Gregor Jost PhD, Presenter: Employee, Bayer AG

Sven Golfier PhD, Abstract Co-Author: Employee, Bayer AG

Philipp Lengsfeld PhD, Abstract Co-Author: Employee, Bayer AG

Peter Seidensticker MD, Abstract Co-Author: Employee, Bayer AG

Matthias Voth MD, Abstract Co-Author: Employee, Bayer AG

Hubertus Pietsch PhD, Abstract Co-Author: Employee, Bayer AG

The exploitation of radiation for medical benefits has increased significantly in the last years, especially with the use of X-Rays in Computed Tomography (CT). The potential effects of exposure to low doses of radiation are still poorly understood. The aim of the study was to evaluate the biological effects induced by radiation based on CT scans and a potential radiation dose enhancement caused by iodinated contrast media (CM) due to the photoelectric effect.  

Human blood was collected and immediately irradiated using a 64-slice-scanner (CT Siemens Sensation 64, Erlangen) after adding 0 (control) 5 and 50 mg Iodine/ ml blood Iotrolan 300 (ISOVIST® Bayer Schering Pharma, Berlin), respectively. CT Tube settings were 120 kV and 150 mAs using a rotation time of 1s. Radiation-doses were determined using a UNIDOS-dosimeter and a ionizationchamber. Blood-samples were placed in a tissue equivalent body phantom to achieve realistic scattering conditions. To allow γ-H2AX foci formation, samples were incubated for 45 min. Lymphocytes were isolated, stained for γ-H2AX and analyzed by confocal microscopy and flow cytometry.  

For a clinical relevant Iodine concentration (5mg Iodine/ml blood) and a clinical relevant radiation dose (25, 50 and 100 mGy) contrast media did not cause an increase in γ- H2AX foci number compared to the control. An increase in γ-H2AX foci number, caused by contrast media could be detected by confocal microscopy at 100 mGy for 50 mg Iodine/ml and at 1000 mGy for 5 mg Iodine/ml blood. FACS analysis could only detect this dose enhancement at 1000 mGy and 50 mg Iodine/ml blood.  

No relevant biological dose effects caused by contrast medium enhancement could be detected for CT at clinically relevant radiation doses and iodine concentrations.  

Ionizing radiation can lead to a variety of deleterious effects in humans, most importantly to the induction of cancer.

Jost, G, Golfier, S, Lengsfeld, P, Seidensticker, P, Voth, M, Pietsch, H, No Relevant Additional Effect of Contrast Media on Occurrence of DNA Double Strand Breaks Following Diagnostic Computed Tomography.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6020818.html