advantage of AFCC-based .sup.188Re-generator in the production of the eluate solution of super high concentration of target (daughter) radionuclide .sup.188Re.

[0207] A suitable generator design for separating target radionuclide .sup.188Re from mixtures of generating parent nuclide .sup.188W ions and .sup.188Re ions, is described previously. The generator column, shown in FIGS. 3 and 5, is made from glass or stainless steel or thermoplastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and is provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both its ends. The ends are closed by septa together with silicon rubber gaskets. The generator column ends are capped by aluminium clamping lids. The generator column is from 20 mm to 200 mm in length and from 5 mm to 25 mm inner diameter. The fritted filter disks are of 50 m porosity. The generator column is packed with a sorbent which is detailed in Table 3 herein and both its ends are connected to 2 purification columns loaded with the same sorbent of weight detailed in Table 3. The purification column is made from glass or stainless steel or plastic material (such as polyetheretherketone (PEEK), polypropylene, polyethylene, cellulose acetate etc.) and is provided with fritted sintered quartz or fritted stainless steel or fritted polypropylene filter disks at both its ends. The ends are closed by septa together with silicon rubber gaskets. The purification column ends are capped by aluminium clamping lids. The purification column is from 10 mm to 50 mm in length and from 5 mm to 10 mm in inner diameter. The fritted filter disks are of 20 m porosity.

[0208] The generator column and purification columns are connected to the alternating flow acting valve and assembled into a cartridge chassis of generator cartridge. The feed eluent port, eluate collection port and loading port for the generating .sup.188W-radionuclide solution are assembled as previously described. The assembled cartridge is housed in a radiation protection shielding lead container.

[0209] The details of the columns and sorbents in use are shown in Table 3.

[0210] In operation of the generator, 0.9% NaCl solution is used as an eluent of .sup.188Re. Thus eluent supply is a sterile vial loaded with this eluent solution. This eluent vial is applied to vented spike of the feed eluent port. The sorbent in generator column is loaded with .sup.188W. On the sorbent, this gradually decays to form .sup.188Re.

[0211] In one of the elution of the generator when a solution of .sup.188Re is required, first channel of the dual channel alternating flow acting valve is opened (its second channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the pathway of the First purification column.fwdarw.Generator column.fwdarw.Second purification column connection, so as to elute .sup.188Re into evacuated vial used as .sup.188Re product container. Because the affinity of the sorbent in generator column and purification columns for .sup.188W is high, negligible or zero amounts of .sup.188W are eluted from the sorbent. However, as the affinity of the sorbent in all columns for .sup.188Re is quite low, this species is readily eluted, resulting in an eluent collected in evacuated vial used as .sup.188Re product container which comprises a solution of .sup.188Re substantially free of .sup.188W.

[0212] In the elution following the preceding elution of the generator when a solution of .sup.188Re is required, second channel of the dual channel alternating flow acting valve is opened (the first channel is automatically closed) and an evacuated vial is applied to the needle of the eluate collection port. This causes eluent to flow from eluent supply vial through the reverse pathway of the Second purification column.fwdarw.Generator colum.fwdarw.First purification column connection, so as to elute .sup.188Re into evacuated vial used as .sup.188Re product container. By this way the small amount of .sup.188W broken through from generator column and trapped on second purification column 40(PC) will be washed back to the generator column and this second purification column 40(PC) is cleaned up and regenerated.

Loading of Stock .SUP.188.W Solution on Generator Column

[0213] Before loading with .sup.188W solution, the sorbent column was washed with about 30 mL 0.1M HNO.sub.3 solution. The stock .sup.188W solution was a .sup.188W solution of pH=3. W element concentration was about 20-30 mg W/mL. .sup.99Mo concentration was about 100-150 mCi/mL, e.g. about 125 mCi .sup.188W/mL. The .sup.188W solution volume applied to each generator column was about 5-10 mL. The stock .sup.188W solution was loaded onto a generator column through loading port using an evacuated vial for sucking the .sup.188W solution through the generator column with a flow rate of 1.0 mL/minute. Following the loading, the column was washed with 50 mL 0.1 M HNO.sub.3 solution followed by a 50 ml 0.9% NaCl solution wash. The column was then ready for regular eluting (separating).sup.188Re daughter radioisotope solutions for daily use.

