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TOPOS: a new topometric patient positioning and tracking system for radiation therapy based on structured white light
Bastian L Lindl1, Reinhold G Müller, Stephanie Lang
1Strahlenklinik, Universitätsklinikum Erlangen, Universitätstrasse 27, 91054 Erlangen, Germany.
Medical Physics
|April 6, 2013
Summary
A new patient positioning system for radiation therapy, TOPOS, uses structured white light and off-the-shelf components for accurate, comfortable, and efficient patient alignment without skin marks. This system optimizes treatment workflow and provides objective positioning data.
Area of Science:
- Medical Physics
- Radiation Oncology
- Image-Guided Therapy
Background:
- Traditional patient positioning in radiation therapy can be time-consuming and may require skin marks.
- Advancements in radiation delivery necessitate improved accuracy in patient setup.
- Existing positioning methods may lack objective verification and real-time motion monitoring.
Purpose of the Study:
- To develop a cost-effective, flexible patient positioning system using structured white light and commercial hardware.
- To enhance accuracy, patient comfort, and workflow efficiency in radiation therapy.
- To implement a 6 degrees of freedom tracking system without dose deposition for real-time monitoring.
Main Methods:
- The TOPOS system utilizes two optical sensors with commercial cameras and projectors for continuous surface measurement.
- Patient surface data is registered to a reference CT scan to determine optimal patient position.
- High-speed surface acquisition enables real-time monitoring of patient motion, including respiration.
Main Results:
- Developed two prototypes capable of high-density scanning with a refresh rate of 10 Hz, extendable to 20 Hz.
- Real-time display of surface correction and respiratory motion with a delay under 200 ms.
- Achieved high accuracy, with mean differences of <0.4 mm in the head and neck case and <1.9 mm in the thoracic case using surface registration and color-coding.
Conclusions:
- The TOPOS system meets the demand for increased accuracy in radiation therapy positioning.
- It offers a versatile, cost-effective solution for image-guided radiation therapy, optimizing workflow.
- The system provides objective positioning assessment and has potential for respiratory gating/tracking.
