Unit 4: Conventional Fluoro and Digital Fluoro + Radiation Safety

Question 1

define dynamic imaging:

Answer 1

imaging done through motion

Question 2

fluoroscopy is a __________ study.

Answer 2

dynamic

Question 3

give an example of a static study:

Answer 3

spot films

Question 4

Who created fluoroscopy and when?

Answer 4

Thomas Edison in 1896

Question 5

Who should fluoro?

Answer 5

a radiologist or PA or a tech under guidance of a radiologist or PA

Question 6

the fluoro/image intensification tube operates on __________ mA.

Answer 6

0.5 - 3.0

Question 7

Overhead/static exposures range from __________ mA.

Answer 7

25-1000

Question 8

fixed fluoro tubes should have how much SSD?

Answer 8

15”

Question 9

where is the image intensifier?
where is the x-ray tube?

Answer 9

above the pt

under the table

Question 10

what was the first generation of fluoro?

what did they use?

Answer 10

conventional fluoroscopes

yellow-green phosphors such as barium lead sulfate or zinc cadmium sulfide

Question 11

for conventional, fluoroscopists required how much dark adaptation of the eyes prior to the exam?

Answer 11

20 mins

Question 12

night vision is made possible by __________ located primarily on the periphery of the retina.

Answer 12

rods (scotopic vision)

Question 13

conventional fluoroscopes used __________________ and what did this do?

Answer 13

mirror optics; brought the image somewhere else if you weren’t right in front of the tube

Question 14

conventional fluoroscopes did not allow for __________________

Answer 14

multiple viewing

Question 15

image intensification tubes developed in:

Answer 15

1948

Question 16

digital fluoroscopic systems predominate by ________.

they included _____________ and ___________________________.

Answer 16

2005;
TFT matrices, post processing capabilities

Question 17

what was second generation fluoro?

Answer 17

image intensification

Question 18

image intensification gave us __________________ instead of yellow green images.

Answer 18

gray scale

Question 19

what were some advantages of image intensified fluoro?

Answer 19

brighter image (500-8000x)

less pt dose

allowed for cone vision

not as much radiation needed on front end

remote viewing (more than one)

Question 20

What were the advantages of using CsI as an IP over zinc cadmium sulfide?

Answer 20

less pt dose

better spatial resolution

brighter image

Question 21

describe the basic chain of events taking place in an image intensifier:

Answer 21

1. x-rays exit pt and interact with the cesium iodide IP which emits light
2. the light is converted into electrons/electronic image by the photocathode
3. the electrons travel from cathode side to anode side through electron stream by a PD of about 25 kVp
4. the electrostatic lenses focus the electrons and bring them closer to a focal point
5. the OP made of zinc cadmium sulfide converts the electrons back into light

Question 22

the process of converting light into electrons:

Answer 22

photoemission

Question 23

digital fluoroscopy uses ____________ generator and has ________________ fluoroscopy mode.

Answer 23

high-power; pulsed progressive

Question 24

for digital fluoro, the image intensifier OP screen is coupled to ________ and ____________________.

Answer 24

CCD/TFT; flat panel display

Question 25

first generation digital still had the _________________ but now ___________________ are coupled to the OP phosphor.

Answer 25

imaging intensifier; CCD with fiber optics

Question 26

what is used in digital fluoro to generate an electronic signal from the light output signal?

where is this signal then sent?

Answer 26

CCD

ADC to be displayed on monitor

Question 27

what are the advantages of CCD’s in medical imaging?

Answer 27

high spatial resolution
high SNR
high DQE
no warm-up
no maintenance
unlimited life
lower pt dose

Question 28

what is last image hold?

what is it for?

Answer 28

automatic storage of the last image that was displayed on the monitor

a dose saving feature

Question 29

No light conversion step and photons directly converted into electrons and sent to TFT array and ADC involves what in digital fluoro?

Answer 29

flat panel detectors

Question 30

Describe the relationship between kVp and mAs during fluoroscopy:

Answer 30

if you increase kVp, you have to lower mAs and vice versa

Question 31

reducing kVp during fluoro will:

Answer 31

increase pt dose

Question 32

What is the required SSD for “fixed fluoro”?

Answer 32

15”

Question 33

What is the required SSD for “portable fluoro”?

Answer 33

12”

Question 34

What is a dead man switch?

Answer 34

pedal that when pressed will fluoro and when released, fluoro stops

Question 35

the fluoro x-ray tube filtration is the same as overhead tube, but can have ______________ added to harden the beam

Answer 35

copper filters

Question 36

what is the max exposure rate by law?

Answer 36

88 mGy/min

Question 37

Which method of gonadal shielding is best for use during fluoro?

Answer 37

flat contact shielding

Question 38

What are the Cardinal Principles of Radiation Protection?

Answer 38

minimize time
maximize distance
maximize shielding

Question 39

for the bucky slot cover and the lead drape, how much is required?

Answer 39

0.25 mm pb equiv

Question 40

for the lead apron and thyroid shield, how much is required?

Answer 40

0.5 mm pb equiv

Question 41

what is a radiographer’s responsibility in fluoro?

Answer 41

inform others in the room to wear lead apron

Question 42

what is pulsed fluoroscopic exposure?

Answer 42

where the beam is emitted as a series of short pulses instead of continuously

Question 43

during a fluoroscopy where is the most ideal position for the tech to stand?

Answer 43

in the room, as far from the pt as practical