Does a Positron Emission Tomography (PET) stress test contain iodine?

PET Stress Tests Do Not Contain Iodine

No, PET stress tests do not contain iodine. PET cardiac stress tests use radiopharmaceuticals with very short half-lives such as rubidium-82 (Rb-82), nitrogen-13 (N-13) ammonia, or oxygen-15 (O-15) water, none of which contain iodine 1.

PET Stress Test Radiopharmaceuticals

• PET myocardial perfusion imaging uses specific tracers that do not contain iodine:

  • Rubidium-82 (Rb-82) - produced with a generator 1
  • Nitrogen-13 (N-13) ammonia - requires a local cyclotron 1
  • Oxygen-15 (O-15) water - used in some facilities 1

• These radiopharmaceuticals have extremely short half-lives, measured in minutes, which allows for lower radiation exposure compared to other imaging techniques 1

• The average effective radiation dose for rest/stress PET with Rb-82 is approximately 3 mSv, which is significantly lower than other nuclear imaging techniques 1

Contrast Between PET and Other Imaging Modalities

• Unlike some CT imaging procedures that may use iodinated contrast agents, PET cardiac stress tests rely on radioactive tracers that emit positrons 1

• The PET imaging process detects the 511 keV energy photons produced when positrons interact with electrons in the body 1

• When PET is combined with CT (PET/CT), the CT portion might use iodinated contrast in some cases, but this is separate from the PET radiopharmaceutical 2

Clinical Considerations

• For patients with iodine allergies, a PET stress test is a suitable alternative to other imaging modalities that might require iodinated contrast 1

• For pregnant or breastfeeding women, imaging using ionizing radiation should generally be avoided, but when necessary, PET has a lower radiation dose than some alternatives 1

• PET stress testing is particularly valuable for:

  • Obese patients (due to superior image quality) 1
  • Patients with suspected microvascular coronary disease 1
  • Quantitative measurement of myocardial blood flow 1

Important Note on Iodine-124 in PET

• While iodine-124 (I-124) is a positron emitter that can be used in some PET imaging applications (particularly for thyroid cancer), it is NOT used in cardiac PET stress tests 3, 4, 5

• I-124 has a much longer half-life (4.2 days) compared to the radiopharmaceuticals used in cardiac PET stress tests, which have half-lives measured in minutes 3, 4

• Cardiac PET stress tests specifically use Rb-82, N-13 ammonia, or O-15 water as the radiopharmaceuticals of choice 1