The newest method of diagnosing cancer. Positron Emission Tomography. PET study

Positron emission computer tomography, or PET CT, is a study of human internal organs by radioisotope diagnostic. A PET study is also called a two-photon emission tomography, due to the fact that this method is based on detecting a pair of gamma quanta.

PET is a modern way of early diagnosis of oncological, cardiological and neurological diseases. In oncology, PET is used to diagnose malignant neoplasms, to search for distant metastases and to monitor the treatment.

Positron emission tomography is distinguished by high accuracy of the study, minimal radiation load on the body, the ability to examine all organs in one visit. The research itself is completely painless.

PET, unlike any other methods of research, does not study the anatomical features of organs and tissues, but the chemical processes that take place in them. With oncological diseases, chemical processes change, it can be seen as a change in the color gamut and the intensity of processes, different from the norm.

Thus, thanks to PET, you can see the cancer onset long before the tumor is formed. Ultrasound, CT, MRI can detect a problem only when the tumor has already appeared and reached a certain size (for a modern MRI device at least 1-2 millimeters).

PET also helps to determine whether a malignant or benign tumor is this, which is especially important when it is not possible to obtain a biopsy material.

PET registers the flow of blood in tissues and the consumption of glucose and oxygen by tissues. A certain amount of a radioactive preparation (radioactive glucose) is introduced into the patient's body. Radiation from radioactive glucose is recorded by a special scanner, which transfers all the information received to the computer. The computer processes and visualizes it.

Cells with increased metabolism consume more glucose. This is what distinguishes cancer cells from ordinary cells . The more radioactive material is captured by the tissues, the brighter they look on the resulting image. Such sites are called "hot". Conversely, the less the drug is captured - the dimmer the image is obtained, such areas are called "cold".

The metabolism in malignant neoplasms is much higher than in healthy tissues. Therefore, malignant tumors give a brighter, "hot" picture.

The radioactive glucose itself decomposes in less than a day and is completely excreted by the body.

Due to the fact that the PET study covers the whole body, it is possible to make the most complete operational plan. This will remove all affected tissue, if possible in each case. This, in turn, will significantly reduce the risk of further relapse.

With the help of PET, you can accurately determine the stage of cancer, see if the lymph nodes are affected even before they grow. This makes it possible to apply anticancer therapy significantly more effectively.

At the end of chemotherapy and radiation therapy, PET can determine the effectiveness of the treatment.

A PET study will detect metastases when other diagnostic methods are not yet able to do so.

For example, a study of the lungs with the help of an X-ray can cause in the case of shading only a suspicion of the presence of metastases. Confirm their presence may be a traumatic puncture of tissues or PET, but a PET study will determine the size of metastasis and recognize the spread of cancer cells in the early stages of the disease.

Unlike scintigraphy, which also uses radioisotopes, the image in the PET study is three-dimensional, which makes it possible to more accurately assess the picture of the disease.

The study itself is as follows: the patient lies on the couch, which is pushed inside the apparatus. The apparatus itself is similar to a short tube. The procedure lasts from half an hour to an hour. Before this, the patient receives an inhalation or intravenously specially prepared radioactive preparation.

There are few contraindications to the positron emission tomography. The PET study is contraindicated in pregnant and lactating women, as well as in those patients who are not able to calmly, without any movements, to lie out the time required for the study.

Positron emission tomography is a rather expensive study. It is worth from 50 000 rubles. In Russia, the apparatus for such a study is 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 do regular analysis for oncomarkers.

If by nature the tumor slowly metastasizes, in this case it is also possible to confine itself to oncomarkers or other analyzes and regular medical examination by an oncologist.

If the tumor has been removed at later stages and is prone to rapid metastasis, then it makes sense to conduct a PET study. At the seemingly high cost of this study, the patient receives as a result the whole picture of the changes taking place in him in the body. Based on this, the doctor can choose a more sparing and, accordingly, less expensive method of treatment.

At current prices for drugs, the PET study, in many cases, pays for itself and allows you to save on drugs much more than the cost of the study itself. In addition, tumor processes, thanks 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 patient's body.

And in the case of different kinds of lymphomas, the PET study has nothing to replace in its reliability. Other methods of investigation here will be substantially inferior to PET diagnostics, both in accuracy and completeness, and in the rate of detection of metastases.