Development of an automated system for radiochromic film analysis

초록

Radiochromic films (RCFs) are widely used to check the dose distribution for quality assurance in radiation therapy. A flatbed scanner is the most common tool for RCFs. Analyzing RCFs with a flatbed scanner requires many considerations, including the energy correction for various beams, scanning orientation, film handling, film uniformity in a sheet or in a batch, scanning temperature, scanning software, and optical density to dose conversion. For RCFs to be a good tool for measuring the two-dimensional dose distribution, medical physicists should carefully follow a confirmed procedure to obtain the best dose distribution results. We focused on the absolute dose measurement at a point instead of the two-dimensional dose distribution and reduced human loads. A one-stop processing system from film readings to the dose evaluation was developed using a spectrometer, a light emitting diode (LED), and a film changer. Our system is characterized by the flexibility of selective light sources for RCFs and the ability to analyze absorbance spectra. EBT3 film was selected for this study, and our system was constructed to fit RCFs. The performance of the system was tested, and the evaluated dose was compared with a scanner. The irradiated dose and evaluated dose showed good agreement, within 3.2% deviation.

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