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Role of PET-CT Scan in Cancer Care

PET-CT scan has become the standard choice of investigation in most cancers. A PET-CT scan is needed at every step of cancer care starting from early diagnosis, staging, treatment response evaluation and assessment of early recurrence.


"PET-CT" scan is a very powerful dual imaging modality which combines two very important investigations, i.e. PET scan and CT scan, into a single investigation to provide more detailed and accurate information about the cancer. While a PET scan gives us very sensitive information regarding the metabolic or functional status of the cancer cells in organs or tissues, a CT scan gives us detailed information of the size, shape and location.

The PET scan uses a mildly radioactive drug to show up areas in the body where cancer cells are more active. The CT scan takes a series of x-rays from all around your body and puts them together to create a 3-dimensional (3D) picture.


PET-CT scans can help to:

  • Detect cancer

  • Find out the size & location of the cancer and whether it has spread (stage a cancer).

  • Find out the primary site/organ from which the cancer has started.

  • Planning biopsy from most metabolically active site so that the correct diagnosis is available.

  • Decide whether you can have surgery to remove your cancer (Operable or inoperable).

  • Decide which is the best treatment for your cancer.

  • Check whether your cancer has come back (Recurrence).

  • Plan accurate radiotherapy treatment, so as to give optimum radiation dose to the most active cancer cells while preserving normal surrounding tissues.

A PET-CT scan can also show how well a cancer treatment is working.

After you have had treatment for cancer, a scan may show an area that looks like there might still be some cancer left. This might not be cancer but scar tissue left over from the cancer killed off by your treatment. A PET-CT scan can show whether this tissue is active cancer or not.

Unlike other forms of imaging, a PET scan shows molecular activity and helps doctors detect cancer or assess response very early. For this reason, a PET scan is a highly reliable tool in cancer management.


A radiotracer is injected into a vein in the arm or hand about an hour before the scan, as it takes time to reach the cancer cells within the body. After the waiting period, the patient lies on a flat bed that moves into a large, cylindrical scanner. The scan usually takes 25-30 minutes to complete.

After the PET scan, the patient can go on with his normal activities straight away. The injection of the radiopharmaceutical does not make the patient feel any different or drowsy and the entire procedure is painless.


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