Positron emission tomography, or PET, is a non-invasive way to examine the body using a special machine. This method is used to scan the internal organs.
What is the specifics of diagnostics
PET examination - what is it? Positron emission tomography is an offshoot of nuclear medicine. This area is associated with the use of pharmaceuticals for the diagnosis and treatment of various ailments. Specially manufactured substances contain very small amounts of radioactive isotopes. Their doses are so small that they do not harm the body at all.
Information about the accumulation of nucleotides in tissues with the help of special software is transformed into a graphic image of the human body and three-dimensional projections of internal systems. Spatial visualization of the body makes it possible to assess the localization of the drug. No negative effects of PET examination were noted.
Varieties of tomography
The method of delivering a labeled drug to the affected area of the body is used not only for diagnosis, but also for treatment. It is known that radiation has a destructive effect on humans. But scientists were able to tame it andturn for the good of the people. Very small doses of radiation, targeted to the affected areas, can treat many serious diseases.
Tomography is the visualization of organs and tissues in separate thin layers. Initially, this was the name of the preparation of biological products for research. Fragments of tissue were cut into layers, fixed with special chemicals or frozen, and then photographed.
A bit of history
The forerunner of remote tomography was the traditional x-ray. Today, layer-by-layer visualization is carried out by using special analog and digital equipment. Tomography uses x-rays. Scientists have tried to overcome the static nature of this method for many years. Moving the X-ray machine along the motionless body of the patient was the first step towards layer-by-layer diagnostics of the body. The creators of the method, Godfrey Hounsfield and Alan Cormack, won the Nobel Prize in Physiology or Medicine in 1972.
Computed tomography is a very broad term. Today, all non-invasive body checks are performed using hardware and software. In the narrow sense of the word, computed tomography means a layered study using x-rays.
Another variation of the method is the so-called magnetic resonance imaging (MRI). It is also a method of layer-by-layer remote visualization of internal organs. But it is based not on X-rays, but on the use of the electromagnetic response of atomic nuclei. This is the modern method, it wasfirst tested in 2003 by Peter Mansfield and Paul Lauterbur. Scientists received the Nobel Prize for their invention.
Problems of positron emission scanning
Radioactive components tend to accumulate in the affected areas of the body and are able to glow against the background of other tissues. This makes pharmaceuticals very useful in terms of diagnosing malignant neoplasms.
Cancer cells divide rapidly and accumulate radioactive substances in large quantities. Therefore, the affected areas of the body are clearly visible. Similar methods of non-invasive remote diagnostics, such as x-rays or computed tomography, show only tissue damage. PET examination also marks the degree of activity of the oncological process.
In the diagnosis of tumor diseases, radiopharmaceuticals are used for the following purposes:
- detection of foci of the oncological process and affected tissues;
- differential diagnosis of malignant neoplasms;
- assessment of treatment effectiveness.
During a complete PET examination of the body, the affected areas actively glow, which makes it possible to determine the degree of tumor invasion into neighboring organs, as well as the presence of metastases. They arise because dangerous cells, moving through the circulatory and lymphatic systems, penetrate into tissues that are far from the primary focus.
Differential diagnosis and evaluation of treatment effectiveness
Exceptoncological diseases, benign tumors are also known to medicine. They do not grow, do not penetrate into neighboring organs and do not metastasize. Their cells are mature, active division is absent. Benign formations do not accumulate radionucleotides and do not glow. PET diagnostics also performs the function of distinguishing tumor processes in the body.
This examination helps evaluate the results of treatment. If the activity of cell division, as well as their luminosity, has significantly decreased, the therapy can be considered successful.
What makes the approach unique
The inventor of the method is the Hungarian scientist Georg Hevesy. In 1913, he first came up with ways to use radiation-tagged drugs in medicine. For this, the scientist received the Nobel Prize in Chemistry. The first advanced positron emission tomograph of the modern type was created in 1961 by James Robertson.
PET examination differs from other imaging methods in that it can detect tumor processes at the earliest stages. The focus of the disease is still very small, but it is already actively absorbing labeled drugs. This examination is able to detect malfunctions of the organ at the cellular level, but poorly reflects its structure. Therefore, today the positron emission method is combined with computed tomography, which makes it possible to localize damaged tissue with an accuracy of several millimeters.
Cardiovascular surgery and pathology of the nervous system
PET examination is carried out not only withpurpose of diagnosing neoplastic diseases, but also for checking neurological and cardiac disorders. For example, using this method, you can determine the intensity of the work of organs, a heart attack and even a heart attack. The device is able to detect areas with impaired or weak blood circulation. This is important for diagnosing a heart attack and coronary heart disease. With such diseases, doctors need to know whether the circulatory system is completely affected or whether it is still supplied with oxygen, albeit poorly. PET will help with this, determining the need for surgery.
