Test 2

Question 1

What does digital imaging lack compared to film-based imaging?

Answer 1

Visual Cues

Question 2

What is the goal of radiographic technique?

Answer 2

to ensure adequate signal reaches IR

Question 3

Digital imaging can compensate for ___________ fairly well, but cannot compensate for extreme ___________.

Answer 3

1.scatter
2. Quantum Mottle

Question 4

When would Quantum Mottle appear?(for all systems)

Answer 4

not enough photons reaching the IR (low mA)

Question 5

The “Margin of Error” in setting techniques=

Answer 5

Exposure Lattitude

Question 6

What is the exposure latitude for film and digital?

Answer 6

FILM: -30% - +50%
DIGITAL: -50% - +400% (LEADS TO DOSE CREEP)

Question 7

What would it take to saturate a digital image?

Answer 7

8-10x the normal exposure

Question 8

Without processing, what percent of the digital image does a CR plate lose in 8 hours?

Answer 8

25%

Question 9

Due to sensitivity, how often should CR plates be erased?

Answer 9

every 24 hours

Question 10

What are the benefits/limitations of CR?

Answer 10

Benefits: adaptability, not sensitive to light, dif. imaging plate sizes, different speed sizes
limitations: processing times, sensitive to background radiation, prone to artifacts.

Question 11

What are the benefits/limitations of DR?

Answer 11

Benefits: Consistent speed class, high compatibility with pacs, efficiency.
Limitations: single image at a time, bulky- difficult to manage

Question 12

What is considered the core of the DR system?

Answer 12

The Detector element. (DEL) . DELs capture radiation energy and transfer it into digital information

Question 13

What are the 3 parts of a DEL?

Answer 13

Detector surface – largest part of the DEL. Absorbs and captures radiation energy.
Capacitor – stores the electrical energy from the detector surface.
Thin Film Transistor (TFT) – Gateway that releases the electrical charge when the image data
is read.

Question 14

When the detector surface decreases in size:

Answer 14

1. Spatial resolution increases.
2. The capacitor and TFT cannot decrease in size.
3. Fill factor (the efficiency of the detector) decreases and technique must increase

Question 15

What does direct conversion systems use to convert x-rays into an electrical charge?

Answer 15

amorphous selenium

Question 16

What does indirect conversion systems use to convert x-rays capture the energy of light from a phosphor called CESIUM IODIDE?

Answer 16

amorphous silicon

Question 17

Would direct or indirect conversion systems have higher efficiency and lower dose?

Answer 17

indirect

Question 18

What is the core of a CR system?

Answer 18

Photostimulable Phosphors

Question 19

Barium-fluorobromide and Barium-fluorochloride crystals “doped” with:

Answer 19

europium

Question 20

In CR, what stores energy and releases light energy when stimulated by a laser beam?

Answer 20

Stimulated Phosphorescence

Question 21

Stimulated Phosphorescence gives off ___________ when struck by x-rays

Answer 21

light energy.

Question 22

CR plate is removed from the cassette and pulled into the processor
(lengthwise)

Answer 22

Slow Scan

Question 22

After 8 hours, an unprocessed PSP will lose ______ of the latent image.

Answer 22

25%

Question 23

Laser beam rapidly moves across the CR plate in rows (crosswise)

Answer 23

Fast Scan

Question 24

Light emitted by the PSP is channeled by the light channel guide to the:

Answer 24

Photomultiplier Tube

Question 25

What does the photomultiplier tube do?

Answer 25

Photomultiplier tube amplifies the light signal from the light channel guide and converts the signal into a digital signal (electrons).

Question 26

How do you erase image data from a CR plate?

Answer 26

CR plate is exposed to bright white light to erase all remaining image data and the plate is returned to the cassette.

Question 27

What does luminescence refer to?

Answer 27

Luminescence refers to any emission of light in general

Question 28

What does fluorescence refer to?

Answer 28

Fluorescence refers to the immediate emission of light under stimulation

Question 29

What is Phosphorescence?

