1. A method of acquiring medical data using a data acquisition system including a radiation detector, a storage device, and a processor, said method comprising the steps of: administering a particular bolus to a patient; acquiring, using said radiation detector under control of said processor, a first set of data from a monitored region that is a first region of interest; for n=2 to N, performing, based on the transition of the particular bolus through the patient, the steps of: a) detecting, utilizing the bolus and using said radiation detector under control of said processor, an (n−1) th trigger condition based on an (n−1) th set of data, b) defining, using said processor, an n th region of interest different from the (n−1) th region of interest in response to said (n−1) th trigger condition; c) acquiring, using said radiation detector under control of said processor, an n th set of data from the n th region of interest; and d) repeating steps (a) through (c) for each value of n, where N is equal to or greater than 3; and then recording said N th set of data into said storage device for including in said medical data.