ANTENNA ASSEMBLY FOR A TOMOGRAPHY SYSTEM

Abstract

The present disclosure relates to an antenna assembly for an imaging method, a use of an antenna assembly and a tomography system, in particular for MRI or simultaneous MR-PET/SPECT. An antenna assembly for an imaging method comprises at least two adjacent antennas, wherein each of the at least two antennas is designed as a J-pole antenna with a radiation section and a feed section. The at least two antennas are arranged alternately at a first angle and a second angle different from the first angle in relation to a reference surface. In this way, effective decoupling of the two antennas is achieved by simple means.

Claims

1. An antenna assembly for an imaging method, the antenna assembly comprising at least two adjacent antennas, wherein each of the at least two antennas is configured as a J-pole antenna with a radiation section and a feed section, wherein the at least two antennas are arranged alternately at a first angle and a second angle different from the first angle in relation to a reference surface.

2. The antenna assembly of claim 1, wherein the first angle and the second angle have a difference of 90?.

3. The antenna assembly of claim 1, wherein a first antenna of the two antennas is aligned substantially along the reference surface and a second antenna of the two antennas is aligned substantially perpendicular to the reference surface.

4. The antenna assembly of claim 1, wherein the at least two antennas are arranged in such a way that the two antennas form an angle ? between each other, wherein ? is between 25? and 90?.

5. The antenna assembly of claim 1, wherein the antenna assembly comprises at least three antennas which are designed as J-pole antennas and are arranged alternately at the first angle and the second angle in relation to the reference surface.

6. The antenna assembly of claim 1, wherein the antenna assembly has between 4 and 32 antennas.

7. The antenna assembly of claim 1, wherein the antenna assembly is an antenna assembly for magnetic resonance imaging (MRI), ultra-high field MRI, MR positron emission tomography (MR-PET), MR single proton emission computed tomography (MR-SPECT), MR linear accelerator and/or MR ultrasound.

8. The antenna assembly of claim 1, wherein the antenna assembly is an antenna assembly for simultaneous MR-PET/-SPECT.

9. The antenna assembly of claim 1, wherein the radiation section of each of the two antennas is produced from a material substantially transparent to PET and/or SPECT.

10. The antenna assembly of claim 1, wherein the antennas of the antenna assembly define a hollow body in which a body or a body part can be arranged.

11. The antenna assembly of claim 10, wherein the hollow body has a circular cylindrical basic shape.

12. The antenna assembly of claim 1, wherein the antenna assembly has a radiation part and a feed part adjacent to the radiation part, wherein the radiation sections of the antennas are arranged in the radiation part and the feed sections of the antennas are arranged in the feed part.

13. The antenna assembly of claim 1, wherein the antenna assembly has at least two antennas which are designed as J-pole antennas with a radiation section and a feed section, wherein the radiation sections of the two antennas are arranged crossing each other.

14. A method of using an antenna assembly in a tomography system, the method comprising providing the antenna assembly having at least two adjacent antennas, wherein each of the at least two antennas is configured as a J-pole antenna with a radiation section and a feed section, and wherein the at least two antennas are arranged alternately at a first angle and a second angle different from the first angle in relation to a reference surface, and acquiring imaging via MRI or simultaneous MR-PET/-SPECT using the antenna assembly.

15. A tomography system, adapted for MRI or simultaneous MR-PET/SPECT, the system comprising an antenna assembly having at least two adjacent antennas, wherein each of the at least two antennas is configured as a J-pole antenna with a radiation section and a feed section, and wherein the at least two antennas are arranged alternately at a first angle and a second angle different from the first angle in relation to a reference surface, and wherein the antenna assembly is arranged in particular such that the feed sections are located outside a measuring range of the tomography system.

16. The antenna assembly of claim 4, wherein ??45?.

17. The antenna assembly of claim 4, wherein ??60?.

18. The antenna assembly of claim 6, wherein the antenna assembly has between 6 and 16 antennas.

19. The antenna assembly of claim 2, wherein a first antenna of the two antennas is aligned substantially along the reference surface and a second antenna of the two antennas is aligned substantially perpendicular to the reference surface.

20. The antenna assembly of claim 19, wherein the at least two antennas are arranged in such a way that the two antennas form an angle ? between each other, wherein ? is between 25? and 90?.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0051] The figures show:

[0052] FIG. 1: a schematic representation of a J-pole antenna;

[0053] FIG. 2: a schematic perspective representation of an antenna assembly;

[0054] FIG. 3: a sectional drawing of a further embodiment of an antenna assembly;

[0055] FIG. 4: a perspective representation of an antenna assembly; and

[0056] FIG. 5: a schematic representation of an antenna assembly with two antennas whose radiation sections are arranged crossing each other.

DETAILED DESCRIPTION

[0057] FIG. 1 shows an antenna 1 in the shape of a J-pole antenna. This comprises a straight radiation section 2 and an immediately adjacent feed section 3. The feed section 3 is U-shaped. The radiation section 2 merges seamlessly into a leg of the U. This creates the characteristic J-shape of antenna 1.

[0058] The radiation section 2 serves for transmitting and receiving or exclusively transmitting electromagnetic signals of an imaging method such as, for example, MRI or simultaneous MR-PET/SPECT. The feed section 3 is used to feed the antenna 1, or more precisely the radiation section 2.

[0059] In particular, the cross-section of the antenna 1 does not cause any abrupt changes in the absorption coefficients for y-radiation. For example, the cross-section is circular or elliptical. This can prevent artifacts in PET/SPECT imaging. The antenna 1 is preferably thin. In the sense of the present disclosure, thin means, for example, a thickness corresponding to 3 to 5 times the penetration depth of the radio frequency field into the antenna.