Answer 29

phosphorescence is the delayed emission of light sometime after the original stimulus (exposure) has occurred. “glow in the dark”

Question 30

Stimulated phosphorescence requires:

Answer 30

re-stimulation

Question 31

the efficiency with which a detector can convert input exposure into an output (image).

Answer 31

Detective Quantum Efficiency (DQE)

Question 32

WEAKEST LINK in the imaging chain:

Answer 32

Display system

Question 33

Benefits of Liquid Crystal display monitors? (LCD)

Answer 33

LIGHTWEIGHT PORTABLE INEXPENSIVE GENERATE LESS HEAT LONG LIFE LESS REFLECTIVE PERFECT GEOMETRY

Question 34

What are the Limitations of LCD?

Answer 34

VIEWING ANGLE (Steradian) NO TRUE BLACK WARM-UP TIME (long – 20 – 30 minutes)

Question 35

Polarizing “lenses” that use a grid of long, slender, aligned chains of iodine molecules:

Answer 35

polarization

Question 36

if NO electrical current is applied to the pixel electrodes and light is allowed to pass thru, the pixel is in the _____ state?

Answer 36

"on"

Question 37

How is the resolution of the monochrome display monitors compared to color monitors?

Answer 37

3x higher

Question 38

How is spatial resolution of active display matrix often termed?

Answer 38

total # of pixels on entire screen. ex: 3 mega pixels

Question 39

Brightness decreases in what temperatures?

Answer 39

less than 60 degrees and higher than 80

Question 40

How is ambient lighting set in rad reading rooms?

Answer 40

2-25 lux. approx. 1/4 of the natural background light.

Question 41

What does MIMPS stand for?

Answer 41

Medical Image Management and Processing Systems

Question 42

What is Acquisition?

Answer 42

The actual imaging equipment (CR, DR, CT, MR) or a scanning device (analog to digital converter - ADC)

Question 43

A control computer (server) that directs medical images where they need to go

Answer 43

Processing

Question 44

HIS

Answer 44

Hospital Information System

Question 45

CIS

Answer 45

Clinical Information System (Site Wide) 1. Patient scheduling 2. Patient billing 3. Assigns patient number

Question 46

AIS

Answer 46

Administrative Information System (Individual department)

Question 47

RIS

Answer 47

Radiology Information System i. Assigns accession number (unique to patient, time, and exam)

Question 48

EMR

Answer 48

Electronic Medical Record (pt chart for a single institution)

Question 49

Images sent via a network to a viewing station such as the radiologist reading room, radiologist’s home, ordering physician office, or even a patient portal.

Answer 49

Display. (basic PACS system)

Question 50

Basic PACS system storage:

Answer 50

Long-term storage in an optical jukebox, RAID, or individual disk. a. Lossless compression (8:1) – Medical images b. Lossy compression (10:1) – Nonmedical images

Question 51

Common computer language so that all components of a PAC system can communicate, regardless of vendor

Answer 51

Communication Language

Question 52

DICOM

Answer 52

Digital Imaging and Communication in Medicine (standard)

Question 53

DICOM was developed by:

Answer 53

ACR AND NEMA

Question 54

Common DICOM Commands:

Answer 54

1. DICOM get worklist 2. DICOM query 3. DICOM send 4. DICOM print 5. Prefetch – pulling prior studies for comparison on radiologist’s workstation

Question 55

What is DICOM header?

Answer 55

Extensive, detailed information stored “behind the scenes” for every image

Question 56

Image data that cannot be easily seen by the end user

Answer 56

METADATA

Question 57

Data that is displayed on the image and can be seen by the end user.

Answer 57

TRUE HEADER

Question 58

common language for medical data

Answer 58

HL7

Question 59

Constant Potential Generator with little to no “voltage ripple”

Answer 59

MOBILE GENERATORS

Question 60

How is CR in relation to IR?

Answer 60

PERPENDICULAR? always?

