Usefulness of simulation in optimizing imaging settings for pediatric technetium-99m-dimercaptosuccinic acid single-photon emission computed tomography.

Abstract

Technetium-99m (99mTc) dimercaptosuccinic acid (DMSA) single-photon emission computed tomography (SPECT) has been used to diagnose renal scarring. The Japanese Society of Nuclear Medicine recently revised the 'Consensus Guidelines for Pediatric Nuclear Medicine Examination.' In this study, we compared simulation data with actual data obtained using a pediatric phantom for 99mTc-DMSA examinations and evaluated the usefulness of simulations in determining the optimal acquisition conditions for SPECT images. A SPECT quality assurance (QA) phantom study produced images with a renal-to-background 99mTc ratio of 283:1 kBq/ml. The projection data for the simulation were simulated using the simulation of imaging nuclear detectors. To compare the actual measurements and simulations, recovery factors were used for the SPECT QA phantom for image quality assessment. Defect contrast and visual evaluation using Scheffe's method of pairwise comparison were used for the pediatric kidney phantom. The optimal imaging settings using a kidney phantom required an acquisition time of more than 8 min. The maximum difference in the recovery coefficient between the simulation and actual measurement using the SPECT QA phantom was 6%. We showed that an acquisition time of more than 8 min was necessary for DMSA-SPECT. In addition, phantom simulations were approximately equivalent to the actual measurement data and the adaptability of simulations was confirmed.