- PET CT will be done by prior appointment only and on submission of this duly completed and printed form at the centre.
- All patients should have a referral note from the doctor for the Whole Body PET-CT study.
- An additional cost of Rs. 100 per film would be charged at the Centre for CT films, if needed as a part of the report. This is applicable at certain centres
- Please call us for any assistance.
What is PET CT Scan?
PET CT scan is an advanced nuclear imaging technique. This technique combines Positron Emission Tomography (PET) and Computed Tomography (CT). This scan reveals the information about structure and functions of cells and tissues in the body. It reveals about the stage and spread of cancer. It also shows how the internal organs are reacting/ working.
How does a PET CT Scan work?
PET CT Scan Machine
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PET scan creates a picture of organs and tissues of the body. The technician injects a radioactive substance in your body. The organs then pick up this substance. Since the cancer cells have more energy, they pick this substance more. In PET you can see which the cancer affected areas are.
A CT scan creates 3D images of the organs with the help of X-Rays. This scan shows the tumours inside. However, in some cases it requires contrast dye to get better and clear images.
Uses of PET CT scan:
- Detects cancer
- Determine cancer spread and stage
- To determine the effectiveness of cancer treatment
- Reoccurrence of cancer
- Blood flow to heart muscles
- In case of heart diseases
- Brain abnormalities like tumours, central nervous system disorders
How should I prepare for PET CT Scan procedure?
Women should always inform if they are pregnant or are breast feeding. In case you are breast feeding, it may help you pump breast milk ahead of time and keep it on hand for use once the test is complete. It will help you until the contrast is no longer in your body.
Inform your radiologist if you are taking any medications including vitamins and herbal supplements. Also inform about any kind of illness or allergies you might have.
The doctor/ physician/ radiologist will give special instructions depending on your illness.
Any metal dentures, hairpins, jewelry, eyeglasses etc. may affect the CT images. Remove all the metal objects prior to your test. You may also have to remove removable dental work and hearing aids.
The physician/ radiologist may ask you to fast for several hours prior to your test. Because eating may alter the distribution of PET tracer in your body. This may require performing the scan on another day. So you must follow the instructions about eating. Do not drink any liquid containing sugar or calories for hours before the scan. Instead, you can drink a lot of water.
PET CT Scan
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How does the scanner look like?
A PET scanner is a larger machine with a round doughnut shaped hole. Within this machine are multiple rings of detectors to record the emission of energy from the radiotracer in the body.
A CT scanner is a large box like machine with a hole and a tunnel in the center. You need to lie on the scanner bed that slides into and out of this tunnel. Also, the machine contains X-ray tubes and X-ray detectors on opposite sides. The computer work station which processes the imaging information is located in separate room, where the technologist operates the scanner. You can communicate with the radiologist using speaker and microphone.
PET CT scanner is a combination of both PET and CT scanner. The computer aids in creating images from the data obtained by the gamma camera.
What is the procedure of the scan?
During the test:
- When you arrive at the centre, you may have to change into the hospital gown.
- Depending upon the type of nuclear medicine exam you are undergoing, the dose of radiotracer is injected intravenously, swallowed or inhaled as a gas.
- Technologist or nurse will then put an intravenous line (IV). Then they will put the radioactive substance in the IV. It then injects into the veins.
- The substance takes 30-90 minutes to reach the tissues. You need to lie quietly and without moving.
- You will move into the PET CT Scanner and the imaging will begin.
- If your PET CT is for radiation treatment planning, you might wear a mask or cast during the scan. Thus, keeps your body in the same position as for the treatment.
- Total scanning time is approximately 30 min.
- However, depending on which organ to scan, it may require special tests. Thus, may require other tests and drugs. Therefore lengthening the procedure time.
- When your exam is complete, the radiologist may ask you to wait. The radiologist checks the images in case any additional image is required.
Except for the intravenous injections, most nuclear tests are painless and do not cause any discomfort or side effects.
You will feel slight prick of the injection which injects the radiotracer. When the radiotracer moves in your veins, you may feel a cold sensation. However, this does not cause any side effects.
When you swallow a radiotracer, it has little or no taste.
If you are claustrophobic, you may feel some anxiety during the scan.
After the test:
You can resume your normal activities after the scan.
Through the natural process of radioactive decay, a small amount of radiotracer in your body will lose its radioactivity over time.
It will pass out of your body through your urine or stool during the first few hours or days following the test. You need to drink plenty of water to help flush the radioactive material.
What Questions You Should Ask Your Doctor?
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What questions you should ask your doctor before the test?
- Who will do the PET CT scan?
- What will happen during the scan?
- How long will it take?
- What can I drink and eat before the test? What should I avoid?
- Will I need to avoid any activities after the scan?
- When will I get the test results?
- Who will explain the results to me?
- Will I need other test?
- When should I arrive for the test?
Who will interpret the results?
A radiologist or physician who has specialized training in nuclear medicine will interpret the images. They will then send the repot to your referring doctor.
Benefits of the test:
- It provides unique information including details on both function and anatomic structure of the body.
- For diagnosis of many diseases.
- It is less expensive and may yield precise information.
- Greater detail with higher level of accuracy.
Risks of the test:
- Because the doses of radiotracer are small, nuclear medicine procedure results in relatively low radiation exposure to the patient. Therefore the radiation risk is very low.
- Allergic reactions may occur but are extremely rare and are usually mild. You need to inform the nuclear medicine personnel of any allergy you may have.
- Injection of radiotracer may cause slight pain and redness. This will rapidly resolve.
Limitations of the PET CT scan:
- Nuclear medicine scan can be time consuming. It can take several hours to accumulate in the area of interest. Also, the scanning alone takes upto hours to perform.
- Test results of diabetic patients or the patients who have eaten within few hours prior to the examination can be adversely affected because of altered blood sugar level.
- Since, the radioactive substance decays quickly, it is effective only for short period of time. Therefore, you should be on time for the test and receive the radioactive material at scheduled time.
- The person who is obese may not fit into the opening of the PET CT scan machine.