Manipulation of kVp (kilovoltage peak) and mAs (tube current flow) according to a patient's body shape may help reduce radiation doses in pediatric patients during CT, according to a study performed at the Cleveland Clinic Children's Hospital in Cleveland, OH.
Phantoms that were 10, 16 and 32 cm in diameter (canvases of the average waist sizes for children two to 18 years of age) were used during the study. 120 dose measurements were made using various kVp and mAs levels. The lowest dose found on the 10 cm was 12 mGy; the lowest dose found on the 16 cm was 19 mGy; and the lowest dose found on the 32 cm was 20 mGy," said Janet Reid, MD, and William Davros, MD, lead authors of the study. Results showed that although dose reduction is easily achieved through manipulation of mAs, it may be preferable to reduce the dose by adjusting the kVp, especially in the setting of iodinated contrast-enhanced scans which takes advantage of the higher k-edge absorption (enhancing the shades of grey) at a lower kVp.
"Our hopes are to tailor a patient's radiation dose to their body shape, not just their weight and age," said Drs. Reid and Davros. "In doing so, a patient will get a decreased radiation dose that is tailored to them. A personalized radiation dose," they said.
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American Roentgen Ray Society