User manual

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V. PROCEDURE
The film sizes could be 1.5” x 8” strips, or 8” x 10” sheets or anything between. If
multiple films are used they must have the same lot number. When cutting strips be
certain that the orientation is known with respect to the sheet from which they were
obtained.
The radiation source is provided as the means for delivering known exposure doses
to the calibration and application films. For calibration exposure, it is assumed the
user can control the source to deliver the known doses to the film.
The protocol requires a minimum of two non-zero exposure doses, plus a dose of
zero. A greater number of exposure doses could be used, but this is not necessary.
The calibration will be valid for doses between zero and the highest exposure dose
for the calibration. The calibration will be valid for other EBT2 or EBT3 film from the
same production lot scanned on the same scanner as the calibration films. The
protocol requires the calibration films to be scanned together in a single scan with
the exposed areas all located along the central axis of the scanner (see Figure 4).
The exposures could be made on a single film, or on separate films. In any event,
the films should be sized to fit together on the scanner.
The protocol requires a minimum time to elapse between exposure and scanning. It
is most efficient if the exposures are made within a narrow time window, t. The
elapsed time between the last film and film scanning must be a minimum of 4t.
1. Position a calibration film in the center of the radiation field to be delivered by the
exposure source with the plane of the film perpendicular to the beam. Frequently
the film will be exposed in a phantom or between slabs of plastic to achieve
electron equilibrium, but this is not mandatory. The essential requirement is that
the user knows the exposure doses delivered in the plane of the film.