Exposure for medical staff from patients during/after ⁸⁹Sr therapy

Personal dose equivalent, H_p(10) and H_p(0.07) doses were measured using an ionization chamber and personal electric dosimeters to estimate the exposure dose for medical staff members and carers as received from ⁸⁹Sr therapy patients. The H_p(10) for medical workers was measured using personal dosimeters and was found to be <1 μSv during the measurement period. H_p(0.07) for medical workers did not exceed 5 μSv per case during routine work, although the dose on the patient's skin surface was about 20 times that on the medical staff. To investigate the contribution of electrons to the measured dose, the dose on the patient's skin surface as obtained from uniformly distributed ⁸⁹Sr in a similar MIRD phantom was calculated using EGS5 code. The peak energy of the incident photons was approximately 0.6 MeV. The estimated H_p(10) and H_p(0.07) doses for the medical staff were 0.43 and 91 μSv/h, respectively. The contribution of electrons to the calculated H_p(0.07) was approximately 200 times that of photons. Thus, the high H_p(0.07) for medical staff is attributed to the strong contribution of electrons. (author)