What information does an air scan provide regarding detector performance?

An air scan provides critical uniformity information about the detector's performance. During an air scan, the detector responds to the absence of any radioactive source, which allows for evaluation of its response across different areas of the detector's surface. This helps in identifying any discrepancies in uniformity that could affect image quality. If any areas of the detector demonstrate inconsistent response or non-uniformity, it indicates that the detector may not be functioning optimally, potentially leading to artifacts or inaccuracies in subsequent imaging of patients.

The air scan does not provide information regarding the calibration of radiotracer dosage, as that involves specific measurements associated with the radiotracer used rather than the detector itself. It also does not evaluate patient movement artifacts; these are typically assessed through motion correction techniques and during the imaging process. Lastly, the sensitivity to CT imaging is a distinct characteristic that does not pertain to the air scan assessment of the PET detector's performance. Therefore, the primary focus of an air scan is indeed the uniformity of the detector, making this the correct answer.