Hi, Thanks for writing in. PET scan is positron emission tomography which is an imaging investigation that uses a radioactive substance called a tracer to look for disease in the body. In this scan an injection containing radioactive glucose is given in to the vein of the patient and then this goes and gets collected in the area where there is a lot of consumption of glucose. Usually cancer areas have a high energy requirement of glucose and that is the reason the cancer region is seen on a PET scan. It will tell where a cancer might have spread in the body and therefore change the staging. In PET scan it is not possible to tell the grade of cells. However it can pick up areas of active cell multiplication but it will not give a pathological diagnosis. Usually CT scan is also done together with a PET scan to know the exact area of cancer and it is also called PET CT scan. It can cost approximately ten thousand rupees and is done in many cancer hospitals and in private centers across the country. Please do not worry.