Kim Chae-Eon, Park Jong In, Jung Seongmoon, Pak Sang-Il, Jeong Seonghoon, An Seohyeon, Kim Chankyu, Jeong Jong Hwi, Kim Haksoo, Lim Young Kyung, Shin Dongho, Chung Yoonsun, Kim In Jung, Lee Se Byeong
Proton Therapy Center, National Cancer Center, Goyang, Korea; Department of Nuclear Engineering, Hanyang University, Seoul, Korea.
Ionizing Radiation Metrology Group, Korea Research Institute of Standards and Science, Daejoen, Korea.
Phys Med. 2025 Jun;134:104992. doi: 10.1016/j.ejmp.2025.104992. Epub 2025 May 10.
With the advent of FLASH radiotherapy, alanine dosimetry has gained attention as a promising dosimeter owing to its dose-rate independence. However, before utilized in radiotherapy, procedures for determining the absorbed dose to water using alanine under clinical proton beams must be established. This study sought to develop a formula for alanine dosimetry by deriving beam quality correction factors and validating them through Monte Carlo simulations and experimental measurements.
To calculate the absorbed dose to water using alanine dosimeters, a formula was developed specifically for the plateau region. Alanine dosimeters were irradiated under both a reference beam (Cobalt-60) and clinical proton beams. Beam quality correction factors were calculated and subsequently validated through Monte Carlo simulations using the Tool for Particle Simulation (TOPAS), which is based on GEANT4, as well as through experimental measurements. During the simulations, both crystalline and bulk densities of alanine were considered.
The simulation results showed that the average beam quality correction factors for alanine were 1.005 for crystalline density and 1.012 for bulk density. Experimental measurements under clinical proton beams yielded a beam quality correction factor of 1.014, with a standard uncertainty of 2.2%.
These results suggest that alanine dosimeters provide reliable and reproducible measurements for proton therapy. The robust methodology demonstrated here highlights the potential of alanine dosimeters in clinical applications, demonstrating their effectiveness and reliability in determining the absorbed dose to water under clinical proton beam conditions.
随着FLASH放射治疗的出现，由于丙氨酸剂量计与剂量率无关，它作为一种有前景的剂量计受到了关注。然而，在用于放射治疗之前，必须建立在临床质子束下使用丙氨酸确定水吸收剂量的程序。本研究旨在通过推导束流质量校正因子并通过蒙特卡罗模拟和实验测量对其进行验证，从而开发出丙氨酸剂量测定的公式。
为了使用丙氨酸剂量计计算水的吸收剂量，专门为坪区开发了一个公式。丙氨酸剂量计在参考束（钴-60）和临床质子束下进行照射。计算束流质量校正因子，随后使用基于GEANT4的粒子模拟工具（TOPAS）通过蒙特卡罗模拟以及通过实验测量对其进行验证。在模拟过程中，考虑了丙氨酸的晶体密度和体密度。
模拟结果表明，丙氨酸的平均束流质量校正因子对于晶体密度为1.005，对于体密度为1.012。临床质子束下的实验测量得出束流质量校正因子为1.014，标准不确定度为2.2%。
这些结果表明，丙氨酸剂量计为质子治疗提供了可靠且可重复的测量。此处展示的稳健方法突出了丙氨酸剂量计在临床应用中的潜力，证明了它们在临床质子束条件下确定水吸收剂量方面的有效性和可靠性。
