Pulmonary thromboembolism: epidemiology and techniques of nuclear medicine.

Pulmonary thromboembolism is a very common disease (about 500,000 events per year in the United States). The most important risk factors seem to be age, cancer, previous surgery, trauma, coagulation disorders, and immobilization. Analysis of epidemiologic studies shows that the incidence of pulmonary embolism is underestimated clinically. Combined ventilation/perfusion scintigraphy is an established method for the diagnosis of pulmonary embolism, but the specificity of the method still is not high enough. Diagnostic strategies and new techniques in nuclear medicine will probably be able to improve the quality of the management of patients with clinically suspected pulmonary embolism.