Ch 25 Fluoroscopy

Question 1

the primary function of the fluoroscope is:

Answer 1

to provide real-time dynamic viewing of anatomic structures

Question 2

the fluoroscope shows the motion of:

Answer 2

circulation and internal structures

Question 3

angiography is _____ and is now referred to as _____

Answer 3

the visualization of vessels and is now referred ti as interventional radiology

Question 4

the image intensifier is found:

Answer 4

above the patient

Question 5

during fluoroscopy the x-ray tube is operated at:

Answer 5

less than 5 mA

Question 6

the advantage of the image-intensifier is:

Answer 6

increased image brightness

Question 7

illumination levels are measured in:

Answer 7

units of lumen per square meter or lux

Question 8

radiographs are visualized under illumination levels of:

Answer 8

100-1000 lux

Question 9

rods and cones are responsible for:

Answer 9

the sensation of vision

Question 10

light must first pass through the _____ which is a ______ and then through the ______, where the light is focused onto the _______

Answer 10

cornea which is a transparent protective covering, then through the lens, where the light is focused onto the retina

Question 11

between the cornea and the lens is the ____, which ____

Answer 11

iris which controls the amount of light entering the eye

Question 12

the cones are concentrated ______, an area called the _____

Answer 12

cones are concentrated at the center of the retina, in an area called the fovea centralis

Question 13

rods are found ______, there are ___ rods found in the fovea centralis

Answer 13

rods are found on the periphery of the retina, there are no rods found in the fovea centralis

Question 14

the rods threshold is _____ and are _____ vision aka _____ vision

Answer 14

2 lux, night vision aka scotopic vision

Question 15

the cones threshold is ______ and are ____ vision aka _____ vision

Answer 15

100 lux, daylight vision aka photopic vision

Question 16

visual acuity is

Answer 16

the ability to perceive fine details (cone vision)

Question 17

the image intensifier raises the illumination into:

Answer 17

cone vision region where visual acuity is greatest

Question 18

the image intensifier tube receives ______ and converts it into a ______

Answer 18

receives the inmate-forming x-ray beam and converts it into a visible-light image of high intensity

Question 19

input phosphor is made of _______

Answer 19

CsI Cesium Iodine

Question 20

the photocathode is:

Answer 20

bonded directly to the input phosphor; thin metal layer usually made of cesium and antimony compounds that respond to stimulation of input phosphor light by the emission of electrons

Question 21

*the photocathode emits:

Answer 21

electrons when illuminated by the input phosphor

Question 22

photoemission is:

Answer 22

electron emission that follows light stimulation

Question 23

output phosphor is made of ______ and is the site of ______

Answer 23

zinc cadmium sulfide and is the site of where electrons interact and produce light

Question 24

input phosphor has 3 sizes:

Answer 24

sm (10), med (17), lg (25)

Question 25

magnification mode uses the ____size

Answer 25

smallest size (10)

Question 26

the patient dose _____ when you use the magnification mode

Answer 26

increases

Question 27

______ hit the input phosphor and are turned into _____

Answer 27

x-ray photons hit the input phosphor and are turned into light

Question 28

the input phosphor has a ____ diameter measuring ____

Answer 28

larger diameter measuring 10-40 cm

Question 29

the light then hit the photocathode where it turns into _____

Answer 29

electrons

Question 30

the photocathode is made of _____

Answer 30

Cesium Antimony CsSb

Question 31

the electrons then hit the output phosphor and turn into ______

Answer 31

light

Question 32

the output phosphor is made of _____ and has a diameter measuring _____

Answer 32

Zinc Cadmium Sulfide ZnCdSO4 and has a diameter measuring 2.5-5 cm (smaller diameter brighter light)

Question 33

the light exiting the output phosphor is _______ brighter

Answer 33

50-75 times brighter per electron

Question 34

*brightness gain =

the image is _____ times brighter

Answer 34

BG = minification gain x flux gain

the image is 5,000-30,000 brighter

Question 35

*minification gain =

Answer 35

(di/do)²

Question 36

*flux gain =

Answer 36

# x-ray photons : # light photons
                      (in : out)

Question 37

*conversion factor =

Answer 37

BG x 0.01

Question 38

the image intensifier tube is ____ long

Answer 38

50 cm

Question 39

going from input phosphor to output phosphor requires ___ V

Answer 39

25,000 V (25kV)

Question 40

veiling does what?

Answer 40

decreases image contrast

Question 41

*MF =

Answer 41

bigger/smaller

Question 42

the television camera tube is aka _____

the modified version is ____

Answer 42

vidicon

plumbicon

Question 43

3 ways to make the image brighter:

Answer 43

1) use the smallest output phosphor diameter 2.5
2) technical factors (exposure technique or brightness knob)
3) use more magnification

Question 44

*the beam splitting mirror does what?

Answer 44

sends the output phosphor image to multiple places

Question 45

the more line pairs per mm you can see:

Answer 45

the better resolution

Question 46

x-ray tube operates on _____
filament tube operates on _____
fluoro tube operates on _______

Answer 46

x-ray 5 mA
filament 3-6 A
fluoro less than 5 mA