Improvements on a patient-specific dose estimation system in nuclear medicine examination.

The purpose of this paper is to develop a patient-specific dose estimation system in nuclear medicine examination. A dose deposition routine to store the deposited energy of the photons during their flights was embedded in the widely used SimSET Monte Carlo code and a user-friendly interface for reading PET and CT images was developed. Dose calculated on ORNL phantom was used to validate the accuracy of this system. The ratios of S value for Tc-99m, F-18 and I-131 computed by this system to those obtained with OLINDA for various organs were ranged from 0.93 to 1.18, which were comparable to that obtained from MCNPX2.6 code (0.881.22). Our system developed provides opportunity for tumor dose estimation which cannot be known from the MIRD. The radiation dose can provide useful information in the amount of radioisotopes to be administered in radioimmunotherapy.