Positron Emission Tomography( PET) - Causes, Symptoms and Treatment. MF.

Positron Emission Tomography is a new accurate and modern way of early diagnosis of oncological, cardiological and neurological diseases.

Positron emission tomography is a complex study that is used by
In oncology: cancer diagnosis, metastasis diagnostics, cancer treatment effectiveness control
In cardiology: in coronary heart disease, in front of aorto-coronary bypass
In neurology: multiple sclerosis and other diseases
In psychiatry and gerontology - Alzheimer's disease

Positron emission tomography provides information on the metabolism at the cellular level.
Positron emission tomography can detect signs of cancer at the earliest stage.

Advantages of PET over other diagnostic methods:

• High diagnostic accuracy of
• One study replaces several different types of diagnostics
• No pain or discomfort and harmful side effects
• Ability to cover all organs in one study
• Diagnosis of diseases in the early stages of
• Elimination of ineffective or optionalsurgical or drug treatment methods
• Positron emission tomography is practically harmless

Positron emission tomography is the latest diagnostic method that allows physicians to evaluate the functioning of tissues and organs of your body. Unlike other instrumental methods of research, the main task in conducting positron emission tomography is not "photographing the image" of internal organs, but obtaining a color image of the chemical activity of the processes occurring in the patient's body. In tumorous diseases, chemical processes change, and accordingly their color gamut and intensity change, thus, Positron emission tomography detects the disease at the earliest stage, when no structural( visible to the eye) changes have occurred yet.

Principle of positron emission tomography

Despite the introduction of a radioactive preparation, positron emission tomography is practically harmless. A radioactive preparation is prepared in a cyclotron, and breaks up into non-radioactive constituents in an hour. The radiation dose for positron emission tomography is comparable to the radiation dose for X-ray and computed tomography

Positron emission tomography registers blood flow in tissues and tissue consumption of oxygen and glucose. A small amount of a radioactive preparation is introduced into the patient's body, which enters the tissues. A radioactive preparation emits special rays that are invisible to the eye. These beams are registered by the PET scanner, which then transmits the information to the computer. The computer processes it and translates it into a graphical view - it builds images. The more radioactive material is captured by the tissues, the brighter they look on the image - such areas are called "hot", and vice versa, the less the drug is captured - the dimmer the image is, such areas are called "cold".Metabolism in a malignant tumor is much higher than in healthy tissues, therefore, malignant tumors give a brighter image( "hot")

Most often, positron emission tomography is used in the diagnosis of cancer. Also positron emission tomography is used to diagnose diseases of the nervous system and heart diseases. The method is based on the use of radioactive isotopes in minimal quantities, practically harmless to the body.

PET in oncology. Diagnosis of cancer

Positron emission tomography( PET) is the most modern method for diagnosing and controlling the treatment of cancer.

Positron emission tomography can detect oncological diseases at an early stage, before the onset of disease progression.

Modern cancer diagnostics, using PET, allows revealing chains of tumor-affected tissues by introducing into the body of radioactive glucose, which is processed by all cells. Cells with increased metabolism perceive more glucose. This is what distinguishes cancer cells. Cancerous tumors consume more energy than healthy tissues, so they capture more radioactive preparation - so the tumors become visible when performing positron emission tomography. They are fixed by the scanner and displayed on the pictures. PET defines a cancer tumor of even less than 1 cm. The radioactive substance introduced into the body loses its activity for several hours and is harmless. The special value of this diagnostic method is that it allows selecting the most appropriate form of therapy, especially lymphatic oncological diseases. After the end of chemotherapy, PET allows you to determine the effectiveness of the treatment.

PET recognizes metastases when other diagnostic methods are impotent. For example, an X-ray examination of the lungs can cause in the case of shading only suspicion of the presence of metastases. Confirm or refute the suspicion may puncture the tissue or PET, while only PET allows you to determine the size of metastasis, and can also recognize the spread of cancer cells in the early stages of the disease.

The accuracy of PET diagnostics is 80 to 95 percent, while the accuracy of computer tomography diagnosis is 50 to 68 percent. However, computed tomography often does not indicate an existing tumor recurrence or metastasis.

PET, in contrast to CT, is able to identify the cause of growth of tumor markers and determine further therapy.

