A new method of determining pulmonary-to-systemic flow ratios (Qp/Qs) in patients with left-to-right shunts using radionuclide angiocardiography is described. It involves the analysis of pulmonary time-activity histograms using a gamma-variate model. It appears to be simple, relatively atraumatic, and superior to the methods using C2/C1 ratios because, in addition to accurately detecting the pr...
