Three-Dimensional Printer-Aided Casting of Soft, Custom Silicone Boluses(Scsbs) for Head and Neck Radiotherapy

Publication date: Available online 11 November 2017
Source:Practical Radiation Oncology
Author(s): Tsuicheng Chiu, Jun Tan, Mathew Brenner, Xuejun Gu, Ming Yang, Kenneth Westover, Tobin Strom, David Sher, Steve Jiang, Bo Zhao
PurposeCustom tissue compensators provide dosimetric advantages for treating superficial or complex anatomy but currently available fabrication technology is expensive or impractical for most clinical operations and yields compensators that are difficult for patients to tolerate. We aimed to develop an inexpensive, clinically feasible workflow for generating patient-specific, soft, custom silicone boluses (SCSBs) for head-and-neck (HN) radiotherapy.MethodsWe developed a method using 3D–printed parts for generating SCSBs for the treatment of head and neck cancers. The clinical workflow for generation of SCSBs was characterized inclusive of patient simulation to treatment in terms of resource time and cost. Dosimetric properties such as percentage depth dose (PDD) and dose profiles were measured for SCSBs using GaF films. Comprehensive measurements were also conducted on a HN phantom. SCSBs were generated and used for electron or photon based radiation treatments of seven head and neck patients with lesions at nose, cheek, eye or ears. In vivo dose measurements with optically simulated luminescence dosimeters (OSLDs) were performed.ResultsTotal design and fabrication time from patient simulation to radiation treatment start required approximately one week, with fabrication constituting 1–2 working days depending on bolus surface area, volume and complexity. CT and dosimetric properties of the soft bolus were similar to water. In vivo dose measurements on seven treated patients confirmed that the dose deposition conformed to planned doses. Material costs were lower than currently available hard plastic boluses generated with 3D printing technology. All treated patients tolerated SCSBs for the duration of therapy.ConclusionsGeneration and use of SCSBs for clinical use is feasible and effective for the treatment of HN cancers.



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