Digital Notes

What two part process does indirect acquisition involve

scintillator and photodetector

Direct acquisition system

converts x ray photons to electrical signal

What doe CR use

uses a photostimulable phosphor on a solid state image receptor

Voxel

3d volume of tissue

Pixels

individual matrix boxes that are known as picture elemtns

What does smaller pixels mean

higher spatial resolution

Dynamic Range

range of values over which a system can respond

Sampling frequency expressed as

pixel/mm

Window leveling

adjusts brightness

Window Width

Adjusts contrast

Histogram

graphic representation of pixels and signal intensities present in image

What does histogram adjust

yields consistent gray scale regardless of technique

What does CRT require

optical coupling

atomic number of cesium

55

atomic number of iodide

53

What does direct DR interact with

Amorphous selenium

flourohalides luminesce release their energy as what

light