Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HomeStretch/Numbers > HomeStretch CRACK Physics Mammo/Flouro > Flashcards

HomeStretch CRACK Physics Mammo/Flouro Flashcards

1
Q

What is the optimal keV and kVp for mammo?

A

ideal energy for mammo is 16-23 keV

to get this energy, a voltage of 25-30 kVp is used ( general Dx uses 50-120)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the target anode for mammo?

A

Moly or Rho

(gen rad uses republic of Tungsten)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the K-edge of moly? how about Rho?

A

Mo = 20 keV k edge

Rho = 21

(never use Rh target with Mo filter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

K edge filter combos (target/filter)

A

Mo/Mo

Mo/Rho

Rho/Rho (for denser breasts)

can’t use a Rho/Mo since the kedge of a Mo filter will block the characteristic xrays of Rho.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Mammo uses a focal spot of?

General X-rays use focal spot of?

A

Mammo = 0.1 and 0.3 mm

General = 0.6 and 1.2 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Spatial resolution of:

Screen film mammo?

Digital mammo?

DR?

CT?

MR?

A
  • Screen film mammo = 15 lp/mm
  • Digital mammo = 7
  • DR = 3
  • CT = 0.7
  • MR = 0.3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

FRAR version of mammo, focal spots, mA and exposure time?

A

smaller focal spots, lower mA (because of smaller focal spot and heat limits), and increased exposure time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

exit window for mammo

exit window for general x-ray?

A

mammo = beryllium for BooBs

General = glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

most testable advantage for compression in mammo?

A

dose/scatter reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Grids in mammo versus General?

A

Mammo uses a 4-5 grid ratio (general uses 6-16)

mammo bucky factor = 2 and 5 for general x-ray

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Magnification increases with?

A

Greater object to detector distance

Less source to object distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

are mag views lower or higher dose?

A

Higher, since the boob needs to get closer to source (inverse square law)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

mag view focal spot, ma and exposure time

A

mag view uses a smaller focal spot, about a quarter of the mA and about triple exposure time relative to conventional “contact” mammo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

mammo optical denstity and air kerma level relative to general x-ray?

A

mammo hhas higher opical density and higher receptor air kerma (100microGy versus 5).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Mammo

PPV1

PPV2

PPV3

A

PPV1 = cases from positive screening (ie callbacks - BR-0,3,4,5) benchmark = 4.4%

PPV2 = where biopsy is recommended (BR4,5) Benchmark = 25%

PPV3 = results of biopsy = biopsy yield malignancy = PBR (positive biopsy rate); benchmark = 31%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Mammo departments need to be “accredited and certified” every ___ years

A

3 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Who is the evil overlord behind MQSA?

A

FDA! (Boobs are food. . .)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

minimum number of megapixels on a mammo station?

A

3MP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Mammo appropriate target range for medical audit:

recall rate = ?

cancers/1000 screened?

A

recall rate = 5-7%

cancers / 1000 screened - 3 - 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Mammo QA intervals:

Processor QC:

Darkroom Cleanliness:

View box conditions:

Phantom evaluation:

Repeat analysis:

Compression test:

Darkroom Fog:

Screen-Film Contrast:

A
  • Processor QC: Daily
  • Darkroom Cleanliness: Daily
    • “process your cleanliness daily”
  • View box conditions: Weekly
  • Phantom evaluation: Weekly
    • view the phantom weekly
  • Repeat analysis: Quarterly
    • QR - repeat quarterly
  • Compression test: Semi-annually
  • Darkroom Fog: Semi-annualy
  • Screen-Film Contrast: Semi-annualy
    • compress and screen-film contrast the fog semi-annually
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Mammo privileges are bestowed upon you if you do what?

A

read 240 mammos during a 6 month period under direct supervision

3 months of formal training

60 documented hours of mammo education

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the required dose for the phantom in mammo?

A

300 millirads (3mGy) (this is measured with a grid)

1mGy is without a grid

no actual regulation for human breast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How many digital spot films = the dose of 1 minute of fluoroscopy?

A

5-10 digital spot films

24
Q

Differences between Flouro and regular Dx

A
  • Regular Dx
    • mA 200-800
    • kVp = 50 - 120
    • Very short exposure times
    • focal spot 1.0 - 1.2 mm
  • Flouro
    • mA 0-5
    • kVp = 50 - 120
    • Longer exposure times
    • focal spot 0.3 - 0.6 mm
25
Q

Flouro - in what scenario is the tube not under the patient?

Any trivia about that setup?

A

GU radiology set up (bladder close to receptor)

lens dose is higher!

26
Q

what is the scintillator used in image intensifiers?

A

CsI

27
Q

Steps in Image intensifiers

A
  • x-rays hit the input phospor (CsI)
    • xrays turned into light
  • light hits the photocathode
    • light gets converted to e-
  • e- go through electostatic focusing lens
    • this hits the output phosphor
  • converted to light
28
Q

Brightness gain

flux gain

minification gain

conversion gain

A

Brightness gain = flux X minification gain

flux gain = accelerating e- in via focusing lens = more flux gain

minification gain = reducing image size (output versus input) = increased brightness

conversion gain = effieciency of an II in changing incident x-rays into light at the output source (older I.I.s are worse and more dose!)

when conversion gain falls to 50% - get a new one

29
Q

Geometric versus electronic mag (zoom)

A

geometric = bring thing closer to x-ray source

electronic mag = decrease input field of view and keep input phosphor the same, which will decrease brightness, but the ABC kicks in

Both increase radiation (1.4-2x for electronic mag)

30
Q

for general radiology, if you increase geometric mag what do you do to sharpness?

how about in mammo?

