E Morris¹*, C Miller¹, K Woods², M Cao¹, (1) Department of Radiation Oncology, UCLA Health, Los Angeles, CA, (2) Department of Radiation Oncology, University of Southern California, Los Angeles, CA

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  E Morris

WE-C1000-IePD-F5-4 (Wednesday, 7/13/2022) 10:00 AM - 10:30 AM [Eastern Time (GMT-4)]

Exhibit Hall | Forum 5

Purpose: Adequate cranial array placement for stereotactic radiosurgery (SRS) treatments can be hindered by patients presenting with broad torsos. This work presents the development of a novel 3D printed extension device for cranial localization on such SRS patients.

Methods: Ten broad torso patients were sampled to determine an ideal extension shim height. Shims of four different materials were 3D printed using a Formlabs Form2. Material selection was done via analysis of a customized user needs profile outlining necessary qualities for shim design. These specifications were given a weighted value of importance from 1-5 and applied in a Pugh matrix to determine optimal material. Materials were scored from -2 to +2 based on comparability to a baseline. To verify the device met the specifications needed, a quantitative verification of multiple parameters was conducted. This included the testing of durability, resilience, strength, reproducibility, image quality impact, setup reproducibility etc.

Results: Pugh matrix rank scoring determined the best fit material to be acrylic grey resin (AGR). Optimal shim height for accommodation was found to be 3 cm. Verification testing supported that the AGR device met each need sufficiently. Testing revealed the device maintains functionality past 100 uses, withstands 400 psi, and scored a 4.6/5 across 5 therapists on ease of use. Total production cost was ~$20 and install time is ~5s. Setup reproducibly with and without the shim in place was shown to be comparable (<0.1 mm difference). Over the course of 8 months, the shim has been applied to 67 patient cases between our local institution and satellite campuses.

Conclusion: A clinically implemented cranial array shim was generated and provides accurate and reproducible setups for cranial SRS patients with broad torsos. Along with continued use of this shim locally, efforts are being made to implement it across several other hospitals regionally.

Keywords

Stereotactic Radiosurgery, Setup Verification, Immobilization

Taxonomy

TH- RT Interfraction Motion Management: setup errors, immobilization, localization

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