P424 Predialing the Number of Cinegraphic Frames Enables an Effective Patient Dose Due to Invasive Coronary Angiography of 0.8 Millisievert.
1E.Kuon, 1M.Schmitt, 1Chr.Dorn, 2A.Pfahlberg, 2O.Gefeller, 3J.B.Dahm
1Department of Cardiology, Klinik Fraenkische Schweiz, Ebermannstadt; 2Institute for Computer Sciences, Biometry and Epidemiology, Friedrich-Alexander University, Erlangen; 3Department of Cardiology, Ernst-Moritz-Arndt University, Greifswald.

Purpose: To investigate the effect of a new device for predialing the number of cinegraphic frames before each coronary documentation, with the objective of reducing the patient's dose area product (DAP) from coronary angiography, which typically requires 1000 ... 2350 cinegraphic frames. That DAP is high: 53 ± 35 Gy × cm2, equivalent to a mean effective dose (ED) of approx. 10.6 ± 7.0 mSv. Noninvasive coronary imaging, however, by multislice computed tomography (MSCT), typically produces similar patient EDs.

Materials and Methods: For patients undergoing elective coronary angiography, we compared various parameters of radiation exposure obtained with judicious radiation reducing standard techniques (n = 106) - according the recommended ALARA (“as low as reasonably achievable”) principle - with parameters obtained, additionally using a new rotary switch for predialing the number of cinegraphic frames (n = 106).

Results: Patients radiation exposure was significantly lower in the population investigated with the new device. Mean DAPs were 5.5 vs. 9.1 Gy × cm2, corresponding to fractions for left ventriculography and for coronary angiography of 1.3 vs. 1.7, and 4.2 vs. 7.4 Gy × cm2, respectively. The number of cinegraphic frames was 98 vs. 184, whereas the number of cinegraphic runs and fluoroscopy time were comparable.

Conclusion: Predialing the cinegraphic frame number before each cinegraphic run enables reduction in patient's effective dose from coronary angiography to 0.8 mSv, i.e. to levels of 10% of typical values, down to effective doses of a simple coronary calcification scoring by multislice computed spiral tomography (MSCT) or electron beam tomography (EBT), and far below those of detailed noninvasive radiologic coronary imaging.