Rotatable Shield Assemblies for Brachytherapy Dose Precision

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Solution Overview

Problem

Current brachytherapy techniques face challenges in achieving optimal dose distribution due to the proximity of tumors to sensitive organs, leading to excessive radiation exposure to healthy tissues, necessitating the development of a radiation shielded delivery system that can accurately direct radiation to tumor sites while minimizing exposure to organs at risk.

Innovation Solution

A delivery system comprising rotatable shield assemblies with radiation shielding material, driven by a mechanism that synchronously rotates the assemblies to position the shielding material away from the tumor site, allowing precise delivery of radionuclides and restricting radiation to the target area, utilizing a drive assembly with interlocking and link mechanisms for precise control and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If brachytherapy sources are used to deliver high radiation dose to the tumour, then the radiation dose to the target volume is improved, but the radiation exposure to surrounding healthy tissues and organs at risk increases

Engineering Contradiction:
Improvedose distribution precisionVSAvoidradiation exposure to healthy tissues
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The shield assembly is segmented into multiple independent radiation shielding elements (first shielding element, second shielding element, etc.) that can be individually positioned and oriented. Each element can be independently adjusted to create customized radiation shielding patterns, allowing precise control over which areas receive radiation and which are protected, thereby resolving the contradiction between delivering high dose to tumor and protecting healthy tissues.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shield assembly incorporates movable and rotatable shielding elements that can be dynamically adjusted during the brachytherapy procedure. The first and second shielding elements can be rotated about different axes and positioned at various angles, enabling real-time optimization of radiation shielding to match the specific anatomical configuration and tumor location, thus achieving precise dose distribution while minimizing exposure to organs at risk.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If radiation shielding material is added to protect organs at risk, then the protection of healthy tissues is improved, but the device complexity increases

Engineering Contradiction:
Improveradiation exposure to healthy tissuesVSAvoidshield assembly structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The radiation shielding elements are nested within the applicator structure, with the first shielding element positioned within the first cavity and the second shielding element within the second cavity of the applicator. This nested configuration integrates the shielding function into the existing brachytherapy delivery system without requiring separate external shielding devices, thereby providing protection while limiting the increase in overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The shield assembly is designed to be compatible with standard brachytherapy afterloaders and applicators, allowing it to perform multiple functions: delivering radiation sources to the tumor while simultaneously providing adjustable radiation shielding. The same movable elements serve both as positioning mechanisms for the shielding material and as adjustment mechanisms for optimizing radiation protection, reducing the need for additional separate control systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If shielded rotating catheters are used to direct radiation, then the dose distribution to tumour is improved, but the device complexity and operational complexity increase

Engineering Contradiction:
Improvedose distributionVSAvoidoperation complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The radiation shielding function is merged with the existing brachytherapy applicator structure. The shield assembly is integrated into the applicator that is already inserted into the patient, combining the tumor targeting function with the radiation shielding function in a single integrated device. This eliminates the need for separate shielding devices and reduces operational complexity by consolidating functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shield assembly is designed to be automatically positioned and configured by the afterloader system during the brachytherapy procedure. The movable shielding elements can be automatically adjusted to predetermined positions based on treatment planning, reducing the need for manual adjustment and simplifying the operational process while maintaining precise dose distribution.

Inventive Principle:
Principle #25Self-service

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 effectively reduces radiation exposure to healthy tissues by precisely directing radiation to the tumor site, enhancing therapeutic ratios and minimizing integral dose exposure to organs at risk, thereby improving treatment outcomes for various cancer types.

Implementation Method 1

A radiation shielding material extending about a circumferential portion of the tubular body of the needle and disposed radially outwardly of the bore

Methodology Applied
Scientific EffectRadiation shielding: Absorption (EM radiation)

Data Source

PatentEP3558437B1Delivery system for intensity modulated high dose rate brachytherapy with intermediate energy brachytherapy isotopes
Publication Date: 2023.08.02 MCGILL UNIV
  • EP3558437B1 patent drawingFigure 1~2
  • EP3558437B1 patent drawingFigure 3~4A
  • EP3558437B1 patent drawingFigure 4B

AI summary

A delivery system and method for radiation shielded brachytherapy comprises a drive assembly, and a plurality of shield assemblies, pivotally mounted to the drive assembly, each having a tubular body defining an outer surface and a bore longitudinally extending between opposite ends of the tubular body. Each of the shield assemblies comprises radiation shielding material extending about a circumferential portion of the tubular body and disposed between the outer surface and the cavity. An interlocking system is operatively mounted to the rotating assembly, and engages a group of the plurality of shield assemblies. The interlocking system is configured for transmitting a rotational input received from a driving mechanism to the group of shield assemblies, for synchronously rotating each shield assembly of the group about their respective longitudinal axis.