Quiz 6

Question 0

ejected electron with low energy & is absorbed by tissue

Answer 0

•Photoelectron

Question 1

Photoelectric

Answer 1

•total X-ray absorption/true 
absorption 
•photon enters atom & disappears 
•K/L shell electron is ejected
•ionizes inner shell of a human atom 
•positively ionized 
•reason for contrast

Question 2

Coherent unmodified scatter

Answer 2

• incident photon, of low energy, interacts with atom & excites (vibrates) electron
• vibrating gives off photon equal to energy of incident but in a different direction
• no ionization
• only happens below useful range

Question 3

Compton interaction-modified scatter

Answer 3

• ionizes outer shell
• incident photon strikes outer shell electron dislodging it causing a
• change in X-ray direction & loses energy
• main cause of fog

Question 4

Unmodified vs modified X-rays

Answer 4

• both change directions
• unmodified keeps Same X-ray energy
• modified reduces the X-ray energy

Question 5

Compton photon energy

Answer 5

• incident photon energy - the energy it took to recoil (dislodged electron)
• range 180 kV

Question 6

Increase in kV will increase or decrease Compton?

Answer 6

•decrease but cause more scatter

Question 14

Characteristic Radiation

Answer 14

• when electron is ejected next shell fills void
• the shift to fill void gives off a photon, energies are equal to incident photon
• emitts xray when outer shell electron fill inner shell void

Question 15

Coherent scatter modified or unmodified?

Answer 15

•unmodified energy does not change

Question 16

Pair production

Answer 16

• incident photon interacts with nucleus
• 2 particles are emitted from nucleus negatron (absorbed) & positron (combines with neg. electron)
• causing annihilation moving in opposite directions
• occurs 1.02mV

Question 17

Photodisintegration

Answer 17

• above 10meV
• high energy photons don’t interact with electrons but are absorbed by nucleus
• emits nuclear fragment

Question 18

What kind of radiation is produced by photoelectric effect

Answer 18

•characteristic radiation

Question 19

Bremsstrahlung

Answer 19

•Photon/electron decelerates changes direction when approaching the nucleus

Question 20

Primary X-rays produced are

Answer 20

• bremsstrahlung

* characteristic

Question 21

Importance of photoelectric effect?

Answer 21

•major factor in contrast

Question 22

Importance of Compton scatter?

Answer 22

•main cause of fog

Question 23

What type of interaction will diffidently not happen in diagnostic range

Answer 23

•pair production

Question 24

HVL-half value layer

Answer 24

• material usually metal which reduces the exposure to half the original intensity
• primarily for kV

Question 25

When are X-rays produced?

Answer 25

• electron moving from cathode to anode
• when fast moving electrons are caused to slow down & or change direction
• K or L shell electrons are knocked out & outer shell fills in vacancy

Question 26

Compton scattering unmodified or modified?

Answer 26

•modified loses energy

Question 27

What happens to molecules when we heat them up/freeze them

Answer 27

• heat they speed up

* freeze slow down

Question 28

Slip rings produce what kinda current

Answer 28

•AC current