How can CT scans detect soft tissue like lungs but conventional X-ray imaging can't?

Question

I'm doing a report on Egyptian mummies and I want to know how CT detects more than just bone if a contrast agent isn't used.

Answer 1

The values created by a CT scan are absolute densities at a specific point. A X-ray does show soft tissue, but is not generally useful for diagnosing soft tissue injuries because it does not give enough data to make a diagnosis. X-ray films are typically "windowed" (grayscales are adjusted) to mainly show bone structures. A CT is a series of X-rays that can be used to mathematically reconstruct the inner densities, or tomology, of a body or object. Since this gives a much clearer picture of the internal structure of the entire body, the images can be windowed to focus on any density of tissue.

Answer 2

X rays are absorbed by any tissues to varying degree, as a function of density. If you ever seen an X ray, you do notice that not everything is totally black and white, there is a lot of grey.
Again, this is purely a result of how much matter there is between the X ray emitter and the photographic plate.
In computer tomography, several X rays are taken at varying angles, and the computer combines all those images to reconstruct a 3D model. If there is a bone in the way when looking straight on, then looking at an angle, that bone will hide something else. Thus, even organs with very low density can be imaged, since the software "removes" the shadow of very opaque bones.

Answer 3

Conventional xray can detect soft tissue. The technologist must select a technique that will make soft tissue visible before xraying the subject. CT takes multiple images in a rotation to form slices of the subject. All the information is gathered by the machine and can then be reconstructed to show lung detail or liver detail, or soft tissue detail, etc. The contrast agent only highlights vessels, veins, etc. All the organs are visible without contrast. Xrays arent only taken of bones as most people assume. Xrays are also taken of the abdomen to show the kidneys and bowels, etc.

Answer 4

plus the lungs are filled with air and will appear as black on the x-ray because x-rays will pass right through it. the bones are dense and slows some of the x-rays produce an image