You can also identify disorders that occur with Parkinson's disease or epilepsy. PET examination of the brain helps to identify failures leading to senile dementia at the earliest stages. For example, when there are no symptoms yet, but certain parts of the organ are already affected. PET easily identifies epileptic foci that can be treated with therapy.
How scanning works
Before the start of the examination, the patient is injected intravenously with a solution of glucose with radioactive drugs. After some time (about an hour), when the bloodstream distributes the labeled atoms throughout the body, the person lies down on a special couch attached to the scanner. During the waiting period, it is advisable not to move and completely relax. The drug accumulates in working muscles, which may adversely affect the results of the study. The couch with the patient moves through the scanner, and in the meantime, specialdetectors detect active substance absorption centers and display data on a computer monitor.
The software visualizes organs and systems in layers, indicating luminous zones. The specialist studies the results of the test and forms a medical report, which is provided to the patient along with tomography printouts. The minimum scan time is half an hour.
What to tell your doctor about
When diagnosing oncological diseases, PET examination can show the so-called false positive results. The drug is able to accumulate not only in tumor foci, but also during inflammatory processes in a particular organ. Therefore, PET should not be done immediately after surgery or chemotherapy. How much time should pass in each case, the doctor will tell.
The radio drug is excreted from the body within a day. This study is completely safe. The only contraindication is pregnancy. However, the patient must inform the doctor about all chronic diseases, including allergic reactions, before undergoing a PET examination.
Feedback on the procedure is positive. It is effective and safe. Tell your doctor about all medications, vitamins, supplements, and herbal teas you take. If a woman is breastfeeding a child, she must also report this. Usually, after the removal of harmful substances from the body, breastfeeding can be restored. All jewelry and items containingmetal, such as a hearing aid. Tell your doctor if you have dentures (including dentures) or implants. Tell me if you have tattoos. They may contain metal based dyes.
How to get ready
PET diagnostics requires special preliminary steps. If the procedure is scheduled for the morning, in the evening it is necessary to consume a minimum of light food. After that, you can no longer eat. You can only drink water. For people with diabetes, there is a special procedure for preparing for the study. The doctor will tell you about it.
Complications during a PET scan are almost non-existent. This can also be said about side effects and unpleasant consequences. Sometimes patients feel weak and slightly dizzy. But these symptoms can be caused by fasting in preparation for the study. They pass quickly. It should be noted that during the procedure the patient has to lie still. This can cause discomfort, back pain and a feeling of heaviness in the neck. But complete rest is very important for correct scan results.
Take precautions
Preparation for a PET examination involves arriving at a medical institution 15 minutes before the appointed time. Do not bring children or pregnant women with you, they should be kept as far away from radiation sources as possible. Take the results of all previous examinations, extracts from medical records, medical records. After the procedure, you must carefully observe the rules of personal hygiene. ForDrinking plenty of fluids is recommended to make radiopharmaceuticals more quickly excreted from the body.
Medical centers and facilities
Where to do PET examination? This question worries most patients. Today, there are not very many medical centers in Russia where you can undergo positron emission tomography. In Moscow, you can make a diagnosis in the following institutions:
- Scientific Center for Vascular Surgery. Bakuleva.
- Center of Radiosurgery named after Berezina.
- Central Regional Clinical Hospital.
- Central Clinical Hospital No. 1.
- Institute of Clinical Radiology.
- Russian Cancer Research Center. Blokhin.
PET examination at Kashirka is carried out in a confidential manner. The department was opened recently, in 2013. It has already received high marks from experts and positive feedback from patients.
In St. Petersburg, the examination can be done at the following institutions:
- Human Brain Institute.
- Kirov Military Medical Academy.
- Central Research Institute of X-ray Radiology in the village of Pesochny.
Also, positron emission tomography can be done in the Chelyabinsk and Tyumen oncological dispensaries. There are two specialized medical institutions in Kazan:
- Cancer Center of the Republic of Tatarstan.
- Republican Clinical Oncology Center.
Conclusion
Combined PET/CT machinesis not available in all the institutions mentioned above. Some centers have in their arsenal only a positron emission tomograph. When examining, it is better to give preference to combined CT and PET. Reviews about them are extremely positive. Such tomographs are reliable and safe. The availability of combined devices, the price and schedule of the institution should be checked with the administrator.
Conditions for the comfort of patients are created in all medical centers. They have comfortable rest rooms for people waiting for the procedure to begin. In the cafeteria you can order he althy and tasty dishes. After returning home, it is recommended to get some sleep.
