ESTRO 2024 - Abstract Book

S4082

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2024

Evaluation of the dimensional accuracy showed a median [IQR] deviation of -0.02mm [-0.75;1.21] for SLS and 0.45mm [0.28;0.63] for MJF. Visual inspection of the fit of the devices agreed with these findings as SLS was slightly too tight, resulting in 1mm gap in the 2 cranial elastic shell attachment. Sub-millimeter and sub-degree positional reproducibility was achieved, for translations ranging [0.0mm;0.1mm], and rotations [-0.3°;0.2°]. Average CT numbers were 16HU [-39;66] for SLS, and 67HU [-1;124] for MJF. The devices did not cause distortions or artifacts in MRI and CT imaging. The FEM simulation predicted deflections of 2.4mm at the most cranial part of the device, and 1.1mm centrally at the most posterior point. However, the dial gauge measurements indicated a 3.7mm and 2.8mm deflection respectively, indicating that more finetuning of the simulation parameters are required. The IC measurements showed deviations of less than 2% relative to the calculated dose.

Conclusion:

A novel fully 3D-printed head and neck immobilization device design was subjected to an extensive validation study. It was shown that the 3D-printed device could be produced with high accuracy and adequate immobilization functionality for a rigid phantom. The device showed to be compatible with radiotherapy related imaging and dosimetry. Insights into methods for in-silico QA of the customized patient-specific devices were developed with the investigating of FEM simulations. The presented design and validation of this 3D-printed immobilization device provides the basis for further development toward clinical application.

Keywords: 3D-printing, head and neck, immobilisation

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Digital Poster