RADIOACTIVE DRUGS

From Big Medical Encyclopedia

RADIOACTIVE DRUGS — the radioactive materials containing the radioactive nuclides made in various forms and intended for various purposes. In medicine of Genitive treatments of hl are used for diagnosis of diseases, and also. obr. malignant new growths.

Distinguish two groups of Genitive — closed and opened.

Closed by Genitive. are put into the cover from non-toxic material (platinum, gold, stainless steel, etc.) interfering direct contact of radioactive material with the environment. At gamma radiating Genitive a cover performs function of the filter for beta radiation (see) and low-energy gamma radiation (see). These drugs are used for application, interstitial and intracavitary radiation therapy (see). Most often apply gamma radiating Genitive in which as radionuclides use artificial radioisotopes of cobalt ( 60 Co), gold ( 198 Au), tantalum ( 182 Ta), caesium ( 131 Cs), etc. In the past the natural radioactive nuclide radium was widely used. Use also drugs of radioisotope California ( 252 Cf), being generally a source of bystry neutrons (see. Neutron therapy ). Closed by Genitive differ in a big variety of external shape. The greatest distribution was gained by linear Genitive in the form of needles and tubules (cylinders). Needles represent hollow cylinders which one end is pointed, and on another there is an ear for thinning of thread. In a needle (pins) diameter, as a rule, less than 1 mm from alloy of the nickel and cobalt containing radioactive 60so place pieces of a wire. Length of a pin is called the active length of Genitive. Cobalt needles with a length of pin from 5 to 50 mm, and the total length of needles — from 13,5 to 58,5 mm enter standard sets. Tubules (cylinders) differ from needles in the fact that have no the pointed end, their active length fluctuates from 10 to 60 mm. In linear Genitive radionuclide is distributed or evenly on all length — 0,0625 mkyuri/mm (2,3 MBK/mm), or unevenly with the increased linear activity on the ends. A kind of linear Genitive are pieces of the cobalt, tantalic or iridic wire of very small size (to dia. 0,7 mm, length of 3 mm) covered with a layer of gold or platinum, which enter into nylon hollow threads (tubes). Use also drugs 198Au, shaped granules to dia. 0,8 mm and 2,5 mm long which surface is covered with a layer of platinum. Activity of each granule about 3,5 mkyura (130 MBK). In addition to linear, closed by Genitive can have spherical shape with a through hole in the center for threading of thread (a radioactive beads).

Sometimes for superficial applications previously (wax, plastic) make the model repeating a form of a part of the surface which is exposed to radiation of easily formed material. This model with implemented in it closed by Genitive is called a radioactive mask. At interstitial radiation therapy closed by Genitive in the form of needles, pins, granules, nylon threads implement directly in fabric of a tumor by means of special tools (see. Radiological tools , Radio surgery ). At intracavitary radiation therapy (see. Gamma therapy ) the closed Genitive of a linear form is entered in endostat — the hollow tube which is previously entered into a uterus, a bladder, a rectum, etc.

Open Genitive. — the radionuclides which are in various aggregate states (true and colloid solutions, gases, suspensions, the resolving threads and films) coming at their use into direct contact with bodies and fabrics, i.e. participating in a metabolism and activity of separate bodies and systems. Open Genitive applies with the diagnostic and medical purposes. For diagnosis use drugs of radionuclides with short effective half-life (see) that causes insignificant beam load of an organism. They are characterized by lack of toxic action and existence beta or gamma radiations, a cut can be registered by methods of radiometry (see). Most widely apply at a research of functions of kidneys, a liver, a brain, easy and other bodies, the central and peripheral hemodynamics various connections, marked isotopes of technetium ( 99m Tc), iodine ( 131 I), indium ( 111 In, 113m In), and also gaseous Genitive of xenon ( 133 Xe), krypton ( 85 Kr), oxygen ( 15 O), etc. Introduction of Genitive depending on their form is carried out by intake, intravenous administration, inhalation, etc. (see. Radiofarmatsevtichesky drugs ).

With to lay down. the purpose open Genitive most often uses in the form of colloid solutions (see. Radioactive colloids). The choice of radionuclide is defined small (no more than several days are desirable) by half-life, a small effective elimination half-life of connection, suitable physical properties of the used radiation and lack of toxic action on an organism. Fullestly radioisotopes of yttrium meet these requirements ( 90 Y), phosphorus ( 32 P) and gold ( 198 Au). Open Genitive enters into fabric of a tumor by an injection by means of protective syringes (see. Beta-ray therapy ),

are made by Genitive in the industrial way and are delivered in to lay down. institutions. Genitive is contained in special protective rooms — storages from where in transport lead containers deliver in radio handling (see. Radiological department ). Preparation and cultivation of open Genitive are made in special boxes, hoods and radio handling cameras to exclude a possibility of hit of radioisotopes on a body surface or in an organism of medical staff as a result of pollution of hands, tools, inhaled air (see. Antiactinic protection , Radiological protective processing equipment ).


Bibliography: Zedgenidze G. A. and Zubovsky G. A. Clinical radio isotope diagnosis, M., 1968; Pavlov A. S. Interstitial gamma and beta therapy of malignant tumors, M., 1967; Afterloading, 20 years of experience, 1955 — 1975, ed. by B. Hilaris, N. Y., 1975.

V. S. Datsenko, M. A. Fadeyev.

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