Multi-geometric collimation for high sensitivity brain SPECT

Certain neurological disorders such as Parkinson´s disease are diagnosed by imaging centrally located brain structures such as basal ganglia and striatum. High sensitivity imaging of these structures is essential for the early-stage diagnosis of the disorder. We simulated a multi-geometric collimator that combines a short-focal-length astigmatic half-cone-beam collimator, designed to efficiently image the bottom half of the brain and especially the centrally located brain structures, and a spatially-variable-focusing collimator, designed to image the rest of the brain without truncation. We demonstrate that a multi-geometric collimator may offer significant sensitivity increase in imaging of the centrally located brain structures compared to conventional general-purpose parallel-hole and fan-beam collimators. As a result, the noise is reduced in the reconstructed images and lesion visualization is improved. Multi-geometric collimation shows a strong potential for improved regional tomography of the brain and early-stage diagnosis of neurological disorders such as Parkinson´s disease.