Novel thermoluminescence foils for 2-D clinical dosimetry, based on CaSO4:Dy

The newly developed two-dimensional thermoluminescence (TL) foils made from CaSO4:Dy TL powder and the high temperature polymer PFA, were tested for their dosimetric properties. The results were evaluated using laboratory TL reader with PCO CCD camera and round planchet heater, 72 mm in diameter. 55 x 55 x 0.3 mm(3) foils were tested for dose response, reproducibility and spatial resolution. It was found that the detectors are linear up to at least 2 Gy and their spatial resolution is about 1 mm. A loss of sensitivity with repeated re-uses was observed (9% in 10 uses). It is attributable to the darkening of the detector due to oxidizing of impurities gathering at its surface and may be avoided by application of proper cleaning procedure. The foils were tested for measurements of 2-D dose distribution on 60 MeV proton beam at IFJ Krakow. The results show that 2-D TL foils based on CaSO4:Dy can be a useful tool for quality assurance of proton beams. (C) 2009 Elsevier Ltd. All rights reserved.