Positron emission computed tomography,or PET CT is a study of the internal organs of a person by the method of radioisotope diagnostics. PET testing is also called two-photon emission tomography, due to the fact that this method is based on the detection of a pair of gamma rays.
PET is a modern way of earlydiagnostics of oncological, cardiac and neurological diseases. In oncology, PET is used to diagnose malignant neoplasms, search for distant metastases, and monitor treatment.
Positron emission tomography distinguisheshigh accuracy of the study, the minimum radiation load on the body, the ability to explore all the organs in one visit. The study itself is completely painless.
PET, unlike any other methodsstudies, studies not the anatomical features of organs and tissues, but the chemical processes occurring in them. In cancer, chemical processes change, this can be seen as a change in the color gamut and intensity of the processes, which is different from the norm.
Thus, thanks to PET see the beginningOncological process can be long before a tumor is formed. Ultrasound, CT, MRI can detect the problem only when the tumor has already appeared and has reached a certain size (for a modern MRI device at least 1-2 millimeters).
PET can also help determine whether the tumor is malignant or benign, which is especially important when it is not possible to obtain a biopsy material.
PET registers tissue blood flow and consumption.tissues of glucose and oxygen. A certain amount of a radioactive drug (radioactive glucose) is injected into the patient's body. Radiation from radioactive glucose is recorded by a special scanner that transmits all received information to a computer. The computer processes and visualizes it.
Cells with increased metabolism consumemore glucose. This is what distinguishes cancer cells from ordinary ones. The more a radioactive drug is captured by the tissues, the brighter they appear on the resulting image. Such sites are called "hot." And vice versa, the less a drug is captured - the duller the image is obtained, such areas are called “cold”.
The metabolism in malignant tumors is significantly higher than in healthy tissues. Therefore, malignant tumors give a brighter, “hot” picture.
The radioactive glucose itself disintegrates in less than a day and is completely eliminated by the body.
Due to the fact that PET research coversthe whole body, you can make the most complete operational plan. This will remove all affected tissue, if possible in each case. Which in turn will significantly reduce the risk of further relapse.
With the help of PET, you can accurately establish the stage of cancer, see whether the lymph nodes are affected even before they begin to grow. This allows the use of anti-cancer therapy significantly more effectively.
At the end of chemotherapy and radiotherapy, PET allows to determine the effectiveness of the treatment.
A PET test will detect metastases when other diagnostic methods are not yet able to do this.
Скажем, исследование легких с помощью рентгена may in the case of shading cause only suspicion of the presence of metastases. Confirming their presence can either traumatic tissue puncture or PET, but PET examination will determine the size of metastasis and recognize the spread of cancer cells in the early stages of disease.
In contrast to scintigraphy, which also uses radioisotopes, the PET image is a three-dimensional image, which makes it possible to more accurately assess the picture of the disease.
The study itself is as follows:the patient lies down on a couch that slides into the apparatus. The device itself is like a short pipe. The procedure lasts from half an hour to an hour. Before that, the patient receives a specially prepared radioactive drug by inhalation or intravenous administration.
Contraindications forpositron emission tomography a bit. A PET study is contraindicated for pregnant and lactating women, as well as for those patients who are not able to calmly, without any movements, stay out of the time required for the study.
Positron emission tomography - the study is quite expensive. It costs from 50 000 rubles. In Russia, there are devices for such research only in large cities.
Of course, it makes no sense to conduct a PET study as a preventive examination of a healthy person. To do this, it will be enough to regularly analyze tumor markers.
If, by its nature, the tumor slowly metastasizes, in this case it is also possible to confine yourself to oncomarkers or other tests and regular medical examination by an oncologist.
If the tumor was removed laterstages and is prone to rapid metastasis, then it makes sense to conduct a PET study. With the seemingly high cost of this study, the patient receives as a result the whole picture of changes occurring in his body. Based on this, the doctor can choose a more benign and, accordingly, less costly treatment method.
With current drug prices, PET research,in many cases, it pays for itself and allows you to save on drugs much more than the cost of the study itself. In addition, tumor processes, due to the PET study, will be detected and suppressed long before they can be diagnosed by other standard methods. Consequently, they will cause much less harm to the body of the patient.
And in the case of all sorts of lymphomasPET research is simply nothing to replace. Other research methods here will be significantly inferior to PET diagnostics, both in accuracy and completeness, and in the rate of detection of metastases.
