V. B. 3.
Step 1.
Doses to the Bones+
Compute the total dose to an organ from a daily intake of constant
‘yolume or mass but with the activity intake decreasing according to
radiological decay of the isotope.
A.
The dose (ignoring for the time any biological decay) to the organ
from any day's intake is:
T
Tv
D, = Ro fe ~rT aT- Ro fe ~drah
0
0
Where: Dy =dose from any day's intake
Ro =initial daily dose rate
Ay» =radiological decay
T =number of days intake
7 =time in days (variable)
Dy = ae (e “i _ e@ -7)
B.
The total cose (ignoring biological decay) to the organ is:
G.
The dose to +*e 2 organ considering biological decay is:
=>
-
wr
f
mn
pon
Dp =f Terre! Toeli-e -47 - x.Te7Ar
Pa
Sb
Dp = Ulpltipttg}t
-
*
a>
leerT - a,fe7>rt
ee
2F
:
=
soe
Sep
7
rt aan
WOOGUCyD
.
ate. 2
em
On
a
7
uy
tb pe of Sr70 intale on D+ 3
!
a
9
2
4.
3
TNT
Lu
smute initia. asity dcse vate (Ho),
De
Scey 2.
on”
+
(6.37 x 1074)0.25) = 1.69 x 10-u yc Of Sr90 devosited in the bones
UY
(1.59 x 1074) (yo) (3.2 v 107) £4/day-1e) (1.0) (Mov) (1.8 x 107) ergs/nev
L0Overgs/gm - rad)(7 x 1073} (grans)
1.16 x 10-6 rads/day
wUnder the conditions assumed here » that the water is stored and used as the sole
source of supply for 70 years, the strontium-90 content accounts for almost all
of
7
the tutal dose.
ab
“
$
..4
:
.
-~ 45 -
=