Comparison of Gafchromic EBT2 and EBT3 films for clinical photon and proton beams

Journal Article · Wed Aug 15 04:00:00 EDT 2012 · Medical Physics

DOI:https://doi.org/10.1118/1.4737890· OSTI ID:22098963

Reinhardt, S.; Hillbrand, M.; Wilkens, J. J.; Assmann, W. ^[1]

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1. Fakultaet fuer Physik, Ludwig-Maximilians Universitaet Muenchen, 85748 Garching (Germany)

Purpose: Dose verification in highly conformal radiation therapy such as IMRT or proton therapy can benefit from the high spatial resolution offered by radio-chromic films such as Gafchromic EBT or EBT2. Recently, a new generation of these films, EBT3, has become available. The composition and thickness of the sensitive layer are the same as for the previous EBT2 films. The most important change is the symmetric layer configuration to eliminate side orientation dependence, which is reported for EBT2 films. Methods: The general film characteristics such as sensitivity to read-out orientation and postexposure darkening evolution of the new EBT3 film are evaluated. Film response has been investigated in clinical photon and proton beams and compared to former EBT2 films. Quenching effects in the proton Bragg peak region have been studied for both, EBT2 and EBT3 films. Results: The general performance of EBT3 is comparable to EBT2, and the orientation dependence with respect to film side is completely eliminated in EBT3 films. Response differences of EBT2 and EBT3 films are of the same order of magnitude as batch-to-batch variations observed for EBT2 films. No significant difference has been found for both generations of EBT films between photon and proton exposure. Depth dose measurements of EBT2 and EBT3 show an excellent agreement, though underestimating dose by up to 20% in the Bragg peak region. Conclusions: The symmetric configuration of EBT3 presents a major improvement for film handling. EBT3 has similar dosimetric performance as its precursor EBT2 and can, thus, be applied to dose verification in IMRT in the same way. For dose verification in proton therapy the underresponse in the Bragg peak region has to be taken into account.

• OSTI ID: 22098963
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 8 Vol. 39; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
62 RADIOLOGY AND NUCLEAR MEDICINE
BRAGG CURVE
COMPARATIVE EVALUATIONS
DEPTH DOSE DISTRIBUTIONS
DOSIMETRY
ENERGY DEPENDENCE
LAYERS
ORIENTATION
PERFORMANCE
PHOTONS
PROTON BEAMS
PROTONS
QUENCHING
RADIATION DOSES
RADIOTHERAPY
READOUT SYSTEMS
SENSITIVITY
SPATIAL RESOLUTION
THIN FILMS
VERIFICATION