Chapter 6

Question 1

Steps or CR=
1. 
2. 
3. 
4.

Answer 1

1. Expose
2. Stimulate
3. Read
4. Erase

Question 2

(CR) After plate is exposed to X-rays ____ of meta stable electrons relax (EXPOSE)

Answer 2

50%

Question 3

IP is put in plate reader and __1__ passes over remaining metastable excited electrons to stabilize them. They give off __2__ when they relax/stabilize (“__3__”).

Answer 3

1. Neon Laser
2. LIGHT
3. Stimulate

Question 4

Collects light for IP and sends it to Analog-To-Digital Convertor (ADC) which then goes to computer (“Read”).

Answer 4

Photomultiplier Tube (PMT)

Question 5

________ passes over IP to stabilize any remaining exited electrons and clear any remaining image (“Erase”).

Answer 5

Intense White Light

Question 6

Exposed IPs should be processed within _____ because latent image starts to fade.

Answer 6

1 hour

Question 7

Spatial resolution is __1__ with increased sampling frequency, increased number of smaller pixels, smaller __2__, and smaller __3__.

Answer 7

1. Increase
2. Pixel pitch
3. Sampling pitch

Question 8

CR plates can be read approx. _____ before they need to be replaced

Answer 8

10,000 times

Question 9

DR combines __1__ capture and __2__ readout so images are available almost instantly after exposure.

Answer 9

1. Image

2. Image

Question 10

DR is more __1__ and __2__ than CR

Answer 10

1. Expensive

2. Fragile

Question 11

Made with layers in order to receive xray photons and convert them to electrical charges for storage and readout

Answer 11

Flat Panel Detectors

Question 12

Layers of Flat Panel Detectors

1. First Layer=
2. Second Layer=__A__ array which is divided into square detector elements (DELs), each with a __B__ to store electrical charges and switching transistor for readout to be sent to __C__

Answer 12

1. X-Ray Convertor
2. A: Thin Film Transistor (TFT)
   B: Capacitor
   C: ADC

Question 13

1. Can DR systems be permanently mounted?
2. Can DR be available as mobile?
3. Name two ways images are transmitted to the screen

Answer 13

1. Yes
2. Yes
3. Umbilical cord or wireless

Question 14

Which has the more superior spatial resolution?

Answer 14

DR

Question 15

Indirect DR uses a scintillator like __1__ or __2__ to convert exit radiation into visible light, which is converted to __3__ charges by photodetector a (layer of __4__)

Answer 15

1. Cesium Iodide (CsI)
2. Gadolinium Oxysulfide
3. Electrical
4. Amorphous Silicon (a-Si)

Question 16

Indirect (__1__ with __2__)»_space; XRay»_space; __3__»_space; Electrical Charge

Answer 16

1. A-Si
2. CsI
3. Light

Question 17

Direct DR uses _____ to convert X-rays directly into electrical charges.

Answer 17

Amorphous Selenium

Question 18

Direct (__1__)»_space; XRay»_space; __2__

Answer 18

1. A-Se

2. Electrical Charge

Question 19

Ability of detector to capture accurately the range of photon intensities exiting patient

Answer 19

Dynamic Range

Question 20

Digital IRs have a much larger exposure ______ than film screen (analog)

Answer 20

Latitude

Question 21

Image ____ occurs during post processing to help produce images with appropriate grayscale appearance.

Answer 21

RESCALING

Question 22

If IR is UNDEREXPOSED (“__1__” too high), __2__ will result

Answer 22

1. S

2. Quantum Mottle/Noise

Question 23

If IR is overexposed then the “S” number is too __1__ and __2__ will occur

Answer 23

1. Low

2. Dose Creep

Question 24

Always follow the ______ concept

Answer 24

ALARA

Question 25

Increased ________ results in improved image quality ( increased signal and decreased noise)

Answer 25

Signal to Noise Ratio (SNR)

Question 26

Two types of film screen IRs (Analog)

Answer 26

Regular cassettes or Extremity Cassettes

Question 27

``` Regular Cassettes 1. How many intensifying screens? 2. Type(s) of film Extremity Cassettes 3. How many intensifying screens? 4. Types of film? ```

Answer 27

1. Two 2. Duplitized or Double Emulsion Film 3. One 4. Single Emulsion

Question 28

``` Regular Cassettes 1. Pt. Dose 2. Detail Extremity Cassettes 3. Pt. Dose 4. Detail ```

Answer 28

1. Decreased 2. Decreased 3. Increased 4. Increased

Question 29

Film base=__1__ (usually __2__ to decrease eye strain). Film Emulsion=Silver __3__ suspended in __4__. Supercoat=protects __5__ layer.

Answer 29

1. Polyester 2. Tinted blue 3. Halide crystals 4. Gelatin 5. Emulsion

Question 30

Is most widely believed to explain latent image formation on film

Answer 30

Gurney-Mott Theory

Question 31

CR uses BARIUM __1__ CRYSTALS dope with __2__ for photostimulable phosphor (__3__)

Answer 31

1. Flourohalide 2. Europium 3. PSP

Question 32

High KV: 1. _____ scale 2. _____ contrast 3. _____ latitude 4. _____ colors 5. _____ pt. dose 6. _____ scatter 7. _____ penetration

Answer 32

1. Short 2. Low 3. Wide 4. Many 5. Decreased 6. Increased 7. Good

Question 33

Low KV: 1. ____ scale 2. ____ contrast 3. ____ latitude 4. ____ colors 5. ____ pt. dose 6. ____ scatter 7. _____ penetration

Answer 33

1. Short 2. High 3. Narrow 4. Few 5. Increased 6. Decreased 7. Poor

Question 34

Matching light sensitivity of lim to color being given of by screen phosphors.

Answer 34

Spectral matching

Question 35

Calcium Tungstate gives off _____ colored lights

Answer 35

Blue

Question 36

Rare earth gives off

Answer 36

Green light

Question 37

Purpose of screens is to __1__ at is of X-rays to __2__ pt. dose. Faster screen=__3__ detail

Answer 37

1. Intensify 2. Decrease 3. Decreased

Question 38

__1__ or active layer of screens is most important because it absorbs X-rays and converts them to __2__

Answer 38

1. Phosphor | 2. Light

Question 39

__1__ of density on a radiograph is from light; __2__ is rom direct action of X-rays

Answer 39

1. 90-99% | 2. 1-10%

Question 40

Intrinsic factor that affect screen speed: 1. Phosphor size: Large=_____ 2. Phosphor type: ____ is faster than CT 3. Active layer thickness: Thicker=_____ 4. Reflective layer:_____ 5. Light Absorbing Dye: ____

Answer 40

1. Fast 2. RE 3. Faster 4. Faster 5. Slower

Question 41

If you double the screen speed, you do what to the mAs?

Answer 41

Cut in half

Question 42

If you cut the screen speed in half, you do what to the mAs?

Answer 42

Double it

Question 43

Thin sheet of lead foil on the back of the cassette is to

Answer 43

Prevent backscatter