Yasir Andrabi MD, MPH, Presenter: Nothing to Disclose

Jorge Mario Fuentes MD, Abstract Co-Author: Nothing to Disclose

Mukta Dilipkumar Agrawal MBBS, MD, Abstract Co-Author: Nothing to Disclose

Dushyant V. Sahani MD, Abstract Co-Author: Research Grant, General Electric Company

Increased utilization of image guided catheter placement especially for no-cancer indications has increased concerns for radiation exposure. Image quality (IQ) expectations in follow up (F/U) exams are much lower than initial diagnostic exam. We investigated the performance of low dose follow up CT exams for IQ and radiation doses compared to baseline abdomen-pelvic CT exams in patients undergoing CT guided catheter placement.

Between December 2012 to December 2013, 264 patients (M:F=135:129; BW=77.5kg, Age=61.5) had initial and F/U CT exams performed for CT guided catheter placement on 2 GE Healthcare scanners [LightSpeed Pro-16 (FBP=133) and Discovery 750HD(ASiR=130)]. The scanning parameters for F/U exams included weight based kVp (FBP:100/120, IR: 80/100), low mA(75-350) and NI(FBP:25, IR:30) Patient demographics and radiation dose (CTDI, SSDE, DLP, Effective dose(ICRP 103), dose per organs) were retrieved using an automated dose tracking software (eXposure, Radimetrics) and were compared with the baseline CT exam. Subjective IQ assessment of F/U exams to determine diagnostic acceptability was done.  

The overall IQ was acceptable for interpretation in F/U exams. Mean SSDE for F/U exams were 3.8 mGy compared to 9.4 mGy for baseline CT exams corresponding to nearly 65% dose reduction (p<0.0001). Mean radiation doses (SSDE) were 73% lower in F/U exams performed with ASiR technique compared to 48% with FBP technique (mGy, ASiR=2.6, FBP=4.9; p<0.0001). Doses are nearly 80% lower than ACR reported doses for routine abdomen CT exams.

Customizing scan protocols for F/U indications enables substantial dose reduction (65%) compared to baseline diagnostic CT exams. These dose reduction benefits are more drastic in scanners with IR algorithms (73%) compared to FBP exams (48%). 

Continuous protocol optimization based on image quality expectations and clinical indications is integral for adherence to ALARA principle. These are especially true for indications with lower IQ expectations and exams needing repeated follow ups. 

Andrabi, Y, Fuentes, J, Agrawal, M, Sahani, D, Can Patient Radiation Dose Be Drastically Reduced for Monitoring CT Guided Catheter Placement?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045710.html