Deck 14: Positron Emission Tomographyct Petct and Single-Photon Emission Computed Tomographyct Spectct Hybrid Scanners

Question 1

The ring diameter of most clinical PET scanners is about:

A) 10 cm.
B) 25 cm.
C) 50 cm.
D) 100 cm.

Answer 1

50 cm.

Question 2

Clinical examples of PET imaging include each of the following except:

A) cardiac studies.
B) epilepsy studies.
C) oncology studies.
D) trauma.

Answer 2

trauma.

Question 3

A disadvantage of using isotopes such as ¹⁵O, ¹³N, and ¹¹C are their:

A) long half-lives.
B) short half-lives.
C) long persistence.
D) short persistence.

Answer 3

short half-lives.

Question 4

The crystals in the construction of a positron emission tomography (PET) scanner's detectors are:

A) cadmium detectors.
B) helium gas detectors.
C) scintillation detectors.
D) xenon gas detectors.

Question 5

What type of coincidence detection occurs when both annihilation photons exit the patient without incident and are detected in coincidence?

A) True
B) Scatter
C) Random
D) Accidental

Question 6

The most commonly used radiopharmaceutical for PET imaging is:

A) (¹⁵O) carbon monoxide.
B) (¹³N) ammonia.
C) (¹¹C) methionine.
D) (¹⁸F)-2-fluoro-2-deoxy-D-glucose (FDG).

Question 7

If the nucleus contains too many protons, it may emit a:

A) positron.
B) proton.
C) electron.
D) neutron.

Question 8

An atom that has too many protons or too many neutrons or they are configured in such a way so as to render the nucleus unstable is said to be a(n):

A) alpha particle.
B) beta particle.
C) radioactive atom.
D) gamma atom.

Question 9

Radioactive fluorine can be chemically substituted for a:

A) hydrogen atom.
B) deoxyglucose.
C) oxygen atom.
D) iodine component.

Question 10

When using FDG for a whole-body scan, the uptake waiting period is usually:

A) 15-45 minutes.
B) 30-50 minutes.
C) 45-90 minutes.
D) 60-120 minutes.

Question 11

All of the following are scintillating materials used in PET detectors except:

A) bismuth germanate.
B) calcium tungstate.
C) gadolinium oxyorthosilicate (GSO).
D) sodium iodide (NaI).

Question 12

When a photon undergoes Compton scattering prior to exiting the patient, it is referred to as a random coincident detection.

Question 13

A positron has the same mass as an electron but has a positive rather than a negative charge.

Question 14

What modality of imaging provides less noise when reconstructed to a PET or single-photon emission tomography (SPECT) image compared to traditional measured attenuation correction?

A) Ultrasound
B) Computed tomography (CT)
C) Magnetic resonance imaging (MRI)
D) Nuclear medicine

Question 15

NaI and bismuth germinate are newer scintillating materials that have reasonably high detection efficiency.

Question 16

One approach to reducing scatter includes introducing __________ between detection rings.

A) antiscatter grids
B) filtration
C) interplane septa
D) scatter shields

Question 17

The probability of detecting the photons from an annihilation event from one center of an object is less than that for an event on the periphery.

Question 18

Displaying two data sets from two separate modalities as a single fused image is referred to as:

A) comparing.
B) mixing.
C) registering.
D) segmenting.

Question 19

A modern PET scanner might contain tens of thousands of small scintillating detectors.

Question 20

All of the following are limitations of PET/CT technology except:

A) anatomical correlation.
B) increased expense.
C) increased radiation dose.
D) potential attenuation artifacts.

Question 21

PET brain imaging is used for a number of indications such as evaluating dementia, localizing epileptic foci, or evaluating brain injury following head trauma.

Question 22

The availability of interplane septa allows for the acquisition of PET data in 2D mode, which substantially reduces the amount of interplane scatter.

Question 23

Please match the following descriptions as being a featured characteristic of PET/CT, SPECT/CT, or both. Answer selections may be used more than once.

Only one photon (gamma ray) is emitted

A)PET/CT
B)SPECT/CT
C)Both

Question 24

Carbon, nitrogen, and oxygen derived radioisotopes have relatively short half-lives.

Question 25

The use of contrast media in CT can lead to artifacts in the reconstructed PET data.

Question 26

The uptake period for all SPECT/CT exams is 1 hour.

Question 27

FDG PET has not been useful in the localization of epileptic seizures.

Question 28

PET with FDG is a useful tool in the initial diagnosis, staging, and follow-up of lung cancer.

Question 29

Please match the following descriptions as being a featured characteristic of PET/CT, SPECT/CT, or both. Answer selections may be used more than once.

Utilized in cardiac applications

A)PET/CT
B)SPECT/CT
C)Both

Question 30

Please match the following descriptions as being a featured characteristic of PET/CT, SPECT/CT, or both. Answer selections may be used more than once.

Rotating gamma camera system

A)PET/CT
B)SPECT/CT
C)Both

Question 31

Please match the following descriptions as being a featured characteristic of PET/CT, SPECT/CT, or both. Answer selections may be used more than once.

Higher keV photon energies than CT

A)PET/CT
B)SPECT/CT
C)Both

Question 32

Another approach to attenuation correction in PET is to use the data from an MRI scan that are registered to the PET data.

Question 33

Please match the following descriptions as being a featured characteristic of PET/CT, SPECT/CT, or both. Answer selections may be used more than once.

A ring of several hundred, small detectors placed around the patient

A)PET/CT
B)SPECT/CT
C)Both

Question 34

SPECT does not require positron emitting radiopharmaceuticals.

Question 35

SPECT thyroid imaging follows the uptake of radiocalcium within organs and tissues of the body.