physics

Question 1

mammo equipment uses what 3 target (anode) materials

Answer 1

molybdenum Mo
Rhodium Rh
tungsten W

Question 2

system will choose ____ that is best for tissue type and thickness

Answer 2

the best target material

Question 3

_____ will be automatically selected by your machine based on the thickness of the breast

Answer 3

filter type

Question 4

filters are most often made of… (4)

Answer 4

molybdenum Mo
Rhodium Rh
aluminum Al
silver Ag

Question 5

_____ material is inserted into the xray beam to enhance contrast

Answer 5

filter

Question 6

2 types of filtration

Answer 6

inherent and added

Question 7

composed of parts of the xray tube and tube housing

Answer 7

inherent filtration

Question 8

thin sheets of metal inserted in the xray beam

Answer 8

added filtration

Question 9

what is exit window of tube housing made of

Answer 9

beryllium

Question 10

2 important roles of added filtration

Answer 10

removes soft energy photons which add dose
removes higher energy photons which reduce contrast

Question 11

used to absorb scatter and improve contrast

Answer 11

grid

Question 12

grids absorb ___% of scatter

Answer 12

75-85

Question 13

the ratio of the height of the lead strips to the distance between the lead strips

Answer 13

grid ratio

Question 14

high grid ratio= ______ image contrast and _____ patient dose

Answer 14

better,higher

Question 15

grid ratio in mammo

Answer 15

3:1-5:1

Question 16

2 types of grids used in mammo

Answer 16

linear/focused
honeycomb/HTC

Question 17

3 benefits from good compression

Answer 17

uniform breast thickness
reduce blurring
reduce scatter; improves contrast

Question 18

the compression paddle should not extend beyond the chest wall edge of the IR by more than __% when compressed on the average breast

Answer 18

1

Question 19

the mammo light field is controlled by

Answer 19

paddle size

Question 20

the light field will come all the way to the chest wall and not exceed any edge by more than __%

Answer 20

2

Question 21

the radiation shield must have the equivalent attenuation of at least ____ mm lead at __ kVp to limit the operator’s exposure to below __ mSv a week

Answer 21

0.08
35
1

Question 22

the area of the anode (target) bombarded by electrons. this spot never changes

Answer 22

actual focal spot

Question 23

downward projection of the actual focal spot; dependent on the steepness of the anode angle

Answer 23

effective focal spot

Question 24

the steeper the angle the _____ the effective focal spot and the ____ the detail

Answer 24

smaller, better

Question 25

mammo tubes have 2 focal spots

Answer 25

large- 0.3mm small- 0.1mm

Question 26

refers to the intensity of the xray beam which is not uniform in all portions of the beam

Answer 26

anode heel effect

Question 27

in the anode heel effect, the anode acts as a filter- we call this

Answer 27

self filtration

Question 28

the xrays toward the ____ end of the tube have more intensity because they have less of the anode to travel through. the dose will be more at this end.

Answer 28

cathode

Question 29

the xrays toward the ____ end are less intense because they have more of the anode to travel and are more absorbed. there is less dose at this end

Answer 29

anode

Question 30

in mammo the tube is moved anteriorly in the tube head (closer to the patient). lead is used to block half of the beam from the lungs

Answer 30

half field geometry

Question 31

controls the wavelength of the xray beam

Answer 31

kvp

Question 32

penetrating power

Answer 32

kvp

Question 33

influences contrast and exposure latitude

Answer 33

kvp

Question 34

average kvp in mammo

Answer 34

25-35

Question 35

a unit of radiographic exposure equal to the product of the mA and the exposure time in seconds

Answer 35

mas

Question 36

used to control the image blackening

Answer 36

ma

Question 37

typical mA selection

Answer 37

20-100

Question 38

typical time selection

Answer 38

.4-1 second

Question 39

2 types of radiation are produced when electrons hit the anode

Answer 39

characteristic, bremsstrahling

Question 40

xrays produced are confined to 2 energy spikes. the energy spikes will be determined by the anode material. this radiation is most important for determining xray beam penetration and giving up optimal contrast

Answer 40

characteristic radiation

Question 41

xrays produced with multiple energies. this is the most common type of radiation produced

Answer 41

bremsstrahling radiation

Question 42

the max permissible dose for one view of an average breast is ___mRad or __mGy

Answer 42

300 3

Question 43

the distance between the xray source and the image receptor

Answer 43

source to image distance SID

Question 44

average mammo SID

Answer 44

65-66cm

Question 45

the distance between the object to the imaging receptor

Answer 45

object to image distance OID

Question 46

an increase in OID will result in what

Answer 46

mag

Question 47

mag increases the possibility of unsharpness so we use the small focal spot to gain detail; this ____ the dose

Answer 47

increases

Question 48

3 most common mag factors

Answer 48

1.5x 2.0x 1.8x

Question 49

purpose is to ensure that mammo equipment meets FDA

Answer 49

mammography equipment evaluation MEE

Question 50

purpose is to ensure that the xray field aligns with the light field; to ensure it allows for full coverage of the IR by the xray field but does not allow significant radiation beyond its edges; to ensure that the chest wall edge of the paddle aligns with the edge of the IR.

Answer 50

collimation assessment

Question 51

how often is collimation assessment done

Answer 51

done for new units, relevant service and annually

Question 52

how often is mammography equipment evaluation MEE done

Answer 52

completed after installation of new units and relevant service

Question 53

purpose- a more detailed eval to monitor contrast delivered by detector

Answer 53

system resolution tests-modulation transfer function MTF

Question 54

to ensure that the image acquisition chain is consistently producing adequate image quality, that artifacts are not clinically significant, and that the SNR and CNR are adequate

Answer 54

artifact evaluation