目的:本研究旨在设计和制造3D打印的异质儿科头部体模,并为放射治疗剂量学定制胸部体模。
方法:这项研究设计了,制作,并测试了可以模拟软组织的3D打印放射治疗模型,肺,大脑,还有骨头.在设计体模时考虑了各种聚合物。聚乳酸+,尼龙,和石膏用于模拟不同的组织等效性。尺寸精度,并对CT数进行了调查。对体模进行完整的放射治疗临床工作流程。从简单的单个6MV光束在头部和胸部幻影中都提供了几种治疗计划,平行相对梁,和五场调强放射治疗(IMRT)束。将使用电离室和放射变色膜的剂量测量值与VarianEclipse治疗计划系统(TPS)的计算剂量进行比较。
主要结果:根据其辐射衰减和解剖结构,制造的异质体模代表儿科人类头部和成人胸部。测得的肺CT数范围在-786.23±10.55、0.98±3.86、129.51±12.83和651.14±47.76HU内,水/脑,软组织,还有骨头,分别。它具有良好的放射成像视觉相似性,相对于真实的人类头部和胸部描绘软组织,肺,骨头,和大脑。适形放疗和IMRT的累积剂量读数与头部和胸部体模的TPS计算剂量在±2%和±4%范围内匹配,分别。对于3%/3毫米的伽马分析标准,所有交付计划的平均合格率均在90%以上。
意义和结论:制作的异质小儿头胸体模基于其CT图像和测得的辐射剂量,可用于Linac端到端放射治疗的质量保证。本研究的制造和剂量测定工作流程可由其他机构用于剂量测定和培训。
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Objective. This study aims to design and fabricate a 3D printed heterogeneous paediatric head phantom and to customize a
thorax phantom for radiotherapy dosimetry.Approach. This study designed, fabricated, and tested 3D printed radiotherapy phantoms that can simulate soft tissue, lung, brain, and bone. Various polymers were considered in designing the phantoms. Polylactic acid+, nylon, and plaster were used in simulating different tissue equivalence. Dimensional accuracy, and CT number were investigated. The phantoms were subjected to a complete radiotherapy clinical workflow. Several treatment plans were delivered in both the head and the
thorax phantom from a simple single 6 MV beam, parallel opposed beams, and five-field intensity modulated radiotherapy (IMRT) beams. Dose measurements using an ionization chamber and radiochromic films were compared with the calculated doses of the Varian Eclipse treatment planning system (TPS).Main results. The fabricated heterogeneous phantoms represent paediatric human head and adult
thorax based on its radiation attenuation and anatomy. The measured CT number ranges are within -786.23 ± 10.55, 0.98 ± 3.86, 129.51 ± 12.83, and 651.14 ± 47.76 HU for lung, water/brain, soft tissue, and bone, respectively. It has a good radiological imaging visual similarity relative to a real human head and
thorax depicting soft tissue, lung, bone, and brain. The accumulated dose readings for both conformal radiotherapy and IMRT match with the TPS calculated dose within ±2% and ±4% for head and
thorax phantom, respectively. The mean pass rate for all the plans delivered are above 90% for gamma analysis criterion of 3%/3 mm.Significance and conclusion. The fabricated heterogeneous paediatric head and thorax phantoms are useful in Linac end-to-end radiotherapy quality assurance based on its CT image and measured radiation dose. The manufacturing and dosimetry workflow of this study can be utilized by other institutions for dosimetry and trainings.