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Title: Evaluation of the Gafchromic{sup Registered-Sign} EBT2 film for the dosimetry of radiosurgical beams

Abstract

Purpose: Radiosurgery uses small fields and high-radiation doses to treat intra- and extracranial lesions in a single session. The lack of a lateral electronic equilibrium and the presence of high-dose gradients in these fields are challenges for adequate measurements. The availability of radiation detectors with the high spatial resolution required is restricted to only a few. Stereotactic diodes and EBT radiochromic films have been demonstrated to be good detectors for small-beam dosimetry. Because the stereotactic diode is the standard measurement for the dosimetry of radiosurgical beams, the goal of this work was to perform measurements with the radiochromic film Gafchromic{sup Registered-Sign} EBT2 and compare its results with a stereotactic diode. Methods: Total scatter factors, tissue maximum, and off-axis ratios from a 6 MV small photon beams were measured using EBT2 radiochromic film in a water phantom. The film-measured data were evaluated by comparing it with the data measured with a stereotactic field diode (IBA-Dosimetry). Results: The film and diode measurements had excellent agreement. The differences between the detectors were less than or equal to 2.0% for the tissue maximum and the off-axis ratios. However, for the total scatter factors, there were significant differences, up to 4.9% (relative to the referencemore » field), for field sizes less than 1.0 cm. Conclusions: This work found that the Gafchromic{sup Registered-Sign} EBT2 film is adequate for small photon beam measurements, particularly for tissue maximum and off-axis ratios. However, careful attention must be taken when measuring output factors of small beams below 1.0 cm due to the film's energy dependence. The measurement differences may be attributable to the film's active layer composition because EBT2 incorporates higher Z elements (i.e., bromide and potassium), hence revealing a potential energy dependence for the dosimetry of small photon beams.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Laboratorio de Fisica Medica, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, Mexico D.F. 14269 (Mexico) and Unidad de Radioneurocirugia, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, C.P. 14269, Mexico D.F. 14269 (Mexico)
  2. Laboratorio de Fisica Medica, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, Mexico D.F. 14269 (Mexico)
  3. Laboratorio de Fisica Medica, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, Mexico D.F. 14269 (Mexico) and Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Legaria 694, Mexico D.F. 11500 (Mexico)
  4. Laboratorio de Fisica Medica, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, Mexico D.F. 14269 (Mexico) and Unidad de Radioneurocirugia, Instituto Nacional de Neurologia y Neurocirugia, Insurgentes Sur 3877, Mexico D.F. 14269 (Mexico)
  5. Facultad de Medicina, Universidad Autonoma del Estado de Mexico, Paseo Tollocan, Toluca, Estado De Mexico 50180 (Mexico)
Publication Date:
OSTI Identifier:
22099038
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 39; Journal Issue: 10; Other Information: (c) 2012 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; 60 APPLIED LIFE SCIENCES; BRAIN; BROMIDES; COMPARATIVE EVALUATIONS; ENERGY DEPENDENCE; FILM DOSIMETRY; LAYERS; PHANTOMS; PHOTON BEAMS; RADIATION DETECTORS; RADIATION DOSES; RADIOTHERAPY; SPATIAL RESOLUTION; SURGERY

Citation Formats

Larraga-Gutierrez, Jose M., Garcia-Hernandez, Diana, Garcia-Garduno, Olivia A., Galvan de la Cruz, Olga O., Ballesteros-Zebadua, Paola, and Esparza-Moreno, Karina P. Evaluation of the Gafchromic{sup Registered-Sign} EBT2 film for the dosimetry of radiosurgical beams. United States: N. p., 2012. Web. doi:10.1118/1.4752211.
Larraga-Gutierrez, Jose M., Garcia-Hernandez, Diana, Garcia-Garduno, Olivia A., Galvan de la Cruz, Olga O., Ballesteros-Zebadua, Paola, & Esparza-Moreno, Karina P. Evaluation of the Gafchromic{sup Registered-Sign} EBT2 film for the dosimetry of radiosurgical beams. United States. https://doi.org/10.1118/1.4752211
Larraga-Gutierrez, Jose M., Garcia-Hernandez, Diana, Garcia-Garduno, Olivia A., Galvan de la Cruz, Olga O., Ballesteros-Zebadua, Paola, and Esparza-Moreno, Karina P. 2012. "Evaluation of the Gafchromic{sup Registered-Sign} EBT2 film for the dosimetry of radiosurgical beams". United States. https://doi.org/10.1118/1.4752211.
@article{osti_22099038,
title = {Evaluation of the Gafchromic{sup Registered-Sign} EBT2 film for the dosimetry of radiosurgical beams},
author = {Larraga-Gutierrez, Jose M. and Garcia-Hernandez, Diana and Garcia-Garduno, Olivia A. and Galvan de la Cruz, Olga O. and Ballesteros-Zebadua, Paola and Esparza-Moreno, Karina P.},
abstractNote = {Purpose: Radiosurgery uses small fields and high-radiation doses to treat intra- and extracranial lesions in a single session. The lack of a lateral electronic equilibrium and the presence of high-dose gradients in these fields are challenges for adequate measurements. The availability of radiation detectors with the high spatial resolution required is restricted to only a few. Stereotactic diodes and EBT radiochromic films have been demonstrated to be good detectors for small-beam dosimetry. Because the stereotactic diode is the standard measurement for the dosimetry of radiosurgical beams, the goal of this work was to perform measurements with the radiochromic film Gafchromic{sup Registered-Sign} EBT2 and compare its results with a stereotactic diode. Methods: Total scatter factors, tissue maximum, and off-axis ratios from a 6 MV small photon beams were measured using EBT2 radiochromic film in a water phantom. The film-measured data were evaluated by comparing it with the data measured with a stereotactic field diode (IBA-Dosimetry). Results: The film and diode measurements had excellent agreement. The differences between the detectors were less than or equal to 2.0% for the tissue maximum and the off-axis ratios. However, for the total scatter factors, there were significant differences, up to 4.9% (relative to the reference field), for field sizes less than 1.0 cm. Conclusions: This work found that the Gafchromic{sup Registered-Sign} EBT2 film is adequate for small photon beam measurements, particularly for tissue maximum and off-axis ratios. However, careful attention must be taken when measuring output factors of small beams below 1.0 cm due to the film's energy dependence. The measurement differences may be attributable to the film's active layer composition because EBT2 incorporates higher Z elements (i.e., bromide and potassium), hence revealing a potential energy dependence for the dosimetry of small photon beams.},
doi = {10.1118/1.4752211},
url = {https://www.osti.gov/biblio/22099038}, journal = {Medical Physics},
issn = {0094-2405},
number = 10,
volume = 39,
place = {United States},
year = {Mon Oct 15 00:00:00 EDT 2012},
month = {Mon Oct 15 00:00:00 EDT 2012}
}