XP Midterm

Question 1

What’s another term for SPATIAL QUALITY?

Answer 1

Geometric characteristics

Question 2

What 3 factors must be correct to produce OPTIMUM CONTRAST?

Answer 2

Film type
Film processing
Exposure factors

Question 3

Contrast is MEASURED and given a ____ value.

Answer 3

Numerical value

Question 4

How is CONTRAST determined in FILM BASED IMAGING?

Answer 4

The difference between the OBJECT + BACKGROUND.

Ratio of brightness
“OBJECT : BACKGROUND”

Question 5

How is CONTRAST determined in MAMMOGRAPHY?

Answer 5

A measured DENSITY LEVEL

Question 6

DIGITAL IMAGE CONTRAST is obtained by

Answer 6

Proper digital processing

Adjustment of the display + window

Question 7

What 2 compounds are used to ADD CONTRAST to low contrast objects in radiography?

Answer 7

Barium - high physical contrast
Iodine

*Good x-ray absorbers bc of ATOMIC # (size)

Question 8

The source of MRI contrast is

Answer 8

Proton density
T1 LONGITUDINAL relaxation time
T2 TRANSVERSE relaxation time
Fluid movement

Question 9

Do MRIs use x-rays?

Answer 9

Nope.

Uses the MAGNETIC field + radio frequency PULSES

Question 10

NOISE ___ VISIBILITY of low contrast items.

Answer 10

Reduces

Question 11

In NUCLEAR MEDICINE IMAGING, contrast depends on

Answer 11

Variation of radioactivity in a certain section of the body.

Differential uptake of the NUCLIDE + DISTRIBUTION …

Question 12

What are associated with the differential uptake of the NUCLIDE + DISTRIBUTION?

Answer 12

the PHYSIOLOGICAL function

PATHOLOGICAL conditions.

Question 13

ULTRASOUND PHYSICAL CONTRAST comes from

Answer 13

Echo made by differences in ACOUSTICAL IMPEDANCE of tissues

RBC movement

Question 14

Define “Artifacts”

Answer 14

Objects that are NOT part of the patient, but are VISIBLE on the image

Question 15

What is another term for “blur”?

Answer 15

Unsharpness

Question 16

Projection imaging is ___ + ___

Answer 16

Radiography

Flouroscopy

Question 17

Types of Tomographic Imaging

Answer 17

Tomography
CT
MRI
PET
SPECT
Ultrasound

*produce slices

Question 18

3D Imaging is COMPUTER BASED ___ + ___

Answer 18

CT

MRI

Question 19

The amount of BLURRING is dependent upon

Answer 19

Blur characteristic of imaging modality

Selection of technique factors/protocol of procedure

Question 20

____ CAMERA NUCLEAR MEDICINE produces the ____ NOISE.

Answer 20

Gamma Camera NM

Most noise

Question 21

___ produces the LEAST NOISE.

Answer 21

Plain film radiography

Question 22

Highest BLUR

Answer 22

Gamma camera nuclear medicine

Question 23

Lowest BLUR

Answer 23

Mammography

Question 24

Image noise + blur PRODUCE

Answer 24

“Curtain of invisibility”

“Window of invisibility”

Question 25

Modalities with HIGH BLUR use ____ time to produce the image.

Answer 25

Longer

Question 26

CT produces ___ or ___ of TISSUE information.

Answer 26

Voxels or | Cubes

Question 27

The ability to detect an object generally INCREASES with

Answer 27

Background brightness

Question 28

When VIEWER CONTRAST is LOW, what must the OBJECT have in order to be seen?

Answer 28

High SUBJECT contrast

Question 29

Observer contrast sensitivity is effected by

Answer 29

Glare Viewing distance Object size Background structure

Question 30

MASKING extra light from around the IMAGE can

Answer 30

Improve visibility of DETAIL

Question 31

Low contrast film (reduces/increases) NOISE?

Answer 31

Reduces

Question 32

What is the main difference between DIGITAL and FILM RADIOGRAPHY?

Answer 32

Digital Imaging doesn't have a DISTINCT or FIXED SENSITIVITY

Question 33

What is "Image Integration" used for in FLUOROSCOPY?

Answer 33

To reduce noise

Question 34

"Photon fluctuation" is dependent on

Answer 34

The photon concentration of exposure

Question 35

What are the MAJOR FACTORS that affect "Radiographic receptor sensitivity"

Answer 35

Film sensitivity Screen CONVERSION efficiency Screen ABSORPTION efficiency

Question 36

"Round Blur"

Answer 36

Intensifying screens of image intensifiers

Question 37

"Square Blur"

Answer 37

Digital imaging | *Includes CT

Question 38

"Elongation Blur"

Answer 38

Motion

Question 39

"Focal Spot Blur"

Answer 39

Various patterns

Question 40

What is the "Composite Modulation Transfer Function" used for?

Answer 40

To evaluate various components of an imaging system. It's a GRAPHICAL representation of the MODALITY BLUR.

Question 41

In order for ENERGY to be useful in imaging, what does it need to do?

Answer 41

Must be able to penetrate the body.

Question 42

What's the relationship between ENERGY and WAVELENGTH?

