A PET scan is a type of positron emission tomography scan. PET scans are a sort of diagnostic that can be used to diagnose and treat cancer. It’s possible to combine it with a CT scan. A PET-CT scan is what doctors call it if this is the case. However, you may hear it referred to as a PET scan.

A PET-CT scan can help detect cancer and determine its stage in some cancers. The term “stage” refers to the location of the cancer and whether it has spread. Doctors will also discover about the stage of the cancer and how it is affecting your body’s processes. Knowing what stage of cancer you have can help you and your doctor decide on the best treatment option. It also aids your doctor in predicting your prognosis.

PET evaluates organ and tissue functions by using small amounts of radioactive chemicals called radiotracers or radiopharmaceuticals, a specific camera, and a computer. PET may detect the early development of disease before other imaging tests because it detects changes at the cellular level.

If you think you might be pregnant or breastfeeding, let your doctor know. Depending on the sort of exam, your doctor will advise you on how to prepare. Discuss any recent illnesses, medical conditions, drugs you’re taking, and allergies, especially if you’re working with contrasting material. Before your scan, your doctor will probably tell you not to eat anything and to drink only water for several hours. Wear loose, comfy clothing and leave your jewels at home. During the exam, you may wear a gown.


PET Scan


What is PET CT Scan?

PET imaging, often known as PET scanning or a PET scan, is a type of nuclear medicine imaging.

Radiotracers, which are minuscule amounts of radioactive material, are used in nuclear medicine. Nuclear medicine is used by doctors to diagnose, evaluate, and treat a variety of disorders. Cancer, heart disease, gastrointestinal, endocrine, or neurological diseases, among other things, are among them. Nuclear medicine examinations are used to identify molecular activity. They will be able to detect disease in its early stages as a result of this. They can also demonstrate how well you’re doing with your treatment.

Nuclear medicine is a painless procedure. It is normally painless, with the exception of intravenous injections. To diagnose and analyse medical disorders, these tests use radioactive materials known as radiopharmaceuticals or radiotracers.

Radiotracers are molecules that are attached to a little amount of radioactive material, or “labelled” with it. They build up in tumours and inflammatory areas. They have the ability to bind to certain proteins in the body as well. F-18 fluorodeoxyglucose (FDG), a chemical comparable to glucose, is the most often used radiotracer. Cancer cells have a greater metabolic rate and may absorb glucose more quickly. On PET scans, this greater rate can be noticed. This allows your doctor to discover disease before other imaging tests reveal it. FDG is just one of numerous radiotracers that are now in use or being developed.

The radiotracer is commonly given as an injection. Depending on the exam, you can either ingest it or inhale it as a gas. It collects in the area under investigation. The radiotracer emits gamma rays, which are detected by a specific camera. A camera and a computer create images and provide molecular data.

To create unique views, several imaging centres mix nuclear medicine images with computed tomography (CT) or magnetic resonance imaging (MRI). This is referred to as picture fusion or co-registration by doctors. Image fusion allows a doctor to combine and analyse data from two separate exams on a single image. This results in more precise data and a more precise diagnosis. Both SPECT/CT (single photon emission computed tomography/CT) and PET/CT (positron emission tomography/CT) devices may perform both exams at the same time. PET/MRI is a relatively new imaging technique. It isn’t available everywhere right now.

The metabolism, for example, is measured via a PET scan. It aids doctors in determining the health of organs and tissues.

CT imaging creates numerous images of the inside of the body using specialised x-ray equipment and, in certain situations, contrast material. On a computer monitor, a radiologist examines and interprets these images. CT scans provide a wealth of anatomical information.

Today, practically all PET scans are done with combined PET/CT machines. These combined scans can help highlight aberrant metabolic activity and may result in more accurate diagnosis than two independent scans.


Some common usage of PET CT Scan

Doctors perform PET and PET/CT scans to:

  • detect cancer and/or make a diagnosis.
  • determine whether a cancer has spread in the body.
  • assess the effectiveness of treatment.
  • determine if a cancer has returned after treatment.
  • evaluate prognosis.
  • assess tissue metabolism and viability.
  • determine the effects of a heart attack myocardial infarction on areas of the heart.
  • identify areas of the heart muscle that would benefit from angioplasty or coronary artery bypass surgery (in combination with a myocardial perfusion scan).
  • evaluate brain abnormalities, such as tumors, memory disorders, seizures and other central nervous system disorders.
  • map normal human brain and heart function.


