The incident at the Fukushima Daiichi nuclear power station in 2011 has again raised concerns with
the public regarding radiation exposure, especially so in medical workers and patients undergoing treatment involving the
use of radiation. Radioisotopes are currently used during sentinel node navigation surgery (SNNS) in operating rooms
without radiation monitoring. To re-evaluate the safety issues, the potential effective dose (Epoten) from 99mTc-tin (-Sn)
colloid in breast cancer surgery was estimated and personal dose equivalents, Hp(10) and Hp(0.07), were measured during
Materials and methods:
Seventeen breast cancer patients were enrolled. One day before SNNS, 99mTc-Sn colloid was
injected around the tumor and radiation exposure rates were measured using survey meters. Personal dose equivalents for
the surgical workers were measured. Hp(10) and Hp(0.07) for the body and Hp(0.07) for the hands were recorded using
semiconductor detectors and ring-type glass dosimeters.
The maximum Epoten was 29 μSv per 74 MBq injection. The maximum Hp(10) for the primary and assisting
surgeons, nurse, and anesthetist was 3.7, 1.4, 0.3 and 0.6 μSv per SNNS, respectively. The maximum Hp(0.07) for the
hands was 100 μSv. Maximum radiocontamination 20 times higher than background (0.05 μSv/h) was detected in bloody
The workers' radiation dose exposure from SNNS was not high, although radiation management such as a
temporary cooling off period may be required.