on
mw
instantaneous fraction of atoms decaying per unit time, day”!
iu
initial atom ingestion rate, atoms day~!,
vu
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°
~~
x
re
time post onset of uptake, days,
instantaneous fraction of atoms removed from compartment i by
wu
compartment i deposition fraction,
a
<<
--
~:
=<
physiological mechanisms, day7!,
the number of atoms in compartment i relative to the number in all
ut
instantaneous urine activity concentration, Bq grt,
am
Cc
S
compartments at the onset of declining continuous uptake, (¢=0),
subject urine excretion rate, & day~!,
it
fraction excreted by the urine pathway,
“i
Lo
*
wn
fraction from GI tract to blood,
instantaneous fraction of atoms removed or added to the atom uptake
i
it
body burden at the onset of uptake, Bq,
BD
= the number of disintegrations in all compartments occurring during
°
-
instantaneous body burden, Bq,
rs)
per unit time, day~!, due to factors other than radioactive decay,
the uptake interval, Bq days.
The development of Eqs. (1), (2), and (3) was based on the following convolution integral.
At some variable time, tT, defined during a fixed uptake
interval, T, the daily activity ingestion rate crossing the gastrointestinal
tract to blood is given by
A£LP ° e
~(ketA)T
E
.