Questions

Answers

1. True or false: ¹⁸F emits a positron.

1. true

2. True or false: ¹⁵O emits a positron.

2. true

3. True or false: ^99mTc emits a positron.

3. false

4. True or false: ²⁰¹Tl emits a positron.

4. false

5. True or false: ¹¹C emits a positron.

5. true

6. Are positron-emitting radionuclides produced in a generator or in a cyclotron?

6. both

7. What are some of the positron emitters produced in a cyclotron?

7. ¹⁸F, ¹³N, ¹¹C, ¹⁵O, ⁶⁴Cu, ¹²⁴I

8. What are some of the positron emitters produced in a generator?

8. ⁸²Ru, ⁶⁸Ga, ⁶²Cu

9. Is a positron emitted from the nucleus of the atom or from the electron shells?

9. the nucleus

10. What happens when a positron is emitted from a radionuclide?

10. It collides with an electron and is annihilated.

11. Does the positron-electron annihilation take place in the radionuclide emitting the positron or at a short distance from the radionuclide?

11. at a short distance from the radionuclide

12. After annihilation of a positron by an electron, which of the following occurs?

A. Both the electron and positron lose energy and vanish.

B. Two 511-keV photons traveling in opposite directions are released.

C. Two photons are released at 90 degrees to each other.

D. none of the above

12. B, two 511-keV photons traveling in opposite directions are released

13. Is a 511-keV photon effectively detected by a gamma camera or by a coincidence-imaging device?

13. a coincidence-imaging device

14. Is a positron emission tomography (PET) scanner a gamma camera or a coincidence-imaging device?

14. a coincidence-imaging device

15. The scintillation crystals in modern PET scanners are commonly made of:

A. bismuth germinate (BSO)

B. lutetium oxyorthosilicate (LSO)

C. gadolinium silicate (GSO)

D. sodium iodide

E. all of the above

15. E, all of the above

16. The spatial resolution of modern PET scanners is in the range of:

A. 2 mm

B. 5 mm

C. 10 mm

D. 15 mm

E. 25 mm (1 inch)

16. B, 5 mm

17. The following positron-emitting radiopharmaceuticals are in use in clinical centers without a cyclotron (choose as many as apply):

A. ¹³N-labeled ammonia for blood flow

B. ¹⁵O-labeled water for blood flow

C. 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) for metabolism

D. ⁸²Rb for myocardial perfusion

E. none of the above

17. C and D

18. The mechanism of FDG uptake in metabolically active cells is:

A. passive diffusion through the cell membrane

B. facilitated transport via a glucose transporter (Glut) in the cell membrane

C. active transport via adenosine triphosphatase (ATPase) pump

D. all of the above

E. none of the above

18. B, facilitated transport via a glucose transporter (Glut) in the cell membrane

19. What happens to FDG once it is inside the cytoplasm?

A. It is taken up by mitochondria.

B. It is taken up by microsomes.

C. It undergoes phosphorylation to form FDG-6-phosphate (P).

D. all of the above

E. none of the above

19. C. It undergoes phosphorylation to form FDG-6-P.