Establishment of typical values for computed tomography simulation at Sawanpracharak Hospital

Abstract

Background: Diagnostic reference levels (DRLs) serve as essential tools for monitoring and optimizing radiation exposure in computed tomography (CT). At the institutional level, typical values defined as the median of the dose distribution can be used as benchmarks for establishing and reviewing DRLs. Objective: To establish institutional typical values for a CT simulator at Sawanpracharak Hospital. Methods: A total of 292 patients who underwent CT simulation using a Siemens SOMATOM Confidence RT Pro between January and December 2024 were included. Patient characteristics, scan parameters, and dose indices—volume CT dose index (CTDI_vol) and dose length product (DLP)—were collected across five anatomical regions: brain, head–neck, chest, abdomen, and pelvis. Typical values were defined as the median of the dose distributions, and correlations between DLP and patient factors as well as scan parameters were analyzed. Results: Dose levels varied by region, with the highest typical values of CTDI_vol and DLP observed in the brain (68.83 mGy, 2173.05 mGy·cm) and the lowest in the head–neck region (7.24 mGy, 325.00 mGy·cm), while the chest, abdomen, and pelvis showed comparable levels. Strong positive correlations were found between DLP and both mAs and scan length across all regions (p<0.001). Age showed no significant correlation, whereas BMI correlated only in the chest, abdomen, and pelvis. Pitch demonstrated significant associations in all regions except the brain. Conclusion: The derived typical values can serve as baseline data for the future development of DRLs for CT simulation, thereby enhancing radiation safety in radiotherapy treatment planning.