Romeo Mattia, de Farias Soares Alvaro, D'Oca Maria Cristina, Ciocca Mario, Mantovani Laura, Di Liberto Riccardo, Mirandola Alfredo, Rossi Eleonora, Colombo Gomez Luca Maria, Marrale Maurizio
Department of Physics and Chemistry "Emilio Segrè", University of Palermo, Palermo, Italy.
National Institute for Nuclear Physics (INFN), Catania Division, Catania, Italy.
Int J Radiat Biol. 2025 Jun 26:1-12. doi: 10.1080/09553002.2025.2523281.
Hadrontherapy with proton and carbon ion scanning beams is an advanced radiation treatment modality mainly exploiting the finite range of those particles in the matter, to better spare critical organs close to the tumor volume as compared to photons. However, its complexity requires careful management of dosimetric uncertainties to guarantee patient safety. This study aims to reassess the suitability of alanine-based dosimetry for modern hadrontherapy applications.
Alanine pellets based on electron spin resonance (ESR) were used as dosimeters. The response was taken from the peak-to-peak amplitude and compared to the ionization chamber one. Dose response and dependence on energy, beam direction, and linear energy transfer (LET), for both pristine Bragg peak and spread-out Bragg peak (SOBP) were evaluated. The ESR ratio x/y was evaluated as a function of LET and microwave power. Photon irradiations were performed with a 6 MV linear accelerator at the San Matteo Hospital, while with charged particles at CNAO, both located in Pavia, Italy.
Alanine showed a linear dose-response for both protons and carbon ions in the range of 10-45 Gy. For carbon ions, a pronounced quenching effect in the Bragg peak and energy dependence were observed. Alanine effectiveness was reduced by up to 30% due to LET effects. Moreover, the use of the x/y ratio showed potential for LET differentiation.
Alanine may be a promising dosimeter for hadrontherapy. However, further studies are required to investigate factors of correction due to the effects of LET and energy dependence.
质子和碳离子扫描束的强子治疗是一种先进的放射治疗方式，主要利用这些粒子在物质中的有限射程，与光子相比，能更好地保护靠近肿瘤体积的关键器官。然而，其复杂性需要仔细管理剂量不确定性以确保患者安全。本研究旨在重新评估基于丙氨酸的剂量测定法在现代强子治疗应用中的适用性。
基于电子自旋共振（ESR）的丙氨酸颗粒用作剂量计。响应取自峰峰值幅度，并与电离室的响应进行比较。评估了原始布拉格峰和扩展布拉格峰（SOBP）的剂量响应以及对能量、束方向和线能量转移（LET）的依赖性。ESR 比 x/y 作为 LET 和微波功率的函数进行评估。在意大利帕维亚的圣马泰奥医院，使用 6 MV 直线加速器进行光子照射，而在 CNAO 使用带电粒子进行照射。
丙氨酸在 10 - 45 Gy 范围内对质子和碳离子均显示出线性剂量响应。对于碳离子，在布拉格峰中观察到明显的猝灭效应和能量依赖性。由于 LET 效应，丙氨酸的有效性降低了高达 30%。此外，使用 x/y 比显示出 LET 区分的潜力。
丙氨酸可能是一种有前景的强子治疗剂量计。然而，需要进一步研究来探讨由于 LET 和能量依赖性影响而产生的校正因素。
