Nuclides with the same atomic number ( the same number of protons) but a different num-
ber of neutrons are called: - ANSWER isotopes
Two nuclides with the same atomic mass but different atomic numbers are called: - AN-
SWER isobars
A nuclide that emits particulate or photon energy to achieve a more stable state: - AN-
SWER radionuclide
Another name for a helium ion containing two protons and two neutrons: - ANSWER al-
pha particle
What is a beta particle? - ANSWER an electron
Why are alpha and beta particles not used for imaging? - ANSWER They do not efficiently
exit the body, so they can not/ are hard to detect
What ratio of protons and neutrons favors beta decay? - ANSWER A low proton-to-neu-
tron ratio, as compared with stable nuclei
What is the relationship between the mean energy and the maximum energy of a beta spec-
trum? - ANSWER The mean energy is about one-third of the max energy
What ratio of protons and neutrons favors positron decay? - ANSWER A high proton-to-
neutron ratio
1
,What two particles are emitted from the nucleus during beta decay? - ANSWER A beta
particle and an antineutrino
Two nuclides with the same number of neutrons but different atomic numbers are called: -
ANSWER Isotones
What particles are released from the nucleus during positron decay? - ANSWER A posi-
tron and a neutrino
What is the minimum amount of nuclear energy needed required for positron decay? - AN-
SWER 1.02 MeV
What is the fate of a positron? - ANSWER To travel a short distance, combine with an
electron, and be annihilated
When a positron is annihilated via combination with an electron, the result is the production
of __________. - ANSWER two nearly opposed 511-keV photons
What ratio of protons and neutrons favors electron capture decay? - ANSWER A high pro-
ton-to-neutron ratio
What particle is released from the nucleus during electron capture decay? - ANSWER A
neutrino
What is released from the nucleus during isometric transition? - ANSWER Gamma rays
Other than wavelength, frequency, and energy intensity, the fundamental difference be-
tween x-rays and gamma rays is _______. - ANSWER X-rays are produced from energy
2
,released due to changes in the quantum levels/values of orbital electrons of an atom, while
gamma rays are produced from energy shifts within the nucleus
When energy from a nuclear transition results in the emission of an orbital electron rather
than a gamma ray, this processes is called: - ANSWER internal conversion
Internal conversion electrons increase the radiation dose to the patient because
____________. - ANSWER energy from the electron is absorbed into the patients body
When energy from an orbital transition results in the emission of an orbital electron rather
than an x-ray, the electron is called ___________. - ANSWER an Auger electron
What dose the term metastable mean? - ANSWER When an isomeric state is long lived
After an electron is ejected from an inner shell orbital, what occurs? - ANSWER Outer
shell electrons release energy by moving to now unoccupied, less energetic inner orbitals;
the energy released by this transition is termed "characteristic of x-ray radiation"
What are the two methods used to create synthetically radioactive materials? - ANSWER
Radioactive materials are produced by bombarding a target material with either ions or with
neutrons
What is used to bombard elements with neutrons? - ANSWER nuclear reactor
What is used to bombard elements with protons? - ANSWER accelerator (linear or cyclo-
tron)
What are five cyclotron produced radionuclides? - ANSWER In-111, I-123, Ga-67, F-18,
and Tl-201
3
, What is a carrier-free radioisotope? - ANSWER A radioisotope that does not contain any
nonradioactive species
What does the term activity mean? - ANSWER The rate of disintegration of a radionuclide
The unit of activity equivalent to 3.7 x 10^10 dps is called __________. - ANSWER the cu-
rie
What is a becquerel (Bq)? - ANSWER The derived unit of radioactivity used by modern
metric system, the SI, is called the becquerel. The Bq is equal to one dps or 2.7027 x 10^-11
Ci.
