FINAL TQ PART II

Question 1

what are the three basic x-ray components?

Answer 1

generator

X-ray tube

control panel

Question 2

what are the two types of electricity?

Answer 2

static

current

Question 3

name this type of electricity and unit?

electric charge at rest

Answer 3

static

unit: coulombs

Question 4

name this type of electricity and unit?

moving electric charges

Answer 4

current

unit: amperes

Question 5

what law is the electric current based on?

Answer 5

ohm’s law

V=IR

Question 6

what are the two electric currents?

Answer 6

direct and alternating current

Question 7

name this defn?

flow of electrons in one direction only

Answer 7

direct current, flows in one direction only

Question 8

name this defn?

electron flow in alternating opposite directions

Answer 8

alternating current, found in wall plugs

Question 9

why are pulsating X-ray tubes not permitted?

Answer 9

not safe
poor images
hard on tube

Question 10

this X-ray component supplies electric power to the X-ray tube

Answer 10

x-ray generator

Question 11

is this a step-up or step-down transformer?

filament heating, what is the voltage?

what does electron acceleration require?

Answer 11

step down

10 V

40-150 kVp

Question 12

the x-ray generator produces what kind of current? how?

Answer 12

smooth, high voltage direct current out of low voltage AC current

transform
rectify
smooth

Question 13

changing magnetic field produces? electric field?

Answer 13

transient electric field

transient magnetic field

Question 14

what is this principle?

current flow thru one coil can cause mutual inductance in a 2nd coil wrapped around the same iron core or rod

Answer 14

basis of transformer form induced EMFs

Question 15

T/F, the step down voltage in the 2nd coil will be less than the primary circuit?

Answer 15

T

Question 16

for transformers, current flow in one direction means what for voltage?

Answer 16

positive

Question 17

for transformers, flow in the opposite direction means what for the voltage?

Answer 17

negative

Question 18

law one for transformers?

law two?

Answer 18

Np/Ns=Vp/Vs

VpIp=VsIs

N=turns
V=voltage
I=current

Question 19

T/F, a transformer can not create energy?

Answer 19

T

Question 20

the purpose of the rectification is too?

Answer 20

smooth the waves out

Question 21

what are the principle disadvantages of full wave rectification?

Answer 21

tube pulsates and anode receives dif amounts of energy

intensity of x-ray beam

quality of beam varies over each half cycle

Question 22

what does increased pt dose via soft radiation mean?

Answer 22

its bad for patient

Question 23

for best image, what type of rectification do we need?

Answer 23

filtered rectified, full wave

Question 24

name this part of the x-ray machine?

store charge quickly and release charge quickly

Answer 24

capacitor

Question 25

what types of rectified waves do pods use?

Answer 25

half wave

Question 26

name this defn? this is the variation in the voltage across the X-ray tube expressed as a percentage of its maximum value

Answer 26

ripple factor

Question 27

half wave, unfiltered is what percent? half wave, filtered? full wave, unfiltered? full wave, filtered? what do hospitals use?

Answer 27

100% 20% 100% 9% (looks best) hospitals

Question 28

how does the X-ray tube work?

Answer 28

evacuated glass envelope and CRT cathode to anode window added filtration beam limiting device

Question 29

what is important in x-ray generation? the e's conducted away/complete circuit have what units?

Answer 29

high KE e's interact with target atoms to produce photons in x-ray wavelength mA

Question 30

what is the x-ray beam comprised of?

Answer 30

polyenergetic photons made of different energies directed at the window and filter

Question 31

faster moving electrons produce what kind of wavelengths?

Answer 31

higher, shorter wavelengths

Question 32

so this concept is found on the cathodes and the idea is that electrons boil off of cil and form negatively charged electron clouds? what is this idea called

Answer 32

thermionic emission

Question 33

T/F, cathodes have high resistance to heat?

Answer 33

T

Question 34

filament circuit has what kind of current? tube current?

Answer 34

amp mA

Question 35

in the filament circuit what is the voltage, current, power? high resistance in filament causes temp to rise to how much?

Answer 35

10 V 4 amps 40 watts >2200 deg C., requires step down coils, thermionic emission of the electrons

Question 36

electrons emitted from the filament form negative cloud called a?

Answer 36

space charge

Question 37

for the space charge effect, less than what kVp is insufficient for the electrons to be pulled away from the filament keeping the charge in effect?

Answer 37

<40 kVp

Question 38

target bombarded by the electrons is called? the area/shape of the beam projected onto the patient and image receptor? what does angling do?

Answer 38

focal spot effective focal spot effective focal spot is smaller than the actual focal spot

Question 39

what are the two types of anodes?

Answer 39

rotating | stationary

Question 40

so in the anode design, name this principle? anode angled to decrease focal spot size smaller focal spot=? shallow angles=?

Answer 40

line-focus principle sharper images sharper images

Question 41

x-rays produced within the anode are attenuated as they pass out of the anode?

Answer 41

anode heel effect, more pronounced with steep anode angles with higher intensity on the cathode

Question 42

the purpose of filtration does what to the waves?

Answer 42

filters out long wavelengths and lower energy radiation hardening the beam

Question 43

required minimum total filtration for tube potential 50 to 70? under 50? above 70? *what is true total after mirror added with tube potential between 50-70?

Answer 43

1. 5 0. 5 2. 5 * 2.5

Question 44

inherent filtration can consist of?

Answer 44

glass envelope insulating oil window

Question 45

name the compensating filters?

Answer 45

wedge trough step-wedge filter

Question 46

name this type of radiation? electrons do not collide with tungsten anode atoms or their components each deflection results in a braking effect yields a photon of radiation

Answer 46

bremsstrahlung radiation

Question 47

the KE lost by electrons thru the braking effect is converted to _____?

Answer 47

photons of equivalent energy

Question 48

spikes on the curve are called? also this happens when electrons bombarding the target are able to knock out inner orbital electrons

Answer 48

characteristic radiation

Question 49

binding shell energies for the following tungsten shells? K shell L shell M shell

Answer 49

70 keV 11 keV 2 keV

Question 50

the work required to remove the electron from an atom?

Answer 50

binding energy

Question 51

name this type of radiation? positive charged tungsten anode atom returns to its normal energy state by emitting radiation in the x-ray wavelength

Answer 51

characteristic radiation