Introduction to Health Physics: Fourth Edition - Ruang Baca FMIPA UB

(b) Are the distributions normal or log-normal?
Evaluation of Radiation Safety Measures 713
(c) Compute the geometric mean and standard deviations for each of the three
types of distributions.
13.14. An instrument repairman suffered an accidental exposure to 131I while working
in a customer’s laboratory. Two days later, his thyroid gland was found to contain
2 × 104 Bq (0.54 μCi) 131I. Assuming he is a normal healthy man who weighs
70 kg, calculate
(a) the amount of 131I activity originally deposited in the thyroid,
(b) the dose commitment to the thyroid as a result of the accident.
Note: The following thyroid retention function is given in ICRP 10:
R(t) = 0.7 exp − 0.693
t days + 0.3 exp −
0.35 days 0.693
t days .
100 days
13.15. A 20-L breath sample was collected over 2 minutes. Analysis for 222Rn showed the
radon concentration to be 1 × 10−7 Bq/L. Estimate the body burden of 226Ra from these data.
13.16. A laboratory worker accidentally ingested 210Po by using a contaminated cup for
his coffee. Twenty-four hour urine samples were taken over a 60-day period and
analyzed. The following data were obtained:
Days After Ingestion 1 5 10 15 20 25 30 40 50 60
Bq per Sample 25 23 21 19 18 16 15 12 11 9
(a) Plot the data on semi-log paper and fit an equation to the elimination
data.
(b) If 10% of ingested 210Po is known to be eliminated in the urine, and 90% is
eliminated in the feces, how much 210Po was ingested?
(c) If 13% of the 210Po was deposited in the kidneys, what was the committed
dose equivalent to the kidneys from this accidental ingestion?
13.17. What is the dose commitment to the skeleton due to the ingestion of 100 Bq/d,
for 1 year, of 90Sr dissolved in drinking water?
13.18. An accidental release of 210PoO2 from a glove box leads to an atmospheric concentration
of 1500 Bq/m3 (4.05 × 10−8 μCi/cm3 ). From a recording air monitor,
whose alarm had failed, it was later learned that a worker had been exposed to
the airborne 210PoO2 for 1 hour. Measurements made with a cascade impactor
showed the activity-median aerodynamic particle size to be 0.5 μm. Using the
data for the reference person, calculate
(a) the amount of activity deposited in the lung and
(b) the dose commitment to the lung from this accidental exposure.