Estimation of doses to personnel and patients during endovascular brachytherapy applications.

In the last few years coronary endovascular brachytherapy using gamma- and beta-emitting radionuclides has been established as a standard treatment procedure to prevent restenosis after percutaneous coronary interventions. Direct measurements and calculations were made to determine personnel doses and organ doses of patients due to gamma rays of 192Ir and beta rays of 90Sr/90Y and 32P sources. In general, our results show that the dose levels are low compared with the X-ray exposure from angiography. The dose rate from bremsstrahlung at 1 m distance from a device containing a 90Sr/90Y source of 2.3 GBq is 4 micro Sv h(-1). The skin dose from beta rays during source transfer into and from the patient was estimated with the directional dose equivalent H'(0.07) of 10 micro Sv at 1 m distance from the catheter. By maintaining safe distances, the dose levels can be kept well within annual dose limits.