Field correction factors for a PTW-31016 Pinpoint ionization chamber for both flattened and unflattened beams. Study of the main sources of uncertainties

摘要

Purpose: The primary aim of this study was to determine correction factors, (kfclin;fmsr) (Qclin;Qmsr) for a PTW-31016 ionization chamber on field sizes from 0.5 cm x 0.5 cm to 2 cm 9 2 cm for both flattened (FF) and flattened filter-free (FFF) beams produced in a TrueBeam clinical accelerator. The secondary objective was the determination of field output factors, (Omega fclin;fmsr) (Qclin;Qmsr) over this range of field sizes using both Monte Carlo (MC) simulation and measurements.