Chapter 15 - X-rays Flashcards
What are the aims of the radiographer? (2)
Minimum X-Ray exposure Maximum contrast (diff. between light and dark) in image
What are two detection systems for X-Rays?
Film and digital
How does photographic film work and how has it been improved?
Photographic film absorbs X-Rays and thus produces image
Intensifier screens placed around photographic film to reduce exposure times
Explain how image intensifiers work and what they improve?
X-Rays strikes phosphor screen, producing light photons, which release electrons from photocathode by the photoelectric effect. Electrons then accelerated at screen to produce picture.
Image intensifiers improve digital systems
Advantage of digital systems?
Images can easily be stored, shared and viewed
How do doctors improve contrast between tissues?
A contrast medium (absorber of X-Rays such as Barium) is eaten/injected
What is a contrast media and what characteristic do they have?
Materials such as barium which easily absorb X-Rays. A contrast medium is used to reveal outlines/edges of soft tissues in X-Ray images.
High atomic number materials used
Define computerised axial tomography (CAT)?
A technique where X-Rays are used to image slices of the body in order to produce a computerised 3-D image.
What are the aims of the radiographer? (2)
Minimum X-Ray exposure Maximum contrast (diff. between light and dark) in image
What are two detection systems for X-Rays?
Film and digital
How does photographic film work and how has it been improved?
Photographic film absorbs X-Rays and thus produces image
Intensifier screens placed around photographic film to reduce exposure times
What is an image intensifier?
A device used to change a low-intensity X-Ray image into a bright visual image
How do doctors improve contrast between tissues?
A contrast medium (absorber of X-Rays such as Barium) is eaten/injected
What is a contrast media and what characteristic do they have?
Materials such as barium which easily absorb X-Rays. A contrast medium is used to reveal outlines/edges of soft tissues in X-Ray images.
High atomic number materials used
Define computerised axial tomography (CAT)?
A technique where X-Rays are used to image slices of the body in order to produce a computerised 3-D image.
