Print Email Facebook Twitter Multibody dynamic modeling of the behavior of flexible instruments used in cervical cancer brachytherapy Title Multibody dynamic modeling of the behavior of flexible instruments used in cervical cancer brachytherapy Author Straathof, R. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC) Meijaard, J.P. (TU Delft Mechatronic Systems Design) Perez, S.M. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC) Kolkman-Deurloo, Inger Karine K. (Erasmus MC) Nout, Remi A. (Erasmus MC) Heijmen, Ben J.M. (Erasmus MC) Wauben, L.S.G.L. (TU Delft Medical Instruments & Bio-Inspired Technology) Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology) van de Berg, N.J. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC) Date 2024 Abstract Background: The steep radiation dose gradients in cervical cancer brachytherapy (BT) necessitate a thorough understanding of the behavior of afterloader source cables or needles in the curved channels of (patient-tailored) applicators. Purpose: The purpose of this study is to develop and validate computer models to simulate: (1) BT source positions, and (2) insertion forces of needles in curved applicator channels. The methodology presented can be used to improve the knowledge of instrument behavior in current applicators and aid the development of novel (3D-printed) BT applicators. Methods: For the computer models, BT instruments were discretized in finite elements. Simulations were performed in SPACAR by formulating nodal contact force and motion input models and specifying the instruments’ kinematic and dynamic properties. To evaluate the source cable model, simulated source paths in ring applicators were compared with manufacturer-measured source paths. The impact of discrepancies on the dosimetry was estimated for standard plans. To validate needle models, simulated needle insertion forces in curved channels with varying curvature, torsion, and clearance, were compared with force measurements in dedicated 3D-printed templates. Results: Comparison of simulated with manufacturer-measured source positions showed 0.5–1.2 mm median and <2.0 mm maximum differences, in all but one applicator geometry. The resulting maximum relative dose differences at the lateral surface and at 5 mm depth were 5.5% and 4.7%, respectively. Simulated insertion forces for BT needles in curved channels accurately resembled the forces experimentally obtained by including experimental uncertainties in the simulation. Conclusion: The models developed can accurately predict source positions and insertion forces in BT applicators. Insights from these models can aid novel applicator design with improved motion and force transmission of BT instruments, and contribute to the estimation of overall treatment precision. The methodology presented can be extended to study other applicator geometries, flexible instruments, and afterloading systems. Subject cervical cancer brachytherapyfinite element modeling of source motionflexible instrumentmultibody dynamics To reference this document use: http://resolver.tudelft.nl/uuid:9da7e0ad-e8ce-40ed-a915-32ae9749046d DOI https://doi.org/10.1002/mp.16934 ISSN 0094-2405 Source Medical Physics, 51 (5), 3698-3710 Part of collection Institutional Repository Document type journal article Rights © 2024 R. Straathof, J.P. Meijaard, S.M. Perez, Inger Karine K. Kolkman-Deurloo, Remi A. Nout, Ben J.M. Heijmen, L.S.G.L. Wauben, J. Dankelman, N.J. van de Berg Files PDF Medical_Physics_-_2024_-_ ... rvical.pdf 2.72 MB Close viewer /islandora/object/uuid:9da7e0ad-e8ce-40ed-a915-32ae9749046d/datastream/OBJ/view