15 Elemental lead (Pb) sheeting is the standard radiation absorbing medium for protection from medical X-Rays. Traditional shielding includes a ceiling-mounted, leaded acrylic shield, an under-table shield, radiation-blocking garments (aprons, thyroid, cranial) and leaded eyeglasses worn by operators and staff. Shielding is essential to minimizing operator radiation exposure. Haquanni, et al, showed that at table heights above 105 cm, radiation exposure to the operator increases by 0.12 mSv/hr for each cm increase in height. 13 Catheterization table height may also contribute significantly to operator exposure. The extent of cine versus fluoroscopy is of major importance, since cine may be responsible for 5 times the radiation dosage of fluoroscopy. Operators performing transradial procedures with the patient's arm abducted up to 90 degrees may be closer to the scatter radiation source (heart) than with the patient's arm by his/her side. In addition to access site, important variables include patient BMI, operator location 12, and procedure complexity. Since transradial access often involves fluoroscopy of radial loops and other anomalies, as well as subclavian tortuosities, both of which are closer to the operator, an increased operator exposure should be expected. An American College of Cardiologists (ACC) 2017 presentation 11 found that operator radiation exposure using the transradial approach was nearly twice that of the femoral approach. The transradial approach has long been associated with increased operator exposure. 10 Exposure may vary with choice of access site. Operator dose depends upon several important variables. The ever-increasing frequency and complexity of vascular procedures makes the need for additional and improved operator head area protection obvious and imperative. 9 The shielding effect of glasses may provide a 60% reduction in eye exposure, 9 but with little or no protection for the rest of the operator's head. 1 Interventional radiologists and their staff, if not using shielding eyeglasses, may easily exceed the new eye limits. 8 The head dose sustained by cardiologists may occasionally exceed even the old eye exposure standard of 150 mSv per year. In 2013, new standards adopted by the International Atomic Energy Agency (IAEA) reduced radiation exposure to the eyes from 150 mSv per year to 20 mSv per year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. Also, in order to preserve mobility and tactile sense, arm and hand shielding is usually weak or absent. 4 Head and eye protection is thus normally inferior to shielding for the operator's torso and thyroid. head and hands) can receive doses up to 50 mSv per year. Picano, et al, found that "less protected" parts of the body (e.g. Head and eye exposures 1,2,5 are of special significance, both because of their susceptibility to injury and because shielding which protects the head must not interfere with operator vision and mobility. Operator exposures may be highest during emergency PCI procedures involving myocardial infarction (MI), 7 indicating that some precautions are more likely to be compromised in an emergency. In a 2015 SCAI (Society for Cardiovascular Angiography and Interventions) survey of 314 members, 6.9% of operators had been forced to limit their caseload because of excess radiation exposure.
3,4,5 Increased incidences of breast cancer 3,4 and chromosome damage 1 have also been documented. Perhaps the most prominent effects on the interventional operator and staff are lens cataract formation and an increased incidence of left-sided brain tumors. Health effects of long-term, low-level radiation exposure are well documented in the medical literature. Efforts to minimize these exposures include advanced X-Ray equipment design and operational protocols, as well as a variety of shielding devices. 1,2 Diagnostic and interventional cardiology procedures require close proximity to scatter radiation emanating from the patient during fluoroscopy and cineangiography ("cine"). Interventional cardiologists (operators) and their table-side assistants are among the most heavily exposed medical professionals to occupational X-radiation. Scatter Radiation and Ergonomics in the Cardiac Catheterization Lab
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