Response of the FBX system to a carbon beam: its potential as a dosimeter in heavy particle radiotherapy

Abstract

The FBX aqueous chemical dosimeter contains 0.2 mol m−3 ferrous ammonium sulphate, 5.0 mol m−3 benzoic acid and 0.20 mol m−3 xylenol orange in 40.0 mol m−3 sulphuric acid. The dosimeter can measure photon and electron doses in the range 0.1 to 3000 cGy in radiotherapy. The response of this dosimeter was measured for a 53.2 MeV carbon beam in the present work. Our initial result indicates that the sensitivity of the FBX system to the carbon beam as compared to cobalt-60 gamma rays is 25.5%, and thus we believe that the FBX system could be a useful dosimeter for carbon beams and similar heavy ions considered useful in radiotherapy.