Small Animal Proton Arc Therapy Phantom: Design and Validation

Document Type

Conference Proceeding

Publication Date

6-2024

Publication Title

International Journal of Particle Therapy

Abstract

Background and aims: SPArc, an emerging new proton treatment modality, has been proven to offer better dose conformality and plan robustness compared to IMPT. One of the biggest challenges is delivering the proton beam through a dynamic rotational gantry that might not be available in most of the current proton therapy centers. However, delivering the rotational SPArc therapy with a fixed gantry could be an alternative solution. To facilitate SPArc delivery with a fixed gantry and demonstrate its feasibility, a mouse phantom was designed, incorporating a 3D-printed structure that embeds the mouse at the center and allows for rotational proton delivery. Methods: The design of the phantom is depicted in Fig. 1. The mouse phantom was created through 3D printing using resins, utilizing the open-source Digimouse micro-CT dataset. Film slots were integrated to accommodate GAFCHROMIC EB2 film within the phantom. A two-piece cylindric container, also 3D-printed, was tailored to fit the mouse's shape precisely and was filled with water, allowing rotation. A bipolar Nema 17 stepper motor controlled the phantom's rotation during proton delivery. Additionally, a rotational and translational platform was designed to support the mouse phantom, facilitating the alignment and adjustment of the rotational center. The supporting platform was 3D-printed using PLA material, and the design of both the phantom and motion platform was executed using 360 Fusion software. A single spot (227.7 MeV) proton arc plan was simulated in RayStation TPS with 10 beams, as shown to the left in Fig. 2. The phantom rotation was managed by Arduino microcontrollers as shown in the Fig2 right. An EBT-2 film was positioned at the iso-center in axial direction, and the proton arc plan was delivered to the phantom while rotating. Results: The film measurements and plan dose are presented in Fig. 3. The profile comparison indicates acceptable isocentricity from the rotational phantom and good dose agreement. Conclusions: Our preliminary results demonstrate the feasibility of a rotational small animal phantom to simulate proton Arc delivery. This development will enable SPArc research using a fixed beam for in vivo experiments.

Volume

12

Issue

Suppl

First Page

191

Comments

62nd Annual Conferences of the Particle Therapy Cooperative Group (PTCOG), June 10-15, 2024, Singapore

DOI

10.1016/j.ijpt.2024.100540

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