Variable-Volume Brachytherapy Stent for Adjustable In Vivo Dosimetry
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Solution Overview
Problem
Conventional brachytherapy methods risk harming healthy tissue adjacent to targeted diseased tissue due to fixed radiation exposure and volume, necessitating a device and method for varying radiation dose and volume during treatment.
Innovation Solution
A brachytherapy device with a first and second radio-isotope support structure, allowing reversible adjustment of radiation dose and volume without relocating the device, using elastic, hydraulic, and osmotic pressure, or shape memory materials to conform to the treatment site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional brachytherapy uses fixed radiation exposure and volume, then the treatment is simple to implement, but healthy tissue adjacent to targeted diseased tissue is harmed
Solution Approach 1:
The brachytherapy device employs a variable volume balloon that can be dynamically adjusted after implantation. The balloon's volume is controlled by inflating or deflating it with fluid through an access port, allowing the radiation dose volume to be varied in response to treatment response. This dynamic adjustment capability enables the system to adapt radiation delivery to match the actual tumor boundaries and protect healthy tissue, resolving the contradiction between fixed implementation simplicity and adaptive radiation dosing.
Solution Approach 2:
The device changes the physical parameter of balloon volume to control radiation exposure. By adjusting the volume parameter of the balloon (through fluid infusion or withdrawal), the system varies the volume of tissue exposed to radiation from the embedded radioactive source. This parameter change mechanism allows precise control over radiation dose distribution, enabling differentiation between tumor tissue and adjacent healthy tissue, thereby reducing collateral damage while maintaining treatment effectiveness.
2Adaptability or versatility
If the device is made reversible and adjustable in vivo, then radiation volume can be optimized, but the device complexity increases
Solution Approach 1:
The brachytherapy device is segmented into functionally independent components: a radioactive source embedded in the balloon wall, a fluid delivery system with catheter and access port, and the balloon structure itself. This segmentation allows each component to perform its specific function independently - the radioactive source provides radiation, the fluid system controls balloon volume, and the balloon provides the adjustable radiation boundary. The modular segmented design reduces overall system complexity while enabling reversible in vivo adjustment of radiation volume.
Solution Approach 2:
The patent introduces fluid as an intermediary substance to control balloon volume and thereby control radiation exposure. Instead of complex mechanical adjustment mechanisms, the system uses simple fluid infusion and withdrawal through a catheter to adjust the balloon size. This intermediary approach simplifies the adjustment mechanism - clinicians only need to control fluid flow to achieve reversible radiation volume adjustment, significantly reducing device complexity compared to direct mechanical adjustment systems.
3Ease of operation
If the radiation dose is kept constant, then treatment planning is simplified, but the medicament volume cannot be clinically adjusted
Solution Approach 1:
The system maintains constant radiation source activity while dynamically adjusting the balloon volume to control the volume of tissue receiving the radiation dose. The radioactive source remains fixed in strength, but the balloon's adjustable volume creates a variable radiation field boundary. This dynamic volume control allows clinicians to adjust the treated volume without changing the source strength, simplifying treatment planning while providing clinical flexibility in dosing volume based on tumor response and patient condition.
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
Enables precise and reversible variation of radiation dosage and volume in vivo, minimizing collateral damage to healthy tissue by conforming to the treatment site's geometry and physiological conditions.
Implementation Method 1
the manipulation of the volume and dosage may occur spontaneously after implantation. These dimension changes may include changes to its length and cross sections (i.e., diameters) and may be induced by elastic, hydraulic and/or osmotic pressure, mechanical bias imposed by the shape memory constituents of the device
Implementation Method 2
The housings may be leak proof so as to prevent leakage of fluid residing within the voids defined by the housings
Implementation Method 3
elastic, hydraulic, and osmotic pressure, or shape memory materials to conform to the treatment site
Implementation Method 4
elastic, hydraulic, and osmotic pressure, or shape memory materials to conform to the treatment site
Data Source
AI summary
A method for varying the radiation dosage in vivo during brachytherapy treatment is provided. The method includes infinitely varying the volume of radiation exposed to the patient. This volume variation feature is utilized as clinically indicated and can further reduce the risk of slippage of the device in situ.