P425 Identification of Radiation-Attenuating Angulations in Invasive Cardiology. Part I: Practical Focus on Patient Exposure.
1E.Kuon, 2J.B.Dahm
1Department of Cardiology, Klinik Fraenkische Schweiz, Ebermannstadt; 2Department of Cardiology, Ernst Moritz Arndt University, Greifswald.

Objective: To map in an experimental setting the fluoroscopic dose area product per second (DAP/sec) for all tube angulations typically used in invasive cardiology, and to identify tube angulations which promise minimal patient radiation exposure.

Design: We measured the fluoroscopic DAP/sec, applied to a male anthropomorphic Alderson-Rando phantom for simulation of in vivo conditions, in 10° steps from 100° right (RAO 100°/ ...) to 100° left (LAO 100°/...) anterior oblique projection, and for all geometrically feasible cranial and caudal tube angulations (n = 162).

Results: DAP/sec was lowest between PA 0°/0° and RAO 20/0° view (12 mGycm2/sec), and highest at cranial LAO 100°/30°+ (133 mGycm2/sec) and caudal RAO 80°/30°- (108 mGycm2/sec) projections, respectively. The mean radiation exposure for all projections – cranialized and caudalized together, and measured in the various planes along the table – continuously rose to 3.7 times baseline values: towards both the respective mean RAO 90°, as well as LAO 90° angulation planes. The mean radiation exposure of all PA projections, angulated to the right and left in the planes at right angles to the table, continuously rose to 2.6 times baseline values: towards both the respective 30° cranially and caudally angulated planes.

Conclusion: Mapping of time-adjusted fluoroscopic DAP, applied to an Alderson-Rando phantom, for all tube angulations practicable in invasive cardiology, enables identification of patient radiation-attenuating projections. Routine clinical work is now necessary to verify our findings.