Introduction
The high diagnostic value of MDCT is intimately associated with a patient's
high exposure to ionizing radiation. Simply reducing the radiation dose, by lowering X-ray tube
current or voltage, is not effective due to a concomitant loss of image quality. Thus, various new
technologies and scanning protocols have recently been developed to limit the body's exposure,
either temporally or anatomically, and to improve the quality of images obtained by scanning at
lower levels of irradiation. These new scanning approaches have been summarized in a recent review,
published in Emergency Radiology, by Dunn and Kohr, two radiologists at the University of
Washington [
1].
One of the approaches discussed in the review, called peak kilovoltage adjustment, takes
advantage of the fact that enhancement from iodinated contrast agents can actually be better at
lower than higher values of peak kilovoltage. This effect is more apparent when imaging blood
vessels in less dense body regions (e.g. thorax) or when imaging the smaller bodies of children. In
a new study published in the European Journal of Radiology [
2], peak
kilovoltage adjustment was used as one of three features of a low-radiation CT angiography
protocol.