PET due to high accuracy allows to avoid surgical interventions with negative results of CT studies.

When determining the neoplasia of the lymphatic system, PET can replace a whole range of studies: X-rays, CT, MRI, skeletal scintigraphy.

PET, unlike other methods of research, produces differentiation of healthy and diseased tissues: distinguishes chronic inflammatory processes from oncological. However, other methods of research, including puncture with a negative result, do not guarantee the absence of malignancy.

PET allows not only to reveal indications for operation, but also to make an optimal plan for surgical intervention.

Positron emission tomography is also used to determine the stage of cancer. In the past, doctors could judge cancerous lymph nodes only by increasing them. With the help of positron emission tomography, it is possible to detect a cancerous lymph node before it started to increase, which allows for proper treatment. It should be remembered that some non-cancerous processes can also affect the lymph nodes, therefore in certain cases 100% confidence that there is no cancer only gives a biopsy( surgical tissue sampling for analysis) of a suspicious lymph node.

PET in cardiology. Diagnosis of heart diseases

Positron emission tomography can detect areas of the heart with impaired blood flow, so this method of research is used in the early diagnosis of coronary heart disease and to identify old heart attacks. With the help of POSITION-EMISSION TOMOGRAPHY, it is possible to distinguish the dead portion of the heart muscle from the live, but poorly contracting because of the low blood supply. In the latter case, an operation to restore blood flow will improve the function of this affected area.

PET is able to recognize the condition of the tissues of the heart muscle and thereby determine the indications for heart surgery. If all tissues are "alive", enough bypass operation or balloon dilatation. If uncased tissue sites are detected, then indications for heart transplantation are determined.

PET in neurology

PET allows you to identify early brain diseases leading to senile dementia.

PET determines whether the processes that cause Parkinson's disease occur in the brain. Based on the data obtained, sufficiently effective therapy is prescribed.

PET identifies regions of the brain that cause epilepsy. Based on these studies, planning for surgical operations to remove epileptogenic zones is underway.

Positron emission tomography allows you to compare brain activity in patients with depression and brain activity in healthy people. Studies show that, in depression, the activity of some parts of the brain decreases. While in the wide practice, POSITION-EMISSION TOMOGRAPHY is not used to diagnose depression.

Alzheimer's disease( senile dementia).Positron emission tomography shows changes in the brain in Alzheimer's disease at the earliest stages - when no symptoms appear. Positron emission tomography helps distinguish Alzheimer's from other diseases that cause dementia( Parkinson's disease, Huntington's disease).

Other brain diseases. Positron emission tomography is used to diagnose convulsions in epilepsy and to evaluate brain function after a stroke. In some cases, positron emission tomography is used in schizophrenia.

Unfortunately, the Positron emission tomograph is available only in large regional centers of Russia( according to data for April 2010 in Moscow, St. Petersburg, Yekaterinburg), although in Europe and the US, Positron Emission Tomography( PET) has already become widespread indiagnosis of diseases. Why is Positron Emission Tomography usually used?

Most often, PET scans are used to detect cancer and to test the effect of cancer treatment.

Positron emission tomography of the brain is used to assess the condition of patients suffering from memory loss, seizures or a brain tumor.

With the help of PET scan, a specially trained doctor( radiologist) can check if there are any changes in the cells.

Before the positron emission tomography is introduced radioactive sugar 18 FDG, which allows you to obtain an image of the metabolism of cells in your body.

How to prepare for positron emission tomography?

Positron emission tomography is usually performed without hospitalization. Before the procedure, tell your doctor which medications you are taking, including vitamins, folk remedies, etc. Also, tell your doctor if you are suffering from any diseases, especially diabetes, which can affect the results of the study.
Before carrying Positron Emission Tomography, you should not eat anything for at least 6 hours. In the evening before the study, a light dinner is recommended. If you are worried, you can drink Valerian's or Persen's preparations for the night.

If a positron emission tomography of the heart is performed, you can not take caffeine-containing products for 24 hours.

Wear loose, comfortable clothing. Sometimes, before the procedure, you need to change into a hospital gown. If the pelvic area is being examined, a catheter can be inserted into the bladder through the urethra.

How to prepare for a PET scan?

