Radiotherapy Apparatus Prioritizing Doses Near Sensitive Structures
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Solution Overview
Problem
Current radiotherapy techniques fail to accurately maintain patient positioning during treatment sessions, particularly for sensitive regions prone to movement, leading to potential radiation damage and the need for frequent CT scans that increase radiation exposure.
Innovation Solution
The method involves performing an initial cone-beam CT scan to determine patient position, prioritizing doses near sensitive structures for delivery immediately after, and scheduling less critical doses later, with the option to perform additional CT scans if necessary to maintain positioning confidence, and using a classification system to rank doses by sensitivity for optimal delivery timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous or frequent CT scans are performed to monitor patient position, then positioning accuracy is improved, but radiation exposure increases
Solution Approach 1:
The system performs an initial CT scan to establish patient position before treatment begins, and uses this preliminary information to plan the delivery sequence of radiation doses. By prioritizing delivery of doses near sensitive structures immediately after the initial scan, the system maintains positioning accuracy without requiring continuous scanning throughout treatment.
Solution Approach 2:
The treatment fraction is divided into discrete dose deliveries with different priority levels. Doses are segmented into those requiring immediate delivery (near sensitive structures) and those that can be delivered later (remote from sensitive structures). This segmentation allows the system to optimize the balance between positioning confidence and radiation exposure by delivering critical doses first.
2Reliability
If treatment is delayed to perform additional CT scans, then positioning confidence is improved, but treatment time increases
Solution Approach 1:
The system performs necessary positioning assessments and preparations before the treatment fraction begins, including initial CT scanning and treatment plan generation. By having the treatment plan ready in advance with prioritized dose delivery sequencing, the system avoids delays during treatment while maintaining positioning confidence for critical doses.
Solution Approach 2:
The system dynamically adjusts the treatment delivery sequence based on the initial positioning data. Rather than following a fixed schedule, the system prioritizes delivery of doses near sensitive structures immediately when positioning confidence is highest, and schedules less critical doses for later delivery, optimizing both reliability and efficiency.
3Object-affected harmful factors
If doses near sensitive structures are delivered later, then radiation exposure from repeated CT scans is reduced, but positioning accuracy for critical areas deteriorates
Solution Approach 1:
The system applies different delivery timing strategies to different spatial regions based on their sensitivity. Doses delivered to regions near sensitive structures are prioritized for immediate delivery when positioning accuracy is confirmed, while doses to regions farther from sensitive structures are scheduled for later delivery. This local differentiation ensures critical areas receive accurate dosing without requiring uniform re-scanning of the entire treatment volume.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the number of CT scans required, enhances positioning confidence during critical doses, and ensures accurate delivery of radiation while minimizing exposure and movement-related risks, allowing for more efficient and accurate treatment planning.
Implementation Method 1
an initial CT scan is performed to determine the patient's position
Implementation Method 2
Radiotherapy consists of directing beams of ionizing radiation toward a tumor. The radiation (usually high-energy x-rays) is absorbed by the tumor cells causing cell damage.
Data Source
AI summary
Intra-fraction movement of the patient puts at risk sensitive regions that are near to a radiation dose. In a radiotherapy system that delivers a dose as a series of discrete sub-doses, an initial CT scan is performed to determine the patient's position, after which the sub-doses that are directed to regions within a preset distance of a sensitive structure are performed first, while the sub-doses directed to regions that are more remote from a sensitive structure are performed later.