Which of the following are desirable properties of gamma rays produced

1.	Which of the following are desirable properties of gamma rays produced by radionuclides for imaging? a. The energy of the photon should be more than 100 keV b. Emission of polyenergetic gamma rays c. High energy d. Low energy e. Emission of pure gamma rays
Answer» a. True. Below 100 keV, scatter and attenuation within the patient become problematic, e.g. Tl-201. b. False. The pulse height analyser filters out scatter by accepting gamma rays that fall within a small energy window; therefore mono energetic gamma rays are preferable. c. False. High-energy gamma rays are difficult to collimate and a proportion will also pass straight through the crystal of the gamma camera without being detected. d. False. Low-energy gamma rays are absorbed by the patient and do not reach the gamma camera. e. True. Gamma rays result in the formation of the image, whereas the beta particles deposit an unnecessary dose in the patient.

Which of the following are desirable properties of gamma rays produced by radionuclides for imaging? a. The energy of the photon should be more than 100 keV b. Emission of polyenergetic gamma rays c. High energy d. Low energy e. Emission of pure gamma rays

Answer»

a. True. Below 100 keV, scatter and attenuation within the patient become problematic, e.g. Tl-201.

b. False. The pulse height analyser filters out scatter by accepting gamma rays that fall within a small energy window; therefore mono energetic gamma rays are preferable.

c. False. High-energy gamma rays are difficult to collimate and a proportion will also pass straight through the crystal of the gamma camera without being detected.

d. False. Low-energy gamma rays are absorbed by the patient and do not reach the gamma camera.

e. True. Gamma rays result in the formation of the image, whereas the beta particles deposit an unnecessary dose in the patient.

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