10.7 Medical applications and biological effects of nuclear radiation  (Page 6/18)

Why is a PET scan more accurate than a SPECT scan?

Isotopes that emit $\alpha$ radiation are relatively safe outside the body and exceptionally hazardous inside. Explain why.

Ionizing radiation can impair the ability of a cell to repair DNA. What are the three ways the cell can respond?

What is the dose in mSv for: (a) a 0.1-Gy X-ray? (b) 2.5 mGy of neutron exposure to the eye? (c) 1.5m Gy of $\alpha$ exposure?

Find the radiation dose in Gy for: (a) A 10-mSv fluoroscopic X-ray series. (b) 50 mSv of skin exposure by an $\alpha$ emitter. (c) 160 mSv of ${\beta }^{-}$ and $\gamma$ rays from the ${}^{40}\text{K}$ in your body.

Find the mass of ${}^{239}\text{P}\text{u}$ that has an activity of $1.00\text{μCi}$ .

In the 1980s, the term picowave was used to describe food irradiation in order to overcome public resistance by playing on the well-known safety of microwave radiation. Find the energy in MeV of a photon having a wavelength of a picometer.

What is the dose in Sv in a cancer treatment that exposes the patient to 200 Gy of $\gamma$ rays?

One half the $\gamma$ rays from ${}^{99\text{m}}\text{T}\text{c}$ are absorbed by a 0.170-mm-thick lead shielding. Half of the $\gamma$ rays that pass through the first layer of lead are absorbed in a second layer of equal thickness. What thickness of lead will absorb all but one in 1000 of these $\gamma$ rays?

How many Gy of exposure is needed to give a cancerous tumor a dose of 40 Sv if it is exposed to $\alpha$ activity?

A plumber at a nuclear power plant receives a whole-body dose of 30 mSv in 15 minutes while repairing a crucial valve. Find the radiation-induced yearly risk of death from cancer and the chance of genetic defect from this maximum allowable exposure.

Calculate the dose in rem/y for the lungs of a weapons plant employee who inhales and retains an activity of $1.00\mu \text{Ci}$ ${}^{239}\text{Pu}$ in an accident. The mass of affected lung tissue is 2.00 kg and the plutonium decays by emission of a 5.23-MeV $\alpha$ particle. Assume a RBE value of 20.

The wiki-phony site states that the atomic mass of chlorine is 40 g/mol. Check this result. Hint: The two, most common stable isotopes of chlorine are: ${}_{17}^{35}\text{Cl}$ and ${}_{17}^{37}\text{Cl}$ . (The abundance of Cl-35 is $75.8\text{\%}$ , and the abundance of Cl-37 is $24.2\text{\%}$ .)

A particle physicist discovers a neutral particle with a mass of 2.02733 u that he assumes is two neutrons bound together.

(a) Find the binding energy.

(b) What is unreasonable about this result?

A nuclear physicist finds $1.0\text{μ}g$ of ${}^{236}\text{U}$ in a piece of uranium ore ( T _1/2 = $2.348\times {10}^7\text{y}$ ). (a) Use the decay law to determine how much ${}^{236}\text{U}$ would had to have been on Earth when it formed $4.543\times {10}^9\text{y}$ ago for $1.0\mu g$ to be left today. (b) What is unreasonable about this result? (c) How is this unreasonable result resolved?