Thermoluminescent dosimetry measurement of radiation dose to medical staff in interventional radiology

Abstract

Radiological risk to medical staff in interventional radiology is a major concern in hospital, due to the rapidly increasing use of fluoroscopy. The purpose of this study is to determine the dose of medical staff in interventional radiology at different locations on the body using thermoluinescent dosimeter (TLD) as occupational dosimetry and to relate with patient dose using the dose-area product (DAP). Since thermoluminescent dosimeter does not provide a direct indication of absorbed dose, their response to radiation in the form of an emission of light has to be calibrated against a known standard absorbed dose. All thermoluminescent dosimeters were calibrated for the sensitivity, energy response, linearity and minimum detectable dose. Dose measurement accuracy of thermoluminescent dosimeter is within 14 % over the range of measurement. The study covered a sample of 55 procedures in three interventional radiology procedures with three x-ray machines. The radiologists wore eight thermoluminescent dosimeter chips next to eyes, thyroid under thyroid shield, thyroid outside thyroid shield, left shoulder, left forearm, gonad and left leg during procedure. In addition, direct reading for patient dosimetry from dose-area product which placed in front of the collimator of the x-ray tube was recorded to estimate the patient radiation dose. The average dose to the primary radiologist shows maximum value at the left forearm which is 407 microSv. The range for all procedures and machines are 4 to 1211 microSv per procedure. The secondary radiologist who was far behind the primary radiologist received about half of the primary one. The range of dose-area product are 282 to 37937 cGy cm[square]. A clear linear relationship is shown between the dose-area product reading and the dose to the radiologist. The ratio between the radiation dose of interventional radiologist and patient dose is 12.88, 22.58, 148.29 and 100.46 microSv per 10 Gy cm[square] for TOCE (Siemens Polystar), TOCE (Siemens Neurostar), PTBD (Siemens Polystar) and ERCP (GE Advantx), respectively. The estimation of personal dose can be done from the patient dose. This will help the radiologists to avoid the excess dose during their work.