skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: SU-E-T-665: Radiochromic Film Quenching Effect Reduction for Proton Beam Dosimetry

Abstract

Purpose: Depending on the useful dose range in which radiochromic films operate, number of different radiochromic film models have been designed. The impact of different film models on quenching effect for percent depth dose (PDD) measurements in proton beams has been investigated. Methods: Calibrated PTW Markus ionization chamber was used to measure PDD and beam output for 26.5 MeV protons produced by CS30 cyclotron. An aluminum cylinder was added in front of the beam exit serving as a radiation shutter. The measured signal was normalized to a monitor chamber reading and subsequently scaled by ratio of water-to-air stopping powers at given depth, while the effective depth of measurements was scaled by ratios of material-to-water physical densities and CSDA ranges. Output was measured in water at 2.1 mm reference-depth in the plateau upstream from the Bragg peak. Following the TRS-398 reference dosimetry protocol for proton beams, the output was calibrated in water. Three radiochromic film models (EBT, EBT3 and HD-V2) were calibrated within Lexan phantom positioned at the same water-equivalent depth. Thicknesses of films sensitive layers were 34 µm, 30 µm and 8 µm, respectively. Small film pieces (1 x 2 cm{sup 2}) were positioned within polyethylene phantom along the beammore » central axis with an angulation of 5° for PDD measurements. Results: While the output of the proton beam was found to be around 7 Gy/sec, the actual value of the output per monitor chamber reading (2.32 Gy/nC) was used for reference-dose irradiations during film calibration. Dose ratios at the Bragg peak relative to the reference-depth were 3.88, 2.52, 2.19, and 2.02 for the Markus chamber, HD-V2, EBT3, and EBT film models, respectively. Conclusion: Results at hand suggest that quenching effect is reduced when a radiochromic film model with smaller sensitive layer thickness is used for PDD measurements in proton beams. David Lewis is the owner of RCF Consulting, LLC.« less

Authors:
; ; ;  [1];  [2];  [3];  [2];  [4]
  1. King Faisal Specialist Hospital & Research Centre, Riyadh (Saudi Arabia)
  2. McGill University, Montreal, QC (Canada)
  3. RCF Consulting, LLC, Monroe, CT (United States)
  4. (Canada)
Publication Date:
OSTI Identifier:
22538173
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPES AND RADIATION SOURCES; BRAGG CURVE; DEPTH DOSE DISTRIBUTIONS; FILM DOSIMETRY; GY RANGE 01-10; IONIZATION CHAMBERS; MEV RANGE 10-100; PROTON BEAMS; QUENCHING; SIGNALS

Citation Formats

Aldelaijan, S, Alzorkany, F, Moftah, B, Alrumayan, F, Seuntjens, J, Lewis, D, Devic, S, and Jewish General Hospital, Montreal, QC. SU-E-T-665: Radiochromic Film Quenching Effect Reduction for Proton Beam Dosimetry. United States: N. p., 2015. Web. doi:10.1118/1.4925028.
Aldelaijan, S, Alzorkany, F, Moftah, B, Alrumayan, F, Seuntjens, J, Lewis, D, Devic, S, & Jewish General Hospital, Montreal, QC. SU-E-T-665: Radiochromic Film Quenching Effect Reduction for Proton Beam Dosimetry. United States. doi:10.1118/1.4925028.
Aldelaijan, S, Alzorkany, F, Moftah, B, Alrumayan, F, Seuntjens, J, Lewis, D, Devic, S, and Jewish General Hospital, Montreal, QC. Mon . "SU-E-T-665: Radiochromic Film Quenching Effect Reduction for Proton Beam Dosimetry". United States. doi:10.1118/1.4925028.
@article{osti_22538173,
title = {SU-E-T-665: Radiochromic Film Quenching Effect Reduction for Proton Beam Dosimetry},
author = {Aldelaijan, S and Alzorkany, F and Moftah, B and Alrumayan, F and Seuntjens, J and Lewis, D and Devic, S and Jewish General Hospital, Montreal, QC},
abstractNote = {Purpose: Depending on the useful dose range in which radiochromic films operate, number of different radiochromic film models have been designed. The impact of different film models on quenching effect for percent depth dose (PDD) measurements in proton beams has been investigated. Methods: Calibrated PTW Markus ionization chamber was used to measure PDD and beam output for 26.5 MeV protons produced by CS30 cyclotron. An aluminum cylinder was added in front of the beam exit serving as a radiation shutter. The measured signal was normalized to a monitor chamber reading and subsequently scaled by ratio of water-to-air stopping powers at given depth, while the effective depth of measurements was scaled by ratios of material-to-water physical densities and CSDA ranges. Output was measured in water at 2.1 mm reference-depth in the plateau upstream from the Bragg peak. Following the TRS-398 reference dosimetry protocol for proton beams, the output was calibrated in water. Three radiochromic film models (EBT, EBT3 and HD-V2) were calibrated within Lexan phantom positioned at the same water-equivalent depth. Thicknesses of films sensitive layers were 34 µm, 30 µm and 8 µm, respectively. Small film pieces (1 x 2 cm{sup 2}) were positioned within polyethylene phantom along the beam central axis with an angulation of 5° for PDD measurements. Results: While the output of the proton beam was found to be around 7 Gy/sec, the actual value of the output per monitor chamber reading (2.32 Gy/nC) was used for reference-dose irradiations during film calibration. Dose ratios at the Bragg peak relative to the reference-depth were 3.88, 2.52, 2.19, and 2.02 for the Markus chamber, HD-V2, EBT3, and EBT film models, respectively. Conclusion: Results at hand suggest that quenching effect is reduced when a radiochromic film model with smaller sensitive layer thickness is used for PDD measurements in proton beams. David Lewis is the owner of RCF Consulting, LLC.},
doi = {10.1118/1.4925028},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}