Mathias Georg Ludwig Cohnen MD, Presenter: Nothing to Disclose

Ehsan Andabili, Abstract Co-Author: Nothing to Disclose

Frank Wenserski MD, Abstract Co-Author: Nothing to Disclose

Ulrich Moedder MD, Abstract Co-Author: Nothing to Disclose

Ludger Poll, Abstract Co-Author: Nothing to Disclose

Andreas Saleh MD, Abstract Co-Author: Nothing to Disclose

Klaus Ewen, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To assess the effective radiation dose of the patient undergoing Multi-Detector CT (MDCT) of the intracranial vessels in comparison to three-dimensional rotational digital subtraction angiography (3D-RDSA).

Standard Examination protocols of the cerebral vessels were simulated at a MDCT “Volume Zoom” as well as at an “Angiostar” DSA-unit (both Siemens Medical Solutions, Germany). MDCT protocols were performed with varying tube currents (100, 50, 20 mAs) with a constant tube potential of 140 kVp. Slice collimation was 2.5, and 1 mm, respectively, resulting in a total of 6 different protocols. R-DSA was performed with standard parameters (70 kVp, automatic dose adaptation), and two dose reduced protocols (70, and 60 kVp, respectively, with “half-dose” automatic adaptation. Only rotational series without simulation of a complete angiography of the intracerebral vessels were simulated. For assessment of effective dose, LiF-TLD were placed at different sites within an anthropomorphic Alderson-Rando head phantom.

For MDCT of cerebral vessels, an effective dose of 0.7 to 2.4 mSv was measured at 2.5 mm slice collimation, and 1.0 to 4.6 mSv at 1 mm, respectively. Dose measurements revealed 2.3 to 3.9 mSv for R-DSA. Local organ dose of the eye lenses was 5.4 mGy to 26 mGy for MDCT, and 3.4 to 5.4 at R-DSA, respectively.

Effective radiation dose in MDCT and R-DSA of cerebral vessels is not different. Reducing the slice collimation from 2.5 to 1 mm leads to an approximate doubling of effective dose in MDCT. Local organ doses of the eye lenses were lower for R-DSA. Advantages of MDCT include non-invasive imaging including delineation of the cerebral parenchyma while R-DSA provides better spatial resolution and forms the basis of catheter-based interventions.

Cohnen, M, Andabili, E, Wenserski, F, Moedder, U, Poll, L, Saleh, A, Ewen, K, et al, , Dose Measurements in Multidetector CT and Three Dimensional Rotational Angiography of Cerebral Vessels.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4405114.html