Entrance dose determination and effective dose calculation in chest and skull radiographies: an experimental and computational study

This study aimed to determine entrance surface dose (ESD), calculate effective dose (ED), organ dose, and local dose  levels in three general hospitals of Khorramabad in common diagnostic radiographic examinations, including Chest and Skull.

Exposure parameters and data of 110 patients were collected during 6 months. In this study, three radiological devices including Shimadzu R-20, Mehran Teb DMT II and Varian Rad-8, were evaluated. Four radiographic views, including Chest posterior-anterior and lateral projections (PA/LAT), and Skull PA/LAT were also assessed. The index used for comparison and measurement of radiation dose was ESD measured using thermo luminescent dosimeter (TLD). In this study, a pc program for X-ray Monte Carlo (PCXMC) software was used to calculate the organs’ dose and effective dose.

The results obtained show that there is a significant relationship between mAs and kVp changes with ED and ESD values. ESD range in Chest PA, Chest LAT, Skull PA, and Skull LAT examinations were 0.1075-0.8844, 0.2059-2.2997, 0.0729-1.44, and 0.03478-1.15 mGy, respectively. In this study, the mean ESD estimated was lower than the diagnostic reference levels (DRLs) recommended by the National Radiological Protection Board (NRPB), the Commission of Europian Communities (CEC), and International Atomic Energy Agency (IAEA), but the ED calculated was relatively higher than other studies.

A combination of experimental and simulation methods usually makes the accuracy of the dose estimates more reliable. The mean ESD estimated in this study is lower than the DRL published by NRPB, CEC, and IAEA. Also the published ED is almost more than other studies. The results of this study are used to optimize the dose level of patients.