TEST BODY FOR ANALYSING AND MONITORING THE IMAGE QUALITY FROM MR TOMOGRAPHS

Abstract

The invention relates to a phantom for simple calibration and quality assurance in an MR tomograph, having a phantom body (2), measuring aids (10, 11, 12, 13) and an intermediate bottom (14) having an upper and a lower side, wherein the measuring aids (10, 11, 12, 13) and the intermediate bottom (14) are arranged in the phantom body (2) in at least four planes (6, 7, 8, 9) and a first plane (6) comprises as the measuring aid only the measuring fluid (10), a second plane (7) comprises as the measuring aid wedge-shaped elements (11), a third plane (8) comprises as the measuring aid marks (12) of known distance from one another, and a fourth plane (9) comprises as the measuring aid comb-shaped elements (13), wherein the measuring aids (11) of the second plane (7) are arranged on one side of the intermediate bottom (14), the measuring aids (13) of the fourth plane (9) are arranged on the other side of the intermediate bottom (14) and the measuring aids (12) of the third plane (8) are arranged in the intermediate bottom (14). By means of the arrangement of the measuring aids according to the invention, reliable calibration of the MR tomograph is possible in a few steps solely with the aid of the phantom according to the invention.

Claims

1. Phantom for use in an MR tomograph, having a phantom body, measuring aids and an intermediate bottom having an upper and a lower side, wherein the measuring aids and the intermediate bottom are arranged in the phantom body in at least four planes, wherein a first plane comprises as the measuring aid only the measuring fluid; a second plane comprises as the measuring aid wedge-shaped elements; a third plane comprises as the measuring aid marks of known distance from one another; and a fourth plane comprises as the measuring aid comb-shaped elements, wherein the measuring aids of the second plane are arranged on the one side of the intermediate bottom, the measuring aids of the fourth plane are arranged on the other side of the intermediate bottom, and the measuring aids of the third plane are arranged in the intermediate bottom.

2. Phantom according to claim 1, wherein the phantom body comprises a hollow cylindrical base element which is closed at the upper and lower end by at least a head plate and a bottom plate.

3. Phantom according to claim 2, wherein the intermediate bottom is arranged parallel to the head plate and the bottom plate.

4. Phantom according to claim 1, wherein the wedge-shaped elements of a second plane that are provided as measuring aids are arranged in pairs, wherein the individual wedges of a pair are in each case arranged parallel to one another and the tip of one wedge points towards the base of the other wedge and vice versa.

5. Phantom according to claim 1, wherein the marks of a third plane that are provided as measuring aids are provided as bores in the intermediate bottom.

6. Phantom according to claim 1, wherein the comb-shaped elements comprise a base with fins standing perpendicularly thereon and oriented parallel to one another, and at least two of the comb-shaped elements of a fourth plane that are provided as measuring aids are oriented relative to one another in such a way that the fins of the two comb-shaped elements are oriented perpendicularly to one another.

7. Phantom according to claim 1, wherein the measuring fluid comprises a salt solution comprising copper sulfate and sodium chloride.

8. Phantom according to claim 1, wherein the phantom body is manufactured substantially from acrylic glass.

9. Phantom according to claim 1, wherein feed and/or discharge lines for the measuring fluid are provided on the phantom body, in particular on the head and/or bottom plate.

10. Phantom according to claim 9, wherein valve elements are provided on these feed and/or discharge lines.

11. Phantom according to claim 1, wherein the phantom comprises a holder which is individually adapted to an MR tomograph.

Description

[0051] In the figures:

[0052] FIG. 1 is a side view of a phantom according to the invention;

[0053] FIG. 2 is a perspective view of the wedge-shaped measuring elements and, therebeneath, a schematic top view of the arrangement of these elements in the plane;

[0054] FIG. 3 is a perspective view of the third plane with distance marks and, therebeneath, a schematic top view of the arrangement of the marks in the plane;

[0055] FIG. 4 is a perspective view of the fourth plane with comb-shaped measuring elements and, therebeneath, a schematic top view of the arrangement of these elements in the plane;

[0056] FIG. 5 is a perspective view of the holder and, therebeneath, the arrangement of the phantom with the holder in the tube of an MR tomograph.

