CT dose estimation using Gafchromic XR-CT film: Models comparison

Abstract Previous studies have established four dose response models for Gafchromic films. However, there have been no reports comparing the four dose response models for XR-CT film; and the XR-CT film responses in phantoms at different positions remain unclear. The purpose of this study was to compare the dose response models and to determine the most suitable one for XR-CT film. The correction factors for the energy dependencies of films inside the head and body dosimetry phantoms were assessed. The most appropriate dose response model for Gafchromic XR-CT film was D film  =  a (netPV− k ) 2  +  b (netPV− k ). The XR-CT films could be used to measure CTDI values in phantoms with appropriate correction factors. Moreover, the doses estimated from XR-CT films used in the Taiwan CT survey agreed with the data measured using the ionization chamber. The Gafchromic XR-CT film could be used to measure CTDI values with the appropriate dose response model and correction factors.