Patient doses in γ-intracoronary radiotherapy: The Radiation Burden Assessment Study

Abstract

<h3>Purpose</h3> To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with ¹⁹²Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. <h3>Methods and materials</h3> The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing γ-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. <h3>Results</h3> With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2–28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 μSv/treatment. The doses to the other staff members were completely negligible. <h3>Conclusion</h3> Our results have shown that the patient and personnel doses in γ-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.