A

resolution decreases (blurring increases)

in mammo its the opposite

(for reasons beyond the scope of these flash cards)

31
Q

What is the best position of the II and x-ray tube?

A

II very close to patient

x-ray tube distace from patient farther

32
Q

Less minification (smaller FOV) = more/less mag? = more or less bright?

A

Less minification (smaller FOV) = Magnified = Less Brightness

opposite is true

33
Q

Automatic brightness control circuit limiter max number?

A

87 mGy/min = 10 R/min

34
Q

KERMA = ?

Air KERMA = ?

Kerma-Area product = ?

What does electronic mag to air kerma and KAP?

A
  • KERMA = Kinetic Energy Release per unit Mass
    • TOTAL amount of energy deposited from ionizing radiation
  • Air KERMA = estimation of how many photons are in a unit of air prior to the energy striking the skin
  • KAP = amount of kerma X cross sectional area = Dose Area Product
    • the total radiation potentially incident on the patient
    • KAP = dose x cross-sectional area
  • Electronic mag increases Air Kerma, but dose not increase the KAP
35
Q

What is the normal air kerma limit?

What is the high level control limit?

A

87 mGy/min = 10 R/min

176 mGy/min = 20 R/min

36
Q

flouro pincusion artifact is due to ? how about S-distortion?

Flare or glare artifact?

Saturation artifact?

A

pincusion due to large FOV while S is due to earth’s magnetic field (or nearby MRI)

Flare = images become brighter with transition to less attenuation when you transition to heavy attenuation to minimal

Saturation = dose cranked up to penetrate very dense object like metal -> regions around metal very bright

37
Q

Steps in Flouro Flat panel detector

A
  • xrays go through Grid
  • hits the flat panel detector then CsI needles and turns photons into light
  • photodiode array then absorbs light and concerts to e-
  • and then e- hit read out element (transistors and gates)
38
Q

Flouro pitch

A

different that in CT

linear dimension of a detector element

39
Q

Fill factor

A

Fill factor = senstive area / pitch2

40
Q

What is binning?

A

takes several detector elements (DELs) and makes a larger DEL to reduce amount of data (reduce quantum mottle)

Key point = binning improves SNR

41
Q

What is frame averaging (recursive filtration)?

A

image process feature that adds several images together with different weight factor

improves SNR but increases motion and ghosting artifact.

42
Q

regular versus pulse flouro

which has higher mA?

at hat rate pulses / second is pulsed and regular flouro same dose?

if you decrease pulse flouro rate by 50% what percent do you decrease dose?

A

pulse flouro has higher mA

at 30 frames / second they both have same dose

50% reduction in pulse rate = 30 % reduction in dose

43
Q

Flouro spatial resolution limiting factors and actual numbers?

FDP Systems

II systems

A

FDP = Detector element size (3.0 lp/mm)

II = TV system (2.0 lp/mm and 2.0-4.0 lp/mm for angio)

44
Q

Flouro QA

How is spatial resolution tested?

How is distortion check for?

A

lead bar pattern

mesh screen or plate

45
Q

kVp for angio study (using Iodine)

kVp for Barium study?

A

70kV

>100kV

46
Q

What does increasing kVp do to dose in general radiology? how about CT?

A

decreases in gen rad

increases in CT

47
Q

What does magnification due to KAP?

A

no net change in KAP, but does increase air kerma

48
Q

What does collimation do to KAP? how about air kerma?

A

collimation decreases KAP but does nothing to peak skin dose

49
Q

When are grids used in flouro?

A

everthing BUT extremities or peds

50
Q

The dose standing 1 meter from the patient is what fraction of the dose received by the patient?

A

1/1000 of the dose received by the patient

51
Q

how much dose can lead apron decrease?

A

90%

52
Q

for flouro lateral views, where should you stand to decrease your dose?

A

side with the image receptor

53
Q

Timeline and dose for the following:

Transient erythema

Main erythema

Epilation (hair loss)

Desquamation (skin peeling)

Secondary ulcer

Dermal atrophy

Telangiectasis

Dermal necrosis

A
  • Transient erythema: 2-24 hours; 2 Gy
  • Main erythema: 2 weeks; 6 Gy
  • Epilation (hair loss): 3 weeks; 3 Gy = temporary and 7 Gy = permanent
  • Desquamation (skin peeling) = 4 weeks; Dry = 14 Gy and wet = 18 Gy
  • Secondary ulcer: > 6 weeks; 24 Gy
  • Dermal atrophy > 52 weeks; 10 Gy
  • Telangiectasis > 52 weeks; 10 Gy
  • Dermal necrosis; >52 weeks; > 12 Gy
54
Q

Dose levels that trigger follow to detect skin reactions

Peak skin dose

cumulative air kerma

KAP

flouro time

A
  • Peak skin dose = > 2Gy
  • cumulative air kerma = 5Gy
  • KAP = 500 Gy /Cm2
  • flouro time = 60 min
55
Q

a 5 second DSA gives how much times more radiation relative to conventional flouro?

A

10X

56
Q

US regulatory dose limit for a radiologist?

Limits to eyes

Lead apron thickness requirement?

Sentinal event? when to do root cause analysis?

A

50 mSv / year

US limit on eyes = 150 mSv/year while IRCP = 20 mSv/year

0.25mm thickness

cumulative dose > 1500 rads (15Gy) to a single field - root cause analysis within 45 days or fry!

HomeStretch/Numbers (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions