TY - JOUR T1 - Object-specific internal dosimety studies of organs and tumors in a murine model of neuroblastoma using Monte Carlo simulation and voxelized mouse phantom JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1286 LP - 1286 VL - 56 IS - supplement 3 AU - Sang-Keun Woo AU - Shih-ying Huang AU - Joo Hyun Kang AU - Sang Moo Lim AU - Youngho Seo Y1 - 2015/05/01 UR - http://jnm.snmjournals.org/content/56/supplement_3/1286.abstract N2 - 1286 Objectives Geometry and activity distribution must be considered in internal absorbed dose calculation. Unlike dosimetry studies in humans, methods for precise internal dosimetry for laboratory animals are not well developed. We performed calculations of S-values of organs and tumors in a murine model of neuroblastoma using Monte Carlo simulation and voxelized realistic mouse phantom.Methods Three-dimensional voxelized MOBY (Mouse Whole Body, Segars et al., 2004) phantom modified with subcutaneously implanted tumors on both shoulders were used as input for Geant4 Monte Carlo simulations of absorbed fractions and S-factors. The tumor geometry and location were based on our previous experimental animal study using a murine model of neuroblastoma and 124I-mIBG (Mol Imaging Biol, Seo et al., 2012). Subcutaneous tumors were segmented by mean-based region growing 3D segmentation method. Residence times were computed via time activity curves of the acquired dynamic 124I-mIBG PET data for calculation of I-131 absorbed dose.Results In our previous imaging study, NB1691-hNET tumor had significant uptake of 124I-mIBG; however NB1691 tumor did not demonstrate uptake. Representative residence time was 1.47E+01 h for the NB1691-hNET tumor and 3.31E+00 h for kidneys. Monte Carlo simulated S-value was 1.27E-09 Gy/Bq-s for the NB1691-hNET tumor (mIBG-positive), 1.83E-11 Gy/Bq-s for NB1691 tumor (mIBG-negative), 5.22E-08 Gy/Bq-s for kidneys, 1.20E-09 Gy/Bq-s for liver, and 1.97E-08 Gy/Bq-s for bladder. Calculated absorbed doses for the NB1691 tumor, NB1691-hNET tumor, and kidneys were 2.91E-02, 1.87E+01 and 1.73E+02 mGy/MBq, respectively.Conclusions We showed the feasibility of performing object-specific Monte Carlo-based organ and tumor dosimetry in laboratory animals. Our method was applied to actual experimental data for radioiodinated mIBG dose calculation in a murine model of neuroblastoma. ER -