Intended use: In clinical settings, Xe-133 is used for radioisotope diagnostics in the form of an air-xenon mixture and an isotonic solution. Air-xenon (Xe-133) mixture is used as a radioactive indicator in the study of regional pulmonary ventilation, to assess the patency of subarachnoid space and to determine the level and degree of blockade of CSF pathways of the spinal cord. Sterile isotonic solution with Xe-133 is used for quantitative assessment of blood flow in various organs and tissues. In clinical settings, this technique has widely used in evaluation of regional cerebral bloodflow, muscular bloodflow, coronary blood flow, as well as regional bloodflow in the lungs.