1. Do not eat for 12 hours before the test. You can not eat or drink anything but water. If prescribed medications( except for cough syrup) can be taken on an empty stomach, you can take them on the day of the study. If you were told that you can not take medicines, do not take them. Do not chew gum, eat sweets, or take vitamins.
2. Please drink 6-8 glasses of water the day before the test and several glasses of water on the day of the study to avoid dehydration.
3. The last meal before starting the meal should consist of low-carb foods.
4. Do not exercise for 24 hours before the test.
5. If possible, bring snapshots of all previous images, such as Positron Emission Tomography, CT or MRI.They can be on film or on CD-ROM.Our doctors use them for comparison with the results of a new PET scan.
6. Make sure you are satisfied with the reception time. Positron emission tomography should be performed exactly at the appointed time, so please come 15 minutes earlier.
7. Wear comfortable clothing and dress warmly, as in some offices where scanning is performed, it can be cold. On the day of research, jewelry should not be worn, and there should be nothing metallic on clothes.
8. You can bring a compact disc( CD) with you to listen during the PET scan procedure. We will provide warm blankets.
9. Do not come to the procedure with children or pregnant women, since you will be given a radioactive substance.
10. If during the procedure you are supposed to give you a medication to relax the muscles of light action, you must come accompanied by the person who will take you home.
11. If pelvic area scanning is to be performed, you can have a urinary catheter( urine collection tube) before positron emission tomography.

• If you have diabetes, please discuss with your doctor the directions regarding diet and medication.
• Please tell your doctor if you are currently taking granulocyte colony-stimulating factor( G-CSF) preparations( such as Neupogen or Neulasta) or preparations that help form red blood cells( such as epogen( Epogen) or procrit( Procrit)).
• Your doctor may request CT scan on the PET after PET scan.

Be sure to inform your doctor if you are pregnant or may be pregnant or nursing. Take a liter bottle with mineral water .

Do not forget to bring your old X-ray pictures, CT.MRI.Results of ultrasound, etc.

What to expect when you arrive at the PET Center?

A nurse specializing in the field of positron emission tomography will help you prepare for scanning. The nurse will install an intravenous drip( a thin tube through which medication and liquid is injected) and measure the blood sugar level.

You will be given a radioactive label( radiotracer).Approximately 45 minutes after the beginning of circulation of the radioactive label in the blood, you will be transferred to the room for PET scanning. You will be asked to lie on your back on the table for scanning. In most cases, scanning takes approximately 1 hour.
PET scan studies live cells in action.

How is positron emission tomography performed?

The scanner is located in a separate room. The device itself is similar to a large ring( a computer tomograph) - it contains sensors that perceive radioactive radiation.

Prior to the study you will be placed on a special couch built into the device and injected into the vein of a radioactive substance or allowed to inhale it in the form of gas. Then within 30-60 minutes you will be asked to lie down, do not talk and make minimum movements - during this time the drug is distributed throughout the body. No unpleasant sensations from this do not arise.

Then the couch with you "drives into the hole of the ring".Sensors will begin to capture radiation and transmit signals to a computer that will process them and build an image. You will be asked not to stir for 30-45 minutes.

What will you feel during the study?

After putting in operation of a dropper, you should not have any painful sensations. During the PET scan procedure you need to relax, do not move and do not worry.
You will not feel any radiation. Radiation will come out of the body during the day.
After the completion of positron emission tomography you will not be given any special instructions, just recommend a lot to drink. The incoming liquid in the body will accelerate the excretion of radioactive material from the body

Results of the study

It usually takes 1-2 days to describe the images obtained, in some cases the results of the study can be collected in a few hours - the doctor will inform you about it. Sometimes for a more complete picture it is necessary to compare the results of positron emission tomography with the data of other studies-computer tomography or magnetic resonance imaging.

Who reads PET scan images and when do you get results?

PET scan images are read by a radiologist or a nuclear medicine specialist who takes into account the results of previous studies you have made.

Radiation exposure in PET

The dose of radiation that you receive during the study is very small. No side effects it does not cause.

The radioactive drug is contraindicated in pregnant or lactating women - always inform the doctor if you are pregnant( or suspect your pregnancy) or that you are breastfeeding.
After the study, it is recommended to drink plenty of fluids to speed up the removal of radioactive material from the body.