PHYSICS, BIO & PROTECTION
Who first demonstrated the fluoroscope? when?
Thomas Edison in 1898
Special wiring patterns ("wye","star","delta") used to create voltage waveforms that are placed 120 degrees out of phase wiaht one another, these voltage wafeforms are called what?
Three-phase alternating current
Adenine always bonds with ________.
Thymine
What type of cancer continues to be the main adverse health effect of the Chernobyl nuclear power accident?
Thyroid cancer
What is coast time?
Time it takes the rotor to rest after use
What is used to regulate the duration of x-ray exposure?
Timer
What is the function of a filter in diagnostic radiology?
To decrease the x-radiation dose to the patient's skin and superficial tissue
What is the purpose of x-ray beam filtration?
To filter out low energy x-ray photons. Filtration also results in lower patient dose.
27. What is the purpose of using a compensating filter?
To get a uniform picture.
What is the purpose of the autotransformer?
To vary and control the amplitude of the voltage supplied to the high-voltage step-up transformer and the filament transformer
The electron ejected during a Compton scattering interaction is called
a Compton electron (or Compton recoil electron)
List some examples of High-LET radiation:
*Alpha particles *Low-energy neutrons
The occupational effective dose limit of 50 mSv or 5 rem does NOT include:
*Background radiation *Exposure from personal medical procedures
List 4 types of radiosensitive cells:
*Basal cells of the skin *Blood cells such as lymphocytes & erythrocytes *Intestinal crypt cells *Reproductive (germ) cells
List 3 types of radioinsensitive (radioresistant) cells:
*Brain cells *Muscle cells *Nerve cells
Protective structural shielding is placed in the:
*Ceilings *Floors *Walls
List 3 examples of involuntary motion:
*Chills *Muscle spasms *Tremors
List 2 types of chromosome anomalies that have been observed at metaphase:
*Chromosome aberrations *Chromatid aberrations
List 2 types of chromosome anomalies:
*Chromosome aberrations *Chromatid aberrations
The amount of radiation dose received by a patient is usually specified in these 3 ways:
*ESE - Entrance skin exposure *Gonadal dose *GSD - Genetically significant dose
List 4 types of gonadal shielding devices:
*Flat contact shields * Clear lead shields *Shaped contact shields *Shadow shields
Radiographers receive the highest occupational exposure during:
*Fluoroscopy *Mobile radiography *Special procedures
When imaging a child, it is important to:
*Gain cooperation *Communicate *Use gonadal shielding *Collimate
Name the 3 radiation energy transfer determinants:
*LET (Linear Energy Transfer) *OER (Oxygen Enhancement Ratio *RBE (Relative Biological Effectiveness)
List 3 Radiation Energy Transfer Determinants:
*LET - Linear Energy Transfer *RBE - Relative Biological Effectiveness *OER - Oxygen Enhancement Ratio
To DECREASE patient exposure during fluoroscopic procedures, the fluoroscopist can:
*Limit the size of the fluoroscopic field to include only the area of anatomy that is of interest *Employ the practice of intermittent, or pulsed, fluoroscopy to reduce the overall length of exposure
List 2 General Categories of Radiation:
*Low-LET *High-LET
Name the 2 types of RNA:
*Messenger RNA (mRNA) *Transfer RNA (tRNA)
Avoiding repeats reduces:
*Patient exposure *Technologist exposure
List 6 functions of lipids:
*Reservoirs for long-term storage of energy *Insulate & guard body against environment *Support & protect organs *Provide essential substances necessary for growth & development *Lubricate the joints *Assist in digestive process
Name 2 types of nonlinear curves:
*Sigmoid *Linear Quadratic
List the Basic Principles of Radiation Protection for Personnel Exposure Reduction:
*Time *Distance *Shielding
Why was the Alliance for Radiation Safety in Pediatric Imaging founded?
*To increase awareness of the need to reduce patient dose for pediatric patients
these 2 organizations supply information to the (ICRP) International Commission on Radiological Protection
*UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) *NAS/NRC-BEIR (National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation)
Name the 2 types of motion:
*Voluntary *Involuntary
List 2 examples of Low-LET radiation:
*X-rays *Gamma rays
List 2 functions of salts (electrolytes):
*aid in production of energy in the cell *Aid in conduction of nerves impulses
Secondary protective barriers are barriers from:
*leakage radiation *scatter
Dose reduction in mammography can be achieved by:
*limiting the number of projections taken *doing axillary projections ONLY on request of the radiologist
Dose response curves vary in 2 basic ways:
*linear or nonlinear *threshold or non-threshold
What where some of the doses received by workers at the Chernobyl plant from the explosion?
