A Study on Radiation Dose Received by Patients during Extracorporeal Shock Wave Lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is considered as the method of choice for treatment of most stone diseases. The present study aims to evaluate radiation dose received by patients undergoing ESWL. In total, 46 patients from both genders were referred to the Shohadaye Ashayer hospital of Khorramabad, Iran and were included in the present study. Patients were positioned in anteroposterior (AP) projection and along 30° anterior oblique (AO) projection upon the X-ray fluoroscopy table and exposures were conducted. Thermoluminescent dosimeters (TLDs) were used for radiation dose measurements. To evaluate the entrance surface dose (ESD), each TLD chip was taped on back of patient at the entrance surfaces of the X-ray beam. The mean number of stones in each patient was 1.4. The stone sizes ranged from 7 to 29 mm, and a mean of 3200 pulses were need for each patient. The mean ESD in the postero-anterior (PA) and oblique X-ray beam entrance were obtained at 12.04 and 68.84 mGy, respectively. There was linear correlation between patient dose with fluoroscopy time, tube current (mA), tube potential (kVp) and patient position (P < 0.001); however, we found no strong correlation between patient dose with patient body mass (P = 0.837), number of shock wave pulses (P = 0.089), stone size (P = 0.773) and locations (P = 0.463). The data obtained in the current study are comparable with information available in the literature. They emphasized that ESWL exposes patients to much more radiation compared to those from conventional radiography and is in the range of computed tomography (CT) procedures. Therefore, following safety guidelines is recommended.