Ultra-high-resolution brain SPECT imaging: simulation results

A three-dimensional hemispherical SPECT (single photon emission computed tomography) brain imager with a multiple-pinhole coded aperture and modular scintillation detectors has been built. This instrument achieves a reconstructed volume resolution of 4-5 mm. Very high detector spatial resolution can even further improve reconstructed resolution. The authors have designed a novel submillimeter-resolution gamma-ray detector using a hybrid combination of a semiconductor detector and a time-integrating multiplexer readout instead of scintillation detectors and photomultipliers. In order to study the effects of high detector resolution on reconstructions, they have performed computer-simulation studies of a hemispherical brain imager system. Reconstructions were performed using an iterative search algorithm on a custom-designed parallel computer, from a calculated system matrix relating all voxels in the object space to all pixels on the detector. A resolution close to 2 mm on the reconstructed images obtained from these simulations is found.<<ETX>>