Open AccessChoice of a suitable dosimeter for photon percentage depth dose measurements in flattening filter-free beams
Author(s) -
Silvia Castrillón,
Francisco Cutanda Henríquez
Publication year - 2017
Publication title -
journal of medical physics/journal of medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.292
H-Index - 24
eISSN - 1998-3913
pISSN - 0971-6203
DOI - 10.4103/jmp.jmp_11_17
Subject(s) - truebeam , dosimeter , linear particle accelerator , dosimetry , optics , photon , ionization chamber , physics , detector , percentage depth dose curve , materials science , nuclear medicine , radiation , beam (structure) , ion , ionization , medicine , quantum mechanics
The International Atomic Energy Agency Technical Reports Series-398 code of practice for dosimetry recommends measuring photon percentage depth dose (PDD) curves with parallel-plate chambers. This code of practice was published before flattening filter-free (FFF) beams were widely used in clinical linear accelerators. The choice of detector for PDD measurements needs to be reassessed for FFF beams given the physical differences between FFF beams and flattened ones. The present study compares PDD curves for FFF beams of nominal energies 6 MV, 6 FFF, 10 MV, and 10 FFF from a Varian TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, USA) acquired with Scanditronix photon diodes, two scanning type chambers (both PTW 31010 Semiflex), two small volume chambers (Wellhofer CC04 and PTW 31016 PinPoint 3D), PTW 34001 Roos, Scanditronix Roos, and NACP 02 parallel-plate chambers. Results show that parallel-plate ion chambers can be used for photon PDD measurements, although for better accuracy, recombination effects should be taken into account.