HYBRID PHANTOMS FOR TESTING THE MEASUREMENT OF REGIONAL DYNAMICS IN DYNAMIC RENAL SCINTIGRAPHY

A hybrid phantom is a synthetic dynamic scintigraphic study reconstruc ted from dynamic components of real clinical data. The aim of a hybrid simulation is to provide realistic reference studies with systematica lly varying quantitative diagnostic parameters for testing the quality of measurement of regional dynamics. The components of the phantom ar e extracted from a representative patient study using factor analysis. Prior to the construction of the phantom, selected components are mod ified in a known way or substituted with heterologous data. The phanto m study is constituted from the altered components using a procedure i nverse to factor analysis, and completed by the addition of residual n oise. The hybrid phantom is a compromise between simulated and softwar e phantoms. Unlike simulated phantoms, it preserves a significant part of data variability and the natural complex structure of scintigraphi c images. Unlike software phantoms, it provides values for selected di agnostic parameters or magnitudes of their relative changes. A set of hybrid phantoms from a dynamic renal study and the results of a pilot clinical evaluation are presented.