Angiography & DSA Unit

Question 1

What are the Basic Apparatus for
Angiography/DSA Unit

Answer 1

◦ image processor
◦ generator
◦ X-ray tube
◦ image intensifier
◦ camera
◦ TV monitor
◦ analog-to-digital
converter (only
found in DSA
unit)
◦ angiographic
table

Question 2

Capabilities of the Generator

Answer 2

◦ Changes the incoming line voltage to what is
needed to power the X-ray tube
◦ Must be three-phase or high frequency 12-pulse unit.
◦ Capable of short exposures at a high flux level
◦ At least 1000 mA
◦ Capable of very short exposure time
◦ Must be able to change kV rapidly
◦ In-bi-plane filming, each tube must have its own
generator

Question 3

Capabilities of an X-ray Tube

Answer 3

◦ Must be able to withstand a great deal of heat
◦ about 400,000 to 800,000 HU
◦ Made of high-speed rotating anode for better heat dissipation
◦ with a small focal spot for higher resolution

Question 4

Capabilities of an Image Intensifier

Answer 4

◦Introduced by Philips Co. on 1955, highly piece
of equipment which uses x-rays & produces a
live image feed w/c is displayed on T.V
◦ Must be high resolution that is capable of
magnification fluoroscopy.

Question 5

What is the process of producing a image using an intensifier?

Answer 5

convert low levels of light photons into electrons, amplify those electrons, and then convert the electrons back into photons of light.

Question 6

Capabilities of television and Camera

Answer 6

◦ 1. must be ceiling mounted
◦ 2. standard resolution is 525 lines/frame
◦ Must have a signal to noise ratio of 1000:1
◦ Signal to noise ratio - defined as the ratio of a signal
power to the noise power corrupting the signal
◦ Frame rate / Frame frequency – measurement of
frequency (rate) at w/c an imaging device produces
unique consecutive image, expressed as frames/
second (FPS)

Question 7

Capabilities of Angiographic Table

Answer 7

Should allow movement of patient without
being repositioned.

Question 8

2 areas of Radiographic Imaging

Answer 8

Still imaging using film/screen system, and fluoroscopic imaging using the fluoroscopic screen and then followed by the use of image intensifier.

Question 9

What are the two types of FPD?

Answer 9

• Indirect Conversion FPD and Indirect Conversion FPD

Question 10

What is Indirect conversion of FPD?

Answer 10

Flat panel detector initially
converts the X-rays to light with a CsI scintillator or
some other type of scintillator, and then converts
this light to electrical charges with amorphous
silicon photodiodes.

Question 11

What is Direct Conversion FPD?

Answer 11

• Direct conversion flat panel detector uses
  amorphous selenium (a-Se) to directly convert
  the X-ray energy to electrical charges.
• This eliminates the light output permitting good
  MTF characteristics , without dispersion. It offers
  a spatial resolution of at least 3 lp/mm.
  -This direct conversion flat panel detector offers
  enhance visibility of fine blood vessels and
  devices, that was conventionally difficult, to
  permit smoother diagnosis and reduced
  examination times.