APPARATUS FOR LOCALIZING A REGION IN THE HUMAN BODY, IN PARTICULAR VENOUS THROMBI, BY THE UPTAKE OF A RADIOACTIVE SUBSTANCE, PARTICULARLY SU125 XXI-FIBRINOGEN

摘要

Abstract of the disclosure.An apparatus for determining the depth position of venousthrombi in the lower extremities utilizes a unique propertyin 125I. This resides in the fact that in approximately halfof all disintegrations, two photons are emitted simultaneously.These two coincident photons have, like separately emittedphotons, an energy of approximately 28 keV. A scintillationdetector perceives the coincidently emitted photons as onephoton of an energy of 56 keV. The quotient between the numberof separately emitted photons and the number of coincidentphotons may thus be determined. This quotient constitutes aparameter which is greatly dependent on the distance betweenthe detector and the source of radiation, whereby there isobtained a possibility of determining the depth of the thrombus.