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RTE1613 Radiographic Physics > Unit 2 Jeopardy and Quiz questions: > Flashcards

Unit 2 Jeopardy and Quiz questions: Flashcards

1
Q

Which of the following is NOT an interaction that takes place at the anode target:

compton scatter
photoelectric
coherent scatter

A

photoelectric

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2
Q

The incident x-ray interacts with an atom without ionzing during:

A

coherent

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3
Q

Which has the greatest mass density?

A

bone

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4
Q

As kVp _________ the probability of photoelectric absorption _________

A

increases, decreases

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5
Q

Barium is a good contrast agent because of its:

A

high atomic number

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6
Q

Compton interactions, photoelectric absorption and transmitted x-rays all contribute to:

A

differential absorption

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7
Q

Which of the following is the easiest to penetrate?

bone
muscle
fat
water

A

fat

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8
Q

Increasing x-ray energy will result in:

A

fewer average photoelectric interactions

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9
Q

Which interactions involve the process of ionization?

Brems
Characteristic
Coherent scatter
Compton scatter
Photoelectric effect

A

characteristic
compton scatter
photoelectric effect

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10
Q

What is produced as a result of pair production?

A

two electrons: one positive and one negative

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11
Q

What are the other two names for Coherent scatter?

A

Classical and Thompson

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12
Q

What type of technique setting is most likely to produce a greater amount of forward scatter?

A

high kVp

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13
Q

Increased filtration has what effect on subject contrast?

A

decreases it

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14
Q

What is the name of the radiation that is produced inside the pt as a result of the photoelectric effect?

A

secondary radiation

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15
Q

Filtration has what effect on image contrast? Why?

A

increasing filtration decreases contrast bc photons that could contribute to contrast are filtered out

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16
Q

What two factors determine the trajectory of a Compton scattered photon?

A

interaction w/ valence electron
keV of photon

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17
Q

Decreases in kVp have what effect on the total amounts/percentages of Compton scatter?

A

decreases the overall interactions, but percentages of Compton increases

18
Q

What is the controlling factor of subject contrast?

A

kVp

19
Q

Which is more difficult to penetrate? Muscle or fat?

A

muscle

20
Q

A photon entering the body with 9 keV, after scattering, will produce a Coherent scatter photon with what keV value?

A

9 keV (same energy in, same out)

21
Q

What must the keV value of the incident photon be, in order for the photoelectric effect to occur?

A

must be = to or slightly greater than the keV of the valence electron

22
Q

Decreases in kVp have what effect on the total amounts/percentages of photoelectric absorption?

A

total amount of absorption decreases, absorption percentages increase

23
Q

List the 8 factors of image contrast:

A

SID
OID
filtration
collimation
computer processing (LUT)
kVp
grids
scatter

24
Q

Name two differences between Compton and Coherent scatter:

A

Compton ionizes and transfers energy which contributes to dose, Coherent does not

25
Q

What are the two names used to describe an electron that has been removed through ionization during a Compton event?

A

recoil or Compton electron

26
Q

Photons that interact with matter by way of coherent scattering usually possess a keV of less than what?

A

10 keV

27
Q

What are the four factors that affect the likelihood of the photoelectric effect?

A

kVp
body part thickness
body part density
atomic number of tissue

28
Q

Why is coherent scatter not a cause for concern when it comes to image contrast?

A

they rarely make it to the IR due to them being low in energy, so they barely contribute to noise

29
Q

What is the term for the overall reduction in image contrast that is caused by Compton scatter?

A

noise

30
Q

Which type of Compton scatter is the main source of occupational dose?

A

side

31
Q

List three factors that would lead to high subject contrast:

A

low kVp
thicker part
increased part density
high Z-number anatomy

32
Q

How would you define an “attenuated photon”

A

doesn’t reach the IR

33
Q

Why does an increase in kVp create more image noise due to Compton scatter?

A

bigger beam and greater amount of forward scatter

34
Q

What name do we use to refer to an electron that has been ionized through the process of the photoelectric effect?

A

photoelectron

35
Q

Name an exam that the “air gap” technique can be used to improve image contrast:

A

cross table hip

36
Q

What process produces subject contrast?

A

differential absorption

37
Q

kVp is the controlling factor for what?

A

subject contrast

38
Q

What is the most effective way to reduce the loss of image contrast caused by Compton scatter?

A

increase collimation

39
Q

What is the controlling factor for image contrast?

A

LUT

40
Q

Why is Compton scatter just as likely to occur in bone as it is in soft tissue?

A

electron density (increase in water)

RTE1613 Radiographic Physics (9 decks)

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