Intro To Rad Unit 2

Question 1

Physics-

Answer 1

The branch of science that deals with matter and energy and their relationship to each other.

Question 2

Atom

Answer 2

smallest particle of an element that still has its properties

Question 3

Atomic Number

Answer 3

of protons in an atom
-positive charged
-determine what and where atom is on periodic table

Question 4

Atomic Mass-

Answer 4

Particles in nucleus of atoms
protons+neutrons

Question 5

Electrons-

Answer 5

Exist around nucleus in shells; determine how atom combines with other atoms

Question 6

Ionization-

Answer 6

The charging of atoms
(can be negative-gained electrons or
positive-lost electrons)

Question 7

Radiation

Answer 7

Energy transmitted by waves through space;causes ionization

Question 8

X-rays-

Answer 8

man-made ionizing radiation

Question 9

Gamma ray

Answer 9

Naturally occurring ionizing radiation given off from atoms like radioactive isotopes as they decay.

Question 10

Electromagnetic Spectrum order:

Answer 10

-x-rays
-gamma rays
-Ultra Violet
-visible light
-infra red
-radio waves

Question 11

Three ways to write the speed of light:

Answer 11

-186,000 miles/sec
-3X10^10 cm/sec
-3X10^8 m/sec

Question 12

The shorter the wavelength-

Answer 12

The more penetrating

Question 13

Sine waves

Answer 13

waves of energy

Question 14

Wave length distance is_

Answer 14

from peak to peak

Question 15

Amplitude-

Answer 15

The height of peak

Question 16

Cycle-

Answer 16

distance from peak, valley, peak, and valley

Question 17

Frequency-

the smaller the sound wave-

Answer 17

number of cycles per second
-the more penetrating

Question 18

Properties of x-rays-(12)

Answer 18

-highly penetrating
-invisible
-short wavelength
-electrically neutral
-polyenergetic/heterogenous
-liberate small amounts of heat when passing through matter
-travel in straight lines
-cause ionization
-cause fluorescence
-affect photorgraphic film
-produce secondary and scattered radiation
-produce chemical and biological changes

Question 19

Scattered radiation-

Answer 19

hits patient and changes direction

Question 20

Condition for Production:(diagnostic)

Answer 20

1. source of electrons
   2.speeding electrons up
   3.suddenly stopping electrons
2. need a glass tube

Question 21

Condition for Production (not diagnostic):

Answer 21

1. source of electrons
   2.speeding electrons up
   3.suddenly stopping electrons

Question 22

The source of electrons in a radiographic tube come from-

Answer 22

amerage(current) heats filament that causes in thermionic emission

Question 23

Thermionic emission-

Answer 23

the liberation of electrons by virtue of its own temperature

Question 24

How fast do electrons speed up in a radiographic tube?

Answer 24

half the speed of light

Question 25

The electrons are stopped in a radiographic tube by__ and results in_

Answer 25

-interaction with target -99% heat and 1% electromagnetic radiation

Question 26

Cathode-

Answer 26

the negative charged side of x-ray tube -contains 2 wires; tungsten filament

Question 27

Filament -cathode or anode?

Answer 27

2 wires made of tungsten that are the source of electrons -cathode

Question 28

Focusing cup -cathode or anode? made of?

Answer 28

negatively charged that repels electrons and concentrates the electron beam on the focal spot of the anode -cathode -made of molybdenum

Question 29

Anode- made of? (2)

Answer 29

The positive charged side of tube that has a surface called a target and a focal spot -made of tungsten and rhenium

Question 30

Tungsten is used in radiographic tube because-

Answer 30

it has a high atomic number which gives it a high melting point

Question 31

Glass envelope-

Answer 31

made of pyrex to withstand the extra high heat not directed to focal spot

Question 32

Housing- made of-

Answer 32

insulation, cooling, and protection -made of metal and lead; insulating oil

Question 33

Primary radiation-

Answer 33

radiation leaving the tube window open

Question 34

Leakage-

Answer 34

Anything leaving other parts of the tube (housing should prevent leakage)

Question 35

Attenuated-

Answer 35

Absorption and scatter; does not reach the image receptor (cassette)

Question 36

Remnant-

Answer 36

passes completely through patient and exposes image receptor; direct transmission

Question 37

mA- current-amperage

Answer 37

milliamperage-heats up the filament intensity and quantity of electrons -the higher the mA the hotter the filament

Question 38

Time(seconds)-

Answer 38

controls how long the electrons come out -expressed as a fraction or decimal -shorter exposure time for less motion

Question 39

kVp- causes-

Answer 39

-kilovoltage peak -the quality/ strength of x-ray beam; wavelength -1 kV = 1,000 volts of electricity -causes contrast of image( gray scale) -increase in kVp is shorter wavelength

Question 40

Distance(SID)-

Answer 40

;distance from tube to image; source to image distance - as distance gets further away, spatial resolution increases, magnification decreases, and image receptor exposure decreases.

