1. A 25-year-old woman
undergoes cerebral angiography and a CT scan of the brain involving 2-mm-thick
sections that include the orbits. What is the patient’s estimated lifetime risk
probability for radiation-induced cataracts?
2. Which of the following statements best characterizes
A. Cataracts begin in the anterior portion of the lens.
B. A dose of 1 Gy over 5 years is likely to produce a cataract.
C. Prescription eyeglasses protect from 80% of the dose to the lens from
D. Vision-impairing cataracts are preceded by asymptomatic opacities in the
3. Which of the following statements concerning
radiation-induced cataracts are true? (Select all that apply.)
A. A cataract is a stochastic effect.
B. The minimum single acute dose of x rays that will produce a cataract is 2 Gy.
C. A single dose of radiation is more likely to induce a cataract than the same
amount of radiation administered in 10 fractions.
D. For a given dose, neutrons are more effective than gamma rays in producing
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