D-Shaped Collimator for Sharp Radiation Dose Gradient
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Solution Overview
Problem
Current radiation therapy methods struggle to deliver a uniformly high dose of radiation to target tissues while minimizing exposure to adjacent non-target tissues due to limitations in creating a sharp dose gradient at the tissue boundaries, leading to 'dose spillage' and uneven radiation distribution.
Innovation Solution
A system utilizing a D-shaped collimator with a fixed opening and divergence, capable of fully rotating to maintain the central axis on or adjacent to the straight edge of the D-shaped cross-section, combined with a patient support system and computerized control for coordinated beam rotation and patient movement, allows for precise sculpting of radiation beams to achieve a sharp dose fall-off at tissue boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple overlapping radiation beams are used to treat complex tissue volumes, then the radiation dose can be concentrated at the target isocenter, but the beams also overlap in non-target tissue causing dose spillage and making it difficult to deliver uniformly high dose to target while avoiding non-target tissue
Solution Approach 1:
The radiation beam is segmented into multiple discrete small circular collimated beams that are precisely directed at the isocenter. By using many individual sources of radiation with individual collimators, each beam can be independently controlled and positioned, allowing the target to be treated through superposition of multiple precise beams while minimizing overlap in non-target tissue.
Solution Approach 2:
The system applies different beam characteristics to different regions: highly concentrated overlapping beams are directed precisely at the target isocenter to deliver high dose, while the geometric arrangement ensures that non-target tissue receives minimal or no overlapping beam exposure. This creates locally optimized dose distribution with high precision at the target and minimal exposure elsewhere.
2Adaptability or versatility
If the radiation beam is moved by moving the collimator to treat different areas, then the beam can cover the target tissue, but the mechanical accuracy limits the sharpness of dose gradient at tissue boundaries
Solution Approach 1:
Instead of physically moving the entire collimator assembly to change beam direction, the system uses multiple fixed collimators positioned at different locations and angles. Each collimator creates an identical or similar beam pattern, and by activating different collimators, the beam can be effectively 'copied' to different positions around the target, achieving beam movement without mechanical repositioning of the main collimator structure.
3Productivity
If traditional circular collimators are used with isocentric mounting, then multiple beams can be directed at the isocenter, but the circular geometry cannot create sharp dose fall-off at irregular tissue boundaries
Solution Approach 1:
The system replaces traditional circular collimators with asymmetric rectangular or square collimator openings. This asymmetric geometry allows the beam profile to better match irregular tissue boundaries and creates sharper dose fall-off characteristics. The rectangular aperture shape provides more defined edges and better conformability to the target geometry compared to circular openings, enabling precise dose sculpting at tissue boundaries.
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 enables a uniform dose delivery to target tissues with a sharp drop-off at the boundaries, reducing exposure to non-target tissues and improving the precision of radiation therapy by allowing beams to traverse from all directions, thus enhancing the therapeutic effectiveness while minimizing exposure to non-target tissues.
Implementation Method 1
A collimator with a fixed opening and divergence, is provided. The collimator (a) shapes a beam of radiation to have a D-shaped cross-section, (b) maintains the central axis of the beam of radiation on or adjacent to the straight edge of the D-shaped cross-section of the beam of radiation
Implementation Method 2
By applying a precise dosage of radiation to the isocenter, tumors and other lesions, which are otherwise inaccessible or inadequate for open surgery, can be ablated. Typically, only a single or a few treatments are necessary. Radiosurgery typically involves the use of multiple small circular collimated radiation beams directed at the isocenter. Consequently, radiation is concentrated at the isocenter through the superposition of multiple small overlapping beams
Implementation Method 3
A system utilizing a D-shaped collimator with a fixed opening and divergence, capable of fully rotating to maintain the central axis on or adjacent to the straight edge of the D-shaped cross-section, combined with a patient support system and computerized control for coordinated beam rotation and patient movement
Data Source
Figure 1a~1d
Figure 2a~2d
Figure 3a~3d
AI summary
A method of irradiating a target tissue in a patient comprising positioning the patient on a patient support system so that the target tissue in the patient is within irradiating distance of at least one source of a beam of radiation and moving the patient support system relative to the at least one source of a beam of radiation and, coordinately with movement of the patient support system, rotating the at least one source of radiation relative to the target tissue, which comprises and/or is adjacent to a non-target tissue, so that the center of rotation of the beam of radiation is placed at one or more desired locations within the target tissue, while simultaneously and/or sequentially irradiating the target tissue; a collimator; a method of making such a collimator; a system for irradiating a target tissue in a patient; and a method of planning irradiation of a target tissue in a patient.