Comparison of computed tomography dose index measuring by two detector types of computed tomography simulator

Abstract

Introduction: In general, the computed tomography screen displays the volume CT dose index (CTDIvol) received from a computed tomography by following the technique used. Verifying the display values is important before using them. This can be done by measuring the amount of radiation that is presented on the screen. However, there are 2 types of radiation detectors i.e., gas-filled and solid media types. These 2 detectors provide different methods of measurement and calculation. Objective: The purpose of this study was to compare the difference in CTDIvol values obtained from both detectors. Materials and methods: The CTDIvol was measured by using the ionization chamber and semiconductor detector in a phantom computed tomography 16 slices for Optima 580 simulation of GE Health Care Thailand. The CT setting parameters were based on the brain scan technique and the abdominal cavity using in the treatment planning simulation. The values obtained from the displayed on the screen of CT and measured from the detectors were compared and calculated as the percentage difference in CTDIvol. Results: Solid-state detector measured CTDIvol radiation less than conventional gas-filled detector. The different percentages were 10.20 and 5.02 for brain and abdominal cavity examination respectively. Conclusion: Radiation doses from computed tomography simulator measured by solid-state detector are less than those measured by standard gaseous radiation detector.