Eluting .SUP.188.Re

[0214] The generator was eluted with 10 mL 0.9% NaCl solution and the elution profile of the .sup.188Re was recorded. The graphic radioactivity recording system (which is not a part of the .sup.188Re generator system described in this invention) indicated the effective elution volume used for the elution of .sup.188Re. Table 3 shows the performance of the AFCC-based .sup.188Re generator of this invention compared with a conventional DFCC-based .sup.188Re generator. The present invention provides improved elution volume (smaller volume of .sup.188Re eluate) giving higher .sup.188Re-concentration and longer useful life without any additional action during operation.

Example 4: AFCC Method Based .SUP.99m.Tc-Generator with Selective Elution Operation (Operation Per FIG. 13b)

[0215] This example of the present invention relates to the .sup.99mTc-generators produced based on AFCC apparatus designed with incorporation of the specific eluent port and eluent-selective valve as shown in FIG. 5. The inclusion of these component parts offers a capability of eluent variation for an alternating flow chromatography (AFCC) apparatus resulting an advantageous feature of the invention: the separation of daughter radionuclide (product) component with higher purity in higher concentration. This feature is resulted from more operation functions of eluent variation performed with the port and valve. In this example, an additional selective elution function of eluting the purified daughter radionuclide (product) component with purposely used specific eluent from purification column.

[0216] All experimental conditions shown in Table 4 and the loading of stock .sup.99Mo solution on generator column are similar to Example 2, except the processes of selective elution of the daughter radionuclide .sup.99mTc eluate using a specific eluent from purification column.

[0217] Eluting a Raw .sup.99mTc Daughter Radionuclide from the Generator Column with a Primary Eluent and Selectively Eluting the Specific Eluate of .sup.99mTc Daughter Radionuclide from Purification Column

[0218] The generator was eluted with 35.0-40.0 mL primary eluent. The primary eluent is 0.05-0.10% NaCl solution. At this elution step the purification column retains all .sup.99mTc content and a small amount of some contaminants including small breakthrough of .sup.99Mo parent nuclide. In a further step, a specific eluent (SE), 3.0 mL 0.9% NaCl solution (a specific eluent purposely used for eluting the eluate of .sup.99mTc product) is put into use in replacing the primary eluent by actuating the eluent-selective valve (TV) to put it into a suitable position. By this operation way the specific eluent passes through the purification column for eluting the specific eluate (SEL) of .sup.99mTc daughter radionuclide from the purification column into a specific eluate (SEL) receptacle means for use.

[0219] Table 4 shows the performance of the AFCC-based .sup.99mTc generator produced based on AFCC apparatus designed with incorporation of the specific eluent port and eluent selective valve in comparison with AFCC apparatus designed without the specific eluent port and eluent specific valve. It is clear from the results obtained that the inclusion of the specific eluent port and eluent specific valve offers a capability of eluent variation for an alternating flow chromatography (AFCC) apparatus resulting an advantageous feature of our invention: the separation of .sup.99mTc daughter radionuclide in higher concentration.

Example 5: AFCC Method Based .SUP.68.Ga-Generator with Further Purification Operation (Operation Per FIG. 13c)

[0220] This example of the present invention relates to the .sup.68Ga generators produced based on AFCC apparatus designed with incorporation of the specific eluent port and eluent selective valve as shown in FIG. 5. The inclusion of these component parts offers a capability of eluent variation for an alternating flow chromatography (AFCC) apparatus resulting in an advantageous feature of our invention: the separation of daughter radionuclide (product) component with higher purity in higher concentration. This feature is resulted from more operation functions of eluent variation performed with the specific eluent port and eluent specific valve. In this example, an additional operational function of further purification of the daughter radionuclide (product) component with additional specific eluents and then selectively eluting the eluate of purified daughter radionuclide with purposely used specific eluent from purification column.

