Biomedical Engineering Reference
In-Depth Information
FIGURE 5.1: Measurable events in PET.
factor for an emission event measured during a scan would therefore be e
t
.
For a whole time frame between t
1
and t
1
+ t, one has to compare the area
under the curve A(t) = A
0
ยท
e
t
from t
1
to t
1
+ t to the rectangular area
dened by A
0
, t
1
and t
1
+ t (see Figure 5.2). This gives the decay correction
factor DCF as
A
0
t
R
t
1
+t
t
1
t
1 e
t
e
t
1
:
DCF =
=
(5.5)
A(t)dt
Generally, as decay correction does not depend on the spatial location of
emission events, this correction factor does not contribute to the quality of an
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