[Over diagnostic imaging in cardiology].

Medical imaging is one of the major cause of rising health care costs. Diagnostic imaging has increased more rapidly than any other component of medical care. About 5 billion imaging tests are performed worldwide each year. According to recent estimates, at least one-third of all examinations are partially or totally inappropriate. Two out of 3 imaging tests employ ionizing radiations with radiology or nuclear medicine. The medical use of radiation is the largest man-made source of radiation exposure. Medical X-rays and γ-rays are a proven human carcinogen. The attributable long-term extra-risk of cancer due to diagnostic testing is around 10% in industrialized countries. Cardiologists prescribe and/or directly perform >50% of all imaging examinations, accounting for about two-thirds of the total effective dose given to patients. The dose of common cardiological examinations may be significant: 500 chest X-rays= a stress scintigraphy with sestamibi, 750 chest X-rays= a Multislice Computed Tomography, 1,000 chest X-rays= a coronary angiography and stenting. Unfortunately, few doctors are aware of the level of radiation their patients are exposed to during radiological tests and more intensive use of ionizing testing was not associated with greater awareness. Also as a consequence of unawareness, the rate of inappropriate examinations is unacceptably high in cardiology, even for procedures with high radiation load. Higher exposure doses correspond to higher long-term risks; there are no safe doses, and all doses add up in determining the cumulative risks over a lifetime. Doctors should make every effort so that «each patient should get the right imaging exam, at the right time, with the right radiation dose», as suggested by US Food and Drug Administration in the 2010 initiative to reduce unnecessary radiation exposure from medical imaging. This is best obtained through a systematic implementation of the "3 A's strategy" proposed by the International Atomic Energy Agency in 2010: audit (of true delivered dose); appropriateness (since at least one-third of examinations are inappropriate); awareness (since the knowledge of doses and risks is largely). The regular application of "3 A's strategy" is usually not facilitated by a health system that pays for volumes, not for appropriateness.