Sarabjeet Singh MBBS, Presenter: Nothing to Disclose

Mannudeep Karanvir Singh Kalra MD, Abstract Co-Author: Research grant, General Electric Company

Randheer Shailam MD, Abstract Co-Author: Nothing to Disclose

Michael Moore MBBCh, Abstract Co-Author: Nothing to Disclose

Sjirk Jan Westra MD, Abstract Co-Author: Nothing to Disclose

Multifactorial chest and abdominal CT protocols based on multiple factors such as patient weight, clinical indications and number of prior CT exams, for the same clinical indication were implemented for children. We assessed the effect of these multifactorial pediatric CT protocols on image quality and radiation dose.

The study included 110 chest (age range 2-18 years, M:F 57:43) and 150 abdominal (age range 1-18 years, M:F 82:68) CT examinations performed in 260 children on 16 and 64 slice MDCT scanners. All studies were performed using automatic exposure control, auto mA (GE Healthcare) (noise index=6-15, mA range=50-210), kVp (80-120), adapted to patient size, clinical indications, and number of prior CT examinations. These studies were reviewed by two radiologists for subjective image noise (5 point scale; 1= excellent, 5= unacceptable), diagnostic acceptability (4 point scale; 1= fully acceptable, 4= unacceptable), lesion conspicuity, and presence of artifacts. In addition, objective noise was measured in all examinations. Patients’ weight, and CTDI volume and DLP were recorded. Data were analyzed to determine effect on image quality and radiation dose.

All studies were rated as diagnostically acceptable with acceptable lesion conspicuity and above average subjective image noise. Regardless of the size of children, there was reduction in radiation dose with use of multifactorial CT protocols (p<0.0001). For subjects with one or more prior CT, there was 25-80% decrease in CTDI vol (2.8-5.5mGy) for abdominal CT exams and 50-65% decrease in CTDI vol (2.1-3.9mGy) for chest CT exams compared to weight matched subjects without prior examinations but performed with multifactorial CT protocols (p<0.001). For those subjects undergoing first CT, compared to weight and size matched subjects who were not scanned with composite protocols, there was 55.8% dose reduction for multifactorial chest CT protocols (7.7 mGy) and 41.2% dose reduction for abdominal CT protocols (8 mGy) (p<0.0001).

Composite multifactorial protocols for scanning children can help reduce radiation dose by 25-80% based on patients’ size, clinical indications and number of prior CT examinations.

Weight based CT protocols must be supplemented with dose adjustment for clinical indications and prior CT examinations to reduce radiation dose for children.

Singh, S, Kalra, M, Shailam, R, Moore, M, Westra, S, Effect of Multifactorial Pediatric CT Protocols on Radiation Dose and Image Quality: Study of 260 Children.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6016139.html