User:Gil Zweig

Backscatter x-ray imaging, similar to CT imaging, employs a pencil beam of x-rays to scan the subject. With CT imaging, the transmitted component of the x-ray beam is detected. With backscatter imaging the back scattered (Compton scattered) component of the x-rays are detected by a large detector. The radiation density levels within the pencil beam striking the subject can be very high but appear low when mathematically averaged over a large area. It is important to know the radiation flux density within the pencil beam to asses the safety issue.