Maria Anna Staniszewska PhD, Abstract Co-Author: Nothing to Disclose

Jaroslaw Jazwinski, Presenter: Nothing to Disclose

Magdalena Zabicka, Abstract Co-Author: Nothing to Disclose

Computed Tomography Angiography (CTA) is now a commonly used for non-invasive examination of coronary vessels. X-rays exposure pattern for coronary CTA is quite different to conventional coronarography by C-arm unit. This paper is aimed on evaluation of doses obtained by patients during coronarography by MDCT scanners and C-arm units.

The doses were evaluated experimentally, using thermoluminescent dosimeters (TLD) (Polish product, equivalent TLD-100) and anthropomorphic Rando Man phantom (made by Alderson). The measurements were performed for CT protocols covering the coronary arteries used at 16-row and 64-row MSCT scanners and the C-arm units. The organ doses were calculated on the basis of the TLDs readings for the specified volume of the phantom. The effective dose to each the analysed procedure were computed according to the ICRP recommendations given in Publication 60.

The measurements were carried out for 3 MSCT scanners. The protocols covering the chest and allowing to achieve a good contrast resolution were checked for the patient dose i.e.: “the chest angiography”, “HRCT of the chest” and the “coronary arteries”. The organ doses ranged from the tenths of mGy up to over 80 mGy, in dependence on the exposure settings and the CT scanner configuration. The highest values were detected for the organs involved in the scanned band of a body. On the other hand, the traditional chest angiography and coronarography were analysed with recording of the settings for two C-arm units. The highest doses were measured in the area of primary beam incidence, which also achieve 20-30 mGy for a mean time of exposure. The doses for the organs placed around the “main region” are significantly lower (to two orders of magnitude).

1. The spatial distribution of organ doses in CTA is significantly more uniform than at use of C-arm units. 2. Even if the effective dose in angiography procedure performed with C-arm unit is low, the very high doses for some organs are possible.

Optimisation of coronary diagnostics.

Staniszewska, M, Jazwinski, J, Zabicka, M, Doses to Patients in Coronary Examinations by MDCT Scanners and C-arm Units.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5010528.html