Experimental Validation of Treatment Planning for Multiple Radiotherapy Fields by EDR2 Film Dosimeter

Authors: Vahid Fayaz , Asieh Tavakol

Abstract:

To investigate the applicability of the EDR-2 film for clinical radiation dosimetry, percentage depth-doses, profiles and distributions in open and dynamically wedged fields were measured using film and compared with data from a Treatment Planning system.The validity of the EDR2 film to measure dose in a plane parallel to the beam was tested by irradiating 10 cm×10 cm and 4 cm×4 cm fields from a Siemens, primus linac with a 6MV beam and a source-to-surface distance of 100 cm. The film was placed Horizontally between solid water phantom blocks and marked with pin holes at a depth of 10 cm from the incident beam surface. The film measurement results, in absolute dose, were compared with ion chamber measurements using a Welhoffer scanning water tank system and Treatment Planning system. Our results indicate a maximum underestimate of calculated dose of 8 % with Treatment Planning system.

Keywords: 6MV Photon , EDR-2 film, Radiotherapy, TreatmentPlanning system

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1076558

References:

[1] P.Mayles, A.Nahum,J.C.Rosenwald ."Handbook of Radiotherapy Physics Theory and Practice" 2007 by Taylor & Francis Group, LLC
[2] R. Loevinger, C. J. Karzmark, and M. Weissbluth, ÔÇÿÔÇÿRadiation therapy with higher energy electrons. 1. physical considerations, 10 to 60 MeV,--Radiology 77, 906-927 ~1961
[3] Sandra E. Burch, Kimberlee J. Kearfott ,et al "A new approach to film dosimetry for high energy photon beams: Lateral scatter filtering" Med. Phys. 24 (5), May 1997
[4] J. Greening, ÔÇÿÔÇÿThe photographic action of x-rays,-- Proc. Phys. Soc. London,Sec. B 64, 977-992 ~1951!.
[5] J. F. Williamson, ÔÇÿÔÇÿFilm dosimetry of megavoltage photon beams: A practical method of isodensity-to-isodose curve conversion,-- Med. Phys. 8, 94-98 ~1981!.
[6] D. W. Anderson and F. St. George, ÔÇÿÔÇÿComparison of film and ion chamber systems for depth-dose measurements for a 25 MV beam,-- Phys. Med. Biol. 24, 636-638 ~1979!