The principle of As Low as Reasonably Achievable (ALARA) should be applied in all patient populations. For CCTA performed with contemporary equipment in accor- dance with the Society of Cardiovascular Computed Tomog- raphy recommendations, average estimated radiation dose ranges from 5 to 10 mSv.96 For stress nuclear MPI, when the American Society of Nuclear Cardiology recommended rest- stress Tc-99m SPECT or Rb-82 positron emission tomogra- phy (PET) protocol97 is used, the estimated radiation dose is approximately 11 or 3 mSV, respectively.97,98 On the basis of American Society of Nuclear Cardiology guidelines, dual- isotope or rest-stress Tl-201 imaging is discouraged for diagnostic procedures because of its high radiation exposure. The use of new high-efficiency nuclear MPI cameras results in a similar or lower effective dose for both dual-isotope and rest-stress Tc-99m imaging.99 101 For both CT and nuclear imaging, the AHA, Society of Cardiovascular Computed Tomography, and American Society of Nuclear Cardiology recommend widespread application of dose-reduction tech- niques whenever possible.96 98 Clinicians should apply the concept of benefit-to-risk ratio when considering testing. When testing is used appropriately, the clinical benefit in Fihn et al Stable Ischemic Heart Disease: Full Text e373 terms of supportive diagnostic or prognostic accuracy ex- ceeds the projected risk such that there is an advantage to testing.13,14 When it is used inappropriately or overused, the benefit of testing is low, and the risk of exposure is unac- ceptably high. Of note, care should be taken when exposing low-risk patients to ionizing radiation. This is particularly of concern in younger patients for whom the projected cancer risk is elevated.102 Use of contrast agents with CCTA can cause allergic reactions. Contrast agents also can affect renal function and therefore should be avoided in patients with chronic kidney disease. 