[0221] All experimental conditions shown in Table 5 and the loading of stock acidic .sup.68Ge solution on generator column are similar to Example 1, except the processes of further purification of .sup.68Ga and selectively eluting the .sup.68Ga eluate.

[0222] Eluting a Raw .sup.68Ga Daughter Radionuclide from the Generator Column with a Primary Eluent and Further Purification of .sup.68Ga Followed by Selectively Eluting the Specific Eluate of .sup.68Ga Daughter Radionuclide from Purification Column

[0223] The generator was eluted with 2.5-3.0 mL primary eluent. The primary eluent is 0.1 M HCl solution. At this elution step the purification column retains all .sup.68Ga content and a small amount of some contaminants including small breakthrough of .sup.68Ge parent nuclide. In the step of further purification, a specific eluent (SE), 5.0 ml 4 M HCl+1% Ascorbic acid solution, is put into use in replacing the primary eluent by actuating the eluent selective valve to put the valve into a suitable position. By this operation way the specific eluent passes through the purification column only to remove the contaminants from the purification column into the waste container attached to the eluate output port while keeping the .sup.68Ga daughter nuclide further retained on the purification column. In the following step a purposely used specific eluent (1.0 mL 0.05 M HCl solution) is used for selectively eluting the specific eluate (SEL) of .sup.68Ga daughter nuclide (product) component from the purification column into a specific eluate (SEL) receptacle means for use.

[0224] Table 5 shows the performance of the AFCC-based .sup.68Ga generator produced based on AFCC apparatus designed with incorporation of the port and valve in comparison with AFCC apparatus designed without the port and valve. It is clear from the results obtained that the inclusion of the port and valve offers a capability of eluent variation for an alternating flow chromatography (AFCC) apparatus resulting an advantageous feature of our invention: the separation of .sup.68Ga daughter radionuclide with higher purity in higher concentration.

Separation Performance of AFCC Apparatus

[0225] To show the superior separation features of the AFCC apparatus, the separation performance of the apparatus is evaluated based on the improvement in the desired component concentration of the eluate (such as the concentration of daughter radionuclide), in the increase of loaded quantity of the composition to be separated, and in the purity of separated desired component in repeated separation processes. All these performance parameters can be experimentally measured as listed in different examples of this invention. However, the eluate concentration improvement and the loaded quantity of separation composition (in other word the separation capacity) can also be theoretically assessed.

[0226] FIG. 14 shows a superior separation performance parameters achieved in the process of Example 4. Parent .sup.99Mo-radionuclide activity (separation capacity), concentration factors (Fi and Fc) and daughter .sup.99mTc-radionuclide concentration of .sup.99mTc-eluate are significantly increased due to a separation column fully loaded with separation composition (parent .sup.99Mo-radionuclide) of the AFCC apparatus.

It is given that

[0227] Index (x) is for a target process; Index (n) is for a comparative process; (A.sub.n/m.sub.n)=(A.sub.x/m.sub.x) is column-bed-specific radioactivity; (V.sub.n/M.sub.n)=(V.sub.x/M.sub.x) is column-bed-specific elution volume; m.sub.x and m.sub.n are the weight of fully composition-loaded beds of the separation column; L.sub.n=100*(m.sub.n/M.sub.n) and L.sub.x=100*(m.sub.x/M.sub.x) are the composition-loading percentages; p.sub.x and p.sub.n are the composition-unloaded column percentages

[00001]$.Math.\mathrm{Eq}.Math..Math.1$$\begin{array}{c}.Math.C_n=\frac{A_n}{V_n}\\ \begin{array}{c}{C}_x=\frac{A_x}{V_x}=\frac{\left\{\frac{A_n}{\left(M_n-\frac{p_n.Math.M_n}{100}\right)}*\left(M_x-\frac{p_x.Math.M_x}{100}\right)\right\}}{\left(V_n/M_n\right)*M_x}=\frac{A_n}{V_n}*\frac{M_n}{M_x}*\frac{m_x}{m_n}\end{array}.fwdarw..Math..Math.\mathrm{Eq}.Math..Math.2.Math..Math..Math.C_x=\frac{A_n}{V_n}*\frac{M_n}{M_x}*\left\{\frac{\left(100.Math..Math.M_x-p_{x.Math.}.Math.M_x\right)}{\left(100.Math..Math.M_n-p_n.Math.M_n\right)}\right\}\end{array}$

