The exposure rate of an activity of 1 millicurie (mCi) measured at 1 centimeter (cm) is called - Answers -
The exposure rate constant (ERC)
For positron emitters, the exposure rate constant (ERC) is about 6 R/h per milli- curie 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.
Quantitative bias that refers to the underestimation of counts density which differs from what they
should be is called: - Answers 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.
Truncation artifacts in PET/CT imaging are produced by - Answers 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.
Dental fillings, hip prosthetics, or chemotherapy port are examples of PET/CT imaging artifacts described
as: - Answers 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.
The Property of PET detectors that allows them faster timing signals for coincidence detection and to
work at high count rates is called: - Answers 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.
The picturing, description, and measurement of biological processes at the particle and cellular level is
known as - Answers 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.
A PET system capacity to distinguish between two points after image reconstruction is called: - Answers
,Allergic reaction that begins within seconds/minutes of contrast media admin- istration and rapidly
progresses to cause airway constriction, skin and intestinal irritation, and altered heart rhythms is called:
- Answers Anaphylaxis
The first PET radiopharmaceutical to receive the U.S. Food and Drug Administration approval in 1989
was: - Answers Rb-82
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: - Answers Linearity
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
(D) N-13 - Answers F-18
Two photons arising from the same annihilation event and detected by two detectors within the
coincidence time-window are: - Answers True coincidences
Serves as the building blocks for proteins synthesis - Answers Amino acids
Positronium (Ps) is an arrangement of: - Answers An electron and a positron
The most common site of brown fat localization - Answers Neck
Scintillator commonly used in PET imaging that has the highest stopping power - Answers BGO (bismuth
germinate)
A malignant neoplasm of the skin linked with approximately 75% of skin cancer-related mortality is
called: - Answers Melanoma
PET tracers have demonstrated significant potential utility and application in the following clinical areas
EXCEPT:
(A) Oncology
(B) Cardiology
(C) Pulmonology
(D) Neurology - Answers C - Pulmonology
,The sum of the weighted equivalent doses in all the tissues and organs of the body is called: - Answers
Effective dose
The combined whole-body effective dose for a clinically diagnostic PET/CT is typically in the range: -
Answers 20-30 mSv
The positron has the same mass as an electron and an electric charge of: - Answers + 1
The initial diagnosis of melanoma is established by: - Answers Histologic evaluation
In PET scanning process raw data acquired and identified as coincidence events along their LOR are
stored in the raw data format called: - Answers Sinograms
Cyclotron produced positron-emitting radionuclide - Answers Nitrogen-13
A piece of equipment that sorts out photons of different radionuclides with different photon energies
and to separate scattered photons from the useful ones is called: - Answers Pulse height analyzer
DNA synthesis is a measure of cellular: - Answers Proliferation
The F-18 fluoride bone uptake mechanism is similar to that of: - Answers Tc-99 m
methylenediphosphonate (MDP)
The process by which new blood vessels are formed is called: - Answers Angiogenesis
Quality control procedures required for proper functioning of the survey meter - Answers Calibration
and constancy
The Circle of Willis is a circle of arteries that supply blood to: - Answers The brain
The CT X-ray tube: - Answers Produces the X-ray
The radiodensity of distilled water at standard pressure and temperature (STP) on the Hounsfield unit
(HU) scale is equal to: - Answers 0 HU
The dose calibrator quality control procedure testing a long-lived standard at each of the frequently
used radionuclides settings is called: - Answers Constancy
Which of the following radionuclides commonly used in PET imaging has the highest energy?
(A) Carbon-11
(B) Nitrogen-13
(C) Oxygen-15
(D) Fluorine-18 - Answers Oxygen-15
, The PET scanner quality control procedure in which data are used with the transmission data in the
computation of attenuation correction factors is called: - Answers Blank scan
The property of the scintillation detector described as the number of scintilla- tions produced by each
incident photon is called: - Answers The light output
Precursor for the synthesis of phospholipids - Answers Choline
The correct order of scanning when a typical PET/CT protocol is applied - Answers Topogram,
transmission CT, emission PET
Presence of the non-collinearity of the annihilation photons and the finite posi- tron range are inherent
properties of positron emission tomography resulting in: - Answers Positional inaccuracy
Which of the following positron-emitting nuclides has the shortest half-life?
(A) Rubidium-82
(B) Oxygen-15
(C) Nitrogen-13
(D) Carbon-11 - Answers Rubidium-82
The cathode filament of the X-ray tube: - Answers Emits electrons
An oncology patient referred for a positron emission tomography scan should fast prior to his/her
appointment for at least: - Answers 4 hours
When should Daily quality control checks on the PET scanner be performed: - Answers Before the
patient is injected
Patients with malignant melanoma should be scanned with their arms: - Answers Down
The presence of asbestos-related plaques, benign inflammatory pleuritis, tuberculous pleuritis, and
pleural effusion can result in - Answers False-positive uptake in FDG-PET images of patients with
malignant mesothelioma
The earliest disposal of the decay-in-storage waste material is permitted if it was held for a minimum 10
half-lives and has decayed to less than: - Answers Two times background levels
Organizing, problem solving, attention, and planning are controlled by the: - Answers Frontal lobe of the
brain
The recommended time interval for PET imaging after biopsy is: - Answers 1 week
In the PET/CT acquisition, the CT component is performed for: - Answers Attenuation correction