A one-millicurie dose of a radiopharmaceutical is equal to how many becquerels? - AN-
SWER 37 million (37 MBq)
What does the term specific activity mean? - ANSWER The ratio of activity per unit mass
What are some specific activities? - ANSWER mCi/mg, mCi/mole, MBq/mg, or MBq/mole
The time that it takes for a radionuclide to decay to one-half of its original activity is call its
__________ half-life. - ANSWER physical
What is the relationship between the physical half-life and the decay constant? - AN-
SWER Their product equals 0.693
The time that is required for a substance in the body to be reduced to half of its concentra-
tion via biological excretion or metabolism is called its ____________ half-life. - ANSWER
biological
4
ber of neutrons are called: - ANSWER isotopes
Two nuclides with the same atomic mass but different atomic numbers are called: - AN-
SWER isobars
A nuclide that emits particulate or photon energy to achieve a more stable state: - AN-
SWER radionuclide
Another name for a helium ion containing two protons and two neutrons: - ANSWER al-
pha particle
What is a beta particle? - ANSWER an electron
Why are alpha and beta particles not used for imaging? - ANSWER They do not efficiently
exit the body, so they can not/ are hard to detect
What ratio of protons and neutrons favors beta decay? - ANSWER A low proton-to-neu-
tron ratio, as compared with stable nuclei
What is the relationship between the mean energy and the maximum energy of a beta spec-
trum? - ANSWER The mean energy is about one-third of the max energy
What ratio of protons and neutrons favors positron decay? - ANSWER A high proton-to-
neutron ratio
1
,What two particles are emitted from the nucleus during beta decay? - ANSWER A beta
particle and an antineutrino
Two nuclides with the same number of neutrons but different atomic numbers are called: -
ANSWER Isotones
What particles are released from the nucleus during positron decay? - ANSWER A posi-
tron and a neutrino
What is the minimum amount of nuclear energy needed required for positron decay? - AN-
SWER 1.02 MeV
What is the fate of a positron? - ANSWER To travel a short distance, combine with an
electron, and be annihilated
When a positron is annihilated via combination with an electron, the result is the production
of __________. - ANSWER two nearly opposed 511-keV photons
What ratio of protons and neutrons favors electron capture decay? - ANSWER A high pro-
ton-to-neutron ratio
What particle is released from the nucleus during electron capture decay? - ANSWER A
neutrino
What is released from the nucleus during isometric transition? - ANSWER Gamma rays
Other than wavelength, frequency, and energy intensity, the fundamental difference be-
tween x-rays and gamma rays is _______. - ANSWER X-rays are produced from energy
2
,released due to changes in the quantum levels/values of orbital electrons of an atom, while
gamma rays are produced from energy shifts within the nucleus
When energy from a nuclear transition results in the emission of an orbital electron rather
than a gamma ray, this processes is called: - ANSWER internal conversion
Internal conversion electrons increase the radiation dose to the patient because
____________. - ANSWER energy from the electron is absorbed into the patients body
When energy from an orbital transition results in the emission of an orbital electron rather
than an x-ray, the electron is called ___________. - ANSWER an Auger electron
What dose the term metastable mean? - ANSWER When an isomeric state is long lived
After an electron is ejected from an inner shell orbital, what occurs? - ANSWER Outer
shell electrons release energy by moving to now unoccupied, less energetic inner orbitals;
the energy released by this transition is termed "characteristic of x-ray radiation"
What are the two methods used to create synthetically radioactive materials? - ANSWER
Radioactive materials are produced by bombarding a target material with either ions or with
neutrons
What is used to bombard elements with neutrons? - ANSWER nuclear reactor
What is used to bombard elements with protons? - ANSWER accelerator (linear or cyclo-
tron)
What are five cyclotron produced radionuclides? - ANSWER In-111, I-123, Ga-67, F-18,
and Tl-201
3
, What is a carrier-free radioisotope? - ANSWER A radioisotope that does not contain any
nonradioactive species
What does the term activity mean? - ANSWER The rate of disintegration of a radionuclide
The unit of activity equivalent to 3.7 x 10^10 dps is called __________. - ANSWER the cu-
rie
What is a becquerel (Bq)? - ANSWER The derived unit of radioactivity used by modern
metric system, the SI, is called the becquerel. The Bq is equal to one dps or 2.7027 x 10^-11
Ci.
A one-millicurie dose of a radiopharmaceutical is equal to how many becquerels? - AN-
SWER 37 million (37 MBq)
What does the term specific activity mean? - ANSWER The ratio of activity per unit mass
What are some specific activities? - ANSWER mCi/mg, mCi/mole, MBq/mg, or MBq/mole
The time that it takes for a radionuclide to decay to one-half of its original activity is call its
__________ half-life. - ANSWER physical
What is the relationship between the physical half-life and the decay constant? - AN-
SWER Their product equals 0.693
The time that is required for a substance in the body to be reduced to half of its concentra-
tion via biological excretion or metabolism is called its ____________ half-life. - ANSWER
biological
4
