Radiotherapy Patient Support Rotation for Non-Coplanar Treatment
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Solution Overview
Problem
Existing radiotherapy treatments face challenges in minimizing radiation dose to healthy tissue surrounding the target region due to patient movement, table top flexing, and the need for accurate target region positioning without additional imaging, particularly in radiotherapy devices with a bore solution.
Innovation Solution
A radiotherapy apparatus with a subject support surface that can be rotated about an isocenter and equipped with sensors to measure table top deflection, allowing for precise target positioning and minimizing radiation dose to healthy tissue by rotating the patient support surface outside the radiation plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the radiation source is rotated around the patient by a rotating gantry to minimize radiation dose to healthy tissue, then the radiation dose to healthy tissue is reduced, but the treatment is limited to coplanar approaches and cannot effectively treat certain target regions
Solution Approach 1:
The patent introduces a second rotation degree of freedom by rotating the patient support surface about a vertical axis, transforming the treatment from two-dimensional coplanar rotation to three-dimensional non-coplanar rotation. This allows radiation beams to approach the target region from multiple angles in three-dimensional space, improving treatment versatility while maintaining dose minimization benefits.
2Object-affected harmful factors
If the patient support surface is rotated to minimize radiation dose to healthy tissue, then the radiation dose distribution is improved, but the rotation mechanism becomes more complex
Solution Approach 1:
The patient support surface rotation mechanism serves multiple functions: it positions the patient for treatment, enables non-coplanar beam angle variation to spare healthy tissue, and can be integrated with the table top extension mechanism. This multi-functionality reduces the need for separate dedicated rotation mechanisms, thereby managing complexity while achieving dose minimization.
3Measurement precision
If additional imaging is performed to accurately position the target region, then the positioning accuracy is improved, but the treatment time increases and patient throughput decreases
Solution Approach 1:
The system performs preliminary actions by pre-calculating and pre-positioning the patient support surface and table top based on treatment planning data before the actual radiation delivery. This allows accurate target positioning to be established in advance, eliminating the need for additional imaging during treatment and thereby maintaining high patient throughput.
4Ease of operation
If the table top is extended into the bore to position the patient, then the patient positioning capability is improved, but the table top flexes causing positioning errors
Solution Approach 1:
The system incorporates feedback mechanisms that continuously monitor the position of the table top and patient support surface during extension and treatment. Position sensors detect any flexing or displacement, and the control system automatically adjusts the positioning parameters to compensate for these deviations, maintaining accurate target region positioning despite table top flexing.
Data Source
AI summary
The present application relates to a radiotherapy apparatus for delivering radiation to a subject. The apparatus comprises a source of radiation configured to rotate about an isocenter and emit radiation in a radiation plane containing said isocentre. The apparatus also comprises a subject support surface configured such that a portion of the subject support surface can be located substantially at the isocenter. The apparatus also comprises a subject support surface rotation mechanism configured to rotate the subject support surface about an axis of rotation that passes through the isocenter, wherein the subject support surface rotation mechanism is located outside the radiation plane.