Shape-Memory Bladder Brachytherapy Catheters for Precise Tumor Coverage
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Solution Overview
Problem
Current brachytherapy methods for muscle-invasive bladder cancer are invasive and insufficient for accurately targeting tumor cells within the bladder, leading to complications such as urinary tract infections, wound dehiscence, and acute side effects.
Innovation Solution
A collapsible and curved radiation therapy system with flexible, shape-memory catheters that transition from an uncoiled delivery state to a coiled deployed state within the bladder, allowing for precise radiation delivery to target areas and optionally combining radiation with hyperthermia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interstitial brachytherapy using needles or catheters is used, then radiation can be delivered to the tumor site, but the treatment becomes invasive causing complications such as urinary tract infections, wound dehiscence, and acute side effects
Solution Approach 1:
The treatment approach is segmented into two distinct phases: a minimally invasive percutaneous insertion phase followed by a non-invasive transurethral catheterization phase. The catheter system is divided into separate components ( introducer needle, delivery catheter, radiation source) that can be inserted through different routes, allowing the radiation delivery portion to be introduced without surgical incisions.
Solution Approach 2:
The urethra serves as an intermediary pathway that allows the catheter to reach the bladder and tumor site without requiring external surgical incisions. This natural body passage mediates between the external environment and the internal treatment site, eliminating the need for percutaneous access and associated complications.
2Reliability
If current brachytherapy catheters are used, then radiation therapy can be applied, but the tumors are hard to target accurately within the bladder
Solution Approach 1:
The catheter incorporates a flexible distal portion with shape memory material that can dynamically change its configuration. The catheter can be inserted in a straight, collapsed state through the urethra, then transformed into an expanded, curved state within the bladder to conform to the three-dimensional tumor geometry, enabling accurate radiation delivery to irregularly shaped targets.
Solution Approach 2:
The catheter's physical parameters (shape, volume, configuration) are changed between insertion and deployment phases. The distal portion transitions from a compressed linear state during insertion to an expanded spherical or irregular configuration during treatment, allowing the radiation source to be positioned precisely around the tumor volume.
3Ease of operation
If invasive surgical approaches are used for brachytherapy catheter insertion, then catheters can be positioned in the bladder, but complications such as wound dehiscence and postoperative ileus occur
Solution Approach 1:
The invasive surgical step of percutaneous catheter insertion is extracted and replaced with a percutaneous needle puncture followed by transurethral catheter advancement. This removes the need for open surgical incisions and associated wound healing complications while maintaining the ability to position the catheter accurately in the bladder.
Solution Approach 2:
The catheter system utilizes the body's own urethral passage as the insertion route, allowing the device to service itself by navigating through natural anatomical pathways without requiring external surgical creation of access channels. This self-utilization of existing body structures eliminates surgical trauma.
4Object-affected harmful factors
If flexible catheters are used for brachytherapy, then non-invasive surface application is possible, but the catheters cannot maintain precise positioning or conform to complex tumor shapes
Solution Approach 1:
The catheter transitions from a static, fixed-shape design to a dynamic, transformable structure. The distal portion can change its configuration from a collapsed linear state during insertion to an expanded three-dimensional shape during treatment, allowing it to conform to complex tumor geometries while maintaining a simple profile during non-invasive insertion.
Solution Approach 2:
The catheter employs a nested structure where the distal portion can be collapsed within the proximal portion during insertion, similar to nested dolls. This allows the complex three-dimensional treatment configuration to be compressed into a simple linear form for non-invasive delivery through the urethra, then expanded in situ to achieve the required shape for accurate radiation delivery.
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
The system enables less invasive treatment with improved accuracy and coverage of tumor cells, reducing the need for direct positioning at the treatment site and minimizing side effects.
Implementation Method 1
The distal portion of the one or more catheters may be flexible and/or made of a shape memory material. Accordingly, the distal portion of the one or more catheters is transitionable from the uncoiled delivery state to the coiled deployed state when exposed beyond the distal end of the sheath
Data Source
AI summary
Systems and methods for minimally invasively delivering radiation therapy to a patient, e.g., with bladder cancer, is provided. The radiotherapy system includes one or more catheters that may be introduced to a patient's anatomical structure via a sheath using an intracavitary approach. The proximal end of the one or more catheters may be coupled to an afterloader for selectively delivering the radiation therapy, and the distal portion of the one or more catheters is transitionable between an uncoiled delivery state within the sheath and a coiled deployed state having a spherical configuration within the anatomical structure of the patient, such that the one or more catheters contacts at least a portion of the anatomical structure in the deployed state.