title: Potential of 3D printing technologies for fabrication of electron bolus and proton compensators.
abstract: In electron and proton radiotherapy, applications of patient-specific electron bolus or proton compensators during radiation treatments are often necessary to accommodate patient body surface irregularities, tissue inhomogeneity, and variations in PTV depths to achieve desired dose distributions. Emerging 3D printing technologies provide alternative fabrication methods for these bolus and compensators. This study investigated the potential of utilizing 3D printing technologies for the fabrication of the electron bolus and proton compensators. Two printing technologies, fused deposition modeling (FDM) and selective laser sintering (SLS), and two printing materials, PLA and polyamide, were investigated. Samples were printed and characterized with CT scan and under electron and proton beams. In addition, a software package was developed to convert electron bolus and proton compensator designs to printable Standard Tessellation Language file format. A phantom scalp electron bolus was printed with FDM technology with PLA material. The HU of the printed electron bolus was 106.5 ± 15.2. A prostate patient proton compensator was printed with SLS technology and polyamide material with -70.1 ± 8.1 HU. The profiles of the electron bolus and proton compensator were compared with the original designs. The average over all the CT slices of the largest Euclidean distance between the design and the fabricated bolus on each CT slice was found to be 0.84 ± 0.45 mm and for the compensator to be 0.40 ± 0.42 mm. It is recommended that the properties of specific 3D printed objects are understood before being applied to radiotherapy treatments.
authors.affiliation: Rutgers Cancer Institute of New Jersey. weizou@sas.upenn.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Zou
authors.forename: Ted
authors.initials: T
authors.lastname: Fisher
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.forename: Leonard
authors.initials: L
authors.lastname: Kim
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.forename: Venkat
authors.initials: V
authors.lastname: Narra
authors.forename: Beth
authors.initials: B
authors.lastname: Swann
authors.forename: Rachana
authors.initials: R
authors.lastname: Singh
authors.forename: Richard
authors.initials: R
authors.lastname: Siderit
authors.forename: Lingshu
authors.initials: L
authors.lastname: Yin
authors.forename: Boon-Keng Kevin
authors.initials: BK
authors.lastname: Teo
authors.forename: Michael
authors.initials: M
authors.lastname: McKenna
authors.forename: James
authors.initials: J
authors.lastname: McDonough
authors.forename: Yue J
authors.initials: YJ
authors.lastname: Ning
mesh_terms: D004583:Electrons; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D066330:Printing, Three-Dimensional / Q000295:instrumentation*; D011522:Protons; D020266:Radiotherapy, Conformal / Q000295:instrumentation*; D012542:Scattering, Radiation
chemical_list: D011522:Protons