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.