Comprehensive TLD dosimetry of physicians and patients during interventional angiography procedures to estimate the risk of radiation deterministic effect

Introduction: Interventional angiography procedures are increasingly used today. These techniques require a long time of standing near the patient and x-ray tube which lead to increase the radiation-dose of the staff and interventionists. This may also, in turn, lead to the occurrence of radiation deterministic effects. Since a large number of interventional radiology were performed in our center, it was necessary to monitor the radiation-dose of the interventionists and patients. This study intended to measure the patient dose and the radiation dose of the leg, hands and effective radiation-dose of the interventionist in order to determine whether they are under the dose limit or not.   Materials and Methods: To determine the radiation-dose of the interventionist’s leg an anthropomorphic phantom PBU-50 was used. Thermoluminescent-dosimeters (TLD-100) set on the leg of the phantom. The leg dose per each interventional procedures was calculated. In order to measure the dose of the hands and effective-dose the interventionists wear a ring containing three TLD chips and set two packs of TLD, one under the apron and one over the thyroid shield before the interventional procedures. The results of TLD readings were corrected for operational quantity HP (0.07) and HP (10) and using the Nilklason- algorithm, the effective-dose was calculated. To monitor the patient, dose the radiation dose, dose area product (dap) and radiation exposure time were recorded.   Results: The mean radiation-dose of leg per different procedures were 0.39mSv/Pro. The mean radiation-dose of hands per different procedures was between 19.79 to 34.90µSv/pro. The mean effective-dose provided by TLDs, and the annual dose of physicians resulted from these procedures were 30.38µSv, and 350.20µSv/y, respectively. The mean radiation-dose (mGy/min) and the mean dap (µGy.m2/min) of the patients per procedure were 57.27 and 546.89 respectively.   Conclusion: ICRP proposes that the annual dose limit of extremities should be < 500mSv to control the risk of temporary epilation and erythema. In this study, the radiation-dose of leg and hands were less than the dose limit. The annual dose to radiologists was less than the occupational dose limit. In most of the procedures, the patient dose was less than the erythema threshold dose. However, in one of the hepatic procedures (TIPS), the radiation- dose of the patient exceeds the threshold so that designing a plan to reduce the patient dose is necessary. Although the interventional procedures are so time-consuming and deliver the most radiation-dose to the staff among the angiography procedures, if the protection devices were used properly the radiation-dose can be controlled under the dose limit value. In some limit procedures such as TIPS, the radiation-dose of the patients may exceed the threshold of deterministic effect of radiation so that some strategies should be considered to reduce their dose, such as limiting the time of the radiation exposure