Experimental validation of absorbed dose-to-medium calculation algorithms in heterogeneous media.

The aim of this work was to determine heterogeneous correction factorshQclin,Qreffclin,frefdetm,wto validate absorbed dose-to-mediumDm,Qclinm,fclincalculation algorithms from detector readings. The impact of detector orientation perpendicular and parallel to the beam central axis on the correction factors was also investigated.ThehQclin,Qreffclin,frefdetm,wfactors were calculated for four types of detectors (PTW PinPoint T31016, PTW microDiamond T60019, PTW microSilicon T60023 and EBT3 film) placed in different media (cortical bone, lung, adipose tissue, Teflon and RW3) for the 6 MV energy beam with a 10 × 10 cmfield size.

Field output correction factors and electron fluence perturbation of the microSilicon and microSilicon X detectors.

The aim of this study was to determine field output correction factorskQclin,Qreffclin,frefand electron fluence perturbation for new PTW unshielded microSilicon and shielded microSilicon X detectors.kQclin,Qreffclin,freffactors were calculated for 6 and 10 MV with and without flattening filter beams delivered by a TrueBeam STx. Correction factors were determined for field sizes ranging from 0.

Technical note: GAMMORA, a free, open-source, and validated GATE-based model for Monte-Carlo simulations of the Varian TrueBeam.

Purpose: Monte Carlo (MC) is the reference computation method for medical physics. In radiotherapy, MC computations are necessary for some issues (such as assessing figures of merit, double checks, and dose conversions). A tool based on GATE is proposed to easily create full MC simulations of the Varian TrueBeam STx.

Towards the standardization of the absorbed dose report mode in high energy photon beams.

The benefits of using an algorithm that reports absorbed dose-to-medium have been jeopardized by the clinical experience and the experimental protocols that have mainly relied on absorbed dose-to-water. The aim of the present work was to investigate the physical aspects that govern the dosimetry in heterogeneous media using Monte Carlo method and to introduce a formalism for the experimental validation of absorbed dose-to-medium reporting algorithms. Particle fluence spectra computed within the sensitive volume of two simulated detectors (T31016 Pinpoint 3D ionization chamber and EBT3 radiochromic film) placed in different media (water, RW3, lung and bone) were compared to those in the undisturbed media for 6 MV photon beams.

On the conversion from dose-to-medium to dose-to-water in heterogeneous phantoms with Acuros XB and Monte Carlo calculations.

The method implemented in Monte Carlo (MC) algorithm to convert dose-to-medium (D ) to dose-to-water (D ) is usually based on the Bragg-Gray cavity theory. Acuros XB (AXB) reports also D and D but the method to calculate D is based on the energy deposition cross sections for water in place of those for the local media. For both algorithms, the calculation of D in non-water media is similar to the dose received in a small volume of water, small enough not to disturb the fluence of charged particles.