Question

Thallium-201 is a radioisotope used in brain scans. If the recommended dose is 3.0 mCi and a vial contains 45 mCi in 50 mL, how many milliliters should be injected?

A) 5.0 mL
B) 6.0 mL
C) 7.5 mL
D) 8.0 mL

Answer 1

To calculate the required volume to be injected with a dose of 3.0 mCi of thallium-201, the concentration of the vial is used. However, the correct volume calculated (approximately 3.3 mL) does not match any of the provided options A) 5.0 mL, B) 6.0 mL, C) 7.5 mL, or D) 8.0 mL.

Step-by-step explanation:

To calculate the volume of the thallium-201 solution to be injected, we use the concentration of the vial and the required dose. If a vial contains 45 mCi in 50 mL, then the concentration of the vial can be calculated as:

Concentration = 45 mCi / 50 mL = 0.9 mCi/mL.

A dose of 3.0 mCi is recommended. To find out how many milliliters should be injected, we divide the desired dose by the concentration:

Volume = Desired Dose / Concentration

Volume = 3.0 mCi / 0.9 mCi/mL = 3.333... mL.

Since medical dosages are often rounded to the nearest practical measure for ease of administration, the volume that should be injected is approximately 3.3 mL, which is closest to option A) 5.0 mL, but none of the given options are correct.