Identification of less-irradiating tube angulations in invasive cardiology

OBJECTIVES: We sought to identify tube angulations in invasive cardiology, which promise minimal radiation exposure to patients and operators. BACKGROUND: Radiation exposure in invasive cardiology is high. METHODS: We mapped the fluoroscopic dose-area product per second (DAP/s), applied to an anthropomorphic Alderson-Rando phantom and, in absence of radiation protection devices, the mean personal dose in the operator's position in 10 degrees steps from the 100 degrees right anterior oblique (RAO) to the 100 degrees left anterior oblique (LAO) projection, as well as for all geometrically feasible craniocaudal tube angulations. RESULTS: For our specific setting conditions RAO 20 degrees /0 degrees tube angulation generated the lowest DAP/s and operator's personal dose. The mean patient DAP/s and operator personal dose for all postero-anterior (PA) projections, cranialized and caudalized together, rose significantly: 3.7 and 10.6 times the PA 0 degrees baseline values toward LAO 100 degrees and 3.7 and 2.4 times toward RAO 100 degrees , respectively. Patient and operator values for all PA projections, angulated to the right and left, increased approximately 2.5 times toward 30 degrees craniocaudal angulations. Caudal PA 0 degrees /30 degrees - angulation instead of caudal LAO 60 degrees /20 degrees - angulation for the left coronary main stem and cranial PA 0 degrees /30 degrees + view in place of cranial LAO 60 degrees /20 degrees + view for the left anterior descending coronary artery bifurcation enable 2.6-fold dose reductions to the patient and eight- and five-fold dose reductions to the operator, respectively. CONCLUSIONS: The PA views and RAO views >or=40 degrees , heretofore unconventional in clinical routine, should be favored over steep LAO projections >or=40 degrees whenever possible. Tube angulations that are radiation intensive to the patient exponentially increase the operator's radiation risk.