[en] Full text: It is now determined that the contents of native iodine in a thyroid gland (TG) depended on its function and physiological status and availability of diseases, and also on quantity of iodine in diet. This parameter is indispensable for the doctors for diagnostic, control of efficiency of iodine preventive maintenance and treatment. In 1968, practically simultaneously in Russia and in USA, it was offered to use X ray fluorescent analysis for research of iodine in TG, but until recently devices and techniques for non-invasive, secure and not burdensome for patient definition of intrathiroid concentration of iodine were not developed. In Russia in 2000, for the first time, a factory-made system for in vivo X ray fluorescent analysis was demonstrated. In its designed use, as sources of exciting radiation - ²⁴¹AM, as the detector - a semiconductor silicon detector which is working without liquid nitrogen. The measurements of the contents of iodine in TG are carried out to straight method, without using padding measurements (for example, sonography) with usage of a designed original technique. These installation and technique of definition of a level of iodine have received the permission of the conforming competent organizations of Russia for usage in clinical practice. The lower detection threshold of iodine in TG, at time of measurement 15c, makes 50 μg/g tissues. The measuring error makes 5-20% depending on concentration of iodine in TG. The technology of definition of concentration intrathyroid of iodine with usage of the called device is simple, reliable and is reproduced, has sufficient sensitivity and throughput capacity. The local radiation dose at such kind of research is very small (less than 0.1 mSv) that allows to inspect a broad quota of population, including children, pregnant and feeding women. It its ground exploitations of the indicated installations in medical entities of Russia the outcomes of examination of children and adult patients in areas with a mild iodine deficit are debated at different diseases TG. The medical indications for usage of a designed new technology are established: screening diagnostic of people having risk to diseases TG; in case of the known diagnosis - severity grade of disease and its forecast; the control efficiency of iodine prophylaxis maintenance and spent treatment. (author)