How PET CT Scan works ?

You will be given a tiny injection of fluorodeoxyglucose-18, a radioactive sugar, prior to your PET-CT scan. FGD-18, radioactive glucose, or a tracer are all terms used to describe this chemical. Sugar is absorbed by your body’s cells. Sugar is absorbed more readily in areas that expend more energy. Cancer cells have a higher energy consumption than healthy cells. The PET scan reveals the location of the radioactive tracer in your body.

A CT scan is a procedure that involves taking x-rays of your body from various angles. Before the x-rays, you may be given a dye shot. This improves the visibility of some of the details. Finally, the PET and CT pictures are combined by a computer. Your doctor will receive a complete 3-D report that will show any abnormalities, including cancers.


Is PET CT Scan safe?

There is a danger of radiation exposure with PET-CT scans. This sort of scan uses x-rays, the material used in the PET scan, or a combination of the two. Less radiation is emitted when scanning a smaller body area. A CT scan without the dye that helps show details achieves the same thing.

The advantages of these testing usually outweigh the hazards. You will be exposed to minor levels of radiation throughout these examinations. There has been no evidence that this tiny dosage of radiation causes harm. There may be a tiny increased risk of cancer in the future for children or other persons who require multiple PET scans, CT scans, and x-rays.

Doctors can utilise lower-dose scans or limit the number of locations that must be scanned. Make sure all of your doctors are aware of how many imaging scans you’ve had, as well as the number and sort of scans you’ve had. This information will aid them in determining which scans to perform in the future in order to lower your risk. If you’re worried about your radiation exposure, talk to your doctor about it. You might be able to have a different sort of test that uses less radiation.


How to prepare for PET CT Scan?

During the exam, you may be required to wear a gown or may be allowed to wear your own clothes.

If a woman is pregnant or breastfeeding, she should always inform her doctor and technician. More information about pregnancy and nursing in relation to nuclear medicine imaging can be found on the page Safety in X-ray, Interventional Radiology, and Nuclear Medicine Procedures.

Any medications you’re taking, including vitamins and herbal supplements, should be disclosed to your doctor and exam technologist. Any allergies, recent illnesses, or other medical issues should be listed.

Depending on the sort of PET scan you had, you will be given precise recommendations. Patients with diabetes will be given particular information on how to prepare for the exam.

Ask your radiologist or doctor how to proceed if you are breastfeeding at the time of the exam. Pumping breast milk ahead of time and keeping it on hand until the PET radiotracer and CT contrast material are no longer in your body may be beneficial.

Metal things, such as jewellery, eyeglasses, dentures, and hairpins, should be left at home because they may interfere with CT pictures. Hearing aids and removable dental procedures may need to be removed.

Before a full body PET/CT scan, your doctor will usually advise you not to eat anything for many hours. Eating can change the distribution of the PET tracer in your body, resulting in a less-than-ideal scan. This may necessitate repeating the scan on a different day, so follow the feeding directions carefully. For several hours before the scan, you should avoid drinking any sugary or calorie-containing liquids. You are instead encouraged to drink water. Your doctor may give you extra advice if you have diabetes. Make a list of all the medications you’re taking and provide it to your doctor. Any allergies, especially to contrast materials or iodine, should be noted.

Your doctor will look for any conditions that could make getting intravenous contrast material more dangerous.


How does PET CT Scan procedure works?

Ordinary x-ray exams create an image by passing x-rays through the body. Radiopharmaceuticals or radiotracers are radioactive materials used in nuclear medicine. This chemical is usually injected into your bloodstream by your doctor. You can also take it by mouth or inhale it as a gas. The substance collects in the area under investigation and emits gamma rays. Special cameras detect this energy and use a computer to create images that show how your organs and tissues look and operate.

Only radiotracer injections are used in PET scans.

Nuclear medicine, unlike other imaging modalities, focuses on inside bodily processes. These include metabolic rates and levels of a variety of different chemical activities. “Hot spots” are areas where the intensity is higher. These may reveal high radiotracer concentrations as well as a high level of chemical or metabolic activity. Less intense patches, or “cold spots,” imply lower radiotracer concentrations and activity.


