Patient dosimetry in intravascular radiation therapy

Percutaneous transluminal coronary angioplasty is a well-accepted method for nonsurgical myocardial revascularization. However, the long-term success of this method is limited by the occurrence of restenosis. Endovascular brachytherapy has been put forward as a means to avoid restenosis. Since this technique involves the placement of a radioactive source in a catheter in the patient's arteries, the possible radiation risk should be considered. In this paper the effective dose of the patient associated with the use of Iridium-192 for IRT treatment has been calculated using Monte Carlo techniques. To put the results into perspective the effective dose form the PTCA procedure was also calculated using the same techniques. Calculations were based on the measurement of DAP (Dose Area Product) for the procedure. We found a mean effective dose of 9 mSv for both the PTCA procedures as for the IRT treatment. Thus leading to the conclusion that, from the perspective of radiation burden, the elimination of one PTCA procedure through the use of IRT is a benefit for the patient. (author)