1
NMTCB PET COMPLETE QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS)
QUESTION: The exposure rate of an activity of 1 millicurie (mCi)
measured at 1 centimeter (cm) is called
Ans: - The exposure rate constant (ERC)
For positron emitters, the exposure rate constant (ERC) is about 6 R/h per
millicurie at 1 cm. The exposure rate of a 10 mCi dose of F-18 is approximately six
times greater than that of a 10 mCi dose of Tc-99 m at a distance of approxi-
mately 8 inches.
QUESTION: Quantitative bias that refers to the underestimation of
counts density which differs from what they should be is called:
Ans: Partial-volume effect
PVE is caused by the finite spatial resolution of the imaging system which reveals
how far the signal "spills out" around its actual location. The signal spreading
falsely increases the object size and volume. Image sampling, where voxels in ROI
include the signal from underlying tissues, also contributes to the phenomenon
known as partial-volume effect.
QUESTION: Truncation artifacts in PET/CT imaging are produced by
Master01 | 2025/2026 | Latest update
, 2
Ans: Difference in size of FOV between PET and the CT
Discrepancy between fields of view (FOVs) in a PET/CT scanner—70 cm causes a
truncation artifact when imaging extends beyond the CT FOV-50 cm; as a result no
attenuation correction values for the truncated anatomy are being applied.
QUESTION: Dental fillings, hip prosthetics, or chemotherapy port are
examples of PET/CT imaging artifacts described as:
Ans: Metallic implants artifacts
Metallic implants create streaking artifacts on CT images because of their high
photon absorption. Higher Hounsfield numbers consequently produce high PET
attenuation coefficients and an overestimation of PET findings.
QUESTION: The Property of PET detectors that allows them faster
timing signals for coincidence detection and to work at high count
rates is called:
Ans: The decay constant
The decay constant decides how long the scintillation flashes in the crystal; a
short decay time reduces detector dead time and as a result higher annihilation
rates can be accepted.
Master01 | 2025/2026 | Latest update
, 3
QUESTION: The picturing, description, and measurement of
biological processes at the particle and cellular level is known as
Ans: Molecular imaging
Radionuclide originated molecular imaging techniques such as positron emission
tomography
(PET) and single-photon emission computed tomography (SPECT) capture
functional or phenotypic changes associated with pathology and unfold the
molecular abnormalities responsible to form basis of many diseases.
QUESTION: A PET system capacity to distinguish between two points
after image reconstruction is called:
Ans: Resolution
A PET system resolution, according to NEMA guidelines, is assessed by imaging a
point source in the air and reconstructing the images with no smoothing or
transformation of images. The resolution of the system is affected by the
annihilation ambiguities, the detector ring diameter and the size of the
scintillation crystal.
QUESTION: Allergic reaction that begins within seconds/minutes of
contrast media administration and rapidly progresses to cause
Master01 | 2025/2026 | Latest update
, 4
airway constriction, skin and intestinal irritation, and altered heart
rhythms is called:
Ans: Anaphylaxis
QUESTION: The first PET radiopharmaceutical to receive the U.S.
Food and Drug Administration approval in 1989 was:
Ans: Rb-82
QUESTION: The dose calibrator quality control procedure performed
to assess the device's ability to measure accurately a range of a low
to high activities is called:
Ans: Linearity
QUESTION: The following positron-emitting radionuclides are
isotopes of natural elements present in most biochemical processes
EXCEPT:
(A) O-15
(B) F-18
(C) C-11
Master01 | 2025/2026 | Latest update
NMTCB PET COMPLETE QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS)
QUESTION: The exposure rate of an activity of 1 millicurie (mCi)
measured at 1 centimeter (cm) is called
Ans: - The exposure rate constant (ERC)
For positron emitters, the exposure rate constant (ERC) is about 6 R/h per
millicurie at 1 cm. The exposure rate of a 10 mCi dose of F-18 is approximately six
times greater than that of a 10 mCi dose of Tc-99 m at a distance of approxi-
mately 8 inches.
QUESTION: Quantitative bias that refers to the underestimation of
counts density which differs from what they should be is called:
Ans: Partial-volume effect
PVE is caused by the finite spatial resolution of the imaging system which reveals
how far the signal "spills out" around its actual location. The signal spreading
falsely increases the object size and volume. Image sampling, where voxels in ROI
include the signal from underlying tissues, also contributes to the phenomenon
known as partial-volume effect.
QUESTION: Truncation artifacts in PET/CT imaging are produced by
Master01 | 2025/2026 | Latest update
, 2
Ans: Difference in size of FOV between PET and the CT
Discrepancy between fields of view (FOVs) in a PET/CT scanner—70 cm causes a
truncation artifact when imaging extends beyond the CT FOV-50 cm; as a result no
attenuation correction values for the truncated anatomy are being applied.
QUESTION: Dental fillings, hip prosthetics, or chemotherapy port are
examples of PET/CT imaging artifacts described as:
Ans: Metallic implants artifacts
Metallic implants create streaking artifacts on CT images because of their high
photon absorption. Higher Hounsfield numbers consequently produce high PET
attenuation coefficients and an overestimation of PET findings.
QUESTION: The Property of PET detectors that allows them faster
timing signals for coincidence detection and to work at high count
rates is called:
Ans: The decay constant
The decay constant decides how long the scintillation flashes in the crystal; a
short decay time reduces detector dead time and as a result higher annihilation
rates can be accepted.
Master01 | 2025/2026 | Latest update
, 3
QUESTION: The picturing, description, and measurement of
biological processes at the particle and cellular level is known as
Ans: Molecular imaging
Radionuclide originated molecular imaging techniques such as positron emission
tomography
(PET) and single-photon emission computed tomography (SPECT) capture
functional or phenotypic changes associated with pathology and unfold the
molecular abnormalities responsible to form basis of many diseases.
QUESTION: A PET system capacity to distinguish between two points
after image reconstruction is called:
Ans: Resolution
A PET system resolution, according to NEMA guidelines, is assessed by imaging a
point source in the air and reconstructing the images with no smoothing or
transformation of images. The resolution of the system is affected by the
annihilation ambiguities, the detector ring diameter and the size of the
scintillation crystal.
QUESTION: Allergic reaction that begins within seconds/minutes of
contrast media administration and rapidly progresses to cause
Master01 | 2025/2026 | Latest update
, 4
airway constriction, skin and intestinal irritation, and altered heart
rhythms is called:
Ans: Anaphylaxis
QUESTION: The first PET radiopharmaceutical to receive the U.S.
Food and Drug Administration approval in 1989 was:
Ans: Rb-82
QUESTION: The dose calibrator quality control procedure performed
to assess the device's ability to measure accurately a range of a low
to high activities is called:
Ans: Linearity
QUESTION: The following positron-emitting radionuclides are
isotopes of natural elements present in most biochemical processes
EXCEPT:
(A) O-15
(B) F-18
(C) C-11
Master01 | 2025/2026 | Latest update
