The recommended dosage of iodine-131 is 21 Ci/5 kg of body mass. How many microcuries of iodine-131 are needed for a 75.0-kg person with hyperthyroidism?
• 1580 Ci
• 17.9 MCi
• 315 Ci
• 1.40 Ci
To calculate the required dosage of iodine-131 for a 75.0-kg person, we use the recommended dosage of 21 Ci/5 kg of body mass.
First, we find the mass of the person in 5 kg intervals:
75.0 kg / 5 kg = 15 intervals
Next, we multiply the recommended dosage by the number of intervals:
21 Ci/5 kg * 15 intervals = 315 Ci
Therefore, the correct answer is:
• 315 Ci
To determine the number of microcuries of iodine-131 needed for a 75.0 kg person with hyperthyroidism, we can use the recommended dosage of 21 Ci/5 kg.
Step 1: Calculate the dosage per kilogram
Dosage per kilogram = 21 Ci / 5 kg
Dosage per kilogram = 4.2 Ci/kg
Step 2: Calculate the total dosage needed for a 75.0 kg person
Total dosage needed = Dosage per kilogram × body mass
Total dosage needed = 4.2 Ci/kg × 75.0 kg
Step 3: Convert the dosage to microcuries
1 Ci = 1,000,000 microcuries
Total dosage needed in microcuries = Total dosage needed × 1,000,000 microcuries/Ci
Calculating the total dosage needed:
Total dosage needed = 4.2 Ci/kg × 75.0 kg
Total dosage needed = 315 Ci
Converting to microcuries:
Total dosage needed in microcuries = 315 Ci × 1,000,000 microcuries/Ci
Total dosage needed in microcuries = 315,000,000 microcuries
Therefore, the correct answer is:
• 315 Ci
To find the number of microcuries of iodine-131 needed for a 75.0-kg person, we can use the recommended dosage of 21 Ci/5 kg of body mass.
First, we need to calculate the number of 5-kg intervals in the person's body mass. For a 75.0-kg person, this would be 75.0 kg / 5 kg = 15 intervals.
Next, we can multiply the number of intervals by the recommended dosage to find the total amount of iodine-131 needed. 15 intervals * 21 Ci/5 kg = 63 Ci.
Finally, we can convert the total amount of iodine-131 to microcuries by multiplying by the conversion factor: 1 Ci = 10^6 microcuries.
Thus, the number of microcuries needed for a 75.0-kg person with hyperthyroidism is 63 Ci * 10^6 microcuries/Ci = 63,000,000 microcuries.
Therefore, none of the given options (1580 Ci, 17.9 MCi, 315 Ci, 1.40 Ci) is correct.