Frameless Pre-positioning for Radiosurgery Using Retroreflective Markers
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Solution Overview
Problem
Current methods for pre-positioning patients during navigated medical procedures, such as radiosurgery, require additional steps and can cause discomfort due to the use of external markers, which is inefficient and inconvenient for the patient.
Innovation Solution
A data processing method that uses a computer program to determine positioning control data by comparing planning CT images of the patient with pre-acquired images of a reference structure, such as a carbon-based headrest, allowing for precise positioning without external markers, using a navigation system to track a retroreflective marker device and adjust the patient's position relative to the treatment beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external markers and invasive frames are used for pre-positioning, then positioning accuracy is improved, but patient comfort and workflow efficiency deteriorate
Solution Approach 1:
The patent removes the invasive frame and external marker array from the patient's head, extracting only the essential reference structure (base plate) that remains integrated with the treatment device. This eliminates the constriction feeling while preserving positioning capability through integration of the reference structure into the treatment apparatus itself.
Solution Approach 2:
The base plate serves multiple functions: it acts as both the support structure for the patient's head and the reference structure for positioning. By combining these functions into a single integrated component, the patent eliminates the need for separate external markers and frames, improving patient comfort while maintaining positioning accuracy.
2Measurement precision
If external markers are placed on the patient, then positioning accuracy is improved, but workflow efficiency and patient comfort worsen due to additional steps
Solution Approach 1:
The reference structure (base plate) is prepared in advance as an integral part of the treatment device, with its position and orientation pre-defined. This preliminary preparation eliminates the need for time-consuming placement of external markers during the procedure, streamlining the workflow while maintaining positioning precision through the pre-configured reference system.
3Measurement precision
If an array of markers is placed in the vicinity of the patient, then positioning accuracy is improved, but patient comfort deteriorates due to feeling of constriction
Solution Approach 1:
The patent completely removes the external marker array from the patient environment, extracting only the essential reference function and integrating it into the treatment device's base plate. This eliminates the feeling of constriction caused by multiple markers around the patient's head while preserving positioning accuracy through the integrated reference structure.
4Measurement precision
If invasive frames are used for pre-positioning, then positioning accuracy is improved, but ease of operation and patient comfort worsen
Solution Approach 1:
The base plate is designed to serve as both the patient support structure and the reference structure for positioning, combining multiple functions into a single component. This integration simplifies the overall positioning system by eliminating the need for separate invasive frames and external markers, reducing device complexity while maintaining positioning accuracy.
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 method streamlines the pre-positioning process, reducing patient discomfort and improving efficiency by eliminating the need for external markers and invasive frames, while maintaining high accuracy in positioning for radiosurgery and radiotherapy procedures.
Implementation Method 1
a retroreflective marker device (which is configured to reflect infrared radiation)
Data Source
AI summary
The presently described method is directed to determining a way of positioning a patient before execution of a medical procedure involving irradiating the patient with ionizing treatment radiation based on comparing medical images of the patient with a pre-acquired medical image. The planning computed tomography is searched for an image of the reference structure in order to determine the position of the patient relative to a patient support device. A retroreflective marker device, having a known and advantageously fixed position relative to the base plate, is detected by a navigation system operatively coupled to a motor of the support device. Based on the detected position of the marker device, the motor of the support device is activated to drive the patient into a desired position relative to beam direction along which the treatment radiation is to be issued towards the patient to execute the medical procedure.