Physics and Radiobiology of Nuclear Medicine

4. A pulse-height analyzer:
   (a) Reduces the background. True or false?
   (b) Rejects g-rays that undergo Compton scattering in the patient and
   the detector. True or false?
   (c) Rejects g-rays undergoing photoelectric effect in patients. True or
   false?
   (d) Increases the signal-to-noise ratio. True or false?


5. (a) The counting efficiency of a gamma camera increases with the thick-
   ness of the detector. True or false?
   (b) What are the most common thicknesses of the NaI(Tl) detector
   used?
   (c) A gamma camera detector with a 20-cm field of view is used to
   image the lungs, which fill 75% of the image. The camera is set to
   accumulate 450,000 counts. Calculate the information density.


6. In pulse-height analysis, a 20% window means 10% on either side of the
   photopeak. True or false?


7. Describe how the digital camera works.


8. What is the advantage of a digital camera over an analog camera (Anger
   type)?

Suggested Readings

Cherry SR, Sorensen JA, Phelps ME. Physics in Nuclear Medicine. 3rd ed.
Philadelphia: W.B. Saunders; 2003.
Early P. Private communication, 2005.
Erickson J. Imaging systems. In: Harbert J, da Rocha AFG, eds.Textbook of Nuclear
Medicine, Volume I: Basic Science.Philadelphia: Lea & Febiger; 1984.
Rollo FD, ed.Nuclear Physics, Instrumentation, and Agents.St Louis: CV Mosby;
1977.

Suggested Readings 117