Dolf..
As I remember the info from a biophysics class four or five years ago, radiological injury of either celluar or genetic components is a function of the number of ionizations caused by an x-ray passing through the body. Hard x-rays [high energy] produce relatively few; they pass through the body unimpeded. Soft x-rays, on the otherhand, produce more ionizations along thier paths; in the absence of shielding, soft x-rays are potentially more harmful. So what do the new scanners use? Why, soft of course! "All the better to see you with," the big bad wolf told Little Red Riding Hood.
Radiological exposure causes mutations, early cell death, suppresses the immune system, yada, yada. Yea, it is associated with birth defects and the big C.
jay