Poster - 40: Treatment Verification of a 3D-printed Eye Phantom for Proton Therapy

Authors

  • Dunning Chelsea,

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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  • Lindsay Clay,

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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  • Unick Nick,

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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  • Sossi Vesna,

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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  • Martinez Mark,

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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  • Hoehr Cornelia

    1. University of British Columbia, University of Victoria, University of British Columbia, University of British Columbia, University of British Columbia, TRIUMF
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Abstract

Purpose:

Ocular melanoma is a form of eye cancer which is often treated using proton therapy. The benefit of the steep proton dose gradient can only be leveraged for accurate patient eye alignment. A treatment-planning program was written to plan on a 3D-printed anatomical eye-phantom, which was then irradiated to demonstrate the feasibility of verifying in vivo dosimetry for proton therapy using PET imaging.

Methods:

A 3D CAD eye model with critical organs was designed and voxelized into the Monte-Carlo transport code FLUKA. Proton dose and PET isotope production were simulated for a treatment plan of a test tumour, generated by a 2D treatment-planning program developed using NumPy and proton range tables. Next, a plastic eye-phantom was 3D-printed from the CAD model, irradiated at the TRIUMF Proton Therapy facility, and imaged using a PET scanner.

Results:

The treatment-planning program prediction of the range setting and modulator wheel was verified in FLUKA to treat the tumour with at least 90% dose coverage for both tissue and plastic. An axial isotope distribution of the PET isotopes was simulated in FLUKA and converted to PET scan counts. Meanwhile, the 3D-printed eye-phantom successfully yielded a PET signal.

Conclusions:

The 2D treatment-planning program can predict required parameters to sufficiently treat an eye tumour, which was experimentally verified using commercial 3D-printing hardware to manufacture eye-phantoms. Comparison between the simulated and measured PET isotope distribution could provide a more realistic test of eye alignment, and a variation of the method using radiographic film is being developed.

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