What is PET SCAN?
What is PET-CT scan: PET-CT scan which stands for Positron emission tomography. It is a nuclear medicine technique which uses two scanners namely positron emission tomography (PET) scanner and an x-ray computed tomography (CT) scanner. The purpose of using two scanners is to acquire sequential images from both devices in the same session, which are combined into a single superposed image. Types of PET-CT scan: PET f-18 FDG scan : A glucose scan sometimes done immediately after the PET scan to determine if heart muscle has permanent damage. Cardiac PET scan: A cardiac PET or SPECT scan is a type of cardiac molecular imaging that involves the injection of a radioactive label or tracer to circulate to the heart. PET/CT scan : A PET/CT scan is a hybrid of imaging technology that combines PET and CT scans, allowing for a more accurate diagnosis. Why it is done: The primary purpose of doing a PET-CT scan is to diagnose cancer. It is also used to find out how big a cancer is and whether it has spread .i.e stage of cancer. It is used to decide whether you patient have surgery to remove his/her cancer It helps doctor decide which is the best treatment for cancer for the patient It also let your doctor check whether patient’s cancer has come back It also let the doctor examine the effectiveness of the current treatment.
What is the difference between PET-CT Scan and CT Scan?
A CT Scan is used by the doctor to get detailed pictures of tissues and organs inside a person?s body. Whereas, a PET Scan can be used to find out abnormal activities inside the body and is more sensitive than other imaging tests that are available. Showing changes happening inside the body sooner than any other test is the main advantage of PET scan. PET-CT Scan is used by doctors to get detailed information about the cancer.
Along with providing detailed information about cancer, PET-CT scan can also be used by a doctor for :
a. Planning radiation therapy.
b. Finding the right place for a biopsy.
c. Checking for new cancer growth after treatment has ended.
d. Learning if cancer treatment is working.
Procedure of performing PET-CT Scan :
PET CT scanner uses a scanning device which is basically a machine with a hole at its center. This scanning device detects the photons emitted by the tissue(containing radionuclide) which is being examined. Radionuclide is made by combining a radioactive atom to chemical substances. These chemical substances are used by a tissue naturally doing its metabolic process.
The person who has to undergo PET-CT scan is given an injection of a small amount of fluorodeoxyglucose-18 ( Radioactive Sugar) . FDG-18, tracer or radioactive glucose are some other names for fluorodeoxyglucose-18. Cells of a human body absorb sugar. More sugar is absorbed by areas in the body which have more energy. Since cancer cells use more energy than healthy cells, absorption is more in them. A PET scan displays the area of the body where a radioactive tracer is present.
X-Rays of the body are then taken from different angles by CT scanner. A contrast material (known as dye) may also be used to get better detailing. Finally PET and CT images are combined by a computer and 3-D results are produced. Doctor then uses these 3-D results to see the presence of any abnormalities in the body including tumors.
Importance of a PET scan
PET scans are useful in detecting the abnormalities happening inside an area of a body where some chemical activity might be happening. Detection of Brain disorders, heart diseases and cancer effectively are the main advantages of this scan.
1. Brain disorders :PET scan can reveal any abnormality in different parts of the brain which are responsible for performing majority of the activities.
Following are the main brain abnormalities that can be detected by PET scan:
a. Tumors
b. Seizures
c. Memory disorders
2. Cancer:Due to high metabolism rate of cancer cells, bright spots around them can be spotted by PET scan. Following are the conditions that can be detected:
a. The spread and extent of some cancers
b. The response of the cancer to the treatment
c. Whether the cancer has recurred
PET scans should be carefully analyzed in order to avoid considering non-cancerous cells as cancer cells.
Following cancers can be detected using PET scan :
a. Lymphoma
b. Thyroid
c. Brain disorders
d. Lung
e. Esophageal
f. Cervical disorders
g. Melanoma
h. Colon
i. Breast
j. Pancreatic
PET Scan in Chandigarh is available at Indus hospital