When examining the condition of the heart and blood vessels, it begins with X-ray angiocardiography. If the doctor suspects coronary heart disease - reduced blood flow to the myocardium, not confirmed by objective research methods in emergency medical care, then additionally radioisotope diagnostics are performed using an orally administered thallium isotope or short-lived radioactive drugs, for example, thallium pertechnetate Tl99m - or technetium 99mTc, India 111