基于平行光孔和针孔准直器的脑SPECT系统的贝叶斯图像重建算法

brain single photon emission computed tomography (SPECT) imager is simulated for obtaining high resolution brain scans for various imaging diagnostic applications such as in diagnosing brain ischemia. In this simulation the camera consists of one large field of view detector with parallel hole collimation and five smaller field of view high resolution detectors with pinhole collimation. The parallel hole collimation detector images the whole brain and acquires data without truncation. It localizes areas of particular diagnostic interest, and also provides support information for the reconstruction of data acquired by the pinhole collimation detectors. The five pinhole collimation detectors image small regions of the brain. They provide high resolution truncated projections, from which high resolution region of interest (ROI) is obtained. The reconstruction is performed using a Bayesian estimate with total variation regularization within the ROI and the low resolution image from the parallel hole collimation detector as the prior information. The camera improves the quantitation for the interior problem. The combination of large field of view parallel hole collimation detector and smaller field of view high resolution pinhole detectors improves the quantitation in simulated brain imaging. It makes use of the high sensitivity of the pinhole collimator while compensates for the degradation in the reconstructed image due to interior problem caused by the small field of view of the pinhole collimator. This work is expected to be verified through phantom data or clinical data acquired in the study of brain ischemia, where the quantitation of cerebral blood flow (CBF) and cerebral vascular reactivity (CVR) are valuable in diagnosis, and the quantitation of benzodiazepine receptor density is important in evaluating neuronal damage due to ischemic effects.