Question

What is the ratio of cost of a “typical” CT scan vs. a few standard radiographs for the same region (head, chest, etc.)?

Briefly, what is a CT scan—what kind of image does it create and how?

Who invented the CT scan and when?

Two reasons to use a CT scan instead of an X ray (radiograph)?

If you get more information from CT scans, why are simple radiographs still used?

What are Hounsfield units? How is windowing used?

What sort of radiation is involved? Are CT scans “perfectly safe”? If not, what are the dangers?

Answer 1

The CT scan is more advanced technique and is used for major issues. Because of the plantation and execution of CT scan machine is costlier, that's why it is costlier than other small radiologic scans.

A CT scan allows doctors to see inside your body. It uses a combination of X-rays and a computer to create pictures of your organs, bones, and other tissues. It shows more detail than a regular X-ray.

They use a narrow X-ray beam that circles around one part of your body. This provides a series of images from many different angles. A computer uses this information to create a cross-sectional picture. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body.

Engineer Godfrey Hounsfield and physicist Allan Cormack invented the CT scan in 1972.

A CT Scan can focus on the target area better than an X-ray
Advanced CT Scan equipment can produce a 3d representation of the target while X-ray is strictly two dimensional

CT Scan exposes the patient to a lot more radiation and equipment for CT Scan costs considerably more than other technologies, That's why for small problems we first prefer simple radiographs than CT scan.

The Hounsfield unit  scale is a linear transformation of the original linear attenuation coefficient measurement into one in which the radiodensity of distilled water at standard pressure and temperature is defined as zero Hounsfield units, while the radiodensity of air at STP is defined as -1000 HU.

CT scan iincreases the possibility of cancer induction from x-ray radiation exposure. The risk of developing cancer as a result of exposure to radiation depends on the part of the body exposed, the individual’s age at exposure, and the individual’s gender. For the purpose of radiation protection, a conservative approach that is generally used is to assume that the risk for adverse health effects from cancer is proportional to the amount of radiation dose absorbed and that there is no amount of radiation that is completely without risk.