The Use of C15O2 in the Evaluation of Cardiac Abnormalities
Carbon dioxide labeled with oxygen- 15 (t 1/2 = 124 sec) is a uniquely useful tracer for cardiopulmonary studies because it can be introduced selectively into the left heart by the simple noninvasive process of inhalation and breath-holding. Externally placed scintillation counters coupled with a high-speed multichannel recorder can be used to measure the rate of clearance of the tracer from the lungs and the rate of filling and emptying of the left heart. The presence of left-to-right intracardiac shunts or mitral or aortic valvular lesions can be inferred from the count rate vs. time curves. Scintigraphic images of the left ventricle in systole and diastole may be made using standard commercially available scintillation camera systems.
KeywordsCount Rate Left Heart Cardiac Abnormality Regurgitant Fraction Absorb Radiation Dose
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