Program Information
Real-Time Prevention of Radiation 'mistakes' Using Cherenkov Light Emission
A Glaser1*, R Zhang2 , J Andreozzi1 , D Gladstone3 , B Pogue1,2 , (1) Thayer School of Engineering, Dartmouth College, Hanover, NH (2) Department of Physics and Astronomy, Dartmouth College, Hanover, NH, (3) Dartmouth Hitchcock-Medical Center, Lebanon, NH
Presentations
TH-AB-204-5 (Thursday, July 16, 2015) 7:30 AM - 9:30 AM Room: 204
Purpose: To determine the feasibility of using real-time imaging of Cherenkov light emission from an object’s surface for the qualitative identification of radiation ‘mistakes’.
Methods: A highly sensitive camera was used to image the Cherenkov light emitted for a solid water phantom. A Varian 2100CD was used to deliver 500 MU for a 6 MV photon beam operating a dose rate of 600 MU/min, and the chosen imaging system and geometry provided data with a field of view of 30x30 cm, at 10 FPS, at a resolution of approximately 0.6 mm. Three mistake scenarios were imaged, two static errors (1) incorrect jaw size for stereotactic delivery using a 20 mm cone, (2) incorrect wedge angle applicator for a 10x10 cm field, and a dynamic errors (3) MLC leaf error and (4) incorrect collimator or gantry angle for IMRT delivery.
Results: Using the real-time results of Cherenkov light emission imaging, the incorrect jaw size setting for SRS or SRT and incorrect wedge angle applicator were clearly identified in the first captured image. For the detection of a MLC leaf error, the proposed method was able to provide 4 frames per field, and detect leaf errors down to 1 mm and collimator and gantry errors down to 1 deg.
Discussion and Conclusions: While the results in this feasibility study were performed using a solid water phantom, the technique could be readily applied in-vivo, as Cherenkov light emission imaging is completely non-invasive and requires no external materials to be introduced into the Linac or radiation beam path. For the detection of static errors, by providing real-time information after a single MU of delivery, further incorrect radiation field delivery could be avoided. Furthermore, dynamic errors in leaf positioning collimator or gantry angle could be detected in real-time down to 1 mm or 1 deg.
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