Radioisotope for occult lesion localisation (ROLL) of the breast does not require extra radiation protection procedures

Aim of study: Dosimetry data from patients and hospital personnel involved in the use of radioisotope for occult lesion localisation (ROLL) of the breast were collected to determine the need for extra radiation protection procedures. Methods: Sixty-three patients have been enrolled to date into a randomised trial evaluating ROLL. Two megabecquerels of 99mTc- MAA in a syringe was mixed with X-ray contrast medium; this was injected directly into the lesion under image guidance. A gamma-detecting probe (Neo-Probe) was used to locate the area of radioactivity. Radiation doses to all staff groups were estimated using time and motion studies and dose rate measurements at a range of distances during each stage of ROLL. Results: The finger dose [FD](±95% CI) was considered to be the critical variable for surgeons and radiologists. Surgeon FD = 9.3±3.3 μSv, Radiologist FD = 0.5±0.13 μSv. Whole body doses [WBD](±95% CI) were estimated for other staff groups. Nurse WBD = 0.4±0.4 μSv, porter WBD: nil, contamination and waste: nil. Conclusions: In the case of a surgeon performing 100 procedures per annum, a FD dose of approximately 1 mSv is received, well within the annual dose limit of 150 mSv. Annual WBD to assisting staff may reach 0.04 mSv, compared to an annual limit of 6 mSv. These low doses and the lack of contamination of radioactive waste indicate that no additional radiation protection measures are required.