1 Suppose a medical PET scan uses an isotope that has a half

1.
Suppose a medical PET scan uses an isotope that has a half-life of 2.0 hr. A sample prepared at 10:00 A.M. has an activity of 25 mCi. What is the activity at 1:00 P.M., when the patient is injected?

2.

What dose of gamma-ray photons causes the same biological damage as 28 rad of alpha radiation with an RBE of 15?

3.

During the 1950s, nuclear bombs were tested on islands in the South Pacific. In one test, personnel on a nearby island received 13 mGy per hour of beta and gamma radiation. At this rate, how long would it take to receive a potentially lethal dose equivalent of 5.4 Sv? Assume RBE = 1.0 for the beta particles.

Solution

2)The dose in rems of the alpha radiation

= 28 rad * 15 = 420 rem

For gamma rays RBE = 1

= 420 rad