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Improvements in Efficiency and Accuracy for HDR Source Positioning Through the Use of a High Resolution Camera Localization System

D Nicewonger*, S Stathakis , N Papanikolaou , N Kirby , D Saenz , P Myers , M Fakhreddine , K Rasmussen , University of Texas HSC SA, San Antonio, TX


(Sunday, 7/14/2019)  

Room: ePoster Forums

Purpose: To determine the efficiency and accuracy of a high resolution camera for verification of the source position for HDR.

Methods: A commercially available document camera (Hue HD Camera) was directed toward a source position check ruler (Nucletron) at a designated source position and connected to an administrative computer via USB. A daily source position check plan was created in Oncentra using a dwell position of 1500mm and a 1 second dwell time utilizing a Nucletron afterloader. When the HDR source reached the dwell position, an image was captured using a camera application on the computer and visually analyzed to 0.5mm accuracy. The position results of the camera were compared to the position results found using a film strip as well as using a CR plate with dummy seeds and a CT scanner.

Results: The position captured in the image, the distance measured on the film strip, and the position measured using the CR plate were all within 0.5mm of the intended dwell position. Using the camera also has the added benefit of being a visual safety check of the HDR source. This method takes less than 30 seconds to verify positioning. The film strip method takes approximately 1 minute, and the CR plate method takes approximately 10 minutes to analyze. The total cost for the camera and active USB cable extension was <$100.

Conclusion: Using a document camera to verify the source position has shown to be more efficient than using a CR plate and dummy seeds, and more economical than using film strips and a source position ruler without a reduction in accuracy.


Not Applicable / None Entered.


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