Introduction to PET CT Scan
PET stands for Positron Emission Tomography scan. It’s an imaging test which reveals how the tissues and organs are functioning. PET CT scan uses the radioactive drug for showing the activity. It detects the disease before it shows on other imaging tests such as CT Scan,MRI Scan.,etc
The radioactive drug can be injected, swallowed or inhaled depending on which organs or tissue to be studied. PET CT scan is useful in examining various conditions which include cancers, heart disease and brain disorders. These scans are combined with CT and MRI for creating special views.
What is a PET CT Scan?
The PET CT scan is an effective way of examining the chemical activity in certain parts of the body. It helps in identifying a variety of conditions which includes cancer, heart disease and brain disorders. PET CT scan helps the doctor in better understanding and diagnosing the illness. This test uses a safe injectable radioactive tracer for scanning the chemical effects.
PET CT scanner helps in measuring the blood flow, oxygen and how the body uses sugar and much more. This is a typical out-patient procedure where you can leave after the test is done.
Why do Hospitals use PET CT Scans?
The PET scanner will check for the signs of:
- Cancer which includes breast cancer, thyroid cancer and lung cancer
- Any heart problems like Coronary Artery Disease(CAD) and Heart Attack
- Various types of brain Disorders like brain tumors, epilepsy, dementia and Alzheimer’s disease.
The cancer cells have a higher metabolic rate than noncancerous cells which can lead to a high level of chemical activity and cancer cells show up as spots on the PET CT scans. PET scan helps in seeing if-
- cancer is spreading in the body parts
- the cancer treatment is progressive or not
- there is any recurrence in cancer
PET scan helps in revealing the areas of decreased blood flow in the heart. It is because healthy heart tissue will take more time to trace than the unhealthy tissue which has decreased the blood flow.
The main fuel of the brain is glucose. During the PET CT scan tracers are attached with the glucose. It detects the radioactive glucose and then the PET CT scan is able to detect the area of the brains that are utilizing glucose at a high rate.
PET CT scans are used in diagnosing and managing many central nervous system disorders:
- Head trauma
- Parkinson’s disease
Difference between PET Scan and CT Scan and MRI Scan
|PET Scan||CT Scan||MRI Scan|
|It’s an imaging exam that is used for diagnosing diseases or issues by looking at how the body is functioning.||CT Scan uses computers and rotating X-Ray machines for creating cross- sectional images of the body.||It uses strong magnetic fields and radio waves to display detailed images of the body.|
|PET-CT Scan uses a special dye with radioactive tracers which help the machine in capturing the changes on how the body is working.||CT Scan shows a clear picture of soft tissues, blood vessels and bones in various parts of the body.||Images are used to determine the injured and unhealthy tissue in the body.|
PET-CT Scan are used to:
CT Scan are used to:
MRI Scan are used for:
For More Information
Types of PET CT Scans
PET f-18 FDG Scan:
Before the scan is performed, a small amount of fluorodeoxyglucose(FDG) is injected in the patient. The FDG traces produce colour-code images of the body that show cancerous tissue. PET scanner detects the radiation emitted by the patient and the computer generates three-dimensional images of tissue function.
Cardiac PET CT Scan:
It scans your heart with the help of specialized dye which allows the doctor in viewing the problems in the heart. It contains radioactive tracers that concentrate on areas of the heart which are injured. It helps in detecting coronary heart disease and damage caused due to heart attack. PET CT scan shows a clear picture of a healthy and damaged heart muscle.
Positron Emission Tomography-Computed Tomography is a nuclear medicine technique which is a combination of a single gantry. This reveals the functioning of the tissues. This detects the diseases before it shows up in other imaging tests.
F-18 Bone Scan:
Bone scan images are the metabolic activity of the skeleton. These are accomplished by imaging a radionuclide where physiology closely mimics the metabolic process within a bone.
Neuro PET scan:
It’s an imaging test of the brain. This uses radioactive substances for looking into the injury in the brain. Also it shows a clear picture on how the brain and the tissues are working.
Risks involved in the PET CT Scan
The risks involved in PET CT Scan are less when compared with the other Scanners:
- PET CT Scan involves radioactive tracers but it has less exposure to harmful radiation.
- The risks are very low as compared to the beneficiary factors.
- The tracer consists of glucose with radioactive components attached. So it makes the body eliminate tracers even if you are having past medical conditions of kidney disease or diabetes.
People with other health conditions
There is a possibility of getting an allergic reaction to the tracer. People who are highly allergic to iodine, aspartame and saccharin need to talk to their doctor. Some of the health conditions include:
- Heart Disease
- Blood cells disorders
- Kidney disease
Some of the measure side effects of PET CT scan are:
- Mild rash
In some cases, a person may get serious allergic reactions which are known as anaphylaxis.
How is a PET CT Scan performed?
Before you go for scan, you’ll get tracers through the vein in your arm through a solution that you drink or a gas that you inhale. The body needs time to absorb the tracers and you have to wait about an hour before the scan begins.
The time that takes to absorb the tracer will depend on the area of the body that should be scanned. During your waiting time, you have to limit your movement, relax and try to stay warm.
Next, you have to undergo the scan for 30-45 mins. You have to lie on the narrow table attached to a PET CT machine which looks like the giant O. The table then slides slowly in the machine so the scan can be conducted.
The doctor will let you know when you have to remain still and when you have to move. When all the necessary images are recorded you can slide out of the machine
PET CT scan is useful in detecting many types of cancers. It can verify the smallest cancer cells. PET CT Scan images are combined with CT or MRI scan for creating special views.
PET CT scans are not painful. These are used for diagnosing the condition and tracking down the development. Scans are not painful but they shouldn’t consume food at least before 4-6 hours.
Pet scan take at least 30minutes. The scan is painless but can feel uncomfortable lying still for a longer period of time.
PET scan is a source of claustrophobic.
The more scan you have the higher will be your lifetime exposure and higher will be the risk. Mainly three scan limit applies for the type of tumor.
Yes, PET scan is effective than CT scan. PET scan show the metallic changes that occur at the cellular level in tissue and organ.
IRT is a potential noninvasive and safe alternative for PT scan.
Avoid drinking of water for 6 hours before the PET scan.
PET CT Scan: https://search.proquest.com/openview/22bef30eb02cfc539a43a62ecf1e382b/1?pq-origsite=gscholar&cbl=40808
PET CT Scan for Cancer: http://jnm.snmjournals.org/content/46/4/608.short
PET/CT scan side effects: https://link.springer.com/article/10.1245/s10434-008-9992-0