Australasian Brachytherapy Group

30th Annual
Scientific Meeting

25 - 27 February 2021
A Virtual Event

Register now

Adaptation of the Mick split-ring applicator for combined IC/IS GYN brachytherapy using 3D-printing

Roy M.-È.(1,2), Kamio Y.(2,3,4), Morgan L.-A.(6), Basaric B.(6), Barkati M.(2), Beauchemin M.-C.(2), Bedwani S.(2,3,5), Carrier J.-F.(2,3,5), DeBlois F.(2,3,5)
1. Département de Génie Physique, Polytechnique Montréal, Montreal, QC, Canada
2. Centre Hospitalier de l’Université de Montréal, Montreal, QC, Canada
3. Centre de Recherche du CHUM, Montreal, QC, Canada
4. Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
5. Département de Physique, Univesité de Montréal, Montreal, QC, Canada
6. Adaptiiv Medical Technologies Inc., Halifax, N.S., Canada

Purpose/Objective
The combination of intracavitary GYN applicators with interstitial needles has been shown to improve treatment outcomes in advanced cervical cancer (stages IIIB-IVA) involving tumor extensions in the parametrium. The multicenter EMBRACE II study protocol provides planning aims and limits. Commercial IC/IS brachytherapy applicators used to achieve the EMBRACE II planning aims are only available at high cost, limiting the adoption of this technology in all clinics. The purpose of this work is to show the feasibility of upgrading IC-only applicators for combined IC/IS brachytherapy using inexpensive 3D-printing technology. This research is focused on cervical cancer applications using the widely used IC-only Mick CT/MR split-ring applicator (Eckert & Ziegler BEBIG, Berlin, Germany).

Material and methods
The Mick CT/MR split-ring applicator comes with disposable or reusable buildup caps that work as sleeves around each split-rings, with sizes going from 5 to 10 mm. A CAD model was realized to reproduce the standard 5 mm buidup caps using Fusion 360TM (Autodesk Inc., California, USA). Caps were extended outward and notches were modeled in different orientations to allow attachment of the guiding tubes of the needles used by the interstitial lunar ovoids of the Venezia IC/IS applicator (Elekta, Stockholm, Sweden). Prototypes were printed using fused deposition modeling (FDM) technology in tough PLA with an Ultimaker S5 3D-printer (Ultimaker Ltd., Geldermalsen, Netherlands).

Results
The 3D-printing of compatible sleeves with Elekta’s interstitial guiding tubes was successful, allowing the use of Elekta’s Proguide round needles with the Mick CT/MR split-ring applicator. Each designed sleeve can accommodate up to 5 needles with tested obliquity angles ranging from 0° to 40° in 5° increments. This sleeve design served as blueprint for more advanced clinical prototypes using low force stereolithography (SLA) technology.

Conclusion
The Mick CT-MR split-ring applicator was successfully upgraded using 3D-printing for combined intracavity/interstitial (IC/IS) brachytherapy of cervical cancer. A collaboration is ongoing to adopt a procedure using Adaptiiv’s brachytherapy software (Adaptiiv Inc., Halifax, Canada) allowing patient-specific optimization of the sleeves’ needle trajectories to a given patient’s target structures to produce easily printable CAD for adaptive brachytherapy planning.

Presenters

Ms Marie-Ève Roy Undergraduate Student, Polytechnique Montréal, Canada

She started university in 2017 in Engineering Physics Baccalaureate Program at Polytechnique Montréal. In the summer of 2018, she did an internship on neutron activation analysis in SLOWPOKE Laboratory at Polytechnique Montréal. In the summer of 2019, she did an internship on the integration of 3D printing in brachytherapy treatments in the Radio oncology department of the Centre Hospitalier de l’Université de Montréal. In the summer of 2020, she did an internship with a CRSNG scholarship on biomarkers for Huntington’s disease in the Mathematics and Industrial Engineering Department of Polytechnique Montréal. She will graduate from her baccalaureate’s degree this spring.