Nuclear Medicine - Viability

What is Viability Imaging?

Viability Imaging is a specialized diagnostic exam that detects for the possibility of functional tissue following a heart attack or damage.


  • Myocardial Infarct
  • Electrocution 
  • Severe Trauma 
  • IV drug abuse

How do I prep for this procedure?

You will be in the department for 90 minutes to 2 hours.  A Nuclear Medicine technologists or Radiology nurse will start a hep-loc so two isotopes can be injected.  Images of the heart at rest will be taken 5-10 minutes post first injection.  During the stress stage a second isotope will be injected and imaging will begin immediately to one hour after stress depending on bowel activity.  You may be sent to eat a good meal or asked to eat cheese and drink milk to help eliminate some bowel activity.

  • Rest injected
    • Patient should be fasting for at least 4 hours (preferably for 12 hours). No caffeine. Consult your cardiologist about wheelchairs and cardiac medications.
  • Exercise Stress 
    • Graded exercise stress is usually performed with a treadmill or bicycle ergometer with continuous patient monitoring. No caffeine. Fasting for a minimum of 4 hours before the stress study is recommended.

Pharmacological stress

Two types of pharmacological stress are useful to evaluate myocardial perfusion:

Vasodilator stress agents may be administered to create coronary adenosine. Caffeine-containing beverages should be taken which interferes with the coronary hyperemia.
Ino/chronotropic adrenegic agents (i.e. dobutamine) are to be administered to increase myocardial oxygen demand. No caffeine is to be taken.


You will be in the department multiple times depending on the exam type.  There are two types of exams:

  • The first exam is in conjunction with a Stress and Rest then Viability to follow
    • A small radioactive dose of 201T1 (Thallium) will be injected 
    • You will return 24 hours later for images 
    • Images will take 15-20 minutes
  • The second exam is a Viability exam itself in Nuclear Medicine or in PET 
    • A small radioactive dose of Thallium will be injected 
    • You will be imaged 5-10 minutes later for 15-20 minutes 
    • You will return 4-5 hours later for another 15-20 minute image 
    • You will receive another injection of Thallium, PET is only 1 injection 
    • You will return 24 hours later for another 15-20 minute image