21. In positron emission tomography, when positrons come into ...

[jazziefee]

21. In positron emission tomography, when positrons come into contact with a free electron, they are annihilated. This annihilation produces two byproducts
 
  a) 2 photons
  b) 2 protons
  c) 2 electrons
  d) 2 positrons

Question 2

What does the half-life of a gamma radiation-emitting tracer refer to?
 
  a) The half-life is the time it takes for the substance to reach a non radioactive state
  b) The half-life is always 3 days
  c) The half-life is the amount of time that the substance requires to begin emitting gamma rays
  d) The half-life is the amount of time that it takes for a substance to reach a radioactive state

[apple]

Answer to Question 1

ANSWER: A

Answer to Question 2

ANSWER: A

[jazziefee]

Great answer, keep it coming

[elyse44]

Thanks for the timely response, appreciate it