The Use of Plane Parallel Ionization Chambers in High Energy Electron and Photon Beams: An International Code of Practice for DosimetryThis report both complements and extends Technical Reports Series No. 277/2, Absorbed Dose Determination in Photon and Electron Beams - An International Code of Practice, IAEA Technical Reports Series No. 277/2. It describes options and how to calibrate plane parallel ionization chambers, against air kerma or absorbed dose to water standards at cobalt-60 gamma ray energies. The use of these chambers to calibrate therapy electron beams, as well as relative dose measurements for photon and electron beams, is presented. This publication also updates some of the data and concepts used in Technical Reports Series No. 277/2. It fills gaps in the latter report with respect to plane parallel chambers with a view to improve accuracy in radiotherapy when these chambers are used. |
Contents
INTRODUCTION | 1 |
USE OF PLANE PARALLEL CHAMBERS | 7 |
NK BASED FORMALISM AND DETERMINATION OF NDair | 25 |
8 other sections not shown
Common terms and phrases
60Co beam 60Co gamma rays AAPM absorbed dose determination air cavity air chamber factor air kerma aluminium ANDREO approximately backscatter beam quality Biol bremsstrahlung calibration factor chambers in electron cm³ Code of Practice correction factors cylindrical chambers Delrin depth in water depth-dose distributions detector dose to air dose to water dosimetry protocols effective point electrometer electron beams electron energy electron fluence experimental graphite high energy photon IAEA ICRU irradiation katt km Klevenhagen mean energy method mg/cm² Monte Carlo calculations Mref NACP chamber Nair ND.air Nref obtained parallel ionization chambers Pcav Peff perturbation effects phantom material phantom surface photon and electron Phys plane parallel chamber plane parallel ionization plastic phantoms PMMA point of measurement polarity effect polarizing voltage polystyrene procedure Pwall radiation radiotherapy recommended reference chamber reference depth reference quality Roos Section SSDL stopping power ratios Sw.air tion user's beam values Zref