[0060] The two dotted lines mark the upper end of the antenna 1 and the boundary between the radiation section 2 and the feed section 3. The length of the radiation section 2 between the two dotted lines is typically ?/2. The length of the feed section 3 from the lower dotted line to the lower end of the U-shape is typically ?/4. This can be adapted as described above.

[0061] FIG. 2 shows a first embodiment of an antenna assembly 10 according to the present disclosure. Two J-pole antennas 1 are arranged adjacent to each other in or on a flat reference surface 4. The first antenna 1 shown on the left is arranged in an auxiliary plane 11; both legs of the U-shaped feed section 3 are therefore located in the auxiliary plane 11. The radiation section 2 and the immediately adjacent lower leg of the U are arranged in the reference surface 4. In this example, the auxiliary plane 11 is aligned at an angle ? of 90? to the reference surface 4. The first antenna 1 shown on the left is therefore arranged at a first angle of 90? to the reference surface.

[0062] The second antenna 1 shown on the right is rotated clockwise by 90? compared to this. Both legs of the U-shaped feed section 3 of this second antenna 1 lie in or on the reference surface. The second antenna 1 is thus arranged at a second angle of 0? to the reference surface. In this way, the alternating arrangement according to the present disclosure is produced. Thus, a decoupling of the two antennas 1 from each other is achieved, which enables an arrangement of more antennas 1 per volume or per surface. In this way, the imaging method is improved, in particular the uniformity and the signal-to-noise ratio are increased. In the event that a third antenna 1 were present to the right of the second antenna 1, it would be arranged at a first angle of 90? to the reference surface in the same way as the first antenna 1 according to the present disclosure in order to achieve the alternating arrangement.

[0063] FIG. 3 shows a sectional drawing through an antenna assembly 10 with a circular cylindrical basic shape in the radial direction. There are twelve antennas 1 evenly distributed around the circumference of the circle. The sectional plane shown runs through the feed part 5 of the antenna assembly 10 (cf. FIG. 4), so that each antenna 1 is represented by two conductors with a circular cross-section, which represent the legs of the U. The plane of each antenna 1 is spanned by these two conductors.

[0064] The reference surface 4 is the lateral surface of the circle. It is therefore a curved reference surface 4. The antennas 1 are arranged alternately at an angle of 0? and 90? to the reference surface 4. The antennas 1 are therefore alternately aligned along the reference surface 4 (shown as filled circles) and perpendicular to the reference surface 4 (shown as circles with a white core). For clarity, one antenna 1 of each of the two described orientations is circled with a dotted line and thus highlighted. Neighboring antennas 1 have an angle ? between them, which is 60? here due to the twelve antennas. If fewer antennas are distributed around the circumference, the angle ? is also smaller. Despite the angle ? deviating from 90?, good decoupling of the antennas is achieved. The antennas 1 aligned perpendicular to the reference surface 4 are arranged here, for example, so that the outer conductor lies approximately on the arc of the circle. Deviating from this, individual or all of the antennas 1 aligned perpendicular to the reference surface 4 can also be shifted further outwards or bent so that, for example, the respectively inner conductor lies approximately on the arc of the circle.

[0065] FIG. 4 shows an antenna assembly 10, e.g., the antenna assembly 10 of FIG. 3, in perspective view. It can be seen that the antenna assembly 10 defines a hollow body 6. The individual antennas 1 surround this hollow body 6, which has a circular cylindrical basic shape 7. A body part or a body can be accommodated in the hollow body 6 in order to be examined using the imaging method. The radiation sections 2 of the antennas 1 together form a radiation part 8 of the antenna assembly 10. The feed sections of the antennas 1 together form a feed part 5 of the antenna assembly 10, which directly adjoins the radiation part. Thus, the radiation sections 2 of the antennas 1 all have the same orientation, namely parallel to the longitudinal extension of the cylinder. For reasons of clarity, only six antennas 1 are shown. However, a total of twelve antennas 1 are typically present here. It can be seen that the feed sections 3, as already shown in FIG. 3, are alternately aligned tangentially and radially.

[0066] FIG. 5 shows an antenna assembly 10 with two antennas 1 whose radiation sections 2 are arranged crossing each other. The antennas are configured as J-pole antennas. A crossing point 9 is formed. The two antennas 1 form an angle ? of approximately 75? between each other. The angle ? is the smaller angle measured between the radiation sections 2 of the two antennas 1. In this way, decoupling of the two antennas 1 from each other is achieved, which allows more antennas 1 to be arranged per volume or per area. In this way, the imaging method is improved, in particular the resolution is increased. This embodiment can be combined as desired with the alternating angular arrangement of the antennas 1 described above in order to achieve a further improved decoupling.

[0067] In particular, the antenna assembly 10 comprises a positioning unit for positioning the antennas 1 in relation to each other and/or to a body to be examined. This can be designed as a holding device for holding the antennas 1 and/or as a fastening unit for mechanically fastening the antennas 1 to one another. The positioning unit can, for example, have the basic circular cylindrical shape 7. The positioning unit may be adapted to the shape and/or size of the body or body part to be examined, here for example the human head.

LIST OF REFERENCE SIGNS

[0068] Antenna 1 [0069] Radiation section 2 [0070] Feed section 3 [0071] Reference surface 4 [0072] Feed part 5 [0073] Hollow body 6 [0074] Circular cylindrical basic shape 7 [0075] Radiation part 8 [0076] Crossing point 9 [0077] Antenna assembly 10 [0078] Auxiliary plane 11 [0079] Angle ? [0080] Angle ? [0081] Angle ?