Spatially resolved measurement of high doses in microbeam radiation therapy using samarium doped fluorophosphate glasses

The measurement of spatially resolved high doses in microbeam radiation therapy has always been a challenging task, where a combination of high dose response and high spatial resolution (microns) is required for synchrotron radiation peaked around 50 keV. The x-ray induced Sm(3+) -> Sm(2+) valence conversion in Sm(3+) doped fluorophosphates glasses has been tested for use in x-ray dosimetry for microbeam radiation therapy. The conversion efficiency depends almost linearly on the dose of irradiation up to similar to 5 Gy and saturates at doses exceeding 80 Gy. The conversion shows strong correlation with x-ray induced absorbance of the glass which is related to the formation of phosphorus-oxygen hole centers. When irradiated through a microslit collimator, a good spatial resolution and high "peak-to-valley" contrast have been observed by means of confocal photoluminescence microscopy. (C) 2011 American Institute of Physics. [doi:10.1063/1.3633102]