Calculation and comparison of MD-55-2 and HS radiochromic films’ responses to the 60Co gamma rays

Abstract

Background: Radiochromic films are one of the useful radiation dosimeters. MD-55-2 and HS radiochromic films have been previously used in medical dosimetry applications. The aim of this study is calculation and comparison of responses of MD-55-2 and HS radiochromic films to gamma rays of 60Co radioisotope. Methods: The sensitivity of MD-55-2 radiochromic film to 60Co gamma rays has been calculated and compared with that of HS film. The films were defined as multiple layers and different tallies of MCNPX Monte Carlo code were scored in water and Perspex phantoms. Results: Following simulation of the radiochromic films irradiated by a 60Co source, it was evident that the sensitivity of a three-layer and a two-layer MD-55-2 film to that of a single-layer film is 2.95-fold and 1.94-fold higher, respectively. Furthermore, the sensitivity of a HS film is 1.0, 1.5 and 2.92 times higher compared to a MD-55-2 film, respectively with 3, 2 and 1layers. Comparing the outputs of F6, *F8 and mesh tallies indicate that the F6 and mesh tallies have the same results but the differences between the results obtained by F6 and *F8 tallies are about 5.8% for the MD-55-2 film and 10.5% for the HS film. Conclusion: Our results show that the sensitivity of MD-55-2 film increases with a relatively linear trend with the number of film layers. Besides, the sensitivity of the HS film is about 2 times higher than that of the MD-55-2 film. Our results are in agreement with the previously published experimental results.

Keywords

• Film dosimetry
• Radiation dosage
• Radiometry
• Cobalt radioisotopes
• Gamma rays
• Monte Carlo method
• Sensitivity and specificity