Unit 1: Target Interactions (review)

Question 1

the cathode houses the:

Answer 1

filaments and focusing cup

Question 2

the focusing cup focuses the electrons during:

Answer 2

thermionic emission

Question 3

thermionic emission:

Answer 3

the boiling off of electrons due to the heating of a small coil of thoriated tungsten wire

Question 4

electrons form a:

Answer 4

thermionic cloud or space charge

Question 5

most common type of x-ray tube failure:

Answer 5

tungsten filament vaporization

Question 6

most x-ray tubes are:

Answer 6

dual focus

Question 7

the chosen filament is heated until it becomes ______________ where electrons are then boiled off

Answer 7

incandescent

Question 8

Why does increasing kVp improve the average quality of the beam

Answer 8

increasing kVp will increase the kinetic energy/keV of the electrons, causing a higher energy photon

Question 9

Why is a tungsten target an “efficient” producer of x-ray photons?

Answer 9

it is able to dissipate heat due to high melting point and high Z number

Question 10

We use keV to discuss what?

Answer 10

kinetic energy of the incoming electron

Question 11

the production of a Brems photon involves interaction between an incident electron and what else?

Answer 11

the nucleus

Question 12

define electromotive force:

Answer 12

another term for kVp (potential difference)

Question 13

most radiographs are produced between what kVp?

Answer 13

50-120

Question 14

tube current is expressed in:

Answer 14

mA

Question 15

Bremsstrahlung x-rays occur when:

Answer 15

the incident electron is slowed down or stopped

Question 16

the “skid mark” resembles the:

Answer 16

x-ray photon that’s created

Question 17

Bremsstrahlung x-ray production is responsible for the:

Answer 17

polyenergetic nature of the beam

Question 18

K-shells have a binding energy of:

Answer 18

69 keV

Question 19

Which form of photon production involves the process of ionization?

Answer 19

characteristic

Question 20

Which portion of the primary beam is the “discrete” portion?

Answer 20

characteristic

Question 21

Characteristic x-rays result when the interaction:

Answer 21

ionizes the target atom through removal of inner-shell that causes a void and is then filled through the cascading effect

Question 22

What percentage of the primary beam will be made of characteristic photons with a kVp setting of 65?

Answer 22

none (has to be 69)

Question 23

a characteristic x-ray is characteristic because:

Answer 23

they are always 57 keV

Question 24

at 100 kVp the percentage of characteristic x-rays will be:

Answer 24

15%