What is the difference between a traditional CT Scanner and a Spiral CT Scanner?

Question

I know that a spiral produces thinner slices and perhaps in more detail, I am not really sure? I would like to better understand the science behind it? Also, could you respond with some understanding of MRI and Doppler scans as well? Could you provide some of the history of the above mentioned diagnostic tests? Thank you.

Answer 1

Computed tomography (CT), originally known as computed axial tomography (CAT or CT scan) and body section roentgenography, is a medical imaging method employing tomography where digital geometry processing is used to generate a three-dimensional image of the internals of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word "tomography" is derived from the Greek tomos (slice) and graphia (to write). CT produces a volume of data which can be manipulated, through a process known as windowing, in order to demonstrate various structures based on their ability to block the X-ray beam. Although historically (see below) the images generated were in the axial or transverse plane (orthogonal to the long axis of the body), modern scanners allow this volume of data to be reformatted in various planes or even as volumetric (3D) representations of structures.

Spiral CT scanning is just a new and advanced from of CT scanning: This is a newer type of CT scan, also known as a 'helical' CT scan. It is faster than a standard CT scan and gives an even more detailed picture of your organs and tissues, including blood vessels. This can make it useful for picking up very small tumours. It's called a spiral scan because the X-ray beam rotates around you during the scan in a spiral shape. This gives the radiographers a continuous picture, with no possible gaps between the 'slices' of the scan.