Image shift for gamma camera

• US 6,147,353 A
• Filed: 05/29/1998
• Issued: 11/14/2000
• Est. Priority Date: 05/30/1997
• Status: Expired due to Fees

• Current Assignee: Picker International, Inc. (Marconi Holdings Company Limited)
• Original Assignee: Picker International, Inc. (Marconi Holdings Company Limited)
• Inventors: Gagnon, Daniel, DiFilippo, Frank P., Matthews, Christopher G.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US09/086,947
• Time in Patent Office: 900 Days
• Field of Search: 250/363.05, 250/363.08, 250/363.04
• US Class Current: 250/363.05
• CPC Class Codes: G01T 1/1648 Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices adapted for flow studies G01T1/1647
• CPC Class Codes: G01T 1/166 involving relative movement between detector and subject scanners in general without using scintigraphy G01T1/2964

Abstract

A gamma camera includes first and second detectors which face an examination region. The detectors are rotatable about the examination region and translatable in a direction tangential to the examination region. Translation of the detectors is coordinated with the rotation of the detectors about the examination so as to increase the effective field of view of the detectors. In a first embodiment, the detectors are translated in the transverse direction when the detectors are located at each of a plurality of positions about the examination region. In a second embodiment, translation of the detectors is coordinated such that, for a given projection angle, the first detector is used to detect radiation data from a subset of the region of interest.

Claims

1. A diagnostic imaging method utilizing a gamma camera having first and second detectors disposed in a relative angular orientation with respect to an examination region, the first and second detectors having respective first and second radiation sensitive faces which face the examination region and first and second transverse fields of view, a region of interest within the examination region having a dimension greater than the first and second transverse fields of view, the method comprising:

utilizing the first and second detectors to detect radiation indicative of radionuclide decays occurring within the examination region;

rotating the first and second detectors about the examination region;

repeating the steps of utilizing and rotating a plurality of times so as to detect radiation with the first and second detectors located at a plurality of projection angles;

in coordination with the rotation of the first and second detectors about the imaging region, moving the first and second detectors in a transverse direction so that, at each of the projection angles, the effective transverse field of view of the first and second detectors includes the region of interest;

reconstructing an image indicative of the detected radiation.

2. The method of claim 1 including positioning the first and second detectors at first and second transverse positions at a plurality of the projection angles.

3. The method of claim 2 wherein, at the plurality of the projection angles, the first detector is translated between a first position wherein the first detector'"'"'s transverse field of view extends to at least a perimeter of the region of interest and a second position wherein the first detector'"'"'s transverse field of view extends to at least an opposite perimeter of the region of interest.

4. The method of claim 3 wherein the velocity at which the detector is translated is varied as a function of the transverse position of the detector.

5. The method of claim 3 wherein the camera includes a third detector.

6. The method of claim 2 wherein the first and second detectors are disposed in a 90 degree configuration.

7. The method of claim 1 wherein the first and second detectors each generate a signal indicative of an x,y position on the face of the detector at which radiation is detected.

8. The method of claim 1 further including reconstructing a plurality of parallel image slices indicative of the detected radiation.

9. The method of claim 1 further including

rotating the first and second detectors about the examination region so that the first detector is located at a first projection angle and the second detector is located at a second projection angle;

utilizing the first detector to detect radiation indicative of radionuclide decays occurring within the examination region, a first portion of the region of interest being located outside of the first detector'"'"'s field of view;

rotating the first and second detectors about the examination region so that the second detector is located at the first projection angle;

positioning the second detector so that the first portion of the region of interest is within the second detector'"'"'s field of view;

utilizing the second detector to detect radiation indicative of radionuclide decays occurring within the examination region.

10. The method of claim 9 wherein the first and second detectors are disposed in a 180 degree opposed configuration.

11. The method of claim 9 including

with the second detector located at the second projection angle, utilizing the second detector to detect radiation indicative of radionuclide decays occurring within the examination region, a second portion of the region of interest being located outside of the second detector'"'"'s field of view;

rotating the first and second detectors about the examination region so that the first detector is located at the second projection angle;

positioning the first detector so that the second portion of the region of interest is within the first detector'"'"'s field of view;

utilizing the second detector to detect radiation indicative of radionuclide decays occurring within the examination region.

12. The method of claim 1 further including estimating a radiation attenuation of the object as a function of transverse position and coordinating the transverse motion of the detectors so as to vary the transverse sensitivity of the detectors as a function of the estimated attenuation.

13. A gamma camera including

a first radiation sensitive detector having a radiation sensitive face which faces an examination region and having a transverse field of view;

a second radiation sensitive detector having radiation sensitive face which faces the examination region and having a transverse field of view, the first and second detectors being disposed in a relative angular position with respect to the examination region;

means for rotating the first and second detectors about the examination region so as to detect radiation with the detectors located at a plurality of projection angles;

means for translating the first and second detectors in a transverse direction in coordination with the rotation of the detectors about the examination region so that the effective transverse fields of view of the first and second detectors are greater than their actual transverse fields of view;

means for reconstructing an image indicative of the detected radiation.

14. The gamma camera of claim 13 including means for translating the first detector between a first position wherein the first detector'"'"'s transverse field of view extends to at least a perimeter of the region of interest and a second position wherein the first detectors transverse field of view extends to at least an opposite perimeter of the region of interest and means for translating the second detector between a first position wherein the first detector'"'"'s transverse field of view extends to at least a perimeter of the region of interest and a second position wherein the first detector'"'"'s transverse field of view extends to at least an opposite perimeter of the region of interest.

15. The gamma camera of claim 13 wherein the detectors are disposed in a 180 degree opposed configuration.

16. A gamma camera including

a first radiation sensitive detector having a radiation sensitive face which faces an examination region and having a transverse field of view;

a second radiation sensitive detector having radiation sensitive face which faces the examination region and having a transverse field of view, the first and second detectors being disposed in a relative angular position with respect to the examination region;

means for rotating the first and second detectors about the examination region so as to detect radiation with the detectors located at a plurality of projection angles;

means for translating the first and second detectors in a transverse direction in coordination with the rotation of the detectors about the examination region so as to increase the effective transverse field of view of the first and second detectors;

means for reconstructing an image indicative of the detected radiation; and

a third detector having a radiation sensitive face which faces the examination region.

17. A diagnostic imaging method utilizing a gamma camera having a detector which includes a radiation sensitive face which faces an examination region and which has a transverse field of view, the method comprising:

utilizing the detector to detect radiation indicative of radionuclide decays occurring within the examination region;

rotating the detector about the examination region

repeating the steps of utilizing and rotating a plurality of times so as to detect radiation with the detector located at a plurality of projection angles;

at a plurality of the projection angles, detecting radiation with the detector located at first and second transverse positions such that the effective transverse field of view of the detector is greater than the actual transverse field of view of the detector;

generating an image indicative of the detected radiation.

18. The method of claim 17 wherein the detector generates a signal indicative of the x,y position on the face of the detector at which radiation is detected.

19. The method of claim 17 further including a parallel hole collimator disposed between the radiation sensitive face and the examination region.

20. The method of claim 17 wherein the step of detecting radiation with the detector located at first and second transverse positions includes detecting radiation while translating the detector between the first and second transverse positions at a constant velocity.