Inherent Concentration Factor Fi(x) Achieved with Operating with Function 1:

[00002]$\begin{array}{cc}\mathrm{Fi}\left(x\right)=\frac{C_x}{C_n}=\frac{M_n}{M_x}*\frac{100*M_x-p_x*M_x}{100*M_n-p_n*M_n}& \mathrm{Eq}.Math..Math.3\end{array}$

Combined Concentration Factor Fc(x) Achieved with Operating with Function 2 or Function 3:

[00003]$\begin{array}{cc}\mathrm{Fc}\left(x\right)=\frac{C_{x\left(c\right)}}{C_n}.fwdarw.\mathrm{Fc}\left(x\right)=\frac{C_x}{C_n}=\frac{\mathrm{Fc}\left(n\right)}{V_n*\mathrm{Fi}\left(n\right)}*V_x*\mathrm{Fi}\left(x\right)& \mathrm{Eq}.Math..Math.4\end{array}$

Equations Used for FIG. 14:

[0228] Starting from a basic equation Eq 3 below, the calculation of the concentration of desired component, concentration factors (Fi and Fc), and the relationship between Inherent Concentration Factor (Fi) and Combined Concentration Factor (Fc) is based on the data of chromatographic columns, specific radioactivity of parent radionuclide, and specific elution volume of the eluents used in the processes of the example 4.

[0229] Index (x) is for a target process/generator, Index (n) is for a comparative process/generator and in the case the comparative process/generator is the one giving the smallest desired component concentration, then n=1. [0230] 1) Inherent concentration factor: [0231] With p.sub.x*M.sub.xp.sub.1*M.sub.1 for all SC columns of the same M value, it means Mx=M.sub.1

[00004]$\begin{array}{cc}\mathrm{Fi}\left(x\right)=\frac{M_x}{M_1}*\frac{100*M_x-p_x*M_x}{100*M_1-p_1*M_1}=\frac{100-p_x}{100-p_1}& \mathrm{Eq}.Math..Math.5\end{array}$ [0232] 2) Ratio of radioactivity of the columns:

[00005]$\begin{array}{cc}\mathrm{Due}.Math..Math.\mathrm{to}.Math..Math.L_x\left(\%\right)=\left(100-p_x\right),.Math.\frac{A_x}{A_1}=\mathrm{Fi}\left(x\right).fwdarw.\frac{A_x}{A_1}=\frac{V*C_x}{V*C_1}=\frac{100-p_x}{100-p_1}& \mathrm{Eq}.Math..Math.6\end{array}$ [0233] 3) Combined Concentration Factor Fc(x) achieved with operating with Function 2 or Function 3

[00006]$\begin{array}{cc}\mathrm{Fc}\left(x\right)=\frac{C_{x\left(c\right)}}{C_1}.fwdarw.\mathrm{Fc}\left(x\right)=\frac{C_x}{C_1}=\frac{\mathrm{Fc}\left(1\right)}{V_1*\mathrm{Fi}\left(1\right)}*V_x*\mathrm{Fi}\left(x\right)& \mathrm{Eq}.Math..Math.7\end{array}$ [0234] 4) Concentration of the eluate of the different columns operated with Function 1 of the apparatus:

C.sub.x(i)=F.sub.i(x)*C.sub.1Eq 8 [0235] 5) Concentration of the eluate of the different columns operated with Function 2 or Function 3 of the apparatus:

