1558-1559 / 2239
DETECTORS FOR MEASUREMENT-2D/3D detectors
Film dosimetry
Principle of measurement
:
Radiation is the catalizer of a chemical reaction in the film emulsion
The film opaqueness is related with radiation dose.
Film opaqueness is quantified through the light transmission factor (T)
T is measured by the optical density (OD)
OD =-log
10
(T) =-log
10
(I
0
/I)
6
Utretch 2016
REAL PROPERTIES OF FILM
OD = f (D,D
R
,E,Q,d,FS,
ϕ
,pc )
D......dose
D
R
....dose rate
E......energy
Q......radiation type
d......depth
FS....field size
ϕ
......orientation
pc…...processor conditions
ADVANTAGES
•
High spatial resolution [1 to 5 um]
•
Low cost (silver-halide)
•
Wide accessibility
•
Can be placed inside different phantoms
without perturbing charged particle
equilibrium
•
Two-dimensional nature
•
Integrating dosimeter