Self-Shielded Radiotherapy System with Rotating Shielding Arch
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Solution Overview
Problem
Current radiation oncology systems are costly and limited in availability due to the need for extensive shielding, making it difficult to integrate high-quality fan beam CT imagers with linac-based X-ray sources, which results in inferior image quality and increased treatment errors, and restricts access to radiotherapy in developing and rural areas.
Innovation Solution
A self-shielded image-guided radiation oncology system that integrates a fan beam CT scanner with a linac-based X-ray source, reducing the need for a conventional vault and utilizing a shielding arch and beam stop to attenuate primary radiation, allowing for high-quality image-guided treatment with minimal shielding requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If extensive concrete shielding is used to protect medical personnel and the public from radiation, then radiation protection is improved, but system cost and complexity increase significantly
Solution Approach 1:
The shielding system is segmented into multiple functional components: a movable shielding barrier that rotates with the linac, fixed shielding walls positioned strategically, and a beam stop. This segmentation allows each component to address specific radiation protection needs rather than requiring a monolithic vault structure, reducing overall system complexity and cost.
Solution Approach 2:
The shielding barrier is made movable, rotating synchronously with the linear accelerator around the patient. This dynamic shielding approach ensures radiation protection is maintained throughout the treatment arc while allowing the treatment area to be accessible during operation, eliminating the need for a permanently enclosed vault structure.
2Measurement precision
If high-quality fan beam CT imaging is integrated with linac-based X-ray sources, then image quality and treatment precision are improved, but system cost and facility requirements increase
Solution Approach 1:
The fan beam CT scanner and linac-based X-ray source are merged into a single integrated system that shares common structural components, positioning mechanisms, and control systems. The CT scanner and treatment head are co-located on the same rotating structure, allowing seamless transition between imaging and treatment modes without requiring separate facilities or complex multi-system integration.
Solution Approach 2:
The integrated system provides multiple functions through a unified platform: the fan beam CT scanner performs high-quality diagnostic imaging and treatment verification, while the linac delivers therapeutic radiation. The shared rotating structure and positioning system serve both imaging and treatment functions, reducing overall system complexity compared to separate systems.
3Object-affected harmful factors
If conventional vaults with extensive shielding are constructed, then radiation safety is improved, but treatment accessibility and geographic availability worsen
Solution Approach 1:
The movable shielding barrier rotates with the linac, providing dynamic radiation protection that maintains safety throughout the treatment arc while allowing the treatment area to be accessible during operation. This eliminates the need for a permanently enclosed vault structure, enabling installation in locations that would not support conventional vault construction.
Solution Approach 2:
The shielding approach transitions from a static, three-dimensional enclosed vault to a dynamic, one-dimensional rotating barrier that moves with the treatment beam. This dimensional change allows radiation protection to be provided only in the direction of the radiation beam rather than requiring complete enclosure, significantly reducing facility requirements and improving geographic accessibility.
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 accurate and cost-effective radiotherapy treatment by integrating high-quality fan beam CT imaging with linac-based X-ray sources, reducing treatment errors and making radiotherapy more accessible by eliminating the need for expensive vaults, thus expanding access to cancer treatment in underserved areas.
Implementation Method 1
utilizing a shielding arch and beam stop to attenuate primary radiation
Implementation Method 2
scatter radiation produced by the patient tissues and parts of the Radiotherapy system that are exposed to the primary radiation
Data Source
AI summary
An image-guided radiotherapy system adapted to be juxtaposed adjacent a CT scanner comprises a frame having an orifice adapted to permit passage therethrough of a couch on which a patient is positioned, together with a gantry assembly rotatably mounted on the frame in which the gantry assembly comprises a shielding cylinder having an orifice therethrough in alignment with the orifice in the frame. The shielding cylinder has affixed thereto a linac-based treatment head configured to provide radiotherapy, and a beamstop positioned angularly opposite the treatment head to absorb radiation from the treatment head. The shielding cylinder provides sufficient shielding of radiation scattered from the patient and the remainder of the system to not require a conventional vault. In some embodiments an arch may be used instead of a cylinder.