Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

Abstract

There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 +/- 1.4 mSv according to ICRP 60 and 6.6 +/- 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

Prediction of Optimal Deployment Projection for Transcatheter Aortic Valve Replacement

“…Three-dimensional angiographic reconstructions (3DA) of the aortic root captured from rotational C-arm fluoroscopic images 6 have been evaluated in different interventional settings, for example, in endovascular aortic aneurysm repair 7,8 and catheter ablation procedures. 9,10 However, the value of this method for TAVR is not yet established.…”

The effective dose assessment of C-arm CT in hepatic arterial embolisation therapy

“…This assessment of clinical effective doses is mainly based on the clinical DAP data collected from liver C-arm CT scans. The assessed effective dose in the study (11.462.5 mSv) is higher than those in other studies (6.6-9.2 mSv) [5][6][7]. The effective doses of Bai et al's and Liu et al's studies were derived only from experiments with a male phantom with TLDs embedded, without using clinical DAP data for correction [5,6] Liver C-arm CT dose…”

“…Although the application of C-arm CT may shorten the surgical time and radiation dose of fluoroscopy, C-arm CT angiography still requires the radiation dose. The effective dose of a C-arm CT body scan is about 6.6-9.2 mSv [5][6][7]. Such an effective dose is considerable, similar to the dose of multidetector computed tomography (MDCT), and it is relatively larger than the dose in general diagnosis photography.…”

Practical patient dosimetry for partial rotation cone beam CT

“…The final kV reported by the unit was used for all projections. Wielandts et al [11] used frame-by-frame kV and mAs values extracted from the X-ray unit. They demonstrated that tube power remains constant throughout the run, so assuming constant kV and DAP per frame was a reasonable approximation.…”

“…The Monte Carlo modelling software PCXMC (STUK, Helsinki, Finland) [10] simulates an X-ray beam by projecting it onto a modified version of the Cristy anthropomorphic mathematical phantom. This gives both organ and effective doses and has recently been used by Wielandts et al [11] for CBCT. Because the beam spectrum and geometry of each exposure is simulated individually, this technique offers a greater degree of accuracy than those developed for conventional CT.…”