XR type-R radiochromic film x-ray energy response.

Gafchromic XR type-R radiochromic film is a relatively new product designed for use at clinical diagnostic x-ray energies both qualitatively and quantitatively. This short note investigates the energy response characteristics of this high-sensitivity radiochromic film for both diagnostic and therapeutic x-ray energies. Results are also compared to conventional silver halide x-ray film for energy response. Results show that the energy response of the new XR type-R film is minimal over the 75-125 kVp range (9% variation with +/-3% error in measurement to 1 SD). This is compared to a 27% variation for X-Omat V radiographic film for the same energy range. XR type-R film does, however, produce a larger energy response variation when compared over a larger therapeutic x-ray range (50 kVp superficial to 10 MV megavoltage) with a relative response of 10.4 at 125 kVp compared to 1 at 6 MV. This is significantly different to MD-55-2 and HS Gafchromic film which has a lower energy response at lower energies. XR type-R film is ideal for a quantitative dosimeter in the low energy range due to its relative energy independence and high sensitivity compared to conventional radiochromic film.