Guillou Manon, L'Homme Bruno, Trompier François, Gruel Gaëtan, Prezado Yolanda, Dos Santos Morgane
Institut de Radioprotection et de Sureté Nucléaire (IRSN), PSE-SANTE/SERAMED/LRAcc, Fontenay-aux-Roses, France.
Institut de Radioprotection et de Sureté Nucléaire (IRSN), PSE-SANTE/SDOS/LDRI, Fontenay-aux-Roses, France.
Front Physiol. 2022 Dec 8;13:1075665. doi: 10.3389/fphys.2022.1075665. eCollection 2022.
Interventional radiology has grown considerably over the last decades and become an essential tool for treatment or diagnosis. This technique is mostly beneficial and mastered but accidental overexposure can occur and lead to the appearance of deterministic effects. The lack of knowledge about the radiobiological consequences for the low-energy X-rays used for these practices makes the prognosis very uncertain for the different tissues. In order to improve the radiation protection of patients and better predict the risk of complications, we implemented a new preclinical mouse model to mimic radiological burn in interventional radiology and performed a complete characterization of the dose deposition. A new setup and collimator were designed to irradiate the hind legs of 15 mice at 30 Gy in air kerma at 80 kV. After irradiation, mice tibias were collected to evaluate bone dose by Electron Paramagnetic Resonance (EPR) spectroscopy measurements. Monte Carlo simulations with Geant4 were performed in simplified and voxelized phantoms to characterize the dose deposition in different tissues and evaluate the characteristics of secondary electrons (energy, path, momentum). 30 mice tibias were collected for EPR analysis. An average absorbed dose of 194.0 ± 27.0 Gy was measured in bone initially irradiated at 30 Gy in air kerma. A bone to air conversion factor of 6.5 ± 0.9 was determined. Inter sample and inter mice variability has been estimated to 13.9%. Monte Carlo simulations shown the heterogeneity of the dose deposition for these low X-rays energies and the dose enhancement in dense tissue. The specificities of the secondary electrons were studied and showed the influence of the tissue density on energies and paths. A good agreement between the experimental and calculated bone to air conversion factor was obtained. A new preclinical model allowing to perform radiological burn in interventional radiology-like conditions was implemented. For the development of new preclinical radiobiological model where the exact knowledge of the dose deposited in the different tissues is essential, the complementarity of Monte Carlo simulations and experimental measurements for the dosimetric characterization has proven to be a considerable asset.
在过去几十年中，介入放射学有了显著发展，并成为治疗或诊断的重要工具。这项技术大多有益且已被掌握，但意外的过度照射仍可能发生，并导致确定性效应的出现。对于这些操作中使用的低能X射线的放射生物学后果缺乏了解，使得不同组织的预后非常不确定。为了改善患者的辐射防护并更好地预测并发症风险，我们建立了一种新的临床前小鼠模型来模拟介入放射学中的放射性烧伤，并对剂量沉积进行了全面表征。设计了一种新的装置和准直器，以80 kV的空气比释动能在30 Gy下照射15只小鼠的后腿。照射后，收集小鼠胫骨，通过电子顺磁共振（EPR）光谱测量来评估骨剂量。使用Geant4进行蒙特卡罗模拟，在简化和体素化的人体模型中进行，以表征不同组织中的剂量沉积，并评估二次电子的特性（能量、路径、动量）。收集30只小鼠的胫骨进行EPR分析。在最初以30 Gy空气比释动能照射的骨中，测得平均吸收剂量为194.0±27.0 Gy。确定骨与空气的转换系数为6.5±0.9。样本间和小鼠间的变异性估计为13.9%。蒙特卡罗模拟显示了这些低X射线能量下剂量沉积的不均匀性以及致密组织中的剂量增强。研究了二次电子的特性，并显示了组织密度对能量和路径的影响。实验和计算得到的骨与空气转换系数之间取得了良好的一致性。建立了一种新的临床前模型，可在类似介入放射学的条件下进行放射性烧伤。对于开发新的临床前放射生物学模型而言，不同组织中沉积剂量的确切知识至关重要，蒙特卡罗模拟和实验测量在剂量学表征方面的互补性已被证明是一项相当大的优势。
