Anna Mench, Presenter: Nothing to Disclose

Rebecca Huke Lamoureux MS, BS, Abstract Co-Author: Nothing to Disclose

Izabella Lipnharski, Abstract Co-Author: Nothing to Disclose

Brian Cormack, Abstract Co-Author: Nothing to Disclose

Sharatchandra S. Bidari MD, Abstract Co-Author: Nothing to Disclose

Lynn Neitzey Rill PhD, Abstract Co-Author: Nothing to Disclose

Manuel M. Arreola PhD, Abstract Co-Author: Nothing to Disclose

To characterize Mild, Standard, and Strong settings of iterative reconstruction algorithm in CT and quantify organ dose savings provided by these settings using post-mortem subjects.

To analyze differences in organ doses and scan parameters for the Mild, Standard and Strong selections of the Adaptive Iterative Dose Reduction (AIDR) technique, nanoDot optically stimulated luminescent dosimeters (OSLDs) were implanted into various organs of interest (OI) within post-mortem subjects. Chest-abdomen-pelvis (CAP) protocol scans of these subjects were conducted on a commercially available 320-slice CT scanner using the 0.5 mm x 64 detector setting. Six post-mortem subjects were initially scanned with AIDR turned off and then again, with fresh OSLDs implanted into OIs and the Standard AIDR option selected. This process was repeated for two additional subjects at the Mild, Standard and Strong AIDR settings. Scan parameters including CTDI, DLP and mA were recorded for all acquisitions. The post-mortem subjects ranged in BMI from 24.4 (underweight) to 43.8 (morbidly obese). 

Organ dose measurements for six post-mortem subjects indicate average dose reductions of 21% to 46% for the Standard AIDR setting. The larger of these six subjects exhibited less significant dose reductions when compared to smaller subjects. It was also found that by decreasing the minimum mA setting, smaller subjects were afforded more AIDR dose reduction. Significant differences in CTDI and DLP were not apparent for the Standard and Strong selections of AIDR and dose reductions were comparable for these two strengths. The Mild AIDR option had higher scan parameter values resulting in more modest dose reduction. 

Iterative reconstruction algorithms such as AIDR provide significant dose reduction to patients undergoing CT scans. Importance lies in fully assessing all three AIDR strength settings in order to maximize patient benefit by delivering the lowest dose possible.  

By comprehensively assessing the AIDR technique, further dose reduction may be possible for certain at-risk patient population groups, such as pediatric or obese patients.   

Mench, A, Lamoureux, R, Lipnharski, I, Cormack, B, Bidari, S, Rill, L, Arreola, M, Characterization and Dose Reduction Assessment of Iterative Reconstruction Algorithm with Mild, Standard and Strong Settings in Computed Tomography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045780.html