Program Information
Development of a Mobile Device Based Film Dosimetry System
M Zhang*, X Wang , Rutgers-The Cancer Institute of New Jersey, New Brunswick, NJ
Presentations
SU-I-GPD-T-534 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: This project is to develop a mobile device based film dosimetry system. Traditional scanner based film dosimetry system suffers from expensive hardware and cumbersome process. The proposed mobile device based film dosimetry system includes a reliable light source, a shooting apparatus, and an imaging analyzing software. With much cheaper cost, it will allow users to take pictures of the film and do analysis on their mobile devices.
Methods: A prototype white LED light source with a light diffuser was built. EBT3 radiochromic film pieces were irradiated from 0 cGy to 400 cGy with 50 cGy increment. The irradiated films were placed on top of the diffuser. The back camera of an iphone 6S was used to take RAW picture. The exposure time, sensor ISO, and aperture settings were fixed for all imaging. Autofocusing feature was turned on for the phone. A prototype apparatus was designed to be placed on top of the light diffuser to seal the ambient light and host the mobile device with a fixed object to camera distance. Images with films and without films (flood field) were taken. The films were also scanned by an Epson Expression 1000XL scanner for comparison. Both images were analyzed in ImageJ.
Results: The LED light source was reliable with consistent pixel values across different flood field images. A film calibration curve was generated for both camera based and scanner based system. The dynamic range of the camera pictures were half of the scanned images within 400 cGy. The estimated dose uncertainty for the camera based system was 5% for dose higher than 1 Gy. It was slightly higher than scanner based system of 2%.
Conclusion: A mobile device based film dosimetry system was approved feasible. Future refinement on light source and imaging analyzing software will be conducted.
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