How is geometry used in medical imaging?

Answer 1

There are a lot of areas in which geometry is applicable in medical imaging.

There is the optics involved in plain x-rays - the x-ray generator, the collimation and directing the beam where you want it and ONLY where you want it so you don't irradiate everyone in the vicinity.

There is the size of structures - the shadows cast by the structures at different distances from the x-ray film. eg if you are standing with your front to the x-ray plate and the Chest x-ray is taken from the back, the heart casts a smaller shadow than if you are sitting up in bed and the x-ray plate is behind you and the Chest x-ray is taken from the front.

This is determined by geometry.

There is the high powered computerised stuff involved in CT and MRI where the signal is taken from the raw data gathered in a spiral or all-around fashion from the patient and the computer has to reconstruct it into a 2D (and these days into a 3D) image. There is a TON of geometry involved there.

Ultrasound measurement of volumes involves geometry.

Answer 2

A picture is worth a thousand words...See the following site from NDT. It is from an industrial x-ray site, but the same principle applies to medical imaging.

You can also calculate size of part magnification on a radiographic image shows using these same distances for source to image, object to image, and source to object.

The second link is for other types of medical imaging.