[0057] FIG. 1 shows a phantom 1 according to the invention having a phantom body 2, measuring aids 10, 11, 12, 13 and an intermediate bottom 14. The phantom body 2 comprises a hollow cylindrical base body 3 and a head plate 4 and a bottom plate 5, which are arranged at the two ends of the hollow cylindrical base body 3. The head plate 4 and the bottom plate 5 are arranged parallel to one another and perpendicularly to the longitudinal center axis of the hollow cylindrical base body 3.

[0058] The head plate 4 and the bottom plate 5 seal the hollow cylindrical base body 3 at least in a fluid-tight manner. At least the hollow cylindrical base body 3 is preferably manufactured from an optically transparent material, for example from acrylic glass, so that damage to the phantom 1 is visually perceivable.

[0059] The measuring aids 10, 11, 12, 13 and the intermediate bottom 14 are arranged inside the phantom body 2. The measuring fluid 10 fills the phantom body 2 almost completely. The other measuring aids 11, 12, 13 are arranged on or in the intermediate bottom 14.

[0060] Overall, the measuring aids are arranged in four planes 6, 7, 8, 9 which are arranged in succession and in parallel along the center longitudinal axis of the phantom body. Of course, the measuring fluid 10 penetrates all the planes 6, 7, 8, 9.

[0061] The first plane 6 comprises as the measuring aid only the measuring fluid 10. The second plane 7 comprises as the measuring aid wedge-shaped elements 11. The third plane 8 comprises as the measuring aid marks 12, which are preferably arranged in or on the intermediate bottom 14. The fourth plane 9 comprises as the measuring aid comb-like elements 13. According to the invention, the wedge-shaped elements 11, the marks 12 and the comb-like elements 13 are arranged on or in the intermediate bottom 14.

[0062] In order to allow the measuring fluid 10 to be exchanged, openings 15 are optionally provided in the head plate 4 and/or in the bottom plate 5, through which openings the measuring fluid 10 can be fed in or discharged. Optional valve elements 16 can increase the tightness of the phantom 1 at these points.

[0063] FIG. 2 shows in detail the wedge-shaped elements 11 of the second plane 7. Preferably, the wedge-shaped elements 11 are of the same size and are arranged in pairs comprising a first wedge-shaped element 11A and a second wedge-shaped element 11B. The individual wedges 11A, 11B of a pair 11 are in each case arranged parallel to one another, wherein the tip of one wedge 11A points towards the base of the other wedge 11B and vice versa. In particular, the tip of one wedge 11A ends at the base of the other wedge 11B and vice versa. If two pairs of wedge-shaped elements 11 are provided, they are preferably arranged perpendicularly to one another. The wedge-shaped elements 11 serve for the determination or calibration of the layer thickness.

[0064] FIG. 3 shows in detail the third plane 8 having the intermediate bottom 4 and the marks 12 arranged thereon. Preferably, the marks 12 are provided as perpendicular bores through the intermediate bottom 14. The marks 14 of known distance from one another serve for the determination or calibration of the geometric distortion. The distribution pattern of these marks 12 shown by way of example in FIG. 3 can be adapted to the normative requirements that apply in a particular case.

[0065] FIG. 4 shows in detail the comb-shaped elements 13 of the fourth plane 9 in detail and, in a plan view, a preferred arrangement. The comb-shaped elements 13 comprise a base 13A, and fins 13B arranged perpendicularly on the base and oriented parallel to one another. The comb-shaped elements 13 serve for the determination or calibration of the spatial resolution. If two comb-shaped elements 13 are provided in the fourth plane 9, they are oriented relative to one another in such a way that the fins 13B of the two elements 13 are arranged perpendicularly to one another.

[0066] FIG. 5 shows a schematic illustration of the holder 17 for receiving the phantom 1. As well as ensuring that the phantom 1 is held securely, the holder 17 also ensures the reproducibility of the maintenance work that is to be carried out. The accuracy of fit of the holder 17 ensures in particular that, for each new maintenance operation that is to be carried out, namely a calibration or a determination of the essential image quality parameters, the phantom 1 will be arranged in the MR tomograph in exactly the same position as for the last maintenance operation.

TABLE-US-00001 List of reference numerals 1 phantom 2 phantom body 3 base element 4 head plate 5 bottom plate 6 first plane 7 second plane 8 third plane 9 fourth plane 10 measuring fluid 11 wedge-shaped elements (A, B individual wedges) 12 marks 13 comb-shaped elements (13A base, 13B fins) 14 intermediate bottom 15 feed or discharge line 16 valve element 17 holder