Positron emission tomography (PET) is a medical imaging technique that produces detailed images of the inside of the body. It is used to diagnose and monitor various medical conditions, including cancer, heart disease, and neurological disorders.
What is a PET scan?
A PET scan is a type of medical imaging that uses a small amount of a radioactive substance, called a tracer, to produce images of the inside of the body. The tracer is injected into the body, swallowed, or inhaled, and then detected by a PET scanner. The PET scanner is a large machine that contains a ring of detectors that can detect the radiation emitted by the tracer.
How does a PET scan work?
The tracer used in a PET scan is typically a compound that contains a small amount of a radioactive substance, such as fluorine-18 or carbon-11. These radioactive substances emit positrons, which are positively charged particles that are the opposite of electrons. When a positron encounters an electron in the body, they annihilate each other and emit two gamma rays in opposite directions.
The PET scanner detects the gamma rays and uses them to create a three-dimensional image of the area being scanned. The scanner can detect the gamma rays from multiple angles, which allows it to create a detailed image of the area.
What happens during a PET scan?
Before the PET scan, the patient is injected with the tracer. The tracer is typically injected into a vein in the arm, but it can also be swallowed or inhaled, depending on the type of scan being done.
After the tracer is injected, the patient is asked to rest for a period of time to allow the tracer to circulate through the body. The amount of time the patient needs to rest depends on the type of scan being done and the tracer being used.
Once the tracer has circulated through the body, the patient is taken to the PET scanner. The scanner is a large machine with a narrow table that slides in and out of the machine.
The patient lies on the table, and the scanner is positioned over the area being scanned. The patient needs to remain still during the scan to ensure the images are clear.
The scanner emits a small amount of radiation to detect the tracer in the body. The patient will not feel anything during the scan, but they may hear a clicking or buzzing sound coming from the machine.
After the scan is complete, the patient can go home. The amount of radiation in the tracer is small, and it typically does not pose a health risk.
What are the uses of PET scans?
PET scans are used to diagnose and monitor a variety of medical conditions, including:
- Cancer: PET scans can help to diagnose cancer and determine the extent of the disease. They can also be used to monitor the effectiveness of cancer treatments, such as chemotherapy.
- Heart disease: PET scans can be used to diagnose heart disease and determine the extent of damage to the heart muscle. They can also be used to assess blood flow to the heart and to determine the effectiveness of treatments, such as angioplasty.
- Neurological disorders: PET scans can be used to diagnose and monitor neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, and epilepsy.
- Mental health disorders: PET scans can be used to study the brain and to diagnose and monitor mental health disorders, such as depression and schizophrenia.