C.sub.x(c)=F.sub.c(x)*C.sub.1Eq 9

[0236] In the case the use of the radionuclide generator columns (separation columns) of different column packing materials (sorbents) with a variable adsorption capacity of parent radionuclide (C) for loading of parent radionuclide with a variable specific radioactivity (SA) is required using a pre-fixed design of apparatus as specified in the example 4, the radioactivity (Ax) of intended new generator and the radioactivity (A.sub.1) of comparative generator are evaluated based on the following conversion relationships:

[00007]$A_1=M_x*\left(\frac{100-p_1}{100}\right)*C*\mathrm{SA}.Math..Math.\mathrm{or}.Math..Math.\mathrm{SA}=\frac{A_1}{M_x*C}*\frac{100}{100-p_1}$$A_x=\mathrm{Fi}\left(x\right)*A_1.Math..Math.\mathrm{or}.Math..Math.A_1=\frac{A_x}{\mathrm{Fi}\left(x\right)}$

[0237] For calculation of A.sub.1 and A.sub.x the parameters of a fixed design of AFCC apparatus (radionuclide generator) M.sub.x, Fi(x), p.sub.1 and p.sub.x (Fi(x) is calculated using Eq. 5) and the C and SA values are needed.

[0238] In relation to the Example 4, the AFCC apparatus design is fixed at the following parameters listed in Table 4 (Generator D) with the specification of the sorbent used as a column packing material of separation column: C=250 mg Mo/g sorbent and the property of the composition to be separated (Parent radionuclide): SA=1.0 mCi .sup.99Mo/mg Mo.

A.sub.1=20*[(10075)/100)]*250*1.0=1250 mCi .sup.99Mo;

A.sub.x=3.775*1250=4178.7 mCi .sup.99Mo

[0239] If a generator of 1268.91 mCi .sup.99Mo activity is intended to produce from a sorbent of adsorption capacity C=200 mg Mo/g sorbent using a fixed design of AFCC apparatus (radionuclide generator D) described in Table 4, then a parent .sup.99Mo-radionuclide of specific radioactivity should be used:

[00008]$.Math.A_1=\frac{A_x}{\mathrm{Fi}\left(x\right)}=\frac{1268.91}{3.775}=336.1.Math..Math.{\mathrm{mCi}}^{99}.Math..Math.\mathrm{Mo}$$\mathrm{SA}=\frac{A_1}{M_x*C}*\frac{100}{100-p_1}=\frac{336.1}{20*200}*\frac{100}{100-75}=0.3361.Math..Math.\mathrm{mCi}.Math.\text{/}.Math.\mathrm{mg}.Math..Math.\mathrm{Mo}$

Superior features of AFCC-apparatus are shown in the following table:

TABLE-US-00003 DFCC-based .sup.99mTc-GENERATOR AFCC-based .sup.99mTc-GENERATOR (Generator A and B in Table 4) (Generator C and D in Table 4) Generator specification: Generator specification: Weight of sorbent in the generator Weight of sorbent in the generator columns: columns: M = 20.0 g (including 1.125 g of the M = 20.0 g (including 1.125 g of the sorbent in the purification column) sorbent in the purification column) Parent .sup.99Mo-radionuclide Loading Parent .sup.99Mo-radionuclide Loading m(L) = 5.0 g, L = 25.0% of M (26.49% m(L) = 18.875.0 g L = 94.375% of M (100% loading of SC column) loading of SC column) Parent .sup.99Mo-radionuclide activity: Parent .sup.99Mo-radionuclide activity: A.sub.1 = 1250.0 mCi .sup.99Mo A.sub.x = 4718.7 mCi .sup.99Mo Weight of sorbent in one Weight of sorbent in one purification column, m(p) = 1.125 g purification column, m(p) = 1.125 g p = 5.625% of M p = 5.625% of M Unloaded zone: 69.375% of M Unloaded zone: 0.00% of M p.sub.1 = p + Unloaded zone = 75.0% of M p.sub.x = p + Unloaded zone = 5.625% of M Separation performance: Separation performance: 1. Operation function 1 (Generator A): 1. Operation function 1 (Generator C): Product-Eluate volume: 40 mL Product-Eluate volume: 40 mL (2.0 mL/g sorbent) (2.0 mL/g sorbent) Inherent concentration factor: Inherent concentration factor Fi(1) = 1 increased: Fi(x) = 3.775 .sup.99mTc-concentration in the eluate: .sup.99mTc-concentration in the eluate C.sub.01 = 31.25 mCi/mL increased: C.sub.0x = 117.97 mCi/mL 2. Operation (Generator B) in 2. Operation function 2 & 3 coupling with ULTRALUTE (Generator D): Radioisotope Concentrator: Primary eluent volume: 40 mL Primary eluent volume: 40 mL (2.0 mL/g sorbent) (2.0 mL/g sorbent) Concentrated product-eluate Concentrated product-eluate volume: Vc = 3.0 mL volume: Vc = 3.0 mL Combined concentration factor Combined concentration factor increased: Fc (94.37%) = 50.33 increased: Fc (25%) = 13.333 Concentrated eluate .sup.99mTc- Concentrated eluate .sup.99mTc- concentration increased: C.sub.c(x) = 1572.9 mCi/mL concentration increased: C.sub.c(1) = 416.67 mCi/mL

