Radiology imaging

Question 1

When were grids invented?

Answer 1

1913 - Gustave Bucky

Question 2

What is the primary function of a grid?

Answer 2

Removing scatter radiation thus improving contrast

Question 3

What does removing scatter improve?

Answer 3

Contrast…. reduces unwanted blackness

Question 4

Grids are made of?

Answer 4

Lead foil (0.05mm) an interspacing material (aluminum or organic material)

Question 5

What are the limitations of a JPEG image?

Answer 5

Limited manipulation - Just magnify

Lossy image compression - Blur edges (decreased detail)

Question 6

PACS is a system of?

Answer 6

Storing

Retreiving

Presenting

Sharing files

Question 7

The amount of bandwidth needed in a server or in a PACS depends on?

Answer 7

The modality it is serving

The work load

CT needs a lot more bandwidth than Nuc Med

Question 8

When were x-rays discovered?

Answer 8

November 8, 1895

Question 9

What is the grid ratio defined as?

Answer 9

Ratio between the height of lead strips: distance between the lead strips

Question 10

Type of grid pattern?

Answer 10

Linear

Crossed

Focused grid

Parallel grid

Question 11

What is the disadvantage of a crossed grid?

Answer 11

Cannot have oblique facing x-ray beam.

Question 12

What is the difference between a convergent line and convergent poinit?

Answer 12

Crossed focused grids have a convergent linie

Linear focused grids have a convergent line

They are just where the source of the x-ray beam would have the best primary transmission

Question 13

What is focusiing range when discussing grids?

Answer 13

It is the range of focal distances that the grid will still work properly

Lower the grid ratio the large the Focusing range is.

Question 14

What are the three ways to evaluate the performance of the grid?

Answer 14

Primary transmission - Only measures attentuation of primary transmission

Bucky factor - Measures attenuation of both primary and secondary transmission

Contrast improvement factor

Question 15

Because the Bucky factor is calculated using the absorption of scatter radiation, the performance of the grid or Bucky factor will do what when kVp is increased?

Answer 15

The Bucky factor will go up with higher kVp.

Higher kVp will create more scatter radiation and therefore at these higher energies the Grid will pick off more radiation (scatter) and thus will increase its performance or Bucky Factor.