Program Information
Real-Time Motion Tracking Using Ultrasound and Intrafractional KV Cone Beam Projection Images
F Mostafaei1*, A Tai2 , W Haase3 , D Cooper4 , M Lachaine5 , X Li6 , (1) Medical College of Wisconsin, Milwaukee, WI, (2) Medical College of Wisconsin, Milwaukee, WI, (3) Medical College of Wisconsin, Milwaukee, WI, (4) Elekta Ltd., Montreal, QC, (5) Elekta Ltd., Montreal, QC, (6) Medical College of Wisconsin, Milwaukee, WI
Presentations
TH-AB-205-8 (Thursday, August 3, 2017) 7:30 AM - 9:30 AM Room: 205
Purpose: The ability to monitor intrafractional tumor motion is essential for radiation therapy of thoracic and abdominal tumors. This study aims to develop a method to estimate lung tumor motion using intrafractional ultrasound (US) and cone beam projection images (CBPI).
Methods: Elekta research software was used to acquire B-mode US and CBPI data with the Clarity® and XVI platforms on an Elekta linac. The data was synchronized through a video capture card (VCE-PRO, IMPERX Inc.) which was triggered by the XVI system. In this way, a system was configured to allow real-time acquisition of the diaphragm position synchronized with periodic acquisition of the lung tumor position. Feasibility of the system was demonstrated by acquiring synchronized data on an in-house motion platform with embedded spheres of different materials, and US images of the diaphragm on a number of volunteers of varying body sizes.
Results: Diaphragm motion under free breathing (FB) was successful with intracostal US imaging. In our experience, ease of diaphragm visualization decreased with the size of the volunteer. The US system was able to track the motion phantom within 2 mm. The intrafractional CBPI acquired during VMAT delivery was successfully synchronized with US acquisition.
Conclusion: The feasibility of tracking a lung tumor motion in real time with continuous ultrasound and periodic CBPI was demonstrated. Future work will include real-time estimation of the target position from the two streams for lung cancer patients, to enable gating and target tracking during SBRT in our clinic.
Funding Support, Disclosures, and Conflict of Interest: This work was Partially supported by Elekta Ltd.
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