A total inverse planning paradigm: Prospective clinical trial evaluating the performance of a novel MR-based 3D-printed head immobilization device

Paola Anna Jablonska; Amy Parent; Nancy La Macchia; Harley H L Chan; Matthew Filleti; Matthew Ramotar; Young-Bin Cho; Maria Braganza; Adam Badzynski; Normand Laperriere; Tatiana Conrad; Derek S Tsang; David Shultz; Anna Santiago; Jonathan C Irish; Barbara-Ann Millar; Tony Tadic; Alejandro Berlin

doi:10.1016/j.ctro.2023.100663

A total inverse planning paradigm: Prospective clinical trial evaluating the performance of a novel MR-based 3D-printed head immobilization device

Clin Transl Radiat Oncol. 2023 Jul 26:42:100663. doi: 10.1016/j.ctro.2023.100663. eCollection 2023 Sep.

Authors

Paola Anna Jablonska^{1

2

3}, Amy Parent², Nancy La Macchia², Harley H L Chan⁴, Matthew Filleti², Matthew Ramotar², Young-Bin Cho^{1

2

5}, Maria Braganza², Adam Badzynski⁶, Normand Laperriere^{1

2}, Tatiana Conrad^{1

2}, Derek S Tsang^{1

2}, David Shultz^{1

2}, Anna Santiago^{2

7}, Jonathan C Irish^{4

8}, Barbara-Ann Millar^{1

2}, Tony Tadic^{1

2

4}, Alejandro Berlin^{1

2

4

6}

Affiliations

¹ Department of Radiation Oncology, University of Toronto, 149 College Street, Unit 504, Toronto, Ontario M5T 1P5, Canada.
² Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, 700 University Avenue, 7th Floor, Toronto, Ontario M5G 1Z5, Canada.
³ Department of Radiation Oncology, Clinica Universidad de Navarra, 31008 Pamplona, Spain.
⁴ Guided Therapeutics (GTx) Program, Techna Institute, University Health Network, University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada.
⁵ Department of Radiation Oncology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
⁶ Cancer Digital Intelligence Program, Princess Margaret Cancer Centre, University Health Network, 700 University Avenue, 7th Floor, Toronto, Ontario M5G 1Z5, Canada.
⁷ Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
⁸ Department of Otolaryngology - Head and Neck Surgery/Surgical Oncology, Princess Margaret Cancer Centre/University Health Network, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.

Abstract

Background and purpose: Brain radiotherapy (cnsRT) requires reproducible positioning and immobilization, attained through redundant dedicated imaging studies and a bespoke moulding session to create a thermoplastic mask (T-mask). Innovative approaches may improve the value of care. We prospectively deployed and assessed the performance of a patient-specific 3D-printed mask (3Dp-mask), generated solely from MR imaging, to replicate a reproducible positioning and tolerable immobilization for patients undergoing cnsRT.

Material and methods: Patients undergoing LINAC-based cnsRT (primary tumors or resected metastases) were enrolled into two arms: control (T-mask) and investigational (3Dp-mask). For the latter, an in-house designed 3Dp-mask was generated from MR images to recreate the head positioning during MR acquisition and allow coupling with the LINAC tabletop. Differences in inter-fraction motion were compared between both arms. Tolerability was assessed using patient-reported questionnaires at various time points.

Results: Between January 2020 - July 2022, forty patients were enrolled (20 per arm). All participants completed the prescribed cnsRT and study evaluations. Average 3Dp-mask design and printing completion time was 36 h:50 min (range 12 h:56 min - 42 h:01 min). Inter-fraction motion analyses showed three-axis displacements comparable to the acceptable tolerance for the current standard-of-care. No differences in patient-reported tolerability were seen at baseline. During the last week of cnsRT, 3Dp-mask resulted in significantly lower facial and cervical discomfort and patients subjectively reported less pressure and confinement sensation when compared to the T-mask. No adverse events were observed.

Conclusion: The proposed total inverse planning paradigm using a 3D-printed immobilization device is feasible and renders comparable inter-fraction performance while offering a better patient experience, potentially improving cnsRT workflows and its cost-effectiveness.

Keywords: 3D printing; Immobilization device; MR-guidance; Mask; Radiotherapy.