Dosimetric evaluation of a patient-specific 3D-printed oral positioning stent for head-and-neck radiotherapy

3D printing technology to produce intraoral stents for head and neck radiotherapy: A scoping review

INTRODUCTION

Radiotherapy remains one of the main treatments for head and neck cancer; however, it is accompanied by acute and chronic adverse effects. Use of three-dimensional (3D) oral stents to modulate radiation intensity to specific target areas have been developed to minimize these adverse effects. This study aimed to present a scoping review of studies published on 3D printing of oral stents and their clinical applicability.

METHODS

MEDLINE/Pubmed, Scopus, Web of Science and CENTRAL Cochrane data bases were searched, studies selected, and data collected by three independent reviewers up to December 2022. The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis-Extension for Scoping Reviews (PRISMA-ScR).

RESULTS

The search resulted in 404 studies and 5 articles fulfilled the eligibility criteria and were considered for this review. Three-dimensional printed intraoral stents were produced for 56 patients with indication for radiotherapy. 3D-printed stents were well-tolerated by all tested patients and demonstrated great reproducibility of maxillomandibular relation, required less time for production and lower cost to manufacture. Two studies showed great protection of healthy tissues with 3D-printed stents during radiotherapy.

CONCLUSIONS

Three-dimensional printing is promising for production of intraoral stents, however, more studies are needed to improve the technique and further investigate the safety and prevention of oral toxicities from radiotherapy.

Development of a customisable 3D-printed intra-oral stent for head-and-neck radiotherapy

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Advanced radiotherapy techniques have improved head-and-neck treatments.

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More improvements are possible with intra-oral stents stabilising sensitive anatomy.

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MRI imaging shows new modular 3D printed stents provide stable displacement.

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Modular stents achieve positive outcomes within standard treatment workflow.

Intra-oral stents (including mouth-pieces and bite blocks) can be used to displace adjacent non-involved oral tissue and reduce radiation side effects from radiotherapy treatments for head-and-neck cancer. In this study, a modular and customisable 3D printed intra-oral stent was designed, fabricated and evaluated, to utilise the advantages of the 3D printing process without the interruption of clinical workflow associated with printing time. The stent design used a central mouth-opening and tongue-depressing main piece, with optional cheek displacement pieces in three different sizes, plus an anchor point for moulding silicone to fit individual patients’ teeth. A magnetic resonance imaging (MRI) study of one healthy participant demonstrated the tissue displacement effects of the stent, while providing a best-case indication of its comfort.

3D printed brachytherapy jig for Reference Air Kerma Rate calibration

3D printing in modern radiotherapy allows users the ability to create custom devices which can be a valuable tool for use in brachytherapy source calibration. Radiotherapy centres may verify their brachytherapy source activity with a calibrated Farmer chamber. For this purpose, a jig was designed, 3D printed and commissioned for in-air source strength calibration. Measurements on four afterloaders with varied equipment and environments were completed. A full uncertainty budget was developed and measurements with the in-air jig were consistently within 3% of the certificate source strength, and within the 4.1% combined uncertainty for comparing a well chamber measurement (1.7%) with the in air jig (3.75%). By creating a jig that is able to be customised to multiple catheter sizes and cylindrical chamber designs, centres can be provided with the option of independently checking their source strength with ease and for little cost.