Nuclear cardiology tests are very safe. Serious complications of the stress medication or exercise are very uncommon.
Relatively minor side effects include brief mild shortness of breath, headache, flushing, abdominal and chest discomforts. These medication side effects can be quickly resolved with a cup of coffee or infusion of a low dose of a caffeine like medication.
The radiation exposure is minimal, and is equivalent to the amount of natural background radiation from the earth and space one receives living in the USA for one to three years (appx 3 – 10 mSv).