This article is translated from:/articles/154877.php.
Other reference links: https://www.mayoclinic.org/tests-procedures/pet-scan/about/PAC-20385078.
PET scanning is an effective method to check the chemical activity of some parts of the body. It may help to identify various diseases, including many cancers, heart diseases and brain diseases. The information provided by the pictures scanned by PET is different from other types of scans, such as computed tomography (CT) or magnetic resonance imaging (MRI). The combination of PET scanning or CT-PET scanning enables your doctor to better diagnose diseases and evaluate your condition.
Positron emission tomography, also known as PET scanning, uses radiation to show in vivo activities at the cellular level.
It is most commonly used in cancer treatment, neurology and cardiology.
Combined with CT or MRI scanning, PET scanning can generate multi-dimensional color images of human internal work.
It not only shows the appearance of organs, but also shows their functions.
PET scanning is used to diagnose some health conditions, plan treatment, and understand the development of existing diseases and the effectiveness of treatment.
Fast facts of PET scanning
The following are some key points of PET scanning. The main text has more details.
PET scan shows the physical state and function of organs.
In PET scanning, the machine detects the radiation emitted by radioactive tracers.
Radiotracer consists of radioactive substances, which are labeled as natural chemicals such as glucose.
This radioactive tracer is injected into the body, where it moves to cells that use glucose as energy.
The more energy a group of cells needs, the more radioactive tracers accumulate in this position. This will be displayed on the image reconstructed by the computer.
Cells or activities will be displayed as "hot spots" or "cold spots".
The active area of PET scanning is very bright. They are called "hot spots"
The less energy cells need, the less bright these areas are. These are "cold spots".
Compared with normal cells, cancer cells use glucose very actively, so radioactive tracers made of glucose will illuminate the cancer area.
The radiologist will check the images generated on the computer and report the results to the doctor.
An example of a radioactive tracer based on glucose is fluorodeoxyglucose (FDG). In FDG, radioactive fluoride molecules are labeled as glucose to make radioactive tracers. FDG is the most commonly used radioactive tracer at present.
Oxygen can be used instead of glucose.
PET scanning is usually used for CT or MRI scanning to help diagnose or obtain more data about health status and any treatment progress.
Although MRI or CT scan shows that a part of the body looks like it, PET scan can reveal how it works.
PET scanning is usually used to study many situations.
Epilepsy: It can reveal which part of the brain epilepsy affects.
This can help doctors decide the most appropriate treatment, which may be useful if surgery is needed.
Alzheimer's Harmo's disease: PET scanning can help diagnose Alzheimer's Harmo's disease by measuring glucose intake in specific parts of the brain.
Brain cells affected by Alzheimer's disease are more likely to use glucose than normal cells.
Cancer: PET scanning can reveal the existence and stage of cancer, show whether it has spread and where it has spread, and help doctors decide the treatment.
PET scanning can let you know the effect of chemotherapy and can detect recurrent tumors faster than other techniques.
Heart disease: PET scanning can help detect which parts of the heart have been damaged or scarred, and it can help identify circulatory problems in heart work.
This information can help plan the treatment of heart disease.
Medical research: researchers can learn important information through PET scanning, especially about the operation of the brain.
CT or MRI scans can evaluate the size and shape of body organs and tissues, but they cannot evaluate how these work.
PET scanning can show the working principle of organs, but without CT or MRI images, it is difficult to determine the exact location of activities in the body.
Combining PET scanning with CT scanning can help us understand the patient's condition more comprehensively.
PET images show that active cells are bright spots or "hot spots".
PET scanning is usually an outpatient operation.
Usually, patients should not eat any food for at least 4 to 6 hours before scanning, but should drink plenty of water. They may need to avoid caffeine for at least 24 hours before the scan.
First, the doctor will inject a small amount of radioactive tracer into the vein. Tracers can also be inhaled as gas, taken orally, or directly injected into organs.
Depending on the organs involved, it may take 30 to 90 minutes for the radioactive tracer to reach the target part of the body.
At the same time, patients are usually asked to stay still and not talk. Some patients may take drugs to relax.
Patients may need to wear robes, and they may need to take off their jewelry.
When the patients are ready, they will be taken to a special room for scanning. They will lie on the padded examination table.
The table slipped into a big hole and the patient was surrounded by machines.
The patient must stay as still as possible. Maybe they can listen to music.
During the scanning process, the machine will take images.
It takes about 30 minutes, depending on which part of the body is scanned.
This is not painful. If patients feel unwell, they can press the buzzer to remind the staff.
During the scanning process, qualified practitioners will observe the patient.
The whole test process usually takes about 2 hours. After scanning, most patients can go home.
Patients should consume a lot of liquid in order to flush radiopharmaceuticals out of the system more quickly. Radiotracer should leave the body completely within 3 to 4 hours.
There is a risk of radiation exposure.
For most people, the benefits of PET scanning outweigh the risks.
But because PET involves radioactive substances, it is not suitable for everyone.
Generally speaking, pregnant women should not have a PET scan because radioactive substances may affect the fetus or baby.
If a woman is breastfeeding, she should follow the instructions of pumping water and discarding breast milk, and ask the doctor when it is safe to resume breastfeeding according to the examination.
Any pregnant or lactating woman should tell her doctor immediately before having a PET scan.
After PET scanning, patients may be advised to stay away from pregnant women, infants and young children for several hours, because radioactivity poses little risk.
In a few cases, individuals may have allergic reactions to tracers.
20 180905