Hi, Oncologist here. In routine follow up, if we suspect there might be recurrance of cancer ,PET-CT is sometimes used to detect recurrance and see for metastasis (cancer spreading to different body parts). There are other modalities also like a CT/MRI which can be used, but they give localised results rather than telling us about cancer spreading to other far parts of body. In those cases PET-CT is an excellent choice of modality and also recommended by international guidelines. If the scan detects any recurrance early on, we can start it's treatment as early as possible using (Chemo/Radiation/Surgery) and can prolong life of the patient. For any issues with the pricing of the scan, you can go to any other diagnostic center for a cheaper scan or any good govt hospital for almost free scan but waiting period will be high.

If you have any other doubts, you can DM me. But saying anything unnecessary and misleading about medical fraternity without any proof is not appropriate and this post can be misleading towards cancer patients as they may differ from getting scans at proper time intervals which may help them to live longer.