Case study of a bolus helmet used to maintain optic chiasm and nerve sparing while improving target coverage using IMPT


      The purpose of this study was to examine if the use of a bolus helmet when treating the head with intensity modulated proton therapy (IMPT) will maintain organs at risk (OAR) sparing while improving the clinical target volume (CTV) coverage. A bolus helmet is a device that aims to improve on the traditionally used range shifter in proton therapy by improving dose distribution characteristics. Ten patients were retrospectively selected who had 2 separate treatment planning scans performed, a scan with the bolus helmet and a second scan without. Plans were created using both scans. Dose to organs at risk (OAR) including the left optic nerve, right optic nerve, optic chiasm, and normal brain minus CTV (brain-CTV), as well as CTV coverage were compared between the 2 plans. The use of the bolus helmet displayed lower mean OAR doses as well as higher CTV coverage, suggesting that use of the bolus helmet provides benefit when treating the head with IMPT.


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        • Ali AM
        • Mathis T
        • Bensadoun RJ
        • Thariat J
        Radiation induced optic neuropathy: does treatment modality influence the risk?.
        Bulletin du Cancer. 2019; 106
        • Brodin NP
        • Kabarriti R
        • Garg MK
        • et al.
        A systematic review of normal-tissue complication models relevant to standard fractionation radiation therapy of the head and neck region published after the QUANTEC reports.
        Int J Radiat Oncol Biol Phys. 2018; 100: 391-407
        • Loganovski K
        • Maraziti D
        • Fedirko P
        • et al.
        Radiation-induced cerebro-ophthalmic effects in humans.
        Life (Basel). 2020; 10: 41
        • Ozkaya Akagunduz O
        • Guven Yilmaz S
        • Yalman D
        • et al.
        Evaluation of the radiation dose-volume effects of optic nerves and chiasm by psychophysical, electrophysiologic tests, and optical coherence tomography in nasopharyngeal carcinoma.
        Technol Cancer Res Treat. 2017; 16: 969-977
        • Mayo C
        • Martel M
        • Marks LB
        • et al.
        Radiation dose-volume effects of optic nerves and chiasm.
        Int J Radiat Oncol Biol Phys. 2010; 76: 28-35
        • Gadient T
        • Mundy D
        • Furutani K.
        Range-shifting helmet for proton radiation therapy.
        Radiat Ther. 2019; 28: 188-191
        • Both S
        • Shen J
        • Kirk M
        • et al.
        Development and clinical implementation of a universal bolus to maintain spot size during delivery of base of skull pencil beam scanning proton therapy.
        Int J Radiat Oncol Biol Phys. 2014; 90: 79-84
        • Beltran C
        • Tseung HWC
        • Augustine KE
        • et al.
        Clinical implementation of a proton dose verification system utilizing a GPU accelerated monte carlo engine.
        Int J Particle Ther. 2016; 3: 312-319
        • Mundy D
        • Corner S
        • King T.
        Range shifting helmet for spot size reduction in shallow head tumors.
        Int J Part Ther. 2018; 4: 47-109