Answer 42

They're INVERSELY proportional

Question 43

When is the chance of PHOTON ABSORPTION greatly enhanced?

Answer 43

If it encounters matter with ELECTRON ENERGY close to that of the PHOTON.

Question 44

High energy ELECTROMAGNETIC RADIATION is measured in

Answer 44

Multiples of electron volts

Question 45

The "Radio frequency" portion of the SPECTRUM is measured in

Answer 45

Frequency

Question 46

What is a POSITRON needed for?

Answer 46

To annihilate an electron

Question 47

Electrical circuits must contain a ___ & ___ connected by CONDUCTORS.

Answer 47

Source | Load

Question 48

"Alternating current" in North America is

Answer 48

Cycles between POSITIVE and NEGATIVE flow | 60 times per SECOND

Question 49

Direct current flows in how many directions?

Answer 49

One Uno Un

Question 50

1 coulomb = ___ mAs

Answer 50

1000

Question 51

What 3 types of energy can ELECTRONS possess?

Answer 51

Kinetic energy Potential energy Rest mass

Question 52

What is "Kinetic Energy"

Answer 52

Energy in motion

Question 53

The ELECTRON is the ___ unit of mass.

Answer 53

Smallest unit

Question 54

What's the difference between the POTENTIAL ENERGY between 2 conductors?

Answer 54

The voltage

Question 55

The AMOUNT of energy TRANSFERRED depends upon what 3 things?

Answer 55

Voltage Current Duration of transfer

Question 56

Conventional "Roentgen R"

Answer 56

SI Units COULOMB/kg

Question 57

SI Unit Gray

Answer 57

Convention RAD

Question 58

SI Becquerel

Answer 58

Conventional Curie | **?

Question 59

SI Sievert

Answer 59

Conventional REM

Question 60

The "Surface Integral Exposure" (SIE) is another way of expressing

Answer 60

Total exposure to the body

Question 61

The possible STOCHASTIC RISKS of cancer relate more to ____ as opposed to Fluoroscopy.

Answer 61

The Surface Integral Exposure

Question 62

What is an alternate name for "Surface Integral Exposure"?

Answer 62

Exposure Area Product

Question 63

Why is the "R" or "Roentgen" still used?

Answer 63

* It honors the physicist that discovered x-ray * The units are CONVENIENT for MEDICAL imagining * It's the right SIZE for imaging techniques

Question 64

"Photoelectric Interactions" happen most often when? | Competition of Photons

Answer 64

Photon energy > Electron binding energy | Slightly more

Question 65

The probability of "Photoelectric Interactions" is dependent on what? (Competition of Photons)

Answer 65

Atomic # of the material

Question 66

"Compton Interactions" occur most often with | Competition of Photons

Answer 66

Electrons with LOW binding energy

Question 67

What is the "Linear Energy Transfer"?

Answer 67

The rate at which ELECTRONS transfer energy

Question 68

What is "Filtration"?

Answer 68

The SELECTIVE ATTENUATION of the photons according to their energy BEFORE entering the patient

Question 69

In terms of "Forward Scatter Radiation", the BEAM SIZE or AREA of EXPOSURE impacts what?

Answer 69

The AMOUNT of forward scatter

Question 70

In terms of "Forward Scatter Radiation", the BODY SECTION THICKNESS ____ the SIZE of what?

Answer 70

Increases the SIZE of the | SOURCE of scatter

Question 71

In terms of "Forward Scatter Radiation", scatter is MORE PENETRATING with (higher/lower) kVp.

Answer 71

Higher kVp

Question 72

In terms of "Forward Scatter Radiation", HIGHER kVp scatter contributes more to what?

Answer 72

The RADIATION penetrating the body

Question 73

In terms of "Forward Scatter Radiation", LOW kVp PHOTONS are absorbed/scatter at the ____ of the body and DOES NOT impact ____.

Answer 73

Surface of the body | Doesn't impact FORWARD SCATTER

Question 74

Photoelectric interactions occur with ___ BOUND ATOMS.

Answer 74

Tightly bound atoms

Question 75

___ + ___ increase with INCREASED kVp.

Answer 75

Compton | Forward scatter radiation

Question 76

Better scatter penetration happens when kVp is (increased/decreased)?

Answer 76

Increased

Question 77

The average range of a group of PHOTONS is ____ related to the ATTENUATION RATE (filtration).

Answer 77

Inversely related

Question 78

(Increasing/decreasing) the rate of attenuation by CHANGING PHOTON ENERGY or TYPE OF MATERIAL (increases/decreases) the average photon range.

Answer 78

Increasing the rate of attenuation | Decreases average photon range

Question 79

The average photon range is EQUAL to

Answer 79

the "Reciprocal Attenuation Coefficient"

Question 80

Average Photon Range

Answer 80

1/A.C.

Question 81

"Beam Quality"

Answer 81

The beam's ability to PENETRATE Stop humping the laser.

Question 82

What 2 things make each imaging method unique?

Answer 82

1. Tissue characteristics visible in image | 2. Viewing perspective

Question 83

What 3 things do blur affect?

Answer 83

Anatomical detail Sharpness of objects Spatial resolution