Cardiac PET Scan

What Is Cardiac Rubidium PET Scan?

rhubidium-pet-scanCardiac PET (or cardiac positron emission tomography) is a form of 3D diagnostic imaging in which patients are evaluated using a PET scanner after intravenously injected with a radioisotope. Although several isotopes have been used for Cardiac PET imaging, the most widely employed in clinical practice is Rubidium-82. In a Cardiac Pet scan, heart muscle that is alive is bright and heart muscle that is dead scar tissue is dark. Hence it is used to pinpoint areas of surviving heart muscle that is deprived of adequate blood flow (ischemic tissue).

What is Cardiac PET scan used for?

Cardiac Pet scan can assess both blood flow as well as metabolism accurately. In patients with blocked coronaries, Cardiac Pet scan can influence the choice between bypass surgery and angioplasty. More importantly, it can be used to predict whether depressed heart function can improve after revascularisation.

Advantages over SPECT Scan/ MIBI scan.

SPECT-scanDue to higher resolution ,PET allows more accurate detection of myocardial ischemia than single photon emission tomography (SPECT). It can overcome artifacts that often are encountered with standard SPECT imaging due to non uniform soft-tissue attenuation.

PET scan offers superior images for woman, obese patients and those who are unable to exercise.


Who should go for Cardiac PET?


  • Patients with many risk factors eg hypertension, high cholesterol, smoking habit , diabetes, obesity, high stress occupation, family history of heart attack
  • Patients who are unable to exercise
  • Patients suspected of heart attack
  • Patients newly diagnosed with heart failure
  • Patients with abnormal ECG or treadmill

How is the scan performed?

  • An IV line is placed in the arm for injection of medicine.
  • The blood pressure and heart rate is monitored at intervals during the scan.
  • A radio-isotope is first injected to allow pictures of the heart to be taken.
  • Dipyridamole, a vasodilator, is then injected into a vein to simulate the stress of exercise, the patient is asked to squeeze a handgrip and the second cycle of pictures are taken.
  • The entire procedure lasts about 50 minutes.

Please note that

  • Patients are asked to avoid food or drink 3 hours before the test to minimise nausea during the test.
  • 48 hours before the scan, patients have to stop Theophylline-containing Medication.
  • This scan is not suitable for patients with Asthma, bronchitis or emphysema.
  • 24 hours before the scan, patients must AVOID the following:
    • Products containing caffeine including Coffee, tea, Milo, Cocoa and all chocolates.
    • Soft drinks containing caffeine including Coke and Mountain Dew.

What are the risks of the scan?

Pet-ScanRadiation exposure for current scans are in the range of 8 to 10 mSV. This is much less than that of a SPECT scan. It should not be performed in pregnant patients.

The risk of an adverse event such as heart attack is less than 1 in 10000.

It should not be done in patients who have:


  • Suffered a heart attack in the previous 2 days
  • Unstable angina
  • Uncontrolled arrhythmias, or abnormal heart rhythms
  • Severe symptomatic aortic heart valve disease
  • Uncontrolled heart failure
  • Infection or inflammation of the heart
  • Acute aortic dissection
  • Acute pulmonary embolism

Lim Ing Haan Cardiology Clinic
3 Mount Elizabeth #04-02
Singapore 228510

Clinic Hours
Mon-Fri : 8.30am - 5.00pm
Sat : 8.30am - 12.30pm