Quantitative Monte Carlo–Based 90Y SPECT Reconstruction

The evaluation of radiation absorbed doses in tumorous and healthy tissues is of increasing interest for 90Y microsphere radioemboliza-tion of liver malignancies. The objectives of this work were to in-troduce and validate a new reconstruction method for quantitative 90Y bremsstrahlung SPECT to improve posttreatment dosimetry. Methods: A fast Monte Carlo simulator was adapted for 90Y and incorporated into a statistical reconstruction algorithm (SPECT-MC). Photon scatter and attenuation for all photons sampled from the full 90Y energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent col-limator–detector response was modeled with precalculated convo-lution kernels. The National Electrical Manufacturers Association 2007/International Electrotechnical Commission 2008 image quality phantom was used to quantitatively evaluate the performance of SPECT-MC in comparison with those of state-of-the-art clinica