TABLE-US-00004 TABLE 1 Performance of comparative conventional DFCC-based .sup.68Ga-generator and AFCC-based .sup.68Ga-generators of this invention, Sorbent: Nano-crystalline mixed metal oxide ZT-11 sorbent (Adsorption capacity: 1.3 mg Ge per gram sorbent; Patent application WO 2011/106847 A1) and Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 3.0 mg Ge/g; Patent Application Publication WO 2015/039170A1); .sup.68Ge-source of high specific activity: 1.6 mCi .sup.68Ge/g Ge Parent Elution nuclide Generator Purification volume of activity column, columns, 0.1M HCl Radio-nuclide Expiry time Generator and its of the (Sorbent/ (Sorbent/ solution purity (.sup.68Ge- .sup.68Ga-elution with one production method generator Weight) Weight) (eluent) break-through yield, elution per day AFCC-based .sup.68Ga- 2083.0 MBq ZT-11 2 columns; 1.5-1.8 mL 10.sup.5-10.sup.6% >85% >500 days last; generators of this (56.3 mCi) Sorbent/ ZT-11 Shorter elution invention 30.0 mg Sorbent/ profile 500 mg each column Comparative 2083.0 MBq ZT-11 Not used 4-6 mL 10.sup.4-10.sup.5% >80% 200 days last; conventional DFCC- (56.3 mCi) Sorbent/ Longer elution based 1500.0 mg profile .sup.68Ga-generators AFCC-based .sup.68Ga- 5550.0 MBq ISOSORB- 2 columns; 2-2.5 mL 10.sup.5-10.sup.6% >85% >500 days last; generators of this (150.0 mCi) MOX-HP ISOSORB- Shorter elution invention sorbent/ MOX-HP profile 50.0 mg sorbent/ 750.0 mg each column

TABLE-US-00005 TABLE 2 Performance of comparative conventional DFCC-based .sup.99mTc-generators and AFCC-based .sup.99mTc-generators of this invention, Sorbents: PZC sorbent (Adsorption capacity: 250 mg W per gram Sorbent) and Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 300 mg Mo/g; Patent Application Publication WO 2015/039170A1); .sup.99Mo source of low specific activity: 1.0 mCi .sup.99Mo/mg Mo. Parent nuclide Generator Purification Elution activity column, columns, volume of Radio-nuclide Expiry time Generator and its of the (Sorbent/ (Sorbent/ Saline purity (.sup.99Mo- .sup.99mTc-elution with one production method generator Weight) Weight) eluent break-through) yield, elution per day AFCC-based .sup.99mTc- 92.0 GBq PZC sorbent/ 2 columns; 20-22 mL <0.001% >85% >60 days last; generators of this (2486.0 mCi) 10.0 g Alumina/ Shorter elution invention 1.5 g profile each column Comparative 92.0 GBq PZC sorbent/ Not used 55-65 mL <0.01% >80% 15 days last; conventional DFCC- (2486.0 mCi) 30.0 g Longer elution based .sup.99mTc- profile generators AFCC-based .sup.99mTc- 200.0 GBq ISOSORB- 2 columns; 35-40 mL <0.001% >85% >60 days last; generators of this (5405.0 mCi) MOX-HP ISOSORB- Shorter elution invention sorbent/ MOX-HP profile 20.0 g sorbent/ 1.5 g each column

