Evaluation in Terms of Dosimetry and Fertility of F18-FDG and Ga68- PSMA in Prostate Cancer Imaging: A Simulation with GATE.

Introduction: F18 and Ga68 radioisotopes are used in PET imaging for prostate cancer. It was aimed to calculate the prostate, testicle and bladder effective doses (ED) caused by F18 and Ga68 used in prostate cancer imaging with PET/CT via simulation with the GATE toolkit and evaluate the ED in terms of fertility.

Methods: The prostate, testicle and bladder were defined together with their geometric properties and densities in GATE simulation. F18 and Ga68 with activity of 277.5 MBq and 151.7 MBq were identified in the prostate as a source organ. The ED, uncertainties, and S values were taken as an output file in the TXT format with the DoseActors command. S values were used for validation of the simulation.

Results: The ED of the prostate, total testicle and bladder for F18 were found to be 6.627E-04 ± 1.799E-06, 12.74E-07 ± 4.11E-08 and 1.617E-05 ± 4.317E-09 (Gy/s), respectively. The ED of the prostate, total testicle, and bladder for Ga68 were found to be 9.195E-04 ± 2.660E-06, 6.54E-07 ± 2.93E-08 and 4.290E-05 ± 6.936E-09 (Gy/s), respectively.

Conclusion: It was found that Ga68 produced high prostate and bladder ED, and F18 produced high testicular ED. In terms of male fertility, Ga68 seems to be a good alternative because it produces low testicular doses. The ED of the testicle both F18 and Ga68 were below the reported spermatogonia and azoospermia dose.