Tech Eval exam #2

blegh

ampere is synonymous with

current

mA dictates

the quantity of the x-ray beam

exposure time is

amnt of time which the beam is activated and exposure occurs

2 seconds is how many milliseconds

2000

ma

mAs is directly proportional to

beam intensity and receptor exposure

mottle is

a grainy appearance in the image due to insufficient exposure

law of reciprocity states

as long as the product stays the same, the mA & s can be altered and still produce the same total exposure (mAs)

mA & time are what to eachother

indirectly proportional

kVp is

the measure of electrical force behind a current of electricity which causes it to flow

kVp measures the what of the x-rays

quality

how many of the photons have the peak energy

1/5

what are the 4 things required for x-ray production

source of electrons

way to focus electrons

way to speed up electrons

a way to abruptly stop or slow down electrons

kVp determines what of the electrons

how fast they accelerate across the tube

an increase in kVp means an increase in electron acceleration, this results in

an increase in the energy of the x-ray photon

an increase in the energy of the x-ray photon then dictates the

penetrability of the x-ray

2 types of x-rays created

Brimms and Chacteristic

quality =

energy/penetrating ability

kVp also has an effect on what

the quantity of the beam

how does kVp effect quantity??

an increase in kVp yields more interactions at the anode

lower kVp x-ray beams may be absorbed completly by

bone

why would bone absorb lower energy x-rays

due to calcium’s higher atomic number

different magnitude of the signal beam equals

subject contrast

a higher kVp yeilds an increase in the amount of light hitting the IR which causes contrast to

decrease

Low contrast means that there are

many shades

Long scale contrast has what type of contrast

low contrast

Short scale contrast has

major differences with high contrast and small # of shades

Long scale contrast has

slight differences with low contrast and a large # of shades

optimal kvp is

the minimum kVp required to penetrate the AOI adequately and produce the desired scale of contrast.

a lower kVp can mean what for pt dose

a higher dose

a higher kVp can mean what or pt dose

a lower dose since the mAs can decrease

KVP for hand/wrist

54

kVp for elbow/foot

60-062

kVp for ankle

64

kVp for knee

70

kVp for femur/shoulder/sinus/ribs

74-76

kVp for c-spine/t-spine

74-76

kVp for torso-abdomen/pelvis/c-spine

76-80

kVp for non-grid CXR

80

kVp for Grid CXR

110-120

kVp for iodinated contrast study

70-76

kVp for air contrast barium study

90-94

kVp for solid column barium

116-120