Question 61

When checking for AIR/FLUID levels portably:

Answer 61

horizontal beam, patient as upright as possible

Question 62

½ angle between part and IR

Answer 62

Ceiszynski’s Law

Question 63

What are common grid ratios for portable exams?

Answer 63

LOW. (5:1,6:1)

Question 64

Tube to table top distance not less than (MOBILE RADIOGRAPHY)

Answer 64

30 CM. 12 INCHES

Question 65

FLOURO IMAGE INTENSIFIER COMPONENENTS:

Answer 65

Large Glass Tube ▪ Input Phosphor – Converts x-radiation to light ▪ Photocathode – Converts light into electrons (~1:200 ratio) ▪ Electrostatic Focusing Lens – Focus electron stream towards the anode and output screen. ▪ Anode – attract electrons from photocathode and accelerates them towards the output screen. ▪ Output Phosphor – Small (2.5 cm). Converts electrons into light. Image is upside down.

Question 66

Overall brightness of the fluoroscopic image is increased by two processes:

Answer 66

Minification Gain – Because the image is “minified” from the input phosphor to the output phosphor, the individual pixels are closer together and appear brighter. Flux Gain - The conversion of light photons to electrons in the photocathode results in more light photons in the output phosphor.

Question 67

magnification mode accomplishes several factors:

Answer 67

smaller region of patient anatomy is imaged. The image is magnified. Spatial resolution to that anatomical part is increased (pixels per square inch is increased). Image is dimmer due to fewer photons reaching the output phosphor. mA is automatically increased to compensate. Patient dose is increased.

Question 68

Adjusting the Field of View (FOV) by moving the focal point

Answer 68

MAGNIFICATION MODE

Question 69

Maintaining the brightness of the image to compensate for part thickness, contrast, and patient position.

Answer 69

Automatic stabilization of brightness

Question 70

Increasing the electrical signal from the output phosphor to the display monitor.

Answer 70

Automatic Gain Control

Question 71

Automatic Brightness Stabilization (ABS)

Answer 71

adjustment of the radiographic technique

Question 72

Image Intensifier Image Quality is subject to:

Answer 72

Quantum Noise. -Increase mA to compensate, *normal Ma is around 5*

Question 73

in Flouro, distortion is due to:

Answer 73

Curved input phosphor Pincushion Distortion – pronounced curve near the edges. Vignetting – brighter in the center

Question 74

Increased _________ reduces scatter production and increases contrast

Answer 74

collimation

Question 75

Image intesnifier recorder that is a small, flat plate about 1 inch in size

Answer 75

Charge-Coupled Device (CCD) Complimentary Metal-Oxide Semiconductor (CMOS)

Question 76

What is a better quality CCD has over CMOS?

Answer 76

BETTER IMAGE QUALITY

Question 77

What is an advantage for CMOS over CCD?

Answer 77

cheaper

Question 77

How are Dynamic flat-panel detectors similar detectors to DR?

Answer 77

indirect amorphous silicon direct amorphous selenium

Question 78

Matrix size for flat pannel detectors?

Answer 78

2048x2048

Question 79

What is the pulse mode called?

Answer 79

Pulsed progressive mode

Question 80

Dynamic flat panel detectors= _________ mA and SNR HIGHER/LOWER

Answer 80

HIGHER

Question 81

Dynamic flat panel detectors= ___________ distortion. MORE/LESS

Answer 81

LESS

Question 82

Dynamic flat panel detectors= _________ contrast, HIGHER/LOWER

Answer 82

HIGHER

Question 83

flouro exposure rate SHALL not be more than

Answer 83

100 mGy/minute

Question 84

flouro exposure rate SHOULD not be more than

Answer 84

50mGy/minute

Question 85

What is the purpose of the audible timer?

Answer 85

alerts the operator of a 5 min flouro time

Question 86

C-ARM Tube to Tabletop Distance not less than

Answer 86

30CM. 12 INCHES

Question 87

FIXED FLOURO SYSTEM Tube to Tabletop Distance not less than

Answer 87

38CM. 15INCHES

Question 88

What is the normal FPS rate?

Answer 88

30