Christopher Herzog MD, Abstract Co-Author: Nothing to Disclose

Denise M. Mulvihill MD, Abstract Co-Author: Nothing to Disclose

Giancarlo Savino MD, Presenter: Nothing to Disclose

Bernhard Schmidt PhD, Abstract Co-Author: Nothing to Disclose

Philip Costello MD, Abstract Co-Author: Nothing to Disclose

U. Joseph Schoepf MD, Abstract Co-Author: Nothing to Disclose

To assess radiation dose savings at pediatric cardiovascular 64-slice CT enabled by the use of automated anatomic tube current modulation.

IRB waiver was obtained for this retrospective analysis. Our pediatric 64-slice CT (Siemens) protocols use a weight based algorithm to determine nominal tube current settings with 80 or 100 kV for CT angiography. Automated anatomic tube current modulation (CAREDose4D, Siemens) was used for each case. With this technology, the tube current is continuously adjusted to the patient’s anatomy so that constant image quality is achieved throughout the body. The actual computed tomography dose index for the scanned volume (CTDIvol), the dose length product (DLP) and mean mAs throughout the scan were recorded for each case. In addition, based on the selected nominal tube current, we calculated the mean CTDIvol and the DLP for each patient, which would have been applied without the use of tube current modulation. The diagnostic quality of each scan was scored by an experienced pediatric radiologist.

We analyzed 30 consecutive cardiovascular 64-slice CT scans in children (13 female, 17 male). The average patient age was 5.3 years (range 2 days-15 years). All scans were deemed to be of diagnostic quality. Without the use of tube current modulation, an average CTDIvol of 6.10mGy (range 1.49-18.9mGy) and a DLP of 169.06mGy (range 10.0-818.69mGy) would have been applied. The actual radiation exposure with use of automated tube current modulation resulted in an average CTDIvol of 2.64mGy (range 0.45-11.56) and an average DLP of 76.52mGy (range 3.0-395mGy). Mean mAs values were 53.12 mAs (range 20 -168mAs) as compared to 128.9 mAs (range 70-276mAs) without automated tube current modulation. All differences were statistically significant with p<0.01.

At pediatric cardiovascular 64-slice CT, use of automated tube current modulation substantially reduces patients’ radiation exposure compared with standard, unmodulated protocols, while diagnostic quality is consistently maintained. Thus, we recommend general use of tube current modulation combined with weight-based selection of scanner settings to minimize radiation exposure to children.

B.S.: Employee, Siemens Medical SolutionsU.S.: Research Support, Consultant, Siemens Medical Solutions

Herzog, C, Mulvihill, D, Savino, G, Schmidt, B, Costello, P, Schoepf, U, Pediatric Cardiovascular 64-Slice CT: Radiation Dose Reduction by Automated Anatomical Tube Current Modulation.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4408912.html