How is PET CT performed?

Nuclear medicine exams are performed on outpatients and hospitalised patients by doctors.

You’ll be lying down on an exam table. If necessary, an intravenous (IV) catheter will be inserted into a vein in your hand or arm by a nurse or technologist.

Only radiotracer injections are used in PET scans.

It takes roughly 30-60 minutes for the radiotracer to go through your body and be absorbed by the area being examined. You will be urged to sit quietly and refrain from moving or chatting.

You may be asked to drink some contrast material, which will help the radiologist interpret the exam by localising in the intestines.

To begin imaging, you will be transferred inside the PET/CT scanner. During imaging, you must remain completely still. The CT scan is done first, and then the PET scan. A second CT scan with intravenous contrast may be performed after the PET scan on rare occasions. See Computed Tomography for further information on how a CT scan is performed. The CT scan only takes around two minutes. It takes 20-30 minutes for a PET scan.

The average scanning time is around 30 minutes.

Additional tests employing other tracers or medications may be done, depending on the area being investigated. The treatment could take up to three hours as a result of this. If you’re being tested for heart problems, for example, you might get a PET scan before and after you exercise, or before and after you get IV medicine to improve blood flow to the heart.

You may have to wait until the technologist determines if more photos are required after the exam. The technician may take additional photographs to clarify or visualise certain locations or structures. The need for more photos does not always imply that the exam went wrong or that something is wrong. It should not be a source of concern for you.

Your technician will normally remove your intravenous (IV) line if you have one for the procedure. If you have another treatment that day that requires an IV line, the technologist will leave it in place.


What a patient experience during PET CT Scan ?

Most nuclear medicine procedures are painless, with the exception of intravenous injections. Significant discomfort or adverse effects have been reported infrequently.

When the technologist puts the needle for the intravenous line into your vein, you will feel a little pin prick. During the radiotracer injection, you may feel a cool sensation travelling up your arm. Other than that, there are no known negative effects. Only radiotracer injections are used in PET scans.

A catheter may be inserted into your bladder during some operations. This might make you feel a little uncomfortable for a while.

During the exam, it is critical to remain completely still. Nuclear imaging is painless. However, being stationary or in one posture for lengthy periods of time can be uncomfortable. You may feel anxious throughout the exam if you have a fear of enclosed areas.

After your exam, unless your doctor informs you differently, you can continue your normal activities. Before you depart, a technologist, nurse, or doctor will give you any particular instructions you may need.

Through the natural process of radioactive decay, the small amount of radiotracer in your body will decrease its radioactivity over time. During the first few hours or days after the test, it may also pass out of your body through your urine or faeces. To assist flush the substance out of your body, drink plenty of water.


What are the benefits of PET Scan ?

  • Nuclear medicine exams provide unique information that is often unattainable using other imaging procedures. This information may include details on the function and anatomy of body structures.
  • Nuclear medicine supplies the most useful diagnostic or treatment information for many diseases.
  • A nuclear medicine scan is less expensive and may yield more precise information than exploratory surgery.
  • By identifying changes in the body at the cellular level, PET imaging may detect the early onset of disease before it is evident on other imaging tests such as CT or MRI.


What are the risks associated with PET CT Scan ?

  • Because nuclear medicine exams use only a small dose of radiotracer, they have a relatively low radiation exposure. This is acceptable for diagnostic exams. Thus, the potential benefits of an exam outweigh the very low radiation risk.
  • Doctors have been using nuclear medicine diagnostic procedures for more than six decades. There are no known long-term adverse effects from such low-dose exposure.
  • Your doctor always weighs the benefits of nuclear medicine treatment against any risks. Your doctor will discuss the significant risks prior to treatment and give you an opportunity to ask questions.
  • Allergic reactions to radiotracers are extremely rare and usually mild. Always tell the nuclear medicine personnel about any allergies you may have. Describe any problems you may have had during previous nuclear medicine exams.
  • The radiotracer injection may cause slight pain and redness. This should rapidly resolve.
  • Women should always tell their doctor and radiology technologist if there is any possibility that they are pregnant, or they are breastfeeding.


How much does PET CT Scan cost?

To know the cost of PET CT Scan in different countries, please visit here and select PET Scan in treatment followed by name of the country.

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