Physics Flashcards

Question 1

Q

Appropriate target range for medical audit:

Recall rate?

Answer

A

4-7%

My note: Prometheus says 4-7 in one place, 5-7 in another, and “less than 10%” in another.

Question 2

Q

Appropriate target range for medical audit:

Cancers/1000 screened?

Question 3

Q

How often:

Processor QC

Question 4

Q

How often:

Darkroom Cleanliness

Question 5

Q

How often:

Viewbox Conditions?

Question 6

Q

How often:

Phantom Evaluation?

Question 7

Q

How often:

Repeat Analysis?

Answer

A

Quarterly

Question 8

Q

How often:

Compression Test?

Answer

A

Semi-Annually

Question 9

Q

How often:

Darkroom Fog?

Answer

A

Semi-Annually

Question 10

Q

How often:

Screen-Film Contrast?

Answer

A

Semi-Annually

Question 11

Q

Places that do mammo have to be “accredited and certified”…..and pay money…. every _________.

Question 12

Q

_______ is the evil overlord begins the MQSA.

Question 13

Q

Gaining the privilege to read mammograms: 3 criteria you must meet

Answer

A

1) read 240 mammography exams over 6 months during last 2 years of training, under direct supervision,
2) 3 months of mammography in residency,
3) 60 documented hours of mammo education

Question 14

Q

Spatial Resolution (mammo):

LP/mm in Anode-Cathode Direction ?

Question 15

Q

Spatial Resolution (mammo):

LP/mm in left-right Direction ?

Question 16

Q

Spatial Resolution (mammo):

MQSA resolution for screen-film: _____

Question 17

Q

Spatial Resolution (mammo):

MQSA resolution for digital: _____

Answer

A

Manufacturer specs (~ 7 LP/mm)

Question 18

Q

What is the MQSA breast dose phantom?

Answer

A

MQSA has breast phantom which is supposed to be an “average breast.”

4.2 cm of compressed breast
50% adipose, 50% glandular.

Question 19

Q

Dose for MQSA phantom

Answer

A

Phantom limit (per image)=

3 mGy (300 millirads) WITH GRID

1 mGy WITHOUT GRID.

Note: Dose limit ONLY for phantom!!! There is no regulation for dose to real human breast.

Question 20

Q

How Often:

Localization/Accuracy (for Stereotactic Biopsy)?

Answer

A

Daily before patient exams

Question 21

Q

Mammography facilities are required to provide patients with a “lay report”

what is it?
when does it need to be provided?

Answer

A

written results of the mammogram in language that is easy to understand.
within 30 DAYS of the study (MUST).

Question 22

Q

Consumer complaint mechanism is required to be established in mammography facilities to provide patients with a process for addressing their concerns.

Question 23

Q

Patients can have their ORIGINAL mammograms (not just copies) when they are needed.

Question 24

Q

If a facilities mammograms are determined to be substandard and a risk to public health, what happens?

Answer

A

Those FACILITIES will notify patients and their doctors and suggest an appropriate plan of action.

Question 25

Q

Who is ultimately responsible for the Quality Control program?

Answer

A

The “INTERPRETING PHYSICIAN”

Not the techs.

Question 26

Q

To make it (the phantom?) pass image quality, must show: _____(4 distinct things)

Answer

A

4 fibers
3 microcalcification clusters,
3 masses
only “acceptable artifacts”

Question 27

Q

Patient dose limit in mammography

Answer

A

THERE IS NONE!

Only a dose limit for phantom (3 mGy/view). But a denser real breast could require more than 3 mGy/view.

Question 28

Q

Typical patient and phantom doses (not limits).

Answer

A

~2 mGy/view

~4 mGy for a two-view screening exam

Question 29

Q

Typical (average) compressed breast is
_______ cm,
_______ % glandularity.

Answer

A

6cm,

15-20%

Question 30

Q

Digital systems generally use higher beam quality, which results in ______ doses.

Question 31

Q

Digital mammography does NOT use fixed dose (screen-film). Can use as much or as little radiation as deem appropriate.

Question 32

Q

Nukes QC: how often to check…

Constancy

(And “Dose should be within ___% of computed activity.”)

Answer

A

Daily

5% of computed activity
Checked with reference sources

Question 33

Q

Nukes QC: how often to check…

Linearity

Answer

A

Quarterly

Question 34

Q

Nukes QC: how often to check…

Accuracy

Answer

A

At installation of device AND

Annually

Question 35

Q

Nukes QC: how often to check…

Geometry

Answer

A

At installation of device AND

Any time you move device

Question 36

Q

Does it affect Spatial resolution or Contrast resolution?:

Focal spot

Answer

A

Spatial

Smaller spot= better

Question 37

Q

Does it affect Spatial resolution or Contrast resolution?:

Detector Width

Answer

A

Spatial

Smaller detector = better

Question 38

Q

Does it affect Spatial resolution or Contrast resolution?:

Nyquist Limitations “Sampling”

Answer

A

Spatial

Oversampling = better

Question 39

Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Filter

Answer

A

Spatial

Ex: bone “sharp” algorithm gives a higher spatial resolution.

