Strategies for reduction of radiation dose in cardiac multislice CT

Abstract

Because cardiac computed tomography (CT) (mainly coronary CT angiography) is a very promising technique, used more and more for coronary artery evaluation, the benefits and risks of this new low-invasive technique must be balanced. Radiation dose is a major concern for coronary CT angiography, especially in case of repeated examinations or in particular subgroups of patients (for example young female patients). Radiation dose to patient tends to increase from 16- to 64-slice CT. Radiation exposure in ECG-gated acquisitions may reach up to 40 mSv; considerable differences are attributable to the performance of CT machines, to technical dose-sparing tools, but also to radiological habits. Setting radiation dose at the lowest level possible should be a constant goal for the radiologist. Current technological tools are detailed in regard to their efficiency. Optimisation is necessary, by a judicious use of technological tools and also by individual adaptation of kV or mAs. This paper reviews the different current strategies for radiation dose reduction, keeping image quality constant. Data from the literature are discussed, and future technological developments are considered in regards to radiation dose reduction. The particular case of paediatric patients with congenital heart disease is also addressed.

Comparison of Radiation Doses between 64-slice Single Source and 128-slice Dual Source CT Coronary Angiography in patient

“…PGT 기법에 서 유효선량은 2.8-6.7 mSv 정도로 보고되고 있으며, RGH 기법과 비교 시 PGT 기법에서 68-87 % 선량을 감소시킬 수 있다고 하였다 [11,12] . 사용되기 때문에 신중하게 적용하여야 한다 [19] .…”

Radiation dose of cardiac computed tomography – what has been achieved and what needs to be done

“…The next step in reducing radiation dose of CT coronary angiography was the application of low tube voltage protocols [16,17]. Lowering the tube voltage represents an important radiation dose reduction approach because the radiation dose varies with the square of the tube voltage [18].…”

“…With reduction of the tube voltage from the standard 120 kV to 100 kV (Fig. 2a), another lowering of the average effective radiation dose of retrospectively ECG-gated cardiac CT with ECG-controlled tube current modulation to around 6.5 mSv was achieved [16,17] (see Fig. 1).…”

The ‘what, when, where, who and how?’ of cardiac computed tomography in 2009: Guidelines for the clinician

“…Retrospectively gated CTA should therefore be used selectively, taking into account dose considerations, patient age and sex (40). The high radiation dose should limit the use of retrospectively gated CTA for repeat assessments and for the evaluation of asymptomatic individuals (41).…”