Program Information
Assessment of Polymer Gel Dosimetry and Radiochromic Gel Dosimetry for Proton Beams by Means of Monte Carlo Simulation
M Park1*, W Ha1 , G Kim2 , K Joo3 , Y Ji4 , S Park4 , H Jung2 , (1) National Radiation Emergency Center, Korea Institute of Radiological and Medical Sciences Seoul, (2) Radiation Safety and Section, Korea Institute of Radiological and Medical Sciences, Seoul, (3) Basic Atomic Energy Research Institute, Myongji University, Seoul, (4) Division of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul,
Presentations
SU-I-GPD-T-113 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: The dosimetric characteristics of polymer gel and radiochromic gel dosimeter for proton beams are evaluated using the Monte Carlo simulation for basic clinical applications.
Methods: The normoxic polymer gel and the Leuco Crystal Violet (LCV) micelle radiochromic gel were used. The composition materials of polymer and radiochromic gel were similar, but the LCV dye was involved in radiochromic gel. The proton beams with five energies (50, 100, 150, 200 and 250 MeV) were directed to the gel dosimeters. The irradiated proton beams were interacted with the gel dosimeters, and these interactions were recorded by a tally in Monte Carlo code. The depth dose profiles and the spread-out Bragg-peaks (SOBP) of polymer gel dosimeters and radiochromic gel dosimeters were evaluated, compared with those of water. Moreover, the lateral distributions in Bragg-peak region were acquired to assess the agreement between gel dosimeters and water.
Results: The water-equivalent dose (WED) of radiochromic gel represented good agreement, compared with that of polymer gel. Compared with the Bragg-peak distance of water, the relative biases of the WED of polymer and radiochromic gel were about 5.6% and 2.2%, respectively. The SOBP tendency of polymer gel was similar to that of water. However, the SOBP of radiochromic gel represented some discrepancies of dose near Bragg-peak of proton beam. The dose discrepancy rate of radiochromic gel was about 16.3% in 150, 200 and 250 MeV energy proton beams, compared with dose of water. The lateral distribution of gel dosimeters represented similar tendency with water, but the dose distribution of polymer gel was closer than that of radiochromic gel.
Conclusion: While the WED of radiochromic gel showed a good agreement, the polymer gel showed the better results. These results represent that some considerations are necessary to apply the gel dosimeters to the quality assurance of proton beam therapy.
Funding Support, Disclosures, and Conflict of Interest: This study was supported by a grant of the Korea Institute of Radiological and Medical Sciences(KIRAMS), funded by Ministry of Science, ICT and Future Planning, Republic of Korea(1711045542/50422-2017)
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