The pet scan test, also called positron emission computed tomography, is an imaging test widely used to diagnose cancer early, check the development of the tumor and whether there is metastasis. The pet scan is able to show how the body is functioning, through the administration of a radioactive substance, called a tracer, that when absorbed by the organism, emits radiation that is captured by the equipment and transformed into an image.
The exam does not cause pain, however it can cause discomfort if the person is claustrophobic, as it is done in a closed equipment. In addition to being widely used in oncology, the pet scan is also useful in the diagnosis of neurological diseases, such as Alzheimer's and epilepsy.
The pet scan is an expensive exam and is often not covered by the health plan. The exam is between R $ 3000 and R $ 4000.00. In addition, the pet scan provided by SUS is only performed for investigation, diagnosis and monitoring of lung cancer, lymphomas, colon cancer, rectal cancer and immunoproliferative diseases, such as multiple myeloma, which is a disease in which the cells of the blood start to proliferate and accumulate in the bone marrow. Find out what the symptoms are and how to identify multiple myeloma.
What is it for
The pet scan is a diagnostic test more advantageous than other imaging tests, such as computed tomography and magnetic resonance imaging, for example. This is because it allows visualizing problems at the cellular level through the emission of radiation, that is, it is able to check the metabolic activity of cells, identifying cancer early.
In addition to the application for cancer identification, pet scan can be used to:
- Detect neurological problems, such as epilepsy and Alzheimer's; Check heart problems; Monitor cancer evolution; Monitor response to therapy; Identify metastatic processes.
The pet scan is also able to determine the diagnosis and define the prognosis, that is, the chances of improvement or worsening of the patient.
How is done
The test is done with oral administration, through liquids, or directly into the vein of a tracer, which is usually glucose marked with a radioactive substance. Because the tracer is glucose, this test does not pose a health risk, as it is easily eliminated by the body. Administration of the tracer should be done fasting for 4 to 6 hours, according to medical advice, and the pet scan is done after 1 hour, to allow time for the radioactive substance to be absorbed by the body, and lasts about 25 to 30 hours. minutes.
The pet scan makes a reading of the body, capturing the emitted radiation and forming images. In the investigation of tumor processes, for example, the consumption of glucose by cells is very large, since glucose is the source of energy necessary for cell differentiation. Thus, the formed image will have denser points where there is greater consumption of glucose and, consequently, greater emission of radiation, which can characterize the tumor.
After the examination it is important that the person drinks a lot of water so that the tracer is eliminated more easily. In addition, there may be mild allergy symptoms, such as redness, at the site where the tracer was injected.
The test has no contraindications and can be performed even on people who have diabetes or kidney problems. However, pregnant women are not advised to perform this diagnostic test, as a radioactive substance that can affect the baby is used.
