The Response of 2D TL Foils After Doses of Co-60 Gamma-ray, 6 MV X-ray and 60 MeV Proton Beams Applied in Radiotherapy

A Two-dimensional Thermoluminescence Dosimetry (2D TLD) system has been developed at the Institute of Nuclear Physics (IFJ PAN) in Krakow, Poland. The system consists of TLD foils and of a TL reader equipped with a 200 200 mm 2 heater and a CCD camera. The foils contain LiF:Mg,Cu,P powder mixed with ETFE polymer pressed at high temperature. The CCD camera is able to read out 2D images of TL light in real time, and the re-usable foils are flexible, mechanically stable and waterresistant. We have determined the response of our 2D TL foils after doses of Co-60 gamma-ray, 6MV X-ray and 60MeV proton radiotherapy beams, over the range between 1 and 30Gy, as required in clinical dosimetry. In measurements, performed at the German Cancer Research Center (DKFZ), at the Heidelberg Ion-Beam Therapy Center (HIT) and at the IFJ PAN, we compared the dose response of our foils with those of Kodak R EDR2 and Gafchromic R EBT films. We find both the sensitivity (signal per dose) and the characteristic (saturation) dose of our 2D TL foils to be higher than those of the EDR2 and EBT films, for all beam modalities tested.