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SRJC RADTECH > Intro To Radtech. X-ray Production > Flashcards

Intro To Radtech. X-ray Production Flashcards

1
Q

What are x-rays?

A

A group or rays belonging to the electromagnetic spectrum

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2
Q

Electromagnetic spectrum measures in…

A

Wavelengths and light

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3
Q

What is radioactivity?

A

Radioactivity is the process of decay.

Everything around us is radioactive

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4
Q

Sine waves travel at what speed

A

The speed of light

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5
Q

What is the speed of light?

A

186,000 miles per second

3x10^8 meters per second

3x10^10 centimeters per second

C=constant

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6
Q

EM wavelengths are measured in

A

The distance between two successive crests in a wave

Lamda

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7
Q

EM Frequency is measure in

A

The time between each crest

Nu

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8
Q

Wavelength and frequency of Em waves are

A

Inversely proportional

Speed of light = wavelength x frequency

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9
Q

What is the crest of a wave?

A

The highest point in the wave

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10
Q

What is the trough of a wave

A

The lowest point

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11
Q

The wavelength of a wave

A

Crest to crest or trough to trough or center to center.

Distance between

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12
Q

What is the wave height?

A

Distance between the crest and its neighboring trough

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13
Q

What is amplitude?

A

The amount that the wave has been displaced from its median position.

Half of the wave height

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14
Q

What is the undisturbed surface of a wave

A

The middle line of the wavelength

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15
Q

What is frequency?

A

The number of crests or troughs that pass through during a specific time interval.

Inverse of period

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16
Q

What is period?

A

.the length of time it takes to complete one cycle

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17
Q

X-Ray beams are

A

Heterogenous

Meaning different energies

Average- very short wavelength

Useful range is 0.1A through 0.5A

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18
Q

What are the two theories on properties of x-rays?

A

Wave concept

Particle concept

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19
Q

What is the wave concept on properties of x-rays

A

It explains how they move through space. And yet travel in a vacuum

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20
Q

What is the particle concept on properties of x-rays?

A

Explains how they can interact with matter as though they were particles.

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21
Q

Define mathematical constant

A
  • constant: a non-varying value
  • variable: changing value
  • constant, in a formula, usually denoted by a letter, such as c for the speed of light
  • or planck’s constant: the letter h
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22
Q

Is there a relationship between photon energy and frequency?

A
  • energy = plancks constant x frequency
  • plancks constant = 6.63x10^-34 joule-seconds

Symbol is h

As frequency increases, photon energy increases

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23
Q

Who discovered x-rays?

A

Wilhelm Conrad Roentgen

November 8, 1895

Discovered by accident

Observed by 12 other scientists previously

Roentgen identified all of the properties of x-rays less than a month after his discovery

Part of university of wurzburg

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24
Q

What is the first known medical radiograph?

