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•
Diacetylene molecules in a w.
sol. polymer matrix coated on
a polyester substrate
•
Radiation
induces
polymerization of diacetylene
molecules
to
form
polydiacetylene dye polymers
(self-developing)
•
These are blue in color and
cause light
absorbance
(mainly) in the other parts of
the visible spectrum
•
The change in net OD is
measured using flat-bed
scanners employing broad
band visible light sources, and
correlated to dose
•
OD=log(1/T)=log(I
0
/I
T
)
Radiochromic films: basic principles
Figure from: Devic, Physica Medica 27(3) 122 (2011)