Symbols,
.
:
and equations used
constants
to calculate
30
Sr-°
30
Y bone marrow
dose equivalent during the uptake interval and the committed dose equivalent
The following definition,
symbols,
constants and equations describe the
mathematical model used to calculate dose equivalent during and post the uptake
interval.
Intermediate steps can be used to determine body burdens or daily ac-
tivity ingestion rates.
The equations were developed with the assumption that
the measured quantity from a bioassay program would be the urine activity concen.
tration.
.
0
.
.
Constant continuous uptake of 3 sr- oy through the ingestion pathway
was assumed for the entire residence period.
equals the residency period.
For 05,, the uptake interval
As indicated previously 905, disintegrations are
divided equally between cortical and trabecular bone.
Mathematical Model
oh
Symbols, Definitions and Units of Physical Quantities
Ne
=
the number of atoms of species of concern present at time zero in com
partment i, atoms,
N;
=
the instantaneous number of atoms of species of concern present at time
t in compartment i, atoms,
Ps
=
atom intake rate into compartment i from blood, atoms day},
Re
=
the instantaneous fraction of atoms removed from compartment i per unit
time by physiological mechanisms, day ',
r
=
the instantaneous fraction of atoms removed from compartment i per unit
time by radiological mechanisms, day,
q;
=
the instantaneous activity in compartment i at time ¢, Becquerels,
ES
=
the instantaneous activity excretion rate from compartment i at time ¢,
Becquerels day|,
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