Fujimoto Koya, Shiinoki Takehiro, Yuasa Yuki, Hanazawa Hideki, Shibuya Keiko
Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, 1-1-1 Minamikogushi, Yamaguchi 755-8535, Japan; Department of Radiological Technology, Yamaguchi University Hospital, 1-1-1 Minamikogushi, Yamaguchi 755-8535, Japan.
Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, 1-1-1 Minamikogushi, Yamaguchi 755-8535, Japan.
Phys Med. 2017 Jun;38:1-9. doi: 10.1016/j.ejmp.2017.04.023. Epub 2017 May 3.
A commercially available bolus ("commercial-bolus") does not make complete contact with the irregularly shaped patient skin. This study aims to customise a patient-specific three-dimensional (3D) bolus using a 3D printing technique ("3D-bolus") and to evaluate its clinical feasibility for photon radiotherapy.
The 3D-bolus was designed using a treatment planning system (TPS) in Digital Imaging and Communications in Medicine-Radiotherapy (DICOM-RT) format, and converted to stereolithographic format for printing. To evaluate its physical characteristics, treatment plans were created for water-equivalent phantoms that were bolus-free, or had a flat-form printed 3D-bolus, a TPS-designed bolus ("virtual-bolus"), or a commercial-bolus. These plans were compared based on the percentage depth dose (PDD) and target-volume dose volume histogram (DVH) measurements. To evaluate the clinical feasibility, treatment plans were created for head phantoms that were bolus-free or had a 3D-bolus, a virtual-bolus, or a commercial-bolus. These plans were compared based on the target volume DVH.
In the physical evaluation, the 3D-bolus provided effective dose coverage in the build-up region, which was equivalent to the commercial-bolus. With regard to the clinical feasibility, the air gaps were lesser with the 3D-bolus when compared to the commercial-bolus. Furthermore, the prescription dose could be delivered appropriately to the target volume. The 3D-bolus has potential use for air-gap reduction compared to the commercial-bolus and facilitates target-volume dose coverage and homogeneity improvement.
A 3D-bolus produced using a 3D printing technique is comparable to a commercial-bolus applied to an irregular-shaped skin surface.
市售的单次大剂量照射装置（“商用单次大剂量照射装置”）无法与形状不规则的患者皮肤完全贴合。本研究旨在使用3D打印技术定制患者特异性三维（3D）单次大剂量照射装置（“3D单次大剂量照射装置”），并评估其在光子放射治疗中的临床可行性。
使用治疗计划系统（TPS）以医学数字成像和通信-放射治疗（DICOM-RT）格式设计3D单次大剂量照射装置，并转换为立体光刻格式进行打印。为评估其物理特性，针对无单次大剂量照射装置、具有平面打印3D单次大剂量照射装置、TPS设计的单次大剂量照射装置（“虚拟单次大剂量照射装置”）或商用单次大剂量照射装置的水等效体模创建治疗计划。基于百分深度剂量（PDD）和靶区剂量体积直方图（DVH）测量对这些计划进行比较。为评估临床可行性，针对无单次大剂量照射装置或具有3D单次大剂量照射装置、虚拟单次大剂量照射装置或商用单次大剂量照射装置的头部体模创建治疗计划。基于靶区DVH对这些计划进行比较。
在物理评估中，3D单次大剂量照射装置在建成区提供了有效的剂量覆盖，这与商用单次大剂量照射装置相当。关于临床可行性，与商用单次大剂量照射装置相比，3D单次大剂量照射装置的气隙更小。此外，可将处方剂量适当地传递至靶区。与商用单次大剂量照射装置相比，3D单次大剂量照射装置在减少气隙方面具有潜在用途，并有助于改善靶区剂量覆盖和均匀性。
使用3D打印技术生产的3D单次大剂量照射装置与应用于形状不规则皮肤表面的商用单次大剂量照射装置相当。
