What is the primary benefic in using a dual- or triple-head scintillation camera in SPECT? What additional problems , if any, do these entail?

1. Is it essential to acquire data from all sides (300o angle) for accurate reconstruction in SPECT? Can it be less than 180o ?

2. What is the primary benefic in using a dual- or triple-head scintillation camera in SPECT? What additional problems , if any, do these entail?

3. Why is quality control important in SPECT?

4. What two factors make quantitation with SPECT less accurate than PET?

5. Why is the resolving time of a coincidence circuit an important parameter in a PET scanner?

6. List the various stages in the development of radiation injury.

7. For the same radiation dose, what are the other factors that can modify the biological effects or their intensity?

8. Generally , below what dose are acute effects not observable?

9. Name the most common late biological effect and give its probability of ocurance after 1 rem of total body irradiation at low dose rate to a general population.

10. What is the most sensitive period during pregnancy for the development of a fetal abnormality?

11. What factor relates absorbed dose to equivalent dose or dose equivalent?

12. What is tissue weighting factor and why is it needed?

13. Effective doses from an internally absorbed radionuclide have to be modified. Why? How ?