*more than 200 people rec'd 1 Sv (100 rem) whole body EqD *2 dozen people rec'd doses greater than 4 Sv (400 rem) *approx. 1/4 million people within 200 miles rec'd 0.2 Sv (20 rem) *some individuals rec'd thyroid doses exceeding several Sieverts from drinking milk containing radioactive iodine)
List the 2 types of nucleons:
*protons (positively charged)
After receiving radiation safety counseling, the pregnant radiologist technologist must read and sign a form for these 2 reasons:
*to acknowlege that she has received counseling *to confirm that she understands the ways to implement appropriate measures to ensure safety of the embryo-fetus.
*neutrons (no charge/neutral)
...
this term means "indivisible"
...
X-rays of any given energy are more penetrating in material with __________ than in material of ____________.
...more penetrating in material with low atomic number than in material of high atomic number.
What would be considered a negligible individual annual dose?
.001 rem
What is the typical radiation dose received on an airplane flight?
.005 to .01 mSv/hr or .5 to 1 mrem/hr
Dose limit to the embryo-fetus per month
.05 rem
The maximum monthly exposure to the fetus is
.05 rem
The annual effective dose limit for education and training is _____.
.1 rem
Dose limit for hospital workers, not radiology employees but may regularly visit x-ray
.1 rem per yr.
Dose limit to the embryo-fetus for the entire gestational period.
.5 rem
General public, infrequent exposure annual dose limit
.5 rem
The maximum exposure to the fetus over the entire gestation period is ____.
.5 rem
electrical charge of a neutron
0
electrical charge of an atom
0
What is the minimum safe dose?
0 rem
When 100% of light is transmitted, the optical density equals
0.0
Optical density (OD) can range from ___ to ___
0.0, 4.0
Fog density on a processed radiograph should not exceed ___
0.1
What is the small focal spot size range?
0.1 to 1 mm
Base plus fog OD has a range of approximately ____ to ____
0.1, 0.3
According to the U.S. Public Health Service, the estimated GSD for the U.S. population is about _______.
0.20 mSv or 20 mrem
All target interactions occur within this distance of the surface of the target.
0.25 - 0.5 mm
What whole body dose delivered within a few days produces a measureable hematologic depression?
0.25 Gy
Bucky slot shielding device should be a minimum of ____mm Pb.
0.25 mm
Protective curtain for the spot film device should be a minimum of ___mm Pb.
0.25 mm
What is the common thickness of lead gloves?
0.25 mm
List 3 thicknesses of lead aprons:
0.25 mm, 0.5 mm, 1.0 mm
When 50% of the light is transmitted, the optical density equals
0.3
What is the large focal spot size range?
0.3 to 2 mm
The log relative exposure (LRE) scale is usually presented in increments of ___, with each increment equal to _____ the exposure
0.3, doubling
What is the common thickness of lead eyeglasses?
0.35 mm
A dose of this level lessens the amount of platelets in human blood:
0.5 Gy
What is the common thickness of neck & thyroid shields?
0.5 mm
The Texas requirement for lead apron thickness is:
0.5 mm Pb
This lead thickness for aprons is most common:
0.5 mm Pb
The diagnostic range of optical density is between ___ and ___ OD
0.5, 2.0
When 25% of the light is transmitted, the optical density equals
0.6
The OER of high-LET radiation is approx. equal to ___.
1
a dose of 1 gray of beta particles, gamma rays or x-rays will give you a dose equivalent to...
1 Sievert (Sv)
One electric charge equals
1 coulomb ( 6.3 x 10^18 electrons)
What is the lowest reading for an OSL?
1 mrem
1 R =
1 rad or 1 rem
Cumulative effective dose limit for occupational exposure
1 rem x age
reproductive death occurs from exposures within this range:
1 to 10 Gy
What is the usual size of the aluminum (Al) metal filter in an x-ray imaging system?
1 to 5 mm
What is the Background Equivalent Radiation Time for a Lumbar spine exam?
1 yr
What percent of projectile kinetic energy is used for the production of x-radiation?
1%
What percent voltage ripple do high-frequency generators have?
1%
What percentage of carbohydrates are contained in the cell?
