Multi-Leaf Collimator Leaf Pair Offset Adjustment
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Solution Overview
Problem
Radiation leakage between leaves of a multi-leaf collimator (MLC) during radiation therapy can lead to undesired radiation accumulation in healthy tissues, necessitating methods to adjust the MLC and reduce leakage distribution.
Innovation Solution
A method and system for adjusting the position of closed leaf pairs in a multi-leaf collimator by determining offsets, either randomly or based on a treatment plan, to move the leaves before or during the treatment process, thereby dispersing the radiation leakage and minimizing its impact on healthy tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the MLC leaves are kept stationary during treatment, then the treatment process is simple and fast, but radiation leakage accumulates in specific spots of healthy tissue
Solution Approach 1:
The patent applies dynamics by transitioning the MLC leaves from a stationary state to a dynamic state during treatment. The leaves are moved along the beam direction based on predetermined offsets that vary between treatment fractions, transforming the static collimation structure into a dynamic system that actively disperses radiation leakage throughout the treatment volume rather than allowing accumulation at fixed locations.
Solution Approach 2:
The patent employs preliminary action by pre-determining the offsets for leaf movements before the treatment process begins. These offsets are calculated in advance based on treatment planning parameters, allowing the MLC system to be prepared with a predetermined movement strategy that will effectively disperse radiation leakage without requiring complex real-time adjustments during beam delivery.
2Object-affected harmful factors
If the MLC leaves are adjusted frequently during treatment, then radiation leakage is reduced, but the treatment time increases
Solution Approach 1:
The patent implements periodic action by applying leaf movements at specific intervals corresponding to treatment fractions rather than continuously during the entire treatment process. The leaves remain stationary during beam delivery but are repositioned between fractions according to predetermined offsets, creating a periodic pattern of movement that reduces radiation leakage while maintaining efficient treatment delivery timing.
Solution Approach 2:
By pre-calculating and predetermined the leaf offsets before treatment begins, the system avoids the need for complex real-time calculations and adjustments during beam delivery. This preliminary planning allows the treatment to proceed efficiently with minimal interruptions, reducing treatment time while still achieving the goal of dispersing radiation leakage through fractionated leaf movements.
3Object-affected harmful factors
If the MLC structure is modified to reduce leakage, then radiation leakage is minimized, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the positional parameters of the MLC leaves rather than changing the physical structure of the device. By adjusting the leaf positions along the beam direction according to predetermined offsets, the system achieves reduced radiation leakage through parameter optimization rather than structural modification, maintaining the simplicity of the existing MLC hardware design.
Solution Approach 2:
The patent replaces potential mechanical structural modifications (such as adding physical barriers or changing leaf geometry) with a control-based approach. Instead of modifying the mechanical structure of the MLC to reduce leakage, the system uses predetermined positional adjustments and control algorithms to achieve the same protective effect, substituting mechanical complexity with computational control.
Data Source
AI summary
The present disclosure provides systems and methods for adjusting a multi-leaf collimator (MLC) in a treatment process according to a treatment plan or a portion thereof. The method may comprise: moving one or more leaves of a multi leaf collimator (MLC), and forming one or more closed leaf pairs in moving process, the moving including: obtaining an offset for each closed leaf pair of the one or more closed leaf pairs, wherein the offset is no larger than a predetermined threshold, and the predetermined threshold is determined in a treatment planning process that generates a radiation treatment plan; and causing the one or more closed leaf pairs to move based on one or more offsets corresponding to the one or more closed leaf pairs, before or during a implementation of the radiation treatment plan.