Final answer:
PET scans are used to detect tumors, coronary artery disease, and to assess the success of cancer treatments, meaning all the given conditions can be evaluated using PET imaging.
Step-by-step explanation:
Positron Emission Tomography (PET scans) are a medical imaging technique that uses radiopharmaceuticals to assess physiological activities such as nutrient metabolism and blood flow in various organs of the body. PET scans measure the metabolic activity of glucose, which is particularly higher in tumor cells as compared to normal cells, making it an effective tool for cancer detection. Therefore, PET scans can be used for various medical evaluations including detecting tumors, assessing heart function to diagnose coronary artery disease, and monitoring the effectiveness of cancer treatment. Consequently, the correct answer to the student's question is '4) All of the above' as PET scans are capable of detecting and assessing all these conditions.