1%
What percentage of nucleic acids are contained in the cell?
1%
The FDA has recommended that a notation be placed in the patient's record if a skin dose in the range of ____ is received.
1-2 Gy
List 2 sources of added filtration:
1-mm or more sheets of aluminum permanently installed in the port of the x-ray tube housing, between the housing and the collimator the collimator
With an appropriate Pb equivalent in the barrier of the control booth, exposure of the radiographer will not exceed a max allowance of:
1mSv per week
What expose time does the electronic timer allow?
1ms (0.001 second)
The most radiosensitive period during pregnancy for radiation induced congenital abnormalities is during the _______.
1st trimester
Diagnostic x-rays should scatter a MINIMUM of ___ times before reaching any area behind the control booth barrier.
2
When radiation dose is low (below 2Gy), low-LET types of radiation have an OER of about ___.
2
single-phase power has this many pulses per 1/60 sec.
2
Source to image receptor distance must be accurate within ___%.
2 %
How many filaments does a cathode assemble have?
2 -- smalll one and large one
What radiation dose may cause temporary sterility?
2 Gy
A primary protective barrier of ___ mm Pb is required for an image intensifier unit.
2 mm
What is the approximate width and length of a filament?
2 mm in diameter & 1 to 2 cm in length
What is the weekly Maximum Permissible Dose for an uncontrolled area?
2 mrem
The risk of radiation-induced leukemia in children after a substantial dose of ionizing radiation is about ____that of adults.
2 times
Approx dose for body in CT imaging
2 to 4 rad
Because the binary system is used, bit depth is express as ______
2 to the power of n
What is the Background Equivalent Radiation Time for a patient who receives a Lower GI series?
2 yrs
Effective dose from Consumer
2%
What percentage of lipids are contained in the cell?
2%
Both alignment and length and width dimensions of the radiographic and light beams must correspond to within:
2% of the SID
If a radiograph transmits 0.32% of incident light as determined with a densitometer, what is the optical density (OD)
2.49
What amount of aluminum equivalent for total permanent filtration meets the minimum requirement for mobile diagnostic and fluoroscopic equipment?
2.5 mm aluminum equivalent
Roentgen (R) is equivalent to this:
2.58 x 10^-4 c/kg
There are ______ base pairs in the human genome that are arranged into approx. ________ genes.
2.9 billion....30,000
Approximately _____ of all radiation-induced damage is believed to be ultimately caused by the hydroxyl free radical (OH*).
2/3 (two-thirds)
the number of elements that have been artificially produced in high-energy particle accelerators
20
a dose of 1 gray of alpha particles will give you a dose equivalent to...
20 Sievert (Sv)
What is the maximum permitted equivalent dose in an uncontrolled area?
20 microSv (2 mrem)
A dose of ___ rads or more to a small area of the body can cause skin erythema.
200
The Alliance for Radiation Safety in Pediatric Imaging was founded in ____
2007
How many different amino acids does protein synthesis involve?
22
most x-ray imaging systems are designed to operate on this voltage
220 V power
primary side- 200 turns; secondary side - 400 turns; primary voltage 110V; secondary voltage = ______
220V
Germ cells have ____ chromosomes, which pair up to form a full set of ____ chromosomes when a sperm fertilizes an egg cell.
23...46
Effective dose from Computed Tomography
24%
What is the usual voltage range for diagnostic x-ray systems?
25 to 150 kVp
The rate of transfer of energy from ionizing radiation used for diagnostic purposes to soft biologic tissue is estimated to be _____ keV/um.
3
When the radiation dose is high, low-LET types of radiation have an OER of about _____.
3
The FDA states that the mean dose to the glandular tissue of a 4.5 cm compressed breast using filmscreen should not exceed ______ per view.
3 mGy (300 mrad)
What is the LD 50/30 (lethal dose) for humans?
3 to 4 Gy
A diagnostic x-ray beam usually has an HVL in the range of:
3 to 5 mm Al or 3 to 6 cm of soft tissue
Approx dose for head in CT imaging
3 to 5 rad
filaments normally operate at these currents:
3 to 6 amperes (A)
the speed of light as represented by the SI system of units
3 x 10^8 m/s
the velocity of all electromagnetic radiation
3 x 10^8 m/s
the speed of light
3 x 10^8 or 186,400 miles per second
Effective Terrestrial dose
3%
What is the rating (range) for a high-voltage generator for a basic radiographic unit?
