| Number | Answer | Rationale |
| 1 | B | The collimator provides directional information by accepting photons travelling along specific trajectories. |
| 2 | A | Parallel-hole collimator resolution improves as the distance between the patient and collimator decreases. |
| 3 | B | Total counts are the product of count rate and acquisition time. If the count rate decreases by half, the acquisition time must be doubled to obtain approximately the same total counts and preserve image count statistics. |
| 4 | C | The photopeak energy window preferentially accepts primary photons and rejects many photons that have undergone Compton scattering. |
| 5 | A | Detector non-uniformities are reproduced at different projection angles and may form ring artefacts after SPECT reconstruction. |
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