Question 40

Q

Does it affect Spatial resolution or Contrast resolution?:

Number of x-rays (mAs, kV, pitch)

Answer

A

Contrast

More dose—less mottle—will improve contrast resolution

Question 41

Q

Does it affect Spatial resolution or Contrast resolution?:

Slice thickness

Answer

A

Contrast

Thicker = more x-ray quanta = less noise

Question 42

Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Method

Answer

A

Contrast

Iterative > Filtered Back

Question 43

Q

Does it affect Spatial resolution or Contrast resolution?:

Reconstruction Filter

Answer

A

Contrast

Soft tissue > bone

Question 44

Q

Choose Increase or Decrease for all:

Holding matrix size constant and DECREASING FOV will
_______ pixel size. This will
_______ spatial resolution, and
_______ contrast resolution.

Answer

A

DECREASE pixel size
INCREASE spatial resolution
DECREASE contrast resolution
(Less photons per box)

Question 45

Q

Choose Increase or Decrease for all:

Holding matrix size constant and INCREASING FOV will
_______ pixel size. This will
_______ spatial resolution, and
_______ contrast resolution.

Answer

A

INCREASE pixel size
DECREASE spatial resolution
INCREASE contrast resolution
(More photons per box)

Question 46

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Shorter pulses

Answer

A

Axial

Smaller spatial pulse length

Question 47

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Greater Damping “Low Q”

Answer

A

Axial

Shorter pulses

Question 48

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Higher frequency

Answer

A

Axial

Shorter wavelength

Question 49

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Narrowing the beam in the proximal field (adding an acoustic lens). Minimal necessary gain (gain widens the beam).
I.e. “Put the thing you want to look at in the focal zone.”

Question 50

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Phased array with multiple focal zones

Question 51

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Increasing the “line density” or lines per cm

Question 52

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Use fixed focal length across the entire surface of the array (downside is partial volume effects)

Answer

A

Elevation

Question 53

Q

Will it improve Axial, Lateral, or Elevation Resolution?:

Minimize slice thickness— done by phase excitation of the outer to inner arrays

Answer

A

Elevation

Question 54

Q

Axial Resolution is dependent on ________

Answer

A

Spatial Pulse Length

Question 55

Q

Lateral Resolution is dependent on ________

Answer

A

Transducer Element WIDTH

Question 56

Q

Elevation Resolution is dependent on ________

Answer

A

Transducer element HEIGHT

Question 57

Q

Artifacts:

Reverberation—what causes it?

Answer

A

Two parallel highly reflective surfaces

My note: looks like description might have been cut off. May want to double check not missing something

Question 58

Q

Artifacts:

Comet tail—what causes it?

Answer

A

Two parallel highly reflective surfaces —closer together (<1/2 SPL)

Question 59

Q

Artifacts:

Ring Down Artifact —what causes it?

Answer

A

Fluid trapped between tetrahedron of air bubbles

Question 60

Q

Artifacts:

Mirror Image—what causes it?

Answer

A

Trapped behind a strong reflector

My note: not sure this is complete…

Question 61

Q

Artifacts:

Reverberation—what does it look like?

Answer

A

Multiple equidistantly spaced linear reflections.

Question 62

Q

Artifacts:

Comet tail—what does it look like?

Answer

A

Triangle (comet) shaped…

Question 63

Q

Artifacts:

Ring Down Artifact—what does it look like?

Answer

A

Parallel band extending posterior to a collection of gas

Question 64

Q

Artifacts:

Mirror image—what does it look like?

Answer

A

This is almost always shown with the liver on lung.

Answer 48

A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

Answer 49

A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

Answer 50

A

DECREASED signal to noise,
INCREASED spatial resolution,
INCREASED duration of exam

Answer 51

A

INCREASED signal to noise
NO EFFECT on spatial resolution
NO EFFECT on duration of exam

Answer 52

A

DECREASED signal to noise
NO EFFECT on spatial Resolution
DECREASED duration of exam

Answer 53

A

INCREASED signal to noise,
DECREASED spatial resolution,
NO EFFECT on duration of exam

Answer 54

A

INCREASED signal to noise,
NO EFFECT spatial resolution,
INCREASED duration of exam

Answer 55

A

DECREASED signal to noise
NO EFFECT on spatial resolution
DECREASED duration of exam

Answer 56

A

Phase encoding

Answer 57

A

Frequency encoding

Answer 58

A

Both phase AND frequency encoding

Answer 59

A

Phase encoding

Answer 60

A

Phase encoding

Answer 61

A

Occurs at 55 degrees

Answer 62

A

Standing waves created as radiowave approaches length of body part

(My note: unclear if this is a cause or just trivia…they share a box in chart.)

Answer 63

A

Caused by geometric distortion or non-uniformity

Answer 64

A

Augmentation of magnetic field.

