Energy dependence of a scintillating fiber detector for preclinical dosimetry with an image guided micro-irradiator.

Energy dependence of a scintillating fiber detector for preclinical dosimetry with an image guided micro-irradiator.
Phys Med Biol. 2019 Apr 11;:
Authors: Le Deroff C, Frelin AM, Ledoux X
Abstract
The dosimetry of preclinical micro-irradiators is challenging due to their millimetric beams and medium X-ray energy range. Plastic scintillator dosimeters (PSD) are good candidates for such a purpose as they provide a high spatial resolution although they show an energy dependence below 100 keV. The purpose of this study was to assess the energy dependence of a dedicated PSD (called DosiRat) for micro- irradiators dosimetry.
 The response of the PSD relative to air kerma was measured for different beam qualities (40 to 225 kV) with the X-RAD 225Cx irradiator. The corresponding energy spectra, determined by Monte Carlo simulations, allowed for correcting the differences in absorbed dose between the DosiRat material (polystyrene) and the air and therefore allowed to compare DosiRat intrinsic energy response to the Birks scintillation quenching model. The energy response of DosiRat was then assessed under preclinical conditions through percentage depth dose curves (PDD) and relative output factor (ROF) measurements in water for beam diameters ranging from 1 to 25 mm.
 DosiRat energy response showed a coefficient of variation of 23 % from 40 to 225 kV, mainly explained by the mass energy-absorption coefficient variation between...

Source: Physics in Medicine and Biology - April 10, 2019 Category: Physics Authors: Le Deroff C, Frelin AM, Ledoux X Tags: Phys Med Biol Source Type: research