Читать книгу Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology - Rachel A. Powsner - Страница 58

1 Which of the following is true of the interaction of charged particles with matter?Alpha particles have a higher LET than beta particles.The range of alpha particles is generally greater than beta particles.Alpha particles have a higher specific ionization than beta particles.

2 True or false: Bremsstrahlung is X‐ray radiation emitted as a moving electron or positron decelerates and changes direction in close proximity to a nucleus.

3 True or false: The photoelectric effect is the dominant type of photon interaction in tissue for radionuclides used in the practice of nuclear medicine.

4 For each of the terms listed here, select the appropriate definition:HVL (half value layer).TVL (tenth value layer).μ (mu) (linear attenuation coefficient).Thickness of an attenuator that will reduce the intensity (number of photons) in a monoenergetic beam by 90%.Thickness of an attenuator that will reduce the intensity (number of photons) in a monoenergetic beam by 50%.0.693/HVL.

5 Which of the following occur during photon interactions with matter (more than one answer may apply)?Excitation.Pair production.Ionization.Compton scattering.Bremsstrahlung.Photoelectric effect.Annihilation reaction.

6 Which of the following occur during charged particle interactions with atoms (more than one answer may apply)?Excitation.Pair production.Ionization.Compton scattering.Bremsstrahlung.Photoelectric effect.Annihilation reaction.

7 Which of the following are true about annihilation reaction?The conversion of the mass of the positron and electron into energy is an example of the interchangeability of mass and energy as described by Einstein’s famous equation E = mc2.Two oppositely opposed 450 keV photons are emitted as a result of the annihilation reaction.Both (a) and (b).

8 Which of the following are referred to as nonpenetrating radiation?Positrons.Gamma photons.X‐rays.Alpha particles.Beta particles.

9 Which term refers to the loss of photons from a beam of radiation as it passes through matter?Attenuation.Absorption.

10 Which term is used to describe the transfer of energy from radiation to surrounding matter?Attenuation.Absorption.

11 You shield a sample of 99mTc using a 1 mm‐thick sheet of lead. What fraction of the photons will be transmitted through the lead? The linear attenuation coefficient, μ, of lead for 140 keV photons is 23.1 cm–1.