| 摘要 |
A single photon emission computed tomography system produces multiple tomographic images of the type representing a three-dimensional distribution of a photon-emitting radioisotope. The system has a base including a patient support for supporting a patient such that a portion of the patient is located in a field of view. A longitudinal axis is defined through the field of view. A detector module is adjacent the field of view and includes a photon-responsive detector. The detector is operable to detect if a photon strikes the detector. A photon-blocking member is positioned between the field of view and the detector. The blocking member has an aperture slot for passage of photons aligned with the aperture slot. A line of response is defined from the detector through the aperture. A collimating assembly includes a plurality of generally parallel collimating vanes formed of a photon attenuating material. The vanes are spaced apart so as to find a plurality of gaps, with the gaps each having a height. Each of the vanes has a front edge directed toward the field of view and a back edge directed towards the detector. The front-to-back depth of each of the vanes is greater than 10 times the height of the gaps. The plurality of vanes is disposed between the detector and the field of view such that only photons passing through one of the gaps can travel from the field of view to the detector. A displacement device moves either the detector module or the photon-blocking member relative to the other so that the aperture is displaced relative to the detector and the line of response is swept across at least a portion of the field of view. |
