UNIT 2 IMPORTANT STUFF

Question 1

Primary Radiation

Answer 1

All radiation produced directly from the target in an x-ray tube

Question 2

Secondary Radiation

Answer 2

Created when primary beam interacts with matter

Question 3

Scatter radiation

Answer 3

X-rays that travel in different directions after exiting the patient body

Question 4

Remnant radiation

Answer 4

What remains of the primary beam after it has been attenuated by the matter(through the body before going onto the image receptor)

Question 5

3 basic types of beam restriction devices

Answer 5

Aperture diaphragm, cones, collimators

Question 6

Aperture diaphragm

Answer 6

Flat sheet of metal, usually lead, with a hole cut in the center and attached to the X-ray tube

Question 7

Cones and Cylinders

Answer 7

Circular aperture diaphragms with metal extensions

Question 8

Cone

Answer 8

Has an extension that flares or diverges with upper diameter smaller than the bottoms flared end

Question 9

Cylinder

Answer 9

Not flared, has same diameter at the bottom of the extension as it has on the top

Question 10

A grid created with the lead and interspace strips running parallel to one another. If an imaginary line were to extend the lead strips beyond the grid, they would never intersect.

Answer 10

Parallel grid

Question 11

A grid in which the grid sectors are parallel in the center, but are angled progressively more out towards the peripheral edges. If imaginary lines were to extend the lead strips beyond the grid, they would intersect at a Focal Point.

Answer 11

Focused grid

Question 12

The range of source-image distances (SID) at which the grid will not absorb significant amounts of primary radiation.

Answer 12

Focal Range

Question 13

Two linear grids placed on top of one another so that the lead strips form a criss-cross pattern.

Answer 13

Cross-hatched grid

Question 14

A grid with lead strips running in only one direction

Answer 14

Linear grid

Question 15

Occurs when the tube is angled across the long axis of the grid strips. It results in a reduction in IR exposure over the entire Image Receptor.

Answer 15

Off-level grid error

Question 16

Occurs when the Central ray is off-center to the center of a focused grid. The result is a reduction in IR exposure over the entire Image Receptor.

Answer 16

Off-center grid error

Question 17

When a grid is used at a distance other than that specified as the focal range. The result is a reduction in IR exposure in the peripheral edges of the IR and normal exposure in the center.

Answer 17

Off-focus grid error

Question 18

When a grid is placed upside down. The result is a reduction in IR exposure in the peripheral edges of the IR and normal exposure in the center.

Answer 18

Upside-down grid error

Question 19

High frequency grids vs Low frequency grids

Answer 19

Using grids with higher frequency and higher grid ratios cleans up more scatter radiation which increases contrast more than low grid ratios and low frequency grids

Question 20

Dfferential absorption

Answer 20

• Makes diagnostic X-ray work
• Absorbed at different rates

Depends on:
* Patient’s tissue
* Thickness
* Density
* Atomic number

In thicker tissue, dense tissue, or tissue possessing a high atomic number, more x-rays are absorbed in the tissue, a lower percentage exits the patient to expose the film.

Question 21

On an x-ray how do gas, soft tissue, and bone show up?

Answer 21

Gas: black
Soft tissue: gray
Bone: white

Question 22

The force that holds electrons in orbit around the nucleus. It is also the minimum amount of energy required to remove an electron from its orbit.

Answer 22

Electron binding energy

Question 23

The distance from the face of the grid to the point of convergence of the lead strips

Answer 23

Grid radius