In Japan, there are 91 scanners per million people (Coach, 2008). The recent developments in CT technology have made it possible to use Dual Energy Computed (DECT) in routine clinical radiology. The technique utilizes two-photon energy spectra to construct CT images and it was first described in the late 1970s (Millner et al, 1979). DECT imaging technology can provide image contrast optimization, material decomposition, and monochromatic spectral images (Langan, 2008). Because X-ray absorption is energy dependent, changing the kilovoltage of the X-ray tube results in material-specific changes in attenuation.
This means that CT is able to differentiate various materials (tissues) in one scan. Until now, using CT without the Dual Energy feature would require that two scans be needed separate between two materials. The breakthrough offers the potential to enhance cardiovascular and vascular, body perfusion, brain, lung, and liver imaging, which enables physicians to diagnose their patients’ conditions faster and more accurately (Langan, 2008). Unfortunately, the benefits of CT examinations, in general, come at a cost. The radiation dose of CT examinations is much higher compared with other X-ray diagnostic procedures (AAPM 23, 2008).
One estimate showed it contributes almost 70% of the total dose (Huda, 2008). The typical dose for a single CT scan is between 15 mSv in the case of adults, and to 30 mSv in the case of neonates (Brenner & Hall, 2007). Despite these risks, the use of CT is growing annually, offering significant improvements in the variety and quality of CT clinical applications, which raise the need to reevaluate these exam protocols and to compare the radiation risk versus medical benefit (ICRP 103, 2007, AAPM 23, 2008).
The risk of cancer might be increased slightly with the dose from a CT scan, but also it is possible that a poorer image could lead to missing an important detail necessary for correct diagnosis (Brenner & Hall, 2007).