Surface Brachytherapy Applicator Curvature Mitigation
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Solution Overview
Problem
Conventional surface brachytherapy applicator designs face challenges with patient-to-patient reproducibility of source trajectories due to manual technical skills, and they struggle with extreme curvatures, which can impede catheter placement and affect dose distribution.
Innovation Solution
The method involves generating catheter channel trajectories laterally from both sides of a cut plane bisecting the surface brachytherapy applicator model, allowing for spatial distribution and adjustment of catheter channels to reduce curvature, thereby improving reproducibility and dose homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional manual fabrication methods are used for surface brachytherapy applicators, then flexibility in customization is improved, but patient-to-patient reproducibility of source trajectories deteriorates
Solution Approach 1:
The patent uses 3D printing technology to create physical applicators from digital models. The digital model serves as a precise copy that can be reproduced identically across different patients, ensuring consistent source trajectories while maintaining customization capability through digital model modification.
Solution Approach 2:
The patent modifies geometric parameters of the applicator design by generating catheter channel trajectories laterally from both sides of a cut plane, adjusting the radius of curvature to meet minimum thresholds. This parameter optimization resolves the contradiction by enabling precise control over trajectory geometry while maintaining design flexibility.
2Adaptability or versatility
If catheter channels are designed to follow patient surface contours, then adaptability to patient anatomy is improved, but curvature of catheter channels increases
Solution Approach 1:
The patent divides catheter channel trajectory generation into two segments: generating trajectories laterally from both sides of a cut plane bisecting the applicator model. This segmentation allows each segment to have reduced curvature requirements while maintaining overall anatomical adaptation.
Solution Approach 2:
The patent explicitly adjusts the radius of curvature parameter of catheter channels to exceed a minimum threshold value. By changing this geometric parameter, the design maintains anatomical adaptation while ensuring catheter placement feasibility and dose distribution homogeneity.
3Adaptability or versatility
If extreme curvatures are accommodated in catheter channels, then adaptability to complex patient surfaces is improved, but catheter placement safety deteriorates
Solution Approach 1:
The patent sets a minimum threshold for the radius of curvature parameter and adjusts catheter channel geometries to exceed this threshold. This parameter constraint ensures that extreme curvatures are eliminated, making catheter placement safe while still accommodating complex patient surfaces through alternative trajectory designs.
Solution Approach 2:
The patent uses digital modeling to copy and refine catheter channel trajectories before fabrication. This allows virtual optimization of curvature parameters to ensure safety thresholds are met while maintaining adaptability to the patient's complex surface anatomy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces patient-surface-induced curvature of catheter channels, ensuring safer and more effective radiation delivery by minimizing the risk of radiation exposure and improving treatment plan consistency.
Implementation Method 1
The general concept of brachytherapy consists of introducing a sealed radioactive source (or seed) into close proximity of a cancer tissue allowing a natural radioactive decay of the source atoms to irradiate the target. High-dose-rate (HDR) brachytherapy uses most commonly Iridium-192 (Ir-192) sealed sources with activities greater than 12 Gy/hour to treat patients. Ir-192 decays with an average energy of 380 keV and a half-live of 73.8 days.
Implementation Method 2
The source is confined in the radiation protected container called 'afterloader' which determines the position of the source within the catheter (applicator), dwell times at each position, and provides shielding for clinical staff when not in use. Once the treatment is over, the source retracts back into the afterloader which acts as a protecting safe from ionizing radiation produced by Ir-192 nuclear decay.
Data Source
AI summary
Systems and methods are provided for generating surface brachytherapy applicators in which catheter channel trajectories are generated laterally from both sides of a cut plane bisecting an initial model of the surface brachytherapy applicator model, thereby mitigating the effects of patient-surface-induced curvature. The catheter channels may be defined based on catheter channel trajectories that are spatially distributed, relative to the cut plane, on both sides of the cut plane, and spatially offset relative to a patient-facing surface of the surface brachytherapy applicator model. In some example embodiments, catheter channel trajectories are spaced relative to the cut plane such that neighbouring catheter channel trajectories are evenly spaced along a set of contours. Prior to fabrication, the local radius of curvature of catheter channels may be adjusted in a manual or automated manner to exceed a threshold.