Rotating Hoop Chopper Wheel for X-Ray Imagers
An x-ray imaging apparatus includes a holdable housing; an x-ray source mounted within the housing and configured to output a fan beam of x-rays; and a hoop chopper wheel rotatably mounted within the housing and comprising an x-ray attenuating material configured to block x-rays of the fan beam. The hoop chopper wheel defines a set of beam apertures of which each aperture is configured to pass therethrough a corresponding angular portion of x-rays from the fan beam, so that rotation of the hoop chopper wheel causes scanning of the corresponding angular portion of x-rays. The x-ray source may be a transmission-type x-ray tube configured to output the fan beam centered in an x-ray extraction direction forming an angle greater than 0 degrees with respect to a longitudinal axis of the x-ray tube.
1 . An x-ray imaging apparatus comprising:
an x-ray source having a reflection-type anode and configured to output a fan beam of x-rays; and
a hoop chopper wheel rotatably mounted to a cup support mechanism and comprising an x-ray attenuating material configured to block x-rays of the fan beam, the hoop chopper wheel defining a set of beam apertures of which each aperture is configured to pass therethrough a corresponding angular portion of x-rays from the fan beam, so that rotation of the hoop chopper wheel causes scanning of the corresponding angular portion of x-rays.
2 . The apparatus of claim 1 , wherein the x-ray source is a unipolar x-ray tube, and wherein the hoop chopper wheel rotatably mounted to the cup support mechanism is mounted so as to encompass an end of the unipolar x-ray tube having the reflection-type anode.
3 . The apparatus of claim 1 , further comprising a shaft onto which the cup support mechanism is mounted.
4 . The apparatus of claim 3 , further comprising a bearing that supports the shaft.
5 . The apparatus of claim 3 , further comprising an electric motor coupled to the shaft.
6 . The apparatus of claim 1 , further comprising a housing within which the x-ray source and the hoop chopper wheel are mounted.
7 . The apparatus of claim 6 , wherein the housing is holdable.
8 . The apparatus of claim 6 , wherein a minimum distance between an outer surface of the hoop chopper wheel and a front of the housing is less than about 30 mm.
9 . The apparatus of claim 8 , wherein the minimum distance is less than about 10 mm.
10 . The apparatus of claim 9 , wherein the minimum distance is less than about 5 mm.
11 . An x-ray imaging apparatus comprising:
a holdable housing;
an x-ray source comprising a unipolar x-ray tube having a reflection-type anode, the x-ray source mounted within the housing and configured to output a fan beam of x-rays; and
a hoop chopper wheel rotatably mounted to a support mechanism and within the housing, the hoop chopper wheel comprising an x-ray attenuating material configured to block x-rays of the fan beam, the hoop chopper wheel defining a set of beam apertures of which each aperture is configured to pass therethrough a corresponding angular portion of x-rays from the fan beam, so that rotation of the hoop chopper wheel causes scanning of the corresponding angular portion of x-rays.
12 . The apparatus of claim 11 , wherein the hoop chopper wheel rotatably mounted to the support mechanism is mounted so as to encompass an end of the unipolar x-ray tube having the reflection-type anode.
13 . The apparatus of claim 11 , wherein the support mechanism is a cup support mechanism.
14 . The apparatus of claim 11 , wherein the support mechanism is a plate support mechanism.
15 . The apparatus of claim 11 , further comprising a shaft onto which the support mechanism is mounted and an electric motor coupled to the shaft.
16 . The apparatus of claim 15 , further comprising a bearing that supports the shaft.
17 . The apparatus of claim 11 , wherein a minimum distance between an outer surface of the hoop chopper wheel and a front of the holdable housing is less than about 30 mm.
18 . The apparatus of claim 17 , wherein the minimum distance is less than about 10 mm.
19 . The apparatus of claim 18 , wherein the minimum distance is less than about 5 mm.
20 . An x-ray imaging apparatus comprising:
a holdable housing;
an x-ray source mounted within the housing and configured to output a fan beam of x-rays;
a hoop chopper wheel rotatably mounted within the housing and comprising an x-ray attenuating material configured to block x-rays of the fan beam, the hoop chopper wheel defining a set of beam apertures of which each aperture is configured to pass therethrough a corresponding angular portion of x-rays from the fan beam, so that rotation of the hoop chopper wheel causes scanning of the corresponding angular portion of x-rays; and
a set of x-ray detectors configured to detect incident x-rays scattered by, or transmitted through, a target object that receives x-rays of the corresponding angular portion of x-rays from the fan beam, wherein at least one x-ray detector of the set of x-ray detectors comprises:
a scintillator volume having an entrance surface and an exit surface, the entrance surface configured to receive the incident x-rays, the scintillator volume configured to emit scintillation light responsive to the incident x-rays, and the exit surface configured to pass a portion of the incident x-rays that traverse a thickness of the scintillator volume between the entrance surface and the exit surface;
at least one first photodetector configured to output a first signal responsive to scintillation light received through the entrance surface of the scintillator volume;
a plurality of exit surface light guides optically coupled to the exit surface of the scintillator volume; and
at least one second photodetector optically coupled to an end of the plurality of exit surface light guides and configured to output a second signal responsive to scintillation light received through the exit surface of the scintillator volume.