Brainscape's Knowledge GenomeTM

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


See full index

Imaging Review CCPM > mammo > Flashcards

mammo Flashcards

1
Q

mammo beam quality

A

HVL is ~0.3 mm Al

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

mammo matrix size

A

4096x6144
2 bytes/pixel
50 MB

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

mammo resolution

A

7 lp/mm

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

SID

A

65 cm

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

what does increasing breast thickness by 10 cm do to average glandular dose?

A

doubles it

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

cancer detection in mammo

A

4/1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

ACR phantom pass

A

4 fibers
3 specks
3 masses

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

mA for mammo

A

100 mA contact mammo
25 mA magnification

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

what interaction dominates in mammo?

A

PE
Compton dominates in other radiography

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

breast bipsy angles

A

+/- 15 degrees

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

mammo HVL

A

0.5 mm Al

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

grid factor factor in mammo

A

5:1 vs 10:1 for most other radiography
could also use air gao

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

focal spot in mammo

A

0.1 mm magnification mammo
0.3 mm contact mammo

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

pixel sizes mammo

A

50-100 um

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

tomosynthesis arc

A

arc is 15 degrees with image at each degree
shows lesions in given plane

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

power loading in mammo

A

3 kW contact mammo
1 kW magnification mammo
100 kW CT

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

mammo digital vs screen film resolution

A

7 lp/mm vs 12 lp/mm
-but digital mammo has better contrast resolution
-clinically they were found to be equal in efficacy

18
Q

SID effect on focal spot blur

A

reducing SID increases focal spot blur

19
Q

requirement for average glandular dose for 4.2 cm thick breast

A

<3 mGy/image with grid, <1 mGy/image without grid
-for breast with 50% glandularity
left and right breast DONT get added together into total dose
-if each breast gets 3 mGy, patient dose is 3 mGy

20
Q

size of average compressed breast

A

60 mm thick, 15% granularity

21
Q

semi-annual mammo QA items

A

dark room fog
screen-film contact
compression

22
Q

QA tests in safety code 35

A

-reproducibility
-AEC
-linearity |x1-x2|</=0.1(x1+x2)
-HVL
-max exposure rate for fluoro

23
Q

limiting factor for detecting microcalcifications

A

signal difference to noise ratio

24
Q

focal spot size deviation

A

focal spot size gets smaller away from chest wall

25
Q

why is cathode in mammo at chest wall?

A

to account for heel effect

26
Q

GRID RATIO IN MAMMO

A

4:1
material is carbon not Pb

27
Q

moving grid

A

grid moves while you acquire so you don’t get image of grid lines in image

28
Q

benefits of using compression

A

-reduce background
-reduce scatter
-reduce motion
-reduce attenuation (ie lower dose)

29
Q

pros and cons of using magnification

A

-can gain more resolution because you spread over more pixels
-results in more blurr, but can compensate by using smaller focal spot
-if you use smaller focal spot, magnification yields better MTF
-reduces scatter radiation, removes need for grid
-however smaller focal spot= longer exposure time. Can get more motion blurr

30
Q

are parrallex and crossover issues in mammo?

A

no because mammo only uses 1 screen

31
Q

entrance skin exposure in mammo

A

500-1000 mR for 4.5 cm breast
-with kV constant, increasing 1 cm in thickness requires 2x mAs and 2x skin dose

32
Q

direct amorphous Se detector

A

-no blurring
-xrays strike Se- electrons are released and travel to the detector under E field

33
Q

indirect flat panel detector

A

-CsI converts xrays to light- detected by flat panel detector
-detector elements build up charge when exposed to light

34
Q

charged coupled device

A

-light released by screen is focused onto CCD by fiber optic tapers
-visible light falls on pixel- electrons are liberated and stored in each pixel

35
Q

higher DQE, flat panels, CR, or screen film?

A

flat panels have higher DQE than CR and screen film

36
Q

formula for mammo HVL

A

HVL > kV/100+ a constant
constant is 0.03-0.3 mm

37
Q

MRI vs mammo

A

-MRI more useful than mammo for detecting invasive breast cancer
-less useful for micro-calcifications

38
Q

US vs mammo

A

US cannot detect microcalcifications. It can:
-distinguish solid lump from cyst
-guide biopsy needle
-detect met. in lymph nodes

39
Q

mammo imaging parameters

A

25-34 kVp, 100 mA, 1-2 s

40
Q

mammo power rating

A

3 kW

41
Q

In mammography, breast compression typically reduces the scatter-to-primary (i.e., unscattered) ratio from _____ to _____. A. 0.8–1.0; 0.4–0.5 B. 0.6–0.8; 0.4–0.5 C. 0.8–1.0; 0.1–0.2 D. 0.6–0.8; 0.1–0.2 E. Breast compression does not improve the scatter-to-primary ration at all, but simply serves to reduce motion blurring by immobilizing the breast.

A

0.8–1.0; 0.4–0.5
Breast compression minimizes the path length of x-rays through the breast and, therefore, reduces the likelihood of Compton scatter of the x-rays. As a result, breast compression typically reduces the scatter-to-primary ratio by about one-half, from 0.8–1.0 to 0.4–0.5, and thereby improves image contrast and lesion detectability.

Imaging Review CCPM (11 decks)

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