Radioisotope diagnostics

Radioisotope diagnosis is the recognition of the disease through the connection of radiolabelled.
There are four method of radioisotope diagnostics laboratory radiometry, clinical radiometry, clinical radiography, scanning. For their implementation labeled compound is injected into the patient's body through the mouth or directly in the blood, and then to carry out radiometric or radiographic examination.
At carrying out of laboratory of radiometry investigate individual portions of blood, urine or feces in a special ROWLOCK houses with the purpose of definition of their content labeled compounds. Most often this method is used to determine the amount of plasma and erythrocytes, content of thyroxine in the blood, to study clubockova filtering kidney, the absorption of fat in the digestive tract.
Clinical radiometry is based on the determination of the level of accumulation of labelled compounds in the organs and tissues by means of external radiation measurements in the patient. Measurement is carried out using radiometric instruments (see Radiodiagnostic devices and installations). This method is used to determine the function of the thyroid gland, grade tumors of the skin, eyes and brain.
Clinical radiography logs the speed labeled connection through various organs and thus makes it possible to identify their functional activity. For example, to assess the status of the Central circulatory determine the rate of passage through the heart with blood intravenously injected albumin labeled with iodine-131. For research secretory-excretory functions of the kidneys determine the rate of passage through the kidneys intravenously introduced heparana labeled with iodine-131. Clinical radiography is carried out with the help of radiodiagnostic installations. Registration of the results of measurements carried out on a moving paper tape in the form of curves.
Scanning, the most common method of radioisotope diagnostics allows to obtain images of internal organs, which accumulate labeled compounds (see Scanners, Scanning). All labeled compounds used for diagnostic purposes, have low radiotoxicity and a small amount of activity that causes full radiation safety for the subjects. Clinical contraindications to the introduction of labelled compounds - pregnancy, technical - expiry date labeled connection specified in the passport. When conducting radioisotope diagnosis surveyed are in normal mode and in a special isolation is not needed. All results radioisotope diagnosis necessarily fixed in the records, which specifies the activity of the administered drug and passport number of the drug. Radioisotope diagnostic study can be repeated if there is a respective medical indications. Introduction of labelled compounds surveyed also reflected in special log consumption radioactive drugs, which is conducted in all laboratories radioisotope diagnosis.

Radioisotope diagnostics for detection of diseases using radioactive isotopes and their labelled compounds.
Methods radioisotope diagnosis is based on detection, registration and measurement of radiation of radioactive isotopes. These methods allow us to study the absorption, the movement in the body, the accumulation of certain tissues, biochemical transformations and their removal from the body radiodiagnostic drugs. Applying them, you can explore the functional state of almost all organs and systems of the person. They are simple, safe for the patient and in many cases provide such objective information that cannot be obtained by other laboratory and clinical research methods. In radioisotope diagnostics, use drugs, creating minimum radial load on the body (much less the maximum permissible levels of exposure). For this purpose use of short-lived radioactive isotopes and labeled compounds, quickly flushed out of the body. Isotopes with low energy gamma radiation simplify the equipment and increasing the resolution of the method.


In the basis of methods of radioisotope diagnosis rests on four pillars: 1) isotope dilution; 2) determine the accumulation, distribution and time variation of the content radiodiagnostic drugs in organs or tissues; 3) determine the excretion of radiodiagnostic drugs in urine and feces after intravenous or oral administration; 4) research radiodiagnostic drugs in vitro. In this regard, radioisotope methods can be classified in the following way.
I group. Methods based on the principle of isotope dilution, consisting in that after a certain period of time after intravenous radiodiagnostic drug compare its concentration in the input drug and in samples of plasma, red blood cells or tissues. The results of this comparison is possible to calculate the volume of the circulating plasma, erythrocytes and blood; intracellular and extracellular the total water content in the body; communicate potassium, sodium, calcium, magnesium and some other ions and their "space", i.e. the volumes, which are distributed in the body, these electrolytes.
II group. 1. Methods based on the definition of accumulation radiodiagnostic drugs in the organ or tissue at a given time after the introduction (diagnostics of the functional state of the thyroid gland with J131, tumors of the skin, mucous membranes, and bronchi with R, lesions of bones with Sr85 and Sr87M and others). The study will receive the absolute value of the accumulation of drugs (% of input) or their accumulation in the lesion is compared with the accumulation in symmetric healthy parts of the body, taken for 100%.
2. Scanning methods, i.e. graphic registration using scanners distribution radiodiagnostic drugs in one way or another body. Scanning (see) is based on selective accumulation of the drug in a particular organ. It allows to get information about the size, shape and position of the body, the volume of lesions and in some cases allows to judge about the functional state of the body. Currently, the method can be used in the study almost all organs and body systems.
3. Methods, which are based on the definition of the content changes radiodiagnostic drugs in the organ or tissue in time. These changes are registered by external account (usually graphically) or by direct radiometry. The analysis of the received data (curves) and mathematical calculations receive a quantitative characteristic of the investigated process. Thus investigate the functional state of the cardiovascular system, liver, kidneys, erythropoiesis, determine the life expectancy of formed elements of blood and other
Group III. 1. Methods based on the definition of deducing radiodiagnostic drugs from the body with urine or faeces (after intravenous administration). They allow to determine the value of gastrointestinal bleeding, identify exudative enteropathy and explore the functional state of the thyroid gland. 2, Methods, based on the definition absorbability radiodiagnostic drug in the gastro-intestinal tract (after oral administration). They are used in the diagnosis of pernicious anemia, in the study of the metabolism of calcium, copper, magnesium and other electrolytes, the absorption of iron in the blood, in the differential diagnosis steatorrhea. At the basis of the determination of the number of radiodiagnostic drugs absorbed in the gastrointestinal tract (by radiometry Kala, or using a counter of the whole body).
Group IV. A study of thyroid function by using J131-triiodothyronine and J131-thyroxine in vitro without the introduction of radiodiagnostic drugs.
In the table above provides information on the diagnostic applications of radioactive drugs.
Cm. also articles on the individual bodies (section radioisotope diagnosis) and radioactive isotopes (for example, potassium, sodium).