A

A wrist x-ray performed on February 3, 1896 at Dartmouth college

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25
What conditions are needed for x-ray production?
* separation of electrons * high-speed electrons * sudden stopping of electrons * concentration(focusing) of electrons
26
Separation of electrons
Thermionic emission Heating of the tungsten filament Creates electron cloud aka space charge
27
All x-Ray tubes are...
Dual focus Two filaments used one at a time One wired with high voltage and one with low
28
Space charge
"Electron cloud"
29
Space charge effect
Limits the number of electrons present in the space charge Due to the negative charge on the focusing cup, forcing the electrons together In spite of the electrostatic repulsion the electrons have for each other
30
How fast do electron move?
Half of the speed of light Speed of light = 186,000 mi/sec
31
What is the focal spot?
The actual area on the anode that is struck by electrons The smaller the focal spot, the greater the spatial resolution on the resulting images
32
What is the line-focus principle?
Actual focal spot size is larger than the effective focal spot
33
Bremsstrahlung Radiation
Means braking radiation Also known as general radiation Brems makes up 100% of the primary beam If under 70 kVp and ~85% if over 70 kVp is used Caused by deceleration of "cathode rays" when they are near the nucleus of a tungsten atom of the target
34
What moves electrons?
Kinetic energy
35
What is characteristic radiation?
Up to 15% of the primary beam (if over 70 kVp) A direct hit between cathode rays and tungsten atoms Energy of radiation is characteristic of the energy shell of the tungsten atom it interacted with
36
Cathode
The negative electrode Made of two parts - tungsten filaments - nickel focusing cup (or molybdenum) Filament is heated by a separate low-voltage circuit
37
Anode
Positive electrode Made of a tungsten-rhenium alloy (some have layers of molybdenum and graphite) Circular, it rotates to dissipate heat - 3600 to 10,000 RPM
38
What are the properties of x-rays?
A. Can penetrate matter of any kind B. Electrically neutral ( not deflected by magnetic or electric field) C. They occur in a wide range of wavelengths (0.04 A to 1000 A) D. X-ray beams are heterogenous E. x-rays travel in straight lines F. Travel at the speed of light in a vacuum G. Capable of ionizing gases H. Cause fluorescence in certain crystals I. Cannot be focused by a lens J. Affect photographic film K. Produce chemical and biological changes L. Produce secondary and scattered radiation
39
Exposure rate is altered by...
Milliamerage Kilovoltage Distance Filtration
40
Milliamperage (mA)
Determines quantity of radiation Settings on panel go from 25 mA - 1500mA Increases tube current, so increases number of x-rays produced Exposure rate is directly proportional to the mA
41
What is mAs?
Milliamperage x time(in seconds) = mAs Milliampere-second
42
Kilovoltage(kV)
Determines the quality of radiation Quality is the penetrating ability of the beam. (Denotes energy of beam) • kV increases speed of electrons from cathode to anode
43
More kinetic energy of the electrons traveling from cathode to anode results in...
More x-ray energy when those electrons hot the anode
44
The 15% rule
Increasing the kVp by 15% will have the same effect (on density/brightness) as reducing the mAs to 50% Formula: kVp x 1.15; then mAs/2 KVp x 0.85; then mAs x 2
45
Inverse square law
a law stating that the intensity of an effect such as illumination or gravitational force changes in inverse proportion to the square of the distance from the source.
46
Beam quality
The penetrating ability of the beam Longer wavelengths are low kV
47
Crookes x-ray tubes (col cathode tubes) were used until
About 1920
48
What year did eastman introduce radiographic film?
1918
49
What year was the society of radiographers formed?
1920
50
When did Siegbahn receive the nobel prize in physics for x-ray spectroscopy
1924
51
What is an x-ray beam?
A group of rays belonging to the electromagnetic spectrum
52
Wavelength is?
The distance between to successive crests
53
Wave frequency is
The number of crests per second
54
Speed of light =
Wavelength x frequency
55
What is radiation
The transfer of energy in the form of particles or waves Or A relatively high-energy photon having a wavelength in the approximate range from 0.01 to 10 nanometers
56
What is an angstrom
Measurement of wavelength 1A= .1 nanometer 1 electron
57
What is a photon
The smallest amount of any type of electromagnetic radiation Also considered a bundle of energy called a quantum Travels at the speed of light, in waves in a straight path
58
Types of photons
``` X-radiation Gamma Light Radio Etc ```
59
Maximum E in a photon beam is expressed in
KVp
60
The wave equation
Wavelength= velocity/frequency
61
Characteristics of x-rays
* are invisible * are electrically neutral * have no mass * travel at the speed of light in a vacuum * cannot be optically focused * form a polyenergetic or heterogeneous * can be produced in a range of energies * travel in straight lines * can cause some substances to fluoresce * causes chemical changes in radiographic and photographic film * can penetrate the human body * can be absorbed or scattered in the human body * can produce secondary radiation * can cause damage to living tissue
62
In what year where x-rays discovered? A. 1892 B. 1895 C. 1898 D. 1901
B. 1895
63
In what year were some of the biologically damaging effects of x-rays discovered? A. 1892 B. 1895 C. 1898 D. 1901
C. 1898
64
X-rays were discovered in experiments dealing with electricity and___________? A. Ionization B. Magnetism C. Atomic structure D. Vacuum tubes
D. Vacuum tubes
65
X-rays were discovered when they caused a barium platinocyanide-coated plate to ____________? A. Fluoresce B. Phosphoresce C. Vibrate D. Vacuum tubes
A. Fluoresce
66
X-radiation is classified in which spectrum? A. Radiation B. Energy C. Atomic D. Electromagnetic
D. Electromagnetic
67
X-rays have a duel nature, which means that they behave like both _________________ A. Atoms and molecules B. Photons and quanta C. Waves and particles D. Charged and uncharged particles
C. Waves and particles
68
The wavelength and frequency of x-rays are_______________related A. Directly B. Inversely C. Partially D. Not
B. Inversely
69
X-rays have____________electrical charge A. A positive B. A negative C. An alternately positive and negative D. No
D. No
70
X-rays have__________ A. No mass B. The same mass as electrons C. The same mass as protons D. The same mass as neutrons
A. No mass
71
The x-ray beam used in diagnostic radiography can be described as being________________ A. Homogenous B. Monoenergetic C. Polyenergetic D. Scattered
C. Polyenergetic
72
The unit that measures the transfer of radiation energy into tissue is known as the____________ A. Roentgen B. REM C. Gray D. Sievert
C. Gray
73
Which of the following will minimize radiation exposure to the patient? A. Beam restriction B. Gonadal shielding C. Screening for pregnancy D. All of the above
D. All of the above

SRJC RADTECH (15 decks)

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