Trivia: very bad in EPI

Answer 65

A

Geometric distortion

Answer 66

A

Poor shielding

Answer 67

A

Overlap of slices

Answer 68

A

Limited sample of FID

Answer 69

A

Spinal cord

Answer 70

A

Differences in resonance frequencies

Answer 71

A

A small FOV

Answer 72

A

100 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

Answer 73

A

100 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

Answer 74

A

10 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

Answer 75

A

10 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

Answer 76

A

1 mCi

[100 mCi : Tc99m, Tl-201;
10 mCi: In-111, Ga-67;
1 mCi: I-131 ]

Answer 77

A

What: “How much Mo in the Tc?”

Tested: in a dose calibrator with lead shields

Answer 78

A

What: how much Al in the Tc?

Tested: with pH paper

Answer 79

A

What: How much free Tc?

Tested: thin layer chromatography

Answer 80

A

> 2 Gy

[ Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

Answer 81

A

1-6 weeks

[Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

Answer 82

A

Worse with higher dose. It’s possible to survive.

[Bone Marrow:
>2 Gy,
1-6 wk latent period,
Can live.]

Answer 83

A

> 8 Gy

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

Answer 84

A

5-7 days

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

Answer 85

A

Death with 2 weeks

[GI:
> 8 Gy,
5-7 day latent period,
death within 2 weeks.]

Answer 86

A

> 20-50 Gy

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

Answer 87

A

4-6 hours

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

Answer 88

A

Death within 3 days

[CNS:
> 20-50 Gy,
4-6 hour latent period,
death within 3 days.]

Answer 89

A

GI: no vomiting

Skin: no redness

Action: surveillance for 5 weeks

Answer 90

A

GI: vomiting 2-3 hours after exposure

Skin: redness 12-24 hours after

Action: surveillance for 3 weeks, consider general hospital

Answer 91

A

GI: vomiting 1-2 hours after

Skin: redness 8-15 hours after

Action: hospitalize - burn center

Answer 92

A

GI: vomiting < 1 hour after

Skin: redness 1-6 hours after

Action: hospitalize - Specialized radiation center

Answer 93

A

Equilibrium that occurs when half life of the daughter is shorter than the parent (but not by a lot).

Classic example: Moly-99 generator making Tc-99.

A transient equilibrium happens after 4 half lives (usually).

Answer 94

A

Method 1:
  -prednisone, 50 mg, PO
        -13 hours, 7 hours, 1 hour 
                    (before contrast)
  -diphen (50 mg IV) 1 hour before (can PO)

Method 2:
  -methylprednisolone, 32 mg, PO
        -12 hours, 2 hours
                    (before contrast)
  -diphen (50 mg IV) 1 hour before (can PO)

[NOTE: diphen present and EXACTLY same for ALL premeds.]

Answer 95

A

Method 1:
  -methylprednisolone, 40 mg, IV
             OR 
    hydrocortisone sod. succ., 200 mg, IV 
        -q4 until contrast 
  -diphen (50 mg IV) 1 hour before

Method 2:
*If NSAID allergy or history asthma
  -dexamethasone sodium, 7.5 mg, IV
              OR
    Betamethasone, 6 mg, IV
        -Q4 until contrast 
  -diphen (50 mg IV) 1 hour before

Method 3:

If can’t give steroids—infection, risk of bowel perforation
just diphen (50 mg IV) 1 hour before

[NOTE: diphen is present and EXACTLY same for all!]

Answer 96

A

150 mSv/yr

“(Some new papers say 20 mSv)”

Answer 97

A

50 mSv /yr

Answer 98

A

500 mSv/yr

Answer 99

A

5 mSv/yr (1 mSv to fetus directly)

Answer 100

A

0.5 mSv/MONTH

Answer 101

A

50 mSv/yr

Answer 102

A

no special handling

Surface: < 0.5 mrem/hr

1 meter: 0 mrem/hr

Answer 103

A

-special handling, yes

Surface: < 50 mrem/hr

1 meter: < 1 mrem/hr

Answer 104

A

Special handling, yes

Surface: < 200 mrem/hr

1 meter: < 10 mrem/hr

Answer 105

A

Time=TR x Phase Matrix x NEX

TR: time between each RF pulse (usu in milliseconds)

Phase Matrix: data the system collects from each phase encoding step

NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

Answer 106

A

Time=TR x Phase Matrix x NEX x # Slices!!!

[slices # is what’s different from 2D!]

TR: time between each RF pulse (usu in milliseconds)

Phase Matrix: data the system collects from each phase encoding step

NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

Answer 107

A

SMALL voxel

Answer 108

A

SMALL Field of view

Answer 109

A

LARGER matrix

Answer 110

A

THINNER slices

Answer 111

A

STRONGER magnet

Answer 112

A

LARGE slices

Answer 113

A

SMALL Matrix

Answer 114

A

SMALL Receiver Bandwidth

Answer 115

A

Appropriate

Answer 116

A

Fat Receiver Bandwidth =DECREASE SNR

Fat TRANSMIT Bandwidth = Large slice= Increased SNR

Answer 117

A

Narrow Receiver Bandwidth = INCREASED SNR

Narrow TRANSMIT Bandwidth = Small/Thin slice = DECREASED SNR