Multi-leaf collimator identification marks for radiation therapy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The resolution of the irradiation field shape in multi-leaf collimators depends on leaf thickness, but thinning leaves and increasing their number leads to densely aligned markers that are difficult to accurately identify, resulting in challenges with real-time position detection during radiation therapy.
Innovation Solution
A multi-leaf collimator design with identification marks on each leaf that are wider than the leaf thickness, allowing for larger gaps between marks than between leaves, enabling precise detection even with standard camera resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the leaves are thinned and the number of leaves is increased to improve the resolution of the irradiation field, then the resolution of the irradiation field is improved, but the markers become densely disposed and cannot be independently identified, resulting in inaccurate leaf position detection
Solution Approach 1:
The identification mark extends in the thickness direction of the leaf, creating a protrusion that protrudes from the leaf surface. This dimensional extension allows the marker to be captured as a distinct protruding structure in images, enabling independent identification even when markers are densely disposed due to thinned leaves.
2Measurement precision
If the resolution of the camera is improved to allow individual markers to be more accurately identified, then the identification accuracy of markers is improved, but the data volume of captured images increases, causing long image processing time and inability to detect leaf positions in real time
Solution Approach 1:
The identification mark is formed by coating the entire outer surface of the protrusion with a material having a different color from the leaf. This color contrast makes the marker easily distinguishable in images, allowing accurate identification with standard camera resolution and enabling real-time processing.
3Measurement precision
If the identification mark is made wider than the leaf thickness to create larger gaps between marks, then the gaps between adjacent identification marks become larger than gaps between leaves, but the marker unit occupies more space
Solution Approach 1:
The identification mark is formed by coating the outer surface of the protrusion, creating a thin film structure. This approach provides sufficient detection precision with color contrast while maintaining a compact size that does not excessively increase the marker unit volume.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-leaf collimator (60) includes a plurality of leaves (70) aligned in a thickness direction of the leaf, a driving device (90) which advances and retracts the leaves (70) with respect to radiation (Sr), and an identification mark (102) identifiable at least from a direction perpendicular to both the advancing and retracting direction of the leaves (70) and the thickness direction of the leaf(70) to detect positions of the leaves (70), wherein, when the plurality of leaves (70) are disposed in a preset reference position (P), gaps (d2) between adjacent identification marks (102) in the thickness direction are formed to be larger than gaps (d1) between adjacent leaves (70) in the thickness direction.