TABLE-US-00006 TABLE 3 Performance of comparative conventional DFCC-based .sup.188Re- generator and AFCC-based .sup.188Re- generators of this invention, Sorbents: Alumina (Adsorption capacity: 100-120 mg W per gram Sorbent) and Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 500 mg W/g Patent Application Publication WO 2015/039170A1); .sup.188W-source of low specific activity: 5.0 mCi .sup.188W/mg W Parent nuclide Generator Purification Elution activity column, columns, volume of Radio-nuclide Expiry time Generator and its of the (Sorbent/ (Sorbent/ Saline purity (.sup.188W .sup.188Re -elution with one production method generator Weight) Weight) eluent break-through) yield, elution per day AFCC-based .sup.188Re- 20.0 GBq Alumina/ 2 columns; 2.5-3.5 mL 10.sup.4-10.sup.5% >85% >300 days last; generators of this (540.0 mCi) 0.5 g Alumina/ Shorter elution invention 0.5 g profile each column Comparative 20.0 GBq Alumina/ Not used 8-10 mL 10.sup.3-10.sup.4% >80% <150 days last; conventional DFCC- (540.0 mCi) 2.0 g Longer elution based profile .sup.188Re-generators AFCC-based .sup.188Re- 55.0 GBq ISOSORB- 2 columns; 4-5 mL 10.sup.4-10.sup.5% >85% >300 days last; generators of this (1486.0 mCi) MOX-HP ISOSORB- Shorter elution invention sorbent/ MOX-HP profile 0.8 g sorbent/ 0.5 g each column

TABLE-US-00007 TABLE 4 Performance comparison of AFCC-based .sup.99mTc-generators with and without selective elution operation function described in this invention; Sorbent of generator column: Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 250 mg Mo/g; Patent Application Publication WO 2015/039170A1); .sup.99Mo source of low specific activity: 1.0 mCi .sup.99Mo/mg Mo. ISOSORB- MOX-HP Parent sorbent Purification Elution Elution .sup.99mTc- yield; Mo-99 weight of columns, volume of volume of .sup.99mTc-concentration; Generator and nuclide generator (Sorbent/ primary specific Radio-nuclide Concentration factor Fi Operation Function activity column Weight) eluent eluent, Vc purity Concentration factor Fc AFCC-based 174.6 GBq 18.875.0 g; 2 columns; 40.0 mL 3.0 mL 0.9% <0.001% Yield: 100.0%; .sup.99mTc-generator D (4718.7 mCi) L.sub.x = 100% Alumina or 0.05-0.1% NaCl solution (.sup.99Mo-break- Tc-99m Concentration (with specific loading (18.875 ISOSORB- NaCl (for eluting through) in final eluate: elution function)/ g sorbent is MOX-HP/ solution the eluate of 1572.9 mCi/mL, with Function 2 fully loaded 1.125 g .sup.99mTc product) Fc (2) = 50.333 with Mo-99) each column Fi (2) = 3.775 p.sub.x = 94.375% Activity increase: (A.sub.AFCC/A.sub.DFCC) = 3.775 (Activity: 174.6 GBq) AFCC-based 174.6 GBq 18.875.0 g; 2 columns; 40.0 mL Not applied <0.001% Yield: 100.0%; .sup.99mTc-generator C (4718.7 mCi) L.sub.x = 100% Alumina or 0.05-0.1% (.sup.99Mo-break- Tc-99m Concentration (without specific loading (18.875 ISOSORB- NaCl through) in final eluate: elution function)/ g sorbent is MOX-HP/ solution 118.0mCi/mL Function 1 fully loaded 1.125 g Fi (2) = 3.775 with Mo-99) each column Activity increase: p.sub.x = 94.375% (A.sub.AFCC/A.sub.DFCC) = 3.775 (Activity: 174.6 GBq) (*) DFCC-based 46.25 GBq 18.875.0 g; 2 columns; 40.0 mL 3.0 mL 0.9% <0.001% Yield: 100.0%; .sup.99mTc-generator B (1250.0 mCi) L.sub.1 = 25% Alumina or 0.05-0.1% NaCl solution (.sup.99Mo-break- Tc-99m Concentration (with specific loading (5.0 g ISOSORB- NaCl (for eluting through) in final eluate: elution operation sorbent is MOX-HP/ solution the eluate of 416.7 mCi/mL, with function)/Function 2 fully loaded 1.125 g .sup.99mTc product) Fc (1) = 13.333 (**) with Mo-99) each column Fi (1) = 1.00 p.sub.1 = 75% (Activity: 46.25 GBq) (*) DFCC-based 46.25 GBq 18.875.0 g; 2 columns; 40.0 mL Not applied <0.001% Yield: 100.0%; .sup.99mTc-generator A (1250.0 mCi) L.sub.1 = 25% Alumina or 0.05-0.1% (.sup.99Mo-break- Tc-99m Concentration (without specific loading (5.0 g ISOSORB- NaCl through) in final eluate: elution operation sorbent is MOX-HP/ solution 31.25 mCi/mL function)/Function 1 fully loaded 1.125 g Fi (1) = 1.00 with Mo-99) each column (Activity: 46.25 GBq) p.sub.1 =75% (*) For comparative purpose (**) Fc (1) = [(Elution Yield/100) * (V.sub.1 C.sub.1)/V.sub.c]/C.sub.1 = [(100/100) * (40 31.25)/3]/31.25 = 1*(40/3) = 13.333

