Unit 2 Jeopardy and Quiz questions:

Question 1

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

compton scatter
photoelectric
coherent scatter

Answer 1

photoelectric

Question 2

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

Answer 2

coherent

Question 3

Which has the greatest mass density?

Answer 3

bone

Question 4

As kVp _________ the probability of photoelectric absorption _________

Answer 4

increases, decreases

Question 5

Barium is a good contrast agent because of its:

Answer 5

high atomic number

Question 6

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

Answer 6

differential absorption

Question 7

Which of the following is the easiest to penetrate?

bone
muscle
fat
water

Answer 7

fat

Question 8

Increasing x-ray energy will result in:

Answer 8

fewer average photoelectric interactions

Question 9

Which interactions involve the process of ionization?

Brems
Characteristic
Coherent scatter
Compton scatter
Photoelectric effect

Answer 9

characteristic
compton scatter
photoelectric effect

Question 10

What is produced as a result of pair production?

Answer 10

two electrons: one positive and one negative

Question 11

What are the other two names for Coherent scatter?

Answer 11

Classical and Thompson

Question 12

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

Answer 12

high kVp

Question 13

Increased filtration has what effect on subject contrast?

Answer 13

decreases it

Question 14

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

Answer 14

secondary radiation

Question 15

Filtration has what effect on image contrast? Why?

Answer 15

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

Question 16

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

Answer 16

interaction w/ valence electron
keV of photon

Question 17

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

Answer 17

decreases the overall interactions, but percentages of Compton increases

Question 18

What is the controlling factor of subject contrast?

Answer 18

kVp

Question 19

Which is more difficult to penetrate? Muscle or fat?

Answer 19

muscle

Question 20

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

Answer 20

9 keV (same energy in, same out)

Question 21

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

Answer 21

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

Question 22

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

Answer 22

total amount of absorption decreases, absorption percentages increase

Question 23

List the 8 factors of image contrast:

Answer 23

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

Question 24

Name two differences between Compton and Coherent scatter:

Answer 24

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

Question 25

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

Answer 25

recoil or Compton electron

Question 26

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

Answer 26

10 keV

Question 27

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

Answer 27

kVp body part thickness body part density atomic number of tissue

Question 28

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

Answer 28

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

Question 29

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

Answer 29

noise

Question 30

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

Answer 30

side

Question 31

List three factors that would lead to high subject contrast:

Answer 31

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

Question 32

How would you define an "attenuated photon"

Answer 32

doesn't reach the IR

Question 33

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

Answer 33

bigger beam and greater amount of forward scatter

Question 34

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

Answer 34

photoelectron

Question 35

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

Answer 35

cross table hip

Question 36

What process produces subject contrast?

Answer 36

differential absorption

Question 37

kVp is the controlling factor for what?

Answer 37

subject contrast

Question 38

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

Answer 38

increase collimation

Question 39

What is the controlling factor for image contrast?

Answer 39

LUT

Question 40

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

Answer 40

electron density (increase in water)