Calculation of personal dose equivalent for positron-emitting radionuclides using Monte Carlo code EGS5

Abstract

The conversion coefficients, H'(d,α)/Φ, for monoenergetic positrons and positron-emitting radionuclides were calculated by using the user code UCICRPM of the Monte Carlo code EGS5 to estimate the radiation dose for medical staff involved in positron emission tomography examinations. From these coefficients, the dose equivalent rates per unit activity at 0.07 and 10 mm depths in a soft tissue for a straight-line source of 2-deoxy-2-[(18)F]fluoro-d-glucose ((18)F-FDG) were calculated by using the developed user code UCF18DOSE. The dose equivalent rates per unit activity at 0.07 and 10 mm depths were measured by using a personal dosemeter (DOSE(3)) under the same conditions as those considered in the calculation. The calculated dose equivalent rates per unit activity at 0.07 and 10 mm depths were 0.116 and 0.0352 pSv min(-1) Bq(-1), respectively, at 20 cm from the (18)F-FDG injection tube.

Current situations and discussions in Japan in relation to the new occupational equivalent dose limit for the lens of the eye

“…Knowledge of exposure of the lens during nuclear medicine diagnostics has not yet been accumulated sufficiently to discuss the equivalent dose to the lens in Japan. There are calculated estimations for 18 F-fluorodeoxyglucose ( 18 F-FDG) used for a positron emission tomography (PET) at medical facilities [42,43]. In those studies, it was estimated that the equivalent dose to the skin (H p (0.07)), at 60 cm from an injection tube became 20% of the dose at 20 cm from the tube [42], and the calculated equivalent dose to the lens (H p (3)) was 70 μSv/min at 5 cm from the tube [43].…”

“…There are calculated estimations for 18 F-fluorodeoxyglucose ( 18 F-FDG) used for a positron emission tomography (PET) at medical facilities [42,43]. In those studies, it was estimated that the equivalent dose to the skin (H p (0.07)), at 60 cm from an injection tube became 20% of the dose at 20 cm from the tube [42], and the calculated equivalent dose to the lens (H p (3)) was 70 μSv/min at 5 cm from the tube [43]. In 2008, the Medical Science and Pharmaceutical Committee of the Japan Radioisotope Association (JRIA) prepared a questionnaire to determine the occupational dose at nuclear medical facilities [44].…”