Abstract
In the present study, patient exposures Evaluations herein concern patient exposures (positron and gamma-rays) that result from fluoro-D-glucose PET and CT were investigated and radio-carcinogenic risks estimated. The six-month study, conducted at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, included a total of 636 patients (lymphoma = 187, nasopharyngeal carcinoma = 82, thyroid = 30 and others = 337). Patient effective dose estimations were made from administered radioactivity (AA) and CT exposures (General Electric (GE) PET/CT VCT), the mean and range of AA (in MBq) and effective dose (in mSv) were respectively: lymphoma 433.9 +/- 70.6 (297.5-735.9) and 8.2 +/- 1.3 (5.7-13.9); nasopharyngeal carcinoma 417.7 +/- 55.9 (325.6-547.6) and 7.9 +/- 1.1 (6.2-10.4); thyroid 450.1 +/- 71.4 (344.1-566.1) and 8.6 +/- 1.4 (6.5-10.8). In the same units, the mean and range of AA and effective dose for other procedures were 421.6 +/- 58.3 (283.4-606.8) and 8.0 +/- 1.1 (5.4-11.5), respectively. The mean and range of the tube current-time product (mAs) for the CT procedures were 30 (8.2-42.4). A constant tube voltage of 120 kVp was used for all patient procedures. On average, CT contributed 73% to patient effective doses, suggesting that optimisation of CT acquisition parameters are vital in seeking effective dose reduction. Patient effective doses were found to be a little above that of previous studies.