Soft Tissue Shift Determination via Bony Reference in Radiotherapy
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Solution Overview
Problem
During radiotherapy, soft tissue body parts can shift in position between planning and treatment, leading to potential misalignment of the treatment beam, which may result in undesired irradiation of organs at risk, and existing methods for recalculating dose distributions are computationally intensive and often unnecessary.
Innovation Solution
A method that determines the shift in the position of soft tissue body parts by correlating the planned and actual positions of bony body parts, allowing for a net shift assessment, and decides whether to recalculate the dose distribution based on predetermined limits, thereby optimizing the radiotherapy process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dose distribution is recalculated based on the current position of the patient, then the accuracy of treatment targeting is improved, but the computational effort and time required increase significantly
Solution Approach 1:
The patent applies partial action by selectively recalculating the dose distribution only when the net soft tissue shift exceeds a predetermined threshold. Instead of always performing full dose recalculation, the system first checks the magnitude of tissue displacement and only triggers computationally intensive recalculation when necessary, thereby reducing overall computational time while maintaining treatment accuracy when needed.
Solution Approach 2:
The patent segments the shift assessment into two distinct components: bony tissue shift and soft tissue shift. By separating these assessments and applying different evaluation criteria to each, the system can efficiently determine whether full dose recalculation is necessary. The bony shift serves as a reference frame, while the soft tissue shift is evaluated relative to this frame, allowing for optimized computational decision-making.
2Measurement precision
If the dose distribution is recalculated for every position change, then the treatment accuracy is maintained, but the productivity and efficiency of the radiotherapy process decrease
Solution Approach 1:
The system performs partial dose recalculation only when the net soft tissue shift exceeds the predetermined threshold, avoiding unnecessary full recalculations. This selective approach maintains treatment accuracy when shifts are significant while improving overall process efficiency by skipping redundant calculations when tissue positions remain within acceptable limits.
Solution Approach 2:
The system automatically assesses tissue shifts and determines whether dose recalculation is necessary without requiring manual intervention or judgment. The predetermined threshold provides an automated decision criterion that enables the system to self-manage the recalculation process, improving workflow efficiency while maintaining consistent quality standards.
3Device complexity
If the position of soft tissue is determined independently of bony tissue shift, then the soft tissue positioning is simplified, but the accuracy of determining net soft tissue shift decreases
Solution Approach 1:
The patent segments the positioning assessment into two independent but related components: bony tissue shift assessment and soft tissue shift assessment. By separating these assessments, the system maintains relative simplicity in each individual assessment while improving overall accuracy through the combination of both measurements. The bony shift provides a stable reference frame that enhances the precision of soft tissue shift measurement.
Solution Approach 2:
The bony tissue shift acts as an intermediary reference that mediates the measurement of soft tissue shift. By using the bony structures as an intermediate reference frame, the system can more accurately determine the net soft tissue shift relative to the original treatment plan, improving measurement precision without significantly increasing overall system complexity.
Data Source
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AI summary
A medical data processing method for determining a change in the position of a soft tissue body part of a patient's body, the data processing method being constituted to be executed by a computer and comprising the following steps: a) acquiring (S10, S20) bony body part planned position data comprising bony body part planned position information describing a planned position of a bony body part of the patient's body; b) acquiring (S10, S20) soft tissue body part planned position data comprising soft tissue body part planned position information describing a planned position of the soft tissue body part; c) acquiring (S11, S21) bony body part actual position data comprising bony body part actual position information describing an actual position of the bony body part; d) acquiring (S11, S21) soft tissue body part actual position data comprising soft tissue body part actual position information describing an actual position of the soft tissue body part; e) determining (S12, S22), based on the bony body part planned position data and the bony body part actual position data, bony body part position transformation data comprising bony body part position transformation information describing a bony body part position transformation between the planned position and the actual position of the bony body part; f) determining (S13, S23), based on the bony body part position transformation data and the soft tissue body part actual position data, soft tissue transformed actual position data comprising soft tissue transformed actual position information describing a transformed actual position of the soft tissue body part; g) determining (S14, S24), based on the soft tissue transformed actual position data and the soft tissue body part planned position data, soft tissue body part position transformation data comprising soft tissue body part position transformation information describing a soft tissue body part position transformation between the planned position of the of the soft tissue body part and the transformed actual position of the soft tissue body part.