Obtaining patient-specific dose estimates in nuclear medicine studies

A Monte Carlo-based image reconstruction algorithm for SPECT has previously been developed utilizing an accelerated version of the SIMIND Monte Carlo program incorporating convolution-based forced detection. This program has been extended to also provide estimates of patient specific radiation dose by storing energy deposition information inside the object as part of the simulation process. Simulations have been performed with both simple and complex geometries and have been validated against GATE to ensure that the results are reproducible. In simple geometries, energy deposition values agree to within 10% between SIMIND and GATE. However, in higher density materials there is a large discrepancy between the dose estimates found in both programs. Future efforts include determining the source of these discrepancies