Setup used for irradiation of EBT2 film pieces in air using an orthovoltage unit. The EBT2 films were placed on thin plastic Saran Wrap for irradiation with 75, 125, and 250 kVp photon beams at a source-to-film distance of 50 cm. The employed field size was .
Setup used for irradiation of EBT2 film pieces in air with a irradiator. The films were sandwiched between 0.12 cm Solid Water buildup slabs and placed on thin plastic Saran Wrap stretched over a Styrofoam stand. Each film piece was placed in a reference geometry (source-film distance of 21.0 cm)
Dose responses of EBT2 films for a range of beam energies from different radiation sources. The region between the two extreme curves represents the trend of all the data collectively and encompasses more than 95% of the data. The variation in data in this the region between the 3 and 10 Gy doses corresponds to .
[(a) and (b)] The expanded graph to show low and high dose regions of the Fig. 3. The two extreme calibration curves represent the maximum-to-minimum spread in dose over the range of 3–10 Gy to be ±8%, implying to be of the order of ±4.5%.
Representation of dose-response curve for a single beam . The dashed lines represent 95% confidence limits for the fit and the error bars represent one standard deviation (0.9% in OD and 0.5% in dose).
Ratio of OD to initial value showing the variation in OD with time for the films irradiated with 6 MV photon beam to 1, 5, 10, and 15 Gy. Measurements in the red channel were made with an Epson a flatbed scanner using 48-bit color image. After irradiation, the OD reached 99% of its plateau values in 42, 44, 61, and 68 h for films exposed to 15, 10, 5, and 1 Gy, respectively.
Characteristics of radiation sources employed in this investigation.
Postirradiation wait-time spread (hours) to achieve error due to self-development.
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