Couch Rotation Compensation via Isocenter Shifting for Non-Coplanar Radiotherapy
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Solution Overview
Problem
Radiation therapy systems with couches having limited rotation angle ranges are unable to support non-coplanar treatments effectively, as the limited angle range restricts the dose spread and patient positioning adjustments.
Innovation Solution
The method involves generating a first dose spread by shifting the isocenter location of the radiation system and a second dose spread by shifting the couch angle, and combining these to maximize the dose spread in both sides of the target, effectively increasing the effective couch rotation angle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the couch rotation angle range is limited by design, then the device structure is simplified and manufacturing is easier, but the non-coplanar treatment capability and dose spread are reduced
Solution Approach 1:
The patent introduces isocenter shifting as an additional degree of freedom to compensate for limited couch rotation. By moving the isocenter position in space, the system creates a new dimension for achieving non-coplanar beam arrangements, effectively transforming a 2D couch rotation problem into a 3D isocenter positioning problem that achieves the same therapeutic goal without requiring full couch rotation capability
Solution Approach 2:
The patent changes the operational parameters of the radiation therapy system by decoupling the isocenter position from the mechanical rotation angles. Instead of relying solely on couch rotation angles to achieve non-coplanar geometry, the system varies isocenter coordinates (x, y, z positions) to create equivalent beam arrangements, effectively substituting positional parameters for angular parameters
2Device complexity
If the couch rotation angle range is limited, then the mechanical complexity is reduced, but the dose spread volume is insufficient
Solution Approach 1:
The patent expands the dose spread volume by introducing isocenter shifting in three-dimensional space. This creates additional spatial dimensions for beam arrangement, allowing radiation beams to converge from effectively more angles and directions, thereby increasing the volume over which dose can be distributed without requiring increased couch rotation capability
Solution Approach 2:
The isocenter shifting mechanism serves multiple functions: it enables non-coplanar beam arrangements, increases dose spread volume, and maintains compatibility with existing couch designs. This multi-functional approach allows a single isocenter adjustment mechanism to address both the limited angle range problem and the dose spread volume problem simultaneously
3Adaptability or versatility
If the couch rotation angle is shifted for non-coplanar treatment, then the dose spread is improved, but the patient positioning adjustment range is reduced
Solution Approach 1:
The patent resolves the conflict between non-coplanar treatment capability and patient positioning flexibility by introducing isocenter shifting as an alternative mechanism. Instead of using couch rotation for both purposes, the system uses isocenter position adjustments to achieve non-coplanar geometry, freeing up couch rotation capability to be dedicated to patient positioning adjustments
Data Source
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AI summary
Systems, devices, and methods for increasing the dose spread in treatment systems delivering non-coplanar treatments to a patient using a couch 112 with limited couch rotation angle ranges, the increasing including combining dose spreads generated by shifting ±L the isocenter I0 location and shifting the couch angles ±α in such a way as to maximize the dose spread in both sides of the patient, and systems, devices and methods for generating non-coplanar treatment plans with different couch-kick ranges from which the non-coplanar treatment plan that takes into account the couch shifts needed for correcting patient positioning is selected for delivery.