Chapter 6: Radiochemistry and Radiopharmacology
Test Bank
MULTIPLE CHOICE
1. The consequence of a neutron-rich nucleus is:
a. an Auger electron
b. electron capture
c. production of positron emission
d. production of negative beta particle
ANS: D
If a nucleus has a neutron/proton (N/P) ratio that is too high for stability (neutron-rich), it will
undergo radioactive decay in a manner such that the N/P ratio decreases to approach the line of
stability. The consequence is the production of a negative beta particle.
REF: p. 152
2. If the N/P ratio is too low for stability, radioactive decay is accomplished through either:
a. positron emission or electron capture
b. negative beta particle production or electron capture
c. positron or Auger electron emission
d. production of a negative or positive beta particle
ANS: A
If the N/P is too low for stability, radioactive decay occurs in a manner that will reduce the
number of protons and increase the number of neutrons by the net conversion of a proton or a
neutron. This is accomplished through either positron emission or absorption by the nucleus of
an orbital electron (EC).
REF: p. 152
3. Annihilation radiation is characteristic of:
a. electron capture
b. position decay
c. negative beta decay
d. isometric transition
ANS: B
Positron decay leaves the daughter nuclide two electron mass units lower than the parent,
requiring at least 1.022 MeV (2 0.511 MeV/electron) of transition energy. Once released
from the nucleus, the + reacts with an electron, resulting in the release of two 0.511-MeV
photons, which are called annihilation radiation, emitted in opposite directions.
REF: p. 153
Copyright © 2012, 2007, 2004, 1997, 1994, 1989, 1981 by Mosby, Inc., an affiliate of Elsevier Inc. 1
, 4. Radionuclides used to label radiopharmaceutical for nuclear imaging should decay by:
a. alpha or negative beta
b. negative beta or positron
c. positron or gamma
d. gamma or auger electron
ANS: C
Radionuclides used to label radiopharmaceuticals (RaPhs) for nuclear medicine imaging
should decay by either gamma or positron ( ) emission. Gamma radiation emitted from RaPhs
readily penetrates tissues and escapes from the body. Positron-emitting radionuclides produce
two 0.511-MeV gamma photons emitted in opposite directions from the positron-electron
annihilation. The angle of nearly 180 degrees of the emitted 0.511-MeV photons is exploited in
positron emission tomography (PET) to allow electronic collimation of the radiation and
determination of the three-dimensional location of the decay event.
REF: p. 153
5. Specific activity is defined as the:
a. activity of a radioactive isotope per gram of that same element
b. amount of radioactive isotope in a patient dose
c. percentage of carrier-free radioisotope activity in its production
d. percentage of stable isotope activity within a radioisotope
ANS: A
The specific activity of a radioactive isotope is defined as the activity of a radioactive isotope
per gram of that same element.
REF: p. 153
6. The 99Mo- 99mTc generator is an example of:
a. a transient equilibrium system
b. the separation of fission products
c. a secular equilibrium system
d. an accelerator product
ANS: A
In a transient equilibrium system, the half-life of the parent is a factor 10 to 100 times greater
than that of the daughter.
REF: p. 156
Copyright © 2012, 2007, 2004, 1997, 1994, 1989, 1981 by Mosby, Inc., an affiliate of Elsevier Inc. 2
Test Bank
MULTIPLE CHOICE
1. The consequence of a neutron-rich nucleus is:
a. an Auger electron
b. electron capture
c. production of positron emission
d. production of negative beta particle
ANS: D
If a nucleus has a neutron/proton (N/P) ratio that is too high for stability (neutron-rich), it will
undergo radioactive decay in a manner such that the N/P ratio decreases to approach the line of
stability. The consequence is the production of a negative beta particle.
REF: p. 152
2. If the N/P ratio is too low for stability, radioactive decay is accomplished through either:
a. positron emission or electron capture
b. negative beta particle production or electron capture
c. positron or Auger electron emission
d. production of a negative or positive beta particle
ANS: A
If the N/P is too low for stability, radioactive decay occurs in a manner that will reduce the
number of protons and increase the number of neutrons by the net conversion of a proton or a
neutron. This is accomplished through either positron emission or absorption by the nucleus of
an orbital electron (EC).
REF: p. 152
3. Annihilation radiation is characteristic of:
a. electron capture
b. position decay
c. negative beta decay
d. isometric transition
ANS: B
Positron decay leaves the daughter nuclide two electron mass units lower than the parent,
requiring at least 1.022 MeV (2 0.511 MeV/electron) of transition energy. Once released
from the nucleus, the + reacts with an electron, resulting in the release of two 0.511-MeV
photons, which are called annihilation radiation, emitted in opposite directions.
REF: p. 153
Copyright © 2012, 2007, 2004, 1997, 1994, 1989, 1981 by Mosby, Inc., an affiliate of Elsevier Inc. 1
, 4. Radionuclides used to label radiopharmaceutical for nuclear imaging should decay by:
a. alpha or negative beta
b. negative beta or positron
c. positron or gamma
d. gamma or auger electron
ANS: C
Radionuclides used to label radiopharmaceuticals (RaPhs) for nuclear medicine imaging
should decay by either gamma or positron ( ) emission. Gamma radiation emitted from RaPhs
readily penetrates tissues and escapes from the body. Positron-emitting radionuclides produce
two 0.511-MeV gamma photons emitted in opposite directions from the positron-electron
annihilation. The angle of nearly 180 degrees of the emitted 0.511-MeV photons is exploited in
positron emission tomography (PET) to allow electronic collimation of the radiation and
determination of the three-dimensional location of the decay event.
REF: p. 153
5. Specific activity is defined as the:
a. activity of a radioactive isotope per gram of that same element
b. amount of radioactive isotope in a patient dose
c. percentage of carrier-free radioisotope activity in its production
d. percentage of stable isotope activity within a radioisotope
ANS: A
The specific activity of a radioactive isotope is defined as the activity of a radioactive isotope
per gram of that same element.
REF: p. 153
6. The 99Mo- 99mTc generator is an example of:
a. a transient equilibrium system
b. the separation of fission products
c. a secular equilibrium system
d. an accelerator product
ANS: A
In a transient equilibrium system, the half-life of the parent is a factor 10 to 100 times greater
than that of the daughter.
REF: p. 156
Copyright © 2012, 2007, 2004, 1997, 1994, 1989, 1981 by Mosby, Inc., an affiliate of Elsevier Inc. 2
