11-5. A series of radioactive sample of short half-life will be counted
one per day over a period of several days. Explain how variations
in the observed counts caused by fluctuations in the sensitivity
of the counting system can be compensated.
12-1. The uptake of 131I was measured for a patient treated for hyperthyroidism
with the same radioactive nuclide 2 months previously.
The count rates were as follows:
For a 131I standard on day 0 13,260 cpm
For a 131I standard 24 hour later 12,150 cpm
For the patient on day 0 before 131I 6,140 cpm
For the patient 24 hours later 12,840 cpm
Compute the percent uptake of 131I in the thyroid gland. Ignore
the contribution of background radiation to the count rates, but
include the contribution from residual 131I.