Effective Dose Estimation with IDAC and OLINDA for 18 F-FDG and 68 Ga-PSMA PET/CT Procedures

Internal dosimetry is a part of radiation safety for patients and radiation workers in nuclear medicine procedures. This study retrospectively determined the effective dose for oncology patients undergoing PET/CT scans by using widely used computer codes, and the results were compared with each other and literature. The study focused on the radiopharmaceuticals 18 F-FDG (n = 220) and 68 Ga-PSMA (n = 85), administered to 305 patients for cancer imaging at Yeditepe University Kosuyolu Hospital's nuclear medicine department. PET dose was calculated using OLINDA/EXM, IDAC-Dose 1.0 and IDAC-Dose 2.1 programs while ImPACT software was used to determine the effective dose from the CT scan. All effective doses were derived in accordance with ICRP 60 and ICRP 103 tissue weighting factors. PET effective doses from highest to lowest were calculated with OLINDA/EXM, IDAC-Dose 1.0, IDAC-Dose 2.1 (ICRP 60) and IDAC-Dose 2.1 (ICRP 103) as 9.96, 9.07, 7.01, 6.28 mSv respectively for 18 F-FDG. The highest PET effective dose was also calculated with OLINDA/EXM software as 3.65 mSv for 68 Ga-PSMA. For the total effective dose in PET/CT scans, CT contributed about 92% for 68 Ga-PSMA protocol and 75% for 18 F-FDG protocol.