Measurement of centi-Gray X-ray dose levels with radiochromic film

X-ray doses in the range of centi-Gray can be detected and accurately measured on a relative scale for low energy X-rays using a high sensitivity radiochromic film stack. Gafchromic XR type T radiochromic film has been investigated to analyze its ability to measure relative doses below 50 cGy for 100-kVp X-rays using a layered technique. Investigations showed that a 4-layer film stack could produce reproducible results at 50-cGy relative applied dose to within 3% and to within 12% for 5-cGy applied dose. The combination of single sheet higher film sensitivity to low energy X-rays along with a layered film dosimetry technique provides the ability to adequately measure low relative absorbed doses less than 50 cGy if required.