Automated planning of patient-tailored brachytherapy applicators for cervical cancer patients with vaginal involvement
N.M. Jonk (TU Delft - Mechanical Engineering)
R. Straathof – Mentor (TU Delft - Mechanical Engineering)
J. Dankelman – Mentor (TU Delft - Mechanical Engineering)
Nick J.van de Berg – Graduation committee member (Erasmus MC)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Purpose. The ARCHITECT applicator is a 3D-printed, patient-tailored intracavitary/interstitial (IC/IS) brachytherapy (BT) applicator concept in which channel configurations are automatically generated and optimised. Previous work showed that dosimetric advantages of this applicator are not uniform across patients, and that cases with vaginal tumour extension may be more challenging to treat. This study investigated the interaction between ARCHITECT applicator configuration generation and automated treatment planning in BiCycle, with the aim of identifying potential workflow adaptations to improve treatment plans for patients with vaginal extension.
Methods. Treatment plans of the first BT fraction were analysed for 85 patients with LACC previously treated with the Utrecht or Venezia applicator. Of these patients, 32 had vaginal extension greater than 10 mm. In this study, three objectives were addressed. First, dosimetric analysis compared treatment plans generated for the conventional applicator configuration used clinically with plans generated for the ARCHITECT applicator. Second, the interplay between the ARCHITECT RTPlan conversion and automated planning software BiCycle was assessed using a MATLAB-based validation tool. This tool systematically modified the applicator setup in the RTPlan to evaluate the effect on BiCycle-generated treatment plans and validate BiCycle’s handling of applicator configuration. Third, three strategies were investigated to improve ARCHITECT treatment plans for a difficult to irradiate patient case with vaginal extension: adjustment of needle dwell time smoothing, inclusion of inferior dwell positions during geometric coverage planning, and generation of dedicated IC channels.
Results. The ARCHITECT applicator showed dosimetric advantages over the conventional applicator in both patients with and without vaginal extension. In patients without vaginal extension, this advantage was mainly reflected in improved OAR sparing. In patients with vaginal extension, the advantage was more apparent in target coverage. The RTPlan processing validation showed that systematic modifications of the applicator setup resulted in expected changes in BiCycle-generated treatment plans. The strategy involving the addition of dedicated IC channels showed the most favourable effect on ARCHITECT plan quality for vaginal extension.
Conclusion. This study indicates that the ARCHITECT applicator can be used for patients with vaginal extension, although the conventional applicator may remain preferable in specific patient cases. The RTPlan processing validation supported quality assurance by confirming that BiCycle responded as expected to systematic changes in applicator setup. Including IC needle channels during coverage planning in the ARCHITECT workflow was the most promising strategy to improve treatment plans for patients with vaginal extension. This strategy should be further refined and evaluated for a larger patient cohort with vaginal extension to assess its future potential.
help_outline