Highlights
- •EBT2 films can measure all of the dosimetric data in the dedicated IORT machines.
- •Red channel dosimetry of EBT2 film is suitable for IORT machine QA.
- •Green channel dosimetry of EBT2 film is reliable in IORT procedures QA.
Abstract
Purpose
Intraoperative radiation therapy (IORT) using electron beam is commonly done by mobile
dedicated linacs that have a variable range of electron energies. This paper focuses
on the evaluation of the EBT2 film response in the green and red colour channels for
IORT quality assurance (QA).
Methods
The calibration of the EBT2 films was done in two ranges; 0–8 Gy for machine QA by
red channel and 8–24 Gy for patient-specific QA by green channel analysis. Irradiation
of calibration films and relative dosimetries were performed in a water phantom. To
evaluate the accuracy of the film response in relative dosimetry, gamma analysis was
used to compare the results of the Monte Carlo simulation and ionometric dosimetry.
Ten patients with early stage breast cancer were selected for in-vivo dosimetry using
the green channel of the EBT2 film.
Results
The calibration curves were obtained by linear fitting of the green channel and a
third-order polynomial function in the red channel (R2=0.99). The total dose uncertainty was up to 4.2% and 4.7% for the red and green channels,
respectively. There was a good agreement between the relative dosimetries of films
by the red channel, Monte Carlo simulations and ionometric values. The mean dose difference
of the in-vivo dosimetry by green channel of this film and the expected values was
about 1.98% ± 0.75.
Conclusion
The results of this study showed that EBT2 film can be considered as an appropriate
tool for machine and patient-specific QA in IORT.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Physica Medica: European Journal of Medical PhysicsAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Setup verification and in vivo dosimetry during intraoperative radiation therapy (IORT) for prostate cancer.Med Phys. 2007; 34: 3205
- Dosimetric evaluation of Gafchromic EBT2 film for breast intraoperative electron radiotherapy verification.Phys Medica. 2014; 31: 37-42
- A comparison between radiochromic EBT2 film model and its predecessor EBT film model.Phys Medica. 2013; 29: 412-422
- Energy dependence and dose response of Gafchromic EBT2 film over a wide range of photon, electron, and proton beam energies.Med Phys. 2010; 37: 1942-1947
- Precise radiochromic film dosimetry using a flat-bed document scanner.Med Phys. 2005; 32: 2245-2253
- Gafchromic EBT2 self-developing film for radiotherapy dosimetry.(Accessible from:)http://gafchromic.comDate: 2010
- Radiochromic film dosimetry: recommendations of AAPM radiation therapy committee task group 55.Med Phys. 1998; 25: 2093-2115
- Scanning orientation effects on Gafchromic EBT film dosimetry.Australas Phys Eng Sci Med. 2006; 29: 281-284
- 398, Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose to water.International Atomic Energy Agency, Vienna2000
- BEAMnrc users Manual National Research Council of Canada.2002 (NRCC Rep PIRS-0509 (A) revK)
- Monte Carlo simulation of electron beams generated by a 12 MeV dedicated mobile IORT accelerator.Phys Med Biol. 2011; 56: 4579
- Evaluation of the gamma dose distribution comparison method.Med Phys. 2003; 30: 2455-2464
- Linearization of dose–response curve of the radiochromic film dosimetry system.Med Phys. 2012; 39: 4850-4857
- Dosimetric characteristics of electron beams produced by two mobile accelerators, Novac7 and Liac, for intraoperative radiation therapy through Monte Carlo simulation.J Appl Clin Med Phys. 2013; : 14
- Accelerator beam data commissioning equipment and procedures: report of the TG-106 of the Therapy Physics Committee of the AAPM.Med Phys. 2008; 35: 4186-4215
- Intraoperative electron beam radiation therapy: technique, dosimetry, and dose specification: report of Task Force 48 of the Radiation Therapy Committee, American Association of Physicists in Medicine.Int J Radiat Oncol Biol Phys. 1995; 33: 725-746
- In vivo dosimetry using radiochromic films during intraoperative electron beam radiation therapy in early-stage breast cancer.Radiother Oncol. 2003; 69: 285-289
Article info
Publication history
Published online: February 20, 2015
Accepted:
January 31,
2015
Received in revised form:
January 29,
2015
Received:
October 18,
2014
Identification
Copyright
© 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Inc. All rights reserved.
