Radiation Therapy Planning Apparatus for Moving Targets
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Solution Overview
Problem
Current radiation therapy planning methods face challenges in efficiently creating therapy plans that accurately calculate and reduce the radiation dose to moving targets, particularly due to the high radiation exposure and low temporal resolution of 4D-CT images, leading to increased treatment time and patient strain.
Innovation Solution
A radiation therapy planning apparatus that collects three-dimensional data and uses marker position measurements to calculate time-dependent positions of body portions, allowing for more accurate and rapid estimation of radiation doses, and includes features like linear scaling and simulation methods to reduce processing errors and improve time resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 4D-CT images are used for radiation therapy planning, then three-dimensional images for each breathing phase can be obtained, but the radiation exposure to the patient is large and the temporal resolution is low
Solution Approach 1:
The patent segments the breathing cycle into multiple phases and acquires images at specific key phases (end-inhale and end-exhale) rather than continuously throughout the cycle. This segmentation approach reduces the total number of images required, thereby lowering radiation exposure while still capturing the essential motion range of the organ.
Solution Approach 2:
The system utilizes the periodic nature of breathing by acquiring images at regular intervals corresponding to the breathing cycle phases. By sampling at these periodic intervals (end-inhale and end-exhale), the system achieves adequate temporal resolution for therapy planning without requiring continuous high-rate imaging that would increase radiation exposure.
2Manufacturing precision
If gated irradiation is used to treat moving targets, then the radiation can be delivered during specified breathing phases, but the treatment time is increased and patient strain is increased
Solution Approach 1:
The patent extracts and utilizes only the essential motion information from two key breathing phases (end-inhale and end-exhale) rather than requiring continuous monitoring and gating throughout the entire breathing cycle. This extraction of critical motion data allows for accurate therapy planning without the time penalty of continuous gated irradiation.
Solution Approach 2:
The system performs preliminary acquisition of motion data at the planning stage using the two-phase approach, allowing the therapy plan to be created with accurate motion information before actual treatment. This preliminary action eliminates the need for time-consuming real-time gating during treatment, as the motion characteristics are already known from the planning phase.
3Measurement precision
If the position of the affected part is tracked in real time, then the radiation can be delivered accurately to the moving target, but the treatment time is increased
Solution Approach 1:
The patent performs preliminary acquisition of the full motion range data during the planning phase by imaging at end-inhale and end-exhale phases. This preliminary action allows the system to pre-calculate the complete trajectory and position of the organ throughout the breathing cycle, eliminating the need for time-consuming real-time position tracking during actual treatment.
Solution Approach 2:
The system creates a computational model (copy) of the organ's motion trajectory based on the two key phase images. This virtual copy allows for accurate position prediction and dose calculation without requiring physical real-time tracking devices or continuous imaging during treatment, thereby reducing treatment time while maintaining position accuracy.
4Productivity
If the radiation dose to moving targets is calculated using traditional methods, then the planning can be completed, but the dose calculation accuracy is insufficient
Solution Approach 1:
The patent implements dynamic dose calculation by incorporating the temporal motion information from the two breathing phases. The system calculates dose distribution at multiple time points along the organ's motion trajectory and accumulates these doses, rather than using static single-phase calculations. This dynamic approach maintains planning efficiency while significantly improving dose calculation accuracy for moving targets.
Solution Approach 2:
The system combines data from two different breathing phases (end-inhale and end-exhale) to create a composite motion model. By integrating information from both phases, the system constructs a complete picture of the organ's motion range and trajectory, enabling more accurate dose accumulation calculations while maintaining computational efficiency.
Data Source
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AI summary
A radiation therapy planning apparatus is provided with: a three-dimensional data collection part collecting three-dimensional data representing a plurality of positions where a plurality of portions of a subject are positioned; a marker position measurement part measuring a motion of a marker; and a dose calculation part calculating, when the subject is irradiated with therapeutic radiation changing on the basis of the motion of the subject, the dose of the therapeutic radiation with which each of the plurality of portions is irradiated, based on the motion and the three-dimensional data. The radiation therapy planning apparatus thus constructed can calculate the dose of the therapeutic radiation with which each of the respective portions of the subject is irradiated, more accurately, and reduce the dose of radiation with which the subject is irradiated in calculating the motions of the plurality of portions of the subject.