Carcinoma of the breast wire localisation post nuclear medicine sentinel lymph node imaging. Are radiologists receiving a significant dose?

Abstract

To assess the radiation dose received by the radiologist when performing wire localisation for axillary radio-isotope sentinel node imaging-guided biopsy in patients with impalpable breast cancers treated with breast-preserving excision. When wire placement follows radio-isotope sentinel node imaging (RSNI) the radiologist is exposed to a radiation risk that has never been previously assessed. Radiation doses to radiologists performing ultrasound-guided localisation following nuclear medicine sentinel node imaging were measured for procedures on the day of surgery (20 MBq) and also on the day before surgery (40 MBq). These measurements were compared with theoretically calculated doses. Twelve patients showed comparable results between measurements and estimated doses. The mean measured dose was 1.8 muSv (estimated 1.8 muSv) for same-day and 4.8 muSv (estimated 3.4 muSv) for next-day surgery cases. At worst, radiologists who perform 36 wire localisations per year immediately following RSNI receive a radiation dose of 0.17 mSv. This study highlights the need to inform radiologists of the relative risk when performing pre-surgical localisation after RSNI. This risk should be justified locally in accordance with the total dose received by the localising radiologist. Particular consideration should be given to pregnant staff and the possibility of performing wire localisations before radio-isotope injection.