Hi. I recently had a SPECT exam because of a positive treadmill test. I know the part where I rode the bike was positive. I don't know yet about the imaging. My question is this: Riding the stationary bike and while at the target heart rate, I was injected (with the radionuclide?) and exactly one minute was marked from the time of injection. What was going on there? What information was gathered at the one minute point while at the target heart rate? Thanks.