TABLE-US-00008 TABLE 5 Performance comparison of AFCC-based .sup.68Ga-generators with and without further purification operation function described in this invention, Sorbent of generator column: Multifunctional sorbent ISOSORB-MOX-HP (Adsorption capacity: 3.0 mg Ge/g; Patent Application Publication WO 2015/039170A1); Sorbent of purification columns: Mixed resins (Mixture of 50 mg strong cation exchange resin AG-50W-X4 and 50 mg TODGA-OASIS resin (N,N,N,N-tetraoctldiglycoamide impregnated OASIS-HLB resin, Waters's product, 54.4 m particle size); .sup.68Ge-source of high specific activity: 1.6 mCi .sup.68Ge/g Ge Elution Elution volume of volume of Elution specific specific volume of eluent 1 eluent 2 Radio-nuclide Generator Purifying 0.1M HCl for further for eluting purity, (.sup.68Ge- Parent column, columns, solution purifying the eluate break-through; Generators and its nuclide (Sorbent/ (Sorbent/ (Primary .sup.68Ga on of .sup.68Ga- main metallic .sup.68Ga-elution production method activity Weight) Weight) eluent) PC column) product) contaminants) yield, AFCC-based 5550.0 MBq ISOSORB- 2 columns; 2.5-3.0 mL Not applied Not applied 10.sup.5-10.sup.6% .sup.68Ge; >85% .sup.68Ga-generators (151.0 mCi) MOX-HP Mixed resins, 0.05 ppm Cu.sup.2+; without further sorbent/ 100.0 mg 0.5 ppm Fe.sup.3+ purification 50.0 mg each column operation function AFCC-based 5550.0 MBq ISOSORB- 2 columns; 2.5-3.0 mL 5.0 ml 1.0-1.5 mL 10.sup.6-10.sup.8% .sup.68Ge; >85% .sup.68Ga-generators (150.5 mCi) MOX-HP Mixed resins, 4M HCl + 1% 0.05M HCl 0.025 ppm Cu.sup.2+; with further sorbent/ 100.0 mg Ascorbic acid solution 0.15 ppm Fe.sup.3+ purification 50.0 mg each column solution operation function