Halloran Andrew, Newhauser Wayne, Chu Connel, Donahue William
Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, United States of America.
Department of Radiation Physics, Mary Bird Perkins Cancer Center, Baton Rouge, Louisiana, United States of America.
Phys Med Biol. 2021 Nov 18;66(22). doi: 10.1088/1361-6560/ac3047.
Anthropomorphic phantoms used for radiation dose measurements are designed to mimic human tissue in shape, size, and tissue composition. Reference phantoms are widely available and are sufficiently similar to many, but not all, human subjects. 3D printing has the potential to overcome some of these shortcomings by enabling rapid fabrication of personalized phantoms for individual human subjects based on radiographic imaging data.. The objective of this study was to test the efficacy of personalized 3D printed phantoms for charged particle therapy. To accomplish this, we measured dose distributions from 6 to 20 MeV electron beams, incident on printed and molded slices of phantoms.. Specifically, we determined the radiological properties of 3D printed phantoms, including beam penetration range. Additionally, we designed and printed a personalized head phantom to compare results obtained with a commercial, reference head phantom for quality assurance of therapeutic electron beam dose calculations.. For regions of soft tissue, gamma index analyses revealed a 3D printed slice was able to adequately model the same electron beam penetration ranges as the molded reference slice. The printed, personalized phantom provided superior dosimetric accuracy compared to the molded reference phantom for electron beam dose calculations at all electron beam energies. However, current limitations in the ability to print high-density structures, such as bone, limited pass rates of 60% or better at 16 and 20 MeV electron beam energies.. This study showed that creating personalized phantoms using 3D printing techniques is a feasible way to substantially improve the accuracy of dose measurements of therapeutic electron beams, but further improvements in printing techniques are necessary in order to increase the printable density in phantoms.
用于辐射剂量测量的拟人化体模旨在在形状、大小和组织组成方面模仿人体组织。参考体模广泛可得，并且与许多（但不是所有）人体受试者足够相似。3D打印有潜力克服其中一些缺点，通过基于射线成像数据为个体人体受试者快速制造个性化体模。本研究的目的是测试个性化3D打印体模用于带电粒子治疗的效果。为实现这一目标，我们测量了6至20 MeV电子束入射到打印和模制的体模切片上的剂量分布。具体而言，我们确定了3D打印体模的放射学特性，包括束穿透范围。此外，我们设计并打印了一个个性化头部体模，以比较使用商业参考头部体模获得的结果，用于治疗性电子束剂量计算的质量保证。对于软组织区域，伽马指数分析表明，一个3D打印切片能够充分模拟与模制参考切片相同的电子束穿透范围。在所有电子束能量下，打印的个性化体模在电子束剂量计算方面比模制参考体模提供了更高的剂量测定准确性。然而，目前在打印高密度结构（如骨骼）方面的能力限制，在16和20 MeV电子束能量下，通过率限制在60%或更高。这项研究表明，使用3D打印技术创建个性化体模是大幅提高治疗性电子束剂量测量准确性的可行方法，但为了提高体模中的可打印密度，打印技术需要进一步改进。
