Program Information
Fabricating Cerrobend Grids with 3D Printing for Spatially Modulated Radiation Therapy: A Feasibility Study
X Zhu1*, J Driewer1 , Y Lei1 , D Zheng1 , S Li1 , T Cullip2 , S Chang2 , Q Zhang1 , M Zhang1 , S Zhou1 , (1) University of Nebraska Medical Center, Omaha, NE, (2) UNC Hospitals, Chapel Hill, NC.
Presentations
SU-E-T-419 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:
Grid therapy has promising applications in the radiation treatment of bulky and large tumors. However, research and applications of grid therapy is limited by the accessibility of the specialized blocks that produce the grid of pencil-like radiation beams. In this study, a Cerrobend grid block was fabricated using a 3D printing technique.
Methods:
A grid block mold was designed with divergent tubes following beam central rays. The mold was printed using a resin with the working temperature below 230 °C. The melted Cerrobend liquid at 120°oC was cast into the resin mold to yield a block with a thickness of 7.4 cm. The grid had a hexagonal pattern, with each pencil beam diameter of 1.4 cm at the iso-center plane; the distance between the beam centers was 2 cm. The dosimetric properties of the grid block were studied using radiographic film and small field dosimeters
Results:
the grid block was fabricated to be mounted at the third accessory mount of a Siemens Oncor linear accelerator. Fabricating a grid block using 3D printing is similar to making cutouts for traditional radiotherapy photon blocks, with the difference being that the mold was created by a 3D printer rather than foam. In this study, the valley-to-peak ratio for a 6MV photon grid beam was 20% at dmax, and 30% at 10 cm depth, respectively
Conclusion:
We have demonstrated a novel process for implementing grid radiotherapy using 3D printing techniques. Compared to existing approaches, our technique combines reduced cost, accessibility, and flexibility in customization with efficient delivery. This lays the groundwork for future studies to improve our understanding of the efficacy of grid therapy and apply it to improve cancer treatment.
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