Substantiation of a new approach to the criteria for assessing the radiation dose of patients during computed tomography

Abstract

BACKGROUND: In accordance with the requirements of the IAEA basic safety standards and the International Commission on Radiation Protection, comparing the radiation dose for patients undergoing computed tomography (CT) in diagnostic and treatment clinics with national or international DRLs is important for controlling medical radiation doses. The search for ways to improve DRLs calculations determines the relevance of such studies.
 AIM: To analyze the dependence of effective doses (EDs) in CT of different body parts on patients weight and to calculate the standard ED for the patient (70 and 80 kg).
 MATERIALS AND METHODS: CT acquisition protocols in 209 patients were single phase (SP) CT, while 114 patients underwent multi-phase (MP) CT. ED was calculated according to the normalized coefficients for each body area. The values of standard ED was calculated by data approximation using linear function of ED relatively body weight for each type CT scanner and body area scanned.
 RESULTS: The increase in ED following a CT examination was proportional to the body weight of patients. For SP and MP CT scans, the standard EDs were calculated according to all body areas. The mean ED, median ED, and DRLs (mSv) in these groups was slightly higher than standard ED (mSv) if the criterion was 70 kg and were close to standard ED if the criterion was 80 kg. These values give a basis for improving the guidelines concerning the recommended limits of radiation doses for CT in individual patients according to indications and body parts studied.
 CONCLUSIONS: In the study, a methodology for assessing and comparing the dose of CT-radiation at two hospitals in the two CT scanners, considering weight of a standard patient, is described. Our results show that the calculation and analysis of the standard ED of CT-examining areas of the body instead of mean ED and median ED help to compare the radiation exposure in different medical facilities more properly. Given the recent sharp increase in the number of CT studies, not exceeding the standard ED for patients with CT will reduce the long-term consequences in the form of oncological pathology among the population.