Pediatric cardiac-gated CT angiography: assessment of radiation dose.
OBJECTIVE
The purpose of our study was to determine a dose range for cardiac-gated CT angiography (CTA) in children.


METHODS
ECG-gated cardiac CTA simulating scanning of the heart was performed on an anthropomorphic phantom of a 5-year-old child on a 16-MDCT scanner using variable parameters (small field of view; 16 x 0.625 mm configuration; 0.5-second gantry cycle time; 0.275 pitch; 120 kVp at 110, 220, and 330 mA; and 80 kVp at 385 mA). Metal oxide semiconductor field effect transistor (MOSFET) technology measured 20 organ doses. Effective dose calculated using the dose-length product (DLP) was compared with effective dose determined from measured absorbed organ doses.


RESULTS
Highest organ doses included breast (3.5-12.6 cGy), lung (3.3-12.1 cGy), and bone marrow (1.7-7.6 cGy). The 80 kVp/385 mA examination produced lower radiation doses to all organs than the 120 kVp/220 mA examination. MOSFET effective doses (+/- SD) were as follows: 110 mA: 7.4 mSv (+/- 0.6 mSv), 220 mA: 17.2 mSv (+/- 0.3 mSv), 330 mA: 25.7 mSv (+/- 0.3 mSv), 80 kVp/385 mA: 10.6 mSv (+/- 0.2 mSv). DLP effective doses for diagnostic runs were as follows: 110 mA: 8.7 mSv, 220 mA: 19 mSv, 330 mA: 28 mSv, 80 kVp/385 mA: 12 mSv. DLP effective doses exceeded MOSFET effective doses by 9.7-17.2%.


CONCLUSIONS
Radiation doses for a 5-year-old during cardiac-gated CTA vary greatly depending on parameters. Organ doses can be high; the effective dose may reach 28.4 mSv. Further work, including determination of size-appropriate mA and image quality, is important before routine use of this technique in children.
Hollingsworth
Caroline L
CL
Department of Radiology, Division of Pediatric Radiology, 1905 McGovern-Davison Children's Health Center, Durham, NC 27710, USA. holli016@mc.duke.edu
Yoshizumi
Terry T
TT
Frush
Donald P
DP
Chan
Frandics P
FP
Toncheva
Greta
G
Nguyen
Giao
G
Lowry
Carolyn R
CR
Hurwitz
Lynne M
LM
D000792:Angiography; D001822:Body Burden; D002675:Child, Preschool; D004562:Electrocardiography; D006801:Humans; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D012062:Relative Biological Effectiveness; D018570:Risk Assessment / Q000379:methods*; D014057:Tomography, X-Ray Computed; D014915:Whole-Body Counting / Q000379:methods*