Radiation dose and risk of malignancy from cardiovascular imaging
- Thomas C Gerber, MD, PhD, FACC, FAHA
Thomas C Gerber, MD, PhD, FACC, FAHA
- Professor of Medicine and Radiology
- College of Medicine, Mayo Clinic
- Andrew J Einstein, MD, PhD, FACC, FAHA
Andrew J Einstein, MD, PhD, FACC, FAHA
- Herbert Irving Associate Professor of Medicine
- Columbia University Medical Center
- Section Editors
- Donald Cutlip, MD
Donald Cutlip, MD
- Section Editor — Interventional Cardiology
- Professor of Medicine
- Harvard Medical School
- Beth Israel Deaconess Medical Center
- Patricia A Pellikka, MD, FACC, FAHA, FASE
Patricia A Pellikka, MD, FACC, FAHA, FASE
- Section Editor — Noninvasive Cardiac Imaging and Stress Testing
- Professor of Medicine
- Mayo Clinic College of Medicine
The use of diagnostic cardiovascular imaging has increased rapidly over the past decade owing to developments in technology, increased availability, and the perception that imaging can meaningfully affect medical decision making. Studies documenting increasing medical radiation exposure, particularly from cardiovascular imaging, have raised concerns about potential health risks associated with this exposure and have been highly publicized in the professional and lay literature [1,2].
Several of the major imaging modalities for cardiovascular diagnosis and treatment use ionizing radiation. Radionuclide myocardial perfusion imaging in the form of single photon emission computed tomography and positron emission tomography use radionuclides that produce both photon and particulate radiation. Sources of radiograph radiation include cardiovascular computed tomography, which is used for imaging coronary artery plaque and calcification, and radiograph fluoroscopy, which is used to guide established and emerging diagnostic and therapeutic electrophysiologic, coronary, and other cardiovascular procedures.
The potential risks of imaging tests that use ionizing radiation must be weighed against the potential benefits of these tests. This assessment is difficult since the health risks related to radiation exposure at the levels common in cardiovascular imaging are controversial. In addition, limited evidence is available on the impact of these tests on clinical outcomes.
This topic will discuss radiation exposure and potential risks from cardiovascular imaging. Various cardiovascular imaging tests and radiation-related risk of medical imaging studies generally are discussed in detail separately. (See "Radiation-related risks of imaging studies".)
Parameters — Some radiation dosimetry parameters can be measured whereas others are estimates that are modeled using complex assumptions and simulations. Parameters of radiation dosimetry readily derived from physical measurements of radiation exposure (in Coulomb/kg, C/kg) include the accumulated air kerma at a reference point (Ka,r, in mGy) and the kerma-area product (KAP, in cGy × cm2 or related units) in radiography and fluoroscopy (in units of milliGray, mGy), the volume computed tomographic dose index (CTDIvol, in mGy) and the dose-length product (DLP, in mGy x cm) in computed tomography (CT) [3,4]. These parameters are extremely useful to establish so-called "diagnostic reference levels" for quality control and benchmarking among institutions that perform cardiac imaging with ionizing radiation . For example, consistently exceeding the 75th to 80th percentile as established in radiation dose surveys should suggest to an individual institution the need for reevaluation and change of practices. Establishing reference values has been shown to reduce the median dose and interinstitutional dose variability of radiological procedures [6,7]. Parameters of radiation dosimetry are discussed in detail elsewhere. (See "Biology and clinical features of radiation injury in adults".)
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- RADIATION DOSIMETRY
- Radiation doses associated with medical imaging
- - Epidemiology
- - Radiation dose and determinants
- - Multiple testing
- Options for reducing radiation dose
- HEALTH RISKS OF RADIATION EXPOSURE
- Potential carcinogenesis from imaging
- BALANCING RISKS AND BENEFITS
- SUMMARY AND RECOMMENDATIONS