A system and method for obtaining perfusion images is disclosed. The system and method includes hardware and software for determining physiological characteristics of a patient and determining imaging parameter values for an imaging modality based on the patient's physiological characteristics. The system also includes a controller operative to receive the imaging parameter values for controlling an X-ray device. The X-ray device is coupled with the controller and acquires projection images of the patient, and outputs the projection images to a perfusion evaluation computer for evaluating the perfusion of an region of interest represented in the projection images. The perfusion rate of the region of interest is then output to an output device, such as a display or printer.