Hi Pavan D. My wife had her sarcoma removed with clear margins (meaning several centemeters of healthy tissue surrounding the tumor site). A couple weeks later she had six weeks of radiation, five times per week. Our doctors said chemo wouldn't have an effect. She had an MRI, but that only looks for abnormal masses and is much lower than 100% at finding other tumors. I'd suggest trying for a PET scan (which looks for abnormal functioning). The two scans can augment each other. The problem is that PET scans cost between $5,000 to $10,000 and for for many insurance companies, that's a bit steep. Don't be shy about clamoring for the treatment your Dad needs. He's the only Dad you've got.