Bio-Rad Personal Molecular Imager™ (PMI™) System - Manual (Page 20)

Dry Radioactive Samples
Dry thin samples such as nitrocellulose membranes, dried gels, or TLC sheets can be
exposed directly to the imaging screen in the exposure cassette (Figure 4.4). Ensure that
TLC plates are completely dry before placing them against the screen and always cover
with plastic wrap to prevent flecks from contaminating the screen.
When imaging thick samples it is recommended that the screen is simply placed face down
against the sample on a flat surface and the exposure is conducted in a light-tight drawer or
other dark location.
Note: It is important, when placing the screen against the sample, that the samples are
correctly aligned the first time. Adjusting the screen after placement against the sample
may result in a ghost image or double exposure. If the screen needs to be realigned it must
first be erased.
Note: If you are exposing the screen to a frozen sample, the screen should first be sealed
in a plastic bag as condensation may cause screen damage. After exposure the screen
should be equilibrated to room temperature before the bag is opened and the screen
removed.
Caution: Never expose screens to organic solvents or acetic acid vapors as these may
cause screen damage even when the sample is covered with plastic wrap.
Caution: Samples should not contain either scintillants or enhancers, as these will interfere
with the operation of the screen.
Fig. 4.4. Imaging cassette.
A protective sheet should be placed between the sample and the screen to minimize the
chance of radioactive contamination (Figure 4.5).
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