Radiation dosimetry of 18F-fluorocholine PET/CT studies in prostate cancer patients

We aimed to evaluate the Equivalent Doses (HTs) to highly exposed organs as well as the Effective Dose (ED) for (18)F-fluorocholine PET/CT scan in the follow-up of prostate cancer patients.

Fifty patients were administered with (18)F-fluorocholine. The activities in organs with the highest uptake were derived by region-of-interest (ROI) analysis. OLINDA/EXM1.0 and Impact software were used to assess ED for the administered (18)F-fluorocholine and CT scan, respectively, and the (18)F-fluorocholine and CT-scan EDs summed to yield the total ED for the PET/CT procedure.

The calculated (18)F-fluorocholine and CT scans EDs based on ICRP Publication 103 were 5.2 mSv/300 MBq and 6.7 mSv, respectively. The (18)F-fluorocholine HTs to the liver, kidneys, spleen and pancreas were about threefold higher than those from the CT, which contributed a greater proportion of the total ED than the (18)F-fluorocholine did.

For (18)F-fluorocholine PET/CT procedures, about 40% of the ED is contributed by administered (18)F-fluorocholine and 60% by the CT scan. The kidneys and liver were the highly exposed organs. Considering the large number of diagnostic procedures oncology patients undergo, radiation dosimetry is important in relation to the stochastic risk of such procedures.