Improved computer definition of regions of interest by using a double-cursor method.

In the computer analysis of radionuclide studies it is often necessary to define a region of interest (ROI) over an organ or part of an organ. The entire organ boundary is not always apparent on a single image. A method for combining the information from two images in entering the ROI has been developed. It is based on the use of a double cursor that moves simultaneously over both images. Programming was done using special FORTRAN-callable subroutines existing in our system for access to the display. The method is now in routine use for the definition of the left-ventricular ROI during processing of radionuclide cardiac studies.