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PET stands for positron emission tomography. A PET CT scan combines both, a CT scan and a PET scan. The CT scan uses a series of X-rays to create 3 dimensional (3D) pictures of the organs and tissues inside the body while the PET scan uses a mild radioactive drug (tracer) to show areas of the body where cells are more active than usual.

A PET CT scan can be helpful to identify a variety of problems including –

What is a tracer?

The PET CT scan involves the use of a special radioactive drug known as a tracer. The tracer helps to find problems with the organs and tissues of the body. It allows the doctor to evaluate how well the organs and tissues are working.

How does a PET CT scan machine work?

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A PET CT scan machine consists of the following components –

  • Computers(s)
  • Rotating X-ray machines

An X-ray beam is released that circles around the part of the body that is getting tested.

This provides pictures of the organs and tissues of the body at all different angles. The computer then processes these images to create a detailed 3-D image of the particular body part for further analysis. A PET CT scan is carried out with the help of a radioactive dye known as the tracer, which helps in evaluating the working of these organs and tissues.

PET CT scan uses

A PET CT scan inspects the blood flow, oxygen intake, metabolism, and working of the organs and tissues of the body. It helps to identify those organs and tissues that are not working as they should be.

A doctor may recommend a PET CT scan for any of the following reasons –

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1. Cancer

During a PET CT scan, cancer cells appear as bright spots due to higher activity in the cells. This helps in –

  • Detecting cancer
  • Evaluating the spread of cancer
  • Monitoring the cancer treatment
  • Finding any cancer recurrences

2. Heart disease

A PET CT scan helps identify those areas in the body where the blood flow is reduced. It can be used to check for the following –

  • Coronary diseases
  • Blocked heart arteries
  • Heart attacks

3. Brain disorders

A PET CT scan can be used to detect brain-related problems such as –

  • Dementia
  • Epilepsy
  • Brain tumors
  • Alzheimer’s disease
  • Seizures
  • Depression
  • Head trauma

If you have any of the above health complications, get a PET CT scan done in Delhi, India with

PET CT scan preparation

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How can I prepare for a PET CT scan?

Depending on the part of the body getting tested, the doctor may provide the patient with the following instructions –

  • To eat a light meal, the night before the scan is to take place.
  • Fasting (to avoid eating for a certain amount of time before the scan)

On arrival at the hospital, the patient may be asked to remove some items of clothing and change into a hospital gown for the PET CT scan.

All items containing metal must be removed before the PET CT scan. Some of these items include –

  • Jewelry
  • Mobile phone
  • Watches
  • Keys
  • Hearing aids
  • Glasses
  • Dentures (false teeth)
  • Underwire (bras)
  • Belts and buckles
  • Any clothing item that may consist of metallic threads

In case –

  • the patient is experiencing any stress or anxiety, sedatives can be used to help calm them during the scan.
  • the patient is pregnant, the doctor must be informed as the radiation from the PET CT scan may be dangerous for the baby’s development. But if it is important, precautions must be taken before, during, and after the PET CT scan.

Note: If you take any medications, talk to your doctor before fasting for the PET CT scan test. You might have to take your normal dose at a different time or at the same time with less water.

PET CT scan with a tracer

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What is a tracer?

During a PET CT scan, a special material is used that helps find problems inside the body. This special material is known as a tracer and is used in multiple imaging tests to give off certain particles which are eventually turned into pictures that help in evaluating certain medical conditions.

Is it dangerous to use a tracer?

The tracers used in the PET CT scan are not dyes and do not cause any known reactions. The patient will feel nothing unusual post the consumption of a tracer. However, there are certain effects that one may feel including – headaches, vomiting, and nausea.

How is the tracer put inside the body?

There are a few ways that can be used to put the tracer inside the patient’s body before the PET CT scan takes place. The following are the 2 ways the doctor may use –

  • Injection: The tracer is directly injected into the bloodstream.
  • Orally: The tracer is swallowed by taking it in liquid form or inhaling it.

PET CT scan procedure

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What is the procedure for a PET CT scan?

On arrival at the hospital, the PET CT scan procedure usually takes place in the following manner:

  • ​​Depending on the body part that is being examined, the patient may be asked to change into a medical gown
  • The patient is then made to remove all metal items (as mentioned above)
  • A form is then filled out by the patient to take safety precautions in general. The patient is free to discuss any issues/concerns with the doctor
  • Before entering the PET CT scan room, the patient is injected with the tracer and made to wait for a short period
  • The patient is then made to enter the PET CT scan room where with the help of the doctor, the patient is made to lie down on the scanner table, comfortably
  • The scanner will then begin to rotate around the patient and the PET CT scan will start

PET CT scan side effects

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PET CT scans are safe and painless. It is highly unlikely that a patient will experience any sort of side effect post a PET CT scan.

However, there are a few cases that the patient should be made aware of if undergoing a PET-CT scan combination –

1. Contrast dye (may be used for the CT scan component)

The use of the iodine-based material can cause some reactions including –

  • Nausea
  • Vomiting
  • Headaches
  • Stomach issues (loose motions, constipation)
  • Mild rashes (in case of an allergic reaction)

A great amount of water or liquid(s) must be taken post the PET CT scan to remove the material from the system.

2. Nursing mothers

Mothers who are nursing their child should make sure to pump and store the breast milk before the PET CT scan as they will not be able to resume breastfeeding post the PET CT scan for about 24 hours.

How much time does a PET CT scan take?

A PET CT scan usually takes about 30 to 90 minutes but can go up to 2 hours. It takes up to 60 minutes for the body to absorb the tracer that is injected into the body. During this time, the patient is to sit patiently and wait. The actual PET scan usually takes about 45-60 minutes.