Radiation exposure during sentinel lymph node biopsy for breast cancer: effect on pregnant female physicians.

Background: The radionuclide (RN) method employed for sentinel lymph node biopsy is generally safe for adult medical care workers. However, the number of pregnant medical care workers who attend surgery has recently been increasing, along with the increasing number of female surgeons. In particular, female surgeons are concerned about the position of a surgeon's lower abdominal region being close to the RN injection site. We measured the exposure dose of the lower abdominal region in medical care workers and investigated the possible exposure effect on fetuses.

Methods: A dose of (99m)Tc-phytic acid (37 MBq) was subcutaneously injected into the areola of the nipple of patients. Scintigraphy and surgery were performed after 1 and 4 h, respectively. At the time of the local injection, a personal dosimeter measured the exposure dose in the surgeon, first and second assistants, anesthesiologist, and scrub nurse.

Results: The median exposure doses were 3, 1, 1, 0, and 0 μSv in the surgeon, first and second assistants, anesthesiologist, and scrub nurse, respectively. Protective clothing reduced the mean exposure dose by 66 %.

Conclusions: In surgeons, the exposure dose from daily life activities (1 mSv/year) corresponds to the dose received after performing 333 surgeries (using 3 μSv as the median). However, the maximum value measured was 24 μSv; at this value, the total exposure dose exceeds 1 mSV in the 42nd surgery. Medical care workers can further reduce their exposure dose by paying attention to the surgical procedure and to their posture and position.