Role of PET/CT Scan in Cancer Treatment - Medx Health Assistance

Role of PET/CT Scan in Cancer Treatment

The management of cancer has grown over the years to involve several modalities of treatments essentially surgery, chemotherapy and radiation therapy. Actual management needs accurate diagnosis and evaluation of the extension of the tumor. A PET/CT scanner offers sophisticated imaging to assess the original tumor as well as metastatic disease.

Positron Emission Tomography, commonly known as PET scan, uses radiations to show activity within the body on a cellular level. A Computerized Tomography or CT scan is a combination of a series of X-ray images taken out from different positions.

Doctors suggest a combination of this PET scan with CT/MRI scan to get a multidimensional picture along with the colored images of the inside workings of the body. 

Thereafter, this combination along with computer processing forms cross-sectional images of the blood vessels, bones and soft tissues inside a human body. 


How does PET/CT scan work? 

A special dye containing radioactive tracers is used in this scan. These tracers might be swallowed, inhaled or injected into a vein from where it travels within the body to the cells that use glucose for energy, totally depending on what body part is to be examined. This radioactive sugar is known as fluorodeoxyglucose-18, which is to be taken one hour prior to the actual scan. 

More radiotracer will build up in the location, where the group of cells require more energy. PET scan is quite helpful in the treatment of cancer, since cancer cells have a higher metabolic rate than noncancerous cells, they are very active in using glucose; owing to this fact cancer cells pop-up very brightly in PET scans. The activity will display “hot spots” or “cold spots.” Active areas are termed as“Hot spots” and are brighter on the PET scan, whereas, the areas which are less brighter can be referred to as “Cold spots.”

An image of a breast detecting “Hot spots.”

For instance, the main roles of PET/CT scan in breast cancer are spotting and localizing metastasis, examining the response to treatment and early detection of recurrence. 

The actual scan might last for 30 to 45 minutes, where the patient is asked to lay on a narrow table that slides slowly into the PET machine, which looks similar to a giant letter “O”. One may even be instructed to hold their breath for a few seconds. The table should slide back out of the machine once the PET scan is complete, with all the necessary images recorded. Finally, when the computer merges the PET and CT images, the doctor gets a detailed 3-D result that can  reveal any abnormality present inside the body, including tumors. 

A PET scan fulfills following requirements:

  • To detect the extension of the cancer.
  • To stage the cancer.
  • Planning the treatment.
  • To see how effective a treatment is working. 
  • Examine for a cancer recurrence.

CT scan might detect some signs of the cancer left even after the treatment. But they may not be active cells. There are possibilities that those leftovers could be scar tissues from the cancer killed off by the treatment. A PET scan can further be helpful in this situation, as it may show whether these tissues are active cancer or not.

Major tumor kinds in which PET scan can be useful:

  • Lung Cancer
  • Lymphoma 
  • Colorectal Cancer
  • Head and Neck Cancer
  • Melanoma
  • Breast Cancer



Radioactive tracers have a vital role in PET scan but the exposure to these harmful radiation is minimal because it is injected in a very small amount. Typically, the radioactive tracers are attached to the sugar glucose which makes it convenient for one’s body to eliminate the tracers. Allergic reactions to the tracer is a possible risk. Nevertheless, the advantages of these tests are usually greater than the risks.



PET scanner has proven to be superior to conventional imaging in the diagnosis and management of several kinds of cancers. Moreover, the right use of this scan can highlight the need of significant change in the management of a patient’s care, if any.

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