Virtual Perspective Image Generation for Radiotherapy Positioning
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Solution Overview
Problem
The appearance differences between virtual perspective images and actual perspective images in radiotherapy planning, caused by varying imaging parameters such as X-ray tube voltage, affect positioning accuracy, making it difficult to accurately match and correct the position of the target during treatment.
Innovation Solution
An image processor that acquires imaging parameters and generates virtual perspective images based on these parameters, using weighting tables to adjust voxel values and match the appearance of the virtual images to the actual images, thereby reducing the visual differences and improving alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If imaging parameters (X-ray tube voltage, tube current) are varied in the radiographic imaging apparatus, then the appearance of the captured perspective image changes, but this causes significant appearance differences between the virtual perspective image and the actual perspective image, affecting positioning accuracy
Solution Approach 1:
The patent applies parameter changes by modifying the voxel values in the three-dimensional volume data according to the imaging parameters (tube voltage, tube current) used to capture the actual perspective image. This transformation adjusts the virtual perspective image's appearance to match the actual image's appearance, resolving the contradiction between adaptability to different imaging parameters and positioning accuracy
Solution Approach 2:
The patent creates a transformed copy of the three-dimensional volume data by applying transformation values derived from the imaging parameters. This copied and transformed data is then used to generate the virtual perspective image, ensuring it visually matches the actual perspective image captured under specific imaging conditions, thereby maintaining positioning accuracy across different imaging parameters
2Measurement precision
If the appearance of the virtual perspective image is controlled to match the actual perspective image, then positioning accuracy improves, but this requires complex processing to determine transformation values based on imaging parameters
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing the relationship between imaging parameters and transformation values. When generating a virtual perspective image, the system simply retrieves the appropriate transformation values based on the imaging parameters used to capture the actual image, avoiding complex real-time calculations and reducing processing complexity while maintaining positioning accuracy
Solution Approach 2:
The patent introduces transformation values as an intermediary between the imaging parameters and the voxel values. These transformation values serve as a mediator that translates the effect of different imaging parameters into corresponding adjustments of voxel values, simplifying the overall processing by breaking down the complex task into manageable steps: retrieve transformation values, apply to voxel data, generate virtual image
Data Source
AI summary
According to some embodiments, an image processor of an embodiment has an imaging parameter acquirer and a virtual perspective image generator. The imaging parameter acquirer acquires an imaging parameter which is used by a radiographic imaging apparatus in capturing a perspective image of a target. The virtual perspective image generator determines a method of generating a virtual perspective image from volume data acquired by capturing the target in accordance with the imaging parameter. The virtual perspective image generator generates the virtual perspective image from the volume data in accordance with the determined method.