Feasibility study of an inexpensive densitometry system for radiochromic film dosimetry

Abstract

A readout system for radiochromic film dosimetry was developed based on the graphical system design approach, a broadband light-emitting diode, and a webcam. This digitizer works in transmission mode as the flatbed scanner used in dosimetry tasks, and the current clinical protocols were used to compare findings from both devices. Square samples of 3 cm were cut from an EBT3 film batch and irradiated to doses up to 50 Gy, sampling 100 pixels from each film image for noise, optical density, and uncertainty analysis. The imaging prototype has up to 2.2 times the optical density of the scanner, with a maximum of 1.7 corresponding to the red image channel. For both digitizers, the best noise rejection is in the green channel, ≈51 dB. The lowest uncertainty is in the scanner, with 1 % on average. Future efforts must focus on noise reduction to enhance image quality.