Question 41

the higher the mA-

Answer 41

the hotter the filament and more xray electrons will be created( intensity and quantity) -greater image receptor exposure

Question 42

Formula for image receptor exposure-

Answer 42

mA X Time = mAs

Question 43

Inverse square law- formula?- Thumb rule-

Answer 43

- when the distance changes and you want to know what the new intensity will be ; finding intensity( R mR) -old intensity/new intensity=new distance^2/old didstance^2 ½ SID = 4 X mR* 2X SID = ¼ mR

Question 44

Why do you need more radiation for father away images?

Answer 44

due to the beam diverging and covering a larger area

Question 45

Exposure Maintenance Law- Formula-

Answer 45

used to find the new mAs technique when the SID changes and want to maintain IR exposure -mAs1/mAs2 = D1^2/D1^2

Question 46

IR exposure definition- double the mA=__ Double the time=__

Answer 46

the amount of radiation a patient receives. -double the IR exposure -double the IR exposure(increases chance of motion)

Question 47

most dense to least dense on x-ray image-(5)

Answer 47

-metal -bone -muscle -soft tissue -air

Question 47

Subject Contrast- digital or analog?

Answer 47

result of differential absorption of dif. tissues in the body due to atomic number differences and tissue thickness differences of the patient. 'digital

Question 48

Contrast resolution-

Answer 48

the ability to distinguish anatomical structures of similar subject contrast

Question 49

Gray scale-

Answer 49

how many colors we have represented -low kVP=short gray scale(black and white), high subject contrast -high kVp= long gray scale, low subject contrast

Question 50

For the 15% rule when you have too much exposure you-

Answer 50

Multiply kvp by .15 and then subtract product to the original kVp

Question 51

For the 15% rule when you have too little exposure you-

Answer 51

Multiply kVp by .15 and then add product to original kVp

Question 52

Half Value Layer-

Answer 52

The thickness of absorbing material needed to reduce the intensity of x ray beam to 1/2 it’s original value before it hits patient

Question 53

2N^2

Answer 53

N=number of shells k=2 L=8 M=18

Question 54

Heterogenous-

Answer 54

many wavelengths

Question 55

Half value layer-

Answer 55

reduces beam intensity before hitting patient

Question 56

Grid- -protects patient?

Answer 56

placed between patient and image receptor to absorb scattered or secondary radiation -to get better image NOT to protect patient

Question 57

Radioopaque- Radiolucent-

Answer 57

- absorbs x-rays(shows up white on x-rays) bone -x-ray passes through( shows up black on x-ray)

Question 58

Beam restrictors- protects patient?

Answer 58

-collimator;beam limiting device reduce scatter and secondary radiation-patient exposure decreases, subject contrast increases,

Question 59

Filtration-

Answer 59

built in tube feature that removes lower energy(long wavelengths) radiation before it reaches the patient. -lowers patient entrance exposure (ESE)

Question 60

table-

Answer 60

radiolucent and tilts 15/90

Question 61

Image receptor- CR- DR-

Answer 61

to record the image to have a permanent record - uses special cassette -uses digital sensor

Question 62

casette ID contains-

Answer 62

name, date, patient ID number, and facility name

Question 63

spatial resolution- can control by voluntary- involuntary-

Answer 63

sharpness of detail in representing the true edges of anatomy on image; how crisp edges of different bones are -communicate to get them to not move -try to use short exposure time

Question 64

The smaller the focal spot- -the limiting factor is-

Answer 64

the better the spatial resolution -heat produced by high techniques required for thick anatomy

Question 65

Umbra- Penumbra-

Answer 65

'pure shadow -blur

Question 66

Small focal spot- large focal spot-

Answer 66

small anatomy -large anatomy

Question 67

Increased SiD=

Answer 67

increased spatial resolution and decreased IR exposure

Question 68

OID-

Answer 68

distance between part being radiographed and image receptor decreased OID= increased spatial resolution

Question 69

Ideal spatial resolution-

Answer 69

-small focal spot size long SID short OID limited motion small pixel size

Question 70

Magnification-

Answer 70

size distortion; different between real size of object affected by SiD and OID

Question 71

Foreshortening- elongation-

Answer 71

- made smaller - made longer in pic