5. Better resolution with smart photons

There are continued improvements that deal with limitations due to "crosstalk" from CT's utlization of reflectors. New direct conversion photon-counting detectors serve as an excellent solution to this issue because the charge carriers produced in the semiconductor follow electric field lines, allowing them to overcome inefficiencies found in scintillator-photodiode detectors used in current commercial systems.


This lets them “readily achieve much better spatial resolution,” according to Kalorama.

Unlike conventional CT scanners, which utilize energy-integrating detectors (EIDs) to create an electrical signal using X-rays, photon-counting detectors calculate individual photon interactions through high-speed semiconductors, eliminating reliance on resolution-limiting scintillator crystals.


The Clinical Center at the National Institutes of Health (NIH) in Maryland, has begun investigating the potential of a photon-counting CT scanner in a hospital-based research setting. It has outlined three areas where photon CT may yield extra diagnostic value:

•Doctors can identify materials in the body with anatomic precision. A dye, or contrast, is often given to a patient so that researchers can see a selected area in more detail. Different materials in the body can be displayed in different colors for faster diagnosis and precision.

•The new technology may be used to help identify and characterize tumors, plaques, or vessels that are smaller than half a millimeter. For many patients, finding a tumor that size may make a difference in identifying if it is benign or could be cancerous.

•The technology may help to more accurately identify soft tissues such as proteins, tendons or collagen which are hard to differentiate with current equipment.


Next: Portable CT units

CT Homepage