My friend had a test done at the nuclear cardiology department.
The exam was used to find out his heart stress/pressure
condition.  It took one before picture and one after picture of
his heart to do a comparison.  The first picture took about
fifteen minutes.  The second took about 30 minutes.

In between the two pictures, he was injected some medicine that,
according to the doc, would make his heart work as if he had a
good amount of exercise.  He was also injected some radioactive
substance, according to the doc, that allows the machine to
create the image of.

What is this whole procedure called?  What are the two medicine
injected?  The doc told us, but we forgot what they are called.
Thanks.