Roman Kloeckner MD, Presenter: Nothing to Disclose

Daniel Pinto Dos Santos MD, Abstract Co-Author: Nothing to Disclose

Jens Schneider, Abstract Co-Author: Nothing to Disclose

Christoph Düber MD, Abstract Co-Author: Nothing to Disclose

Michael Bernhard Pitton MD, Abstract Co-Author: Nothing to Disclose

To investigate the radiation exposure in CT-guided interventions and to search strategies for dose reduction.

1576 consecutive CT-guided procedures in 1284 patients performed over 4.5 years were analyzed including drainage placements, biopsies of liver, lung, kidney, lymph nodes and other organs, radiofrequency-/ microwave-ablations of liver, bone and lung tumors, pain blockages and vertebroplasties. They were analyzed with respect to the overall radiation doses and individual doses of planning CT-series, CT-intervention and control CT-series. Additionally, the impact of different fluoroscopy settings (kV/mAs) and the fluoroscopy mode (single slice acquisition vs. continuous CT-fluoroscopy) on the radiation dose was investigated.

85% of the total radiation dose was applied during the pre- and post-interventional CT-series leaving only 15% to being applied by the CT-guided intervention itself. Single slice acquisition was associated with lower doses compared to continuous CT-fluoroscopy (37mGy*cm vs. 153mGy*cm, p<0.001), most likely since there was no stratification to intervention-complexity. Overall, the use of 80kV during the interventions led to significantly lower radiation doses compared to 120kV (mean: 86mGy*cm vs. 215mGy*cm, p<0.001). Analyzing both interventional subgroups independently (single slice acquisition vs. continuous CT-fluoroscopy), 80kV led to significantly lower radiation dose in both groups (continuous CT-fluoroscopy: 80kV vs. 120kV: 97mGy*cm vs. 267mGy*cm; p<0.001) (single slice acquisition: 80kV vs. 120kV: 15mGy*cm vs. 59mGy*cm; p<0.001).  

Since the main part of radiation is applied during the pre- and post-interventional CT-series, the scan area should be restricted to the respective ROI. Single slice acquisition is associated with lower doses compared to continuous CT-fluoroscopy. 80kV should be preferred to 120kV for CT-guided interventions.

Radiation exposure during CT-guided interventions can be reduced significantly by lowering CT-fluoroscopy settings dramatically, most ideal to 80kV and 20mAs.

Kloeckner, R, Pinto Dos Santos, D, Schneider, J, Düber, C, Pitton, M, Radiation Exposure in CT-guided Interventions.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029156.html