30 to 50 kW
rating for a high-voltage generator in basic radiographic units
30 to 50 kw
At what mA can either focal spot size be used?
300 mA or less
The human eye can only distinguish between about ____ shades of gray at one time
32
An anode rotates at what rpm?
3300 to 10,000 rpm
What is the speed of most rotating anodes?
3400 rpm
What is the melting point of Tungsten?
3410 celcius
What is the melting point of tungsten?
3410 degrees Celcius
The LD50/60 for humans is approx. ____rads.
350
Full-wave rectified, three-phase units provide an x-ray beam at _____ pulses per second.
360
a full wave rectified three phase generator would have how many x-ray beam pulses per second?
360
Three-phase - 6 pulse waveforms contain how many pulses per second?
360 pulses per second
Effective dose from Radon & Thoron
37%
full-wave rectified x-ray imaging systems contain at least this many diodes in the high-voltage circuit
4
Radiation-induced leukemia has a latent period of ____ years.
4 to 7
Voltage ripple of three-phase, twelve-pulse generator
4%
What percent voltage ripple does three phase, twelve pulse power have?
4%
the numeric value for Planck's constant
4.15 x 10^-15
Fetal doses greater than ____ rem have been shown to greatly increase the incidence of severe mental retardation.
40
To double the output intensity by increasing kVp, one would have to raise the kVp by as much as _____.
40%
humidity range for film storage
40-60%
At what mA should you use only the large focal spot?
400 mA
A 12-bit depth can display ____ shades of gray
4096
A normal human being has ___ different chromosomes (____ pairs) in each somatic (nonreproductive) cell.
46...23 pairs
A shield is recommended if the ovaries and uterus are less than ____cm from any edge of the field.
5 cm
What is the lowest reading for a TLD?
5 mR
Most general purpose radiographic tubes, when operated at approximately 70 kVp, produce x-ray intensities of approximately...
5 mR/mAs at a 100 cm SID
Annual effective dose limit for occupational exposure
5 rem
What radiation dose may cause permanent sterilization?
5 to 6 Gy
Effective Internal dose
5%
Effective dose from Conventional Radiography
5%
Effective dose from Space
5%
What percentage of average radiation exposure to a human is due to medical x-rays?
5%
What is the normal white blood cell count for an adult?
5,000 to 10,000/mm of blood
Annual mammograms for women over ____ is recommended.
50
In Europe, Latin America, and other parts of the world, electric current is supplied at this frequency:
50 Hz
Federal government standards, enforcing a recommendation of the NCRP, permit diagnostic imaging personnel to receive an annual occupational effective dose of _____.
50 mSv or 5 rem
Dose limit to areas of skin, hands & feet for occupational workers
50 rem
Digital image receptors can produce an acceptable diagnostic image as long as the exposure is within +/- ____ of the intended exposure
50%
The central nervous system syndrome occurs following a whole body dose of ____ rads or more.
5000
three-phase power has this many pulses per 1/60 sec.
6
What is the Background Equivalent Radiation Time for a Thoracic Spine exam?
6 months
Three -phase waveforms my have how many pulses per cycle?
6 pulses per cycle or 12 pulses per cycle
a half wave rectified single phase generator would have how many x-ray beam pulses per second?
60
In the United States, electric current is supplied at this frequency:
60 Hz
What is the current from a common wall plug?
60 Hz AC (alternating current)
The LD50/60 is the dose of radiation to the whole-body that will result in death within ____ to ____% of the irradiated population.
60 days, 50%
What is the coast time in new x-ray tube?
60 s
A 16-bit depth can display _____ shades of gray
65,536
K-Characteristic x-rays require an x-ray tube potential of at least ______
69 kVp
What is the minimum required kVp to produce characteristic radiation?
69%
Control booth barriers must extend __ ft up from the floor and be permanently secured to the floor.
7
the periods in the Periodic Table of the Elements is represented by this
7 horizontal rows
Effective dose from Interventional Fluoroscopy
7%
Three-phase - 12 pulse waveforms contain how many pulses per second?
720 pulses per second
What is the atomic number of tungsten?
74
the groups in the Periodic Table of the Elements is represented by this
8 vertical columns
The greatest risk for radiation-induced mental retardation occurs when the embryo-fetus is exposed _____ weeks after conception.
8-15 weeks
Water accounts for what percentage of protoplasm?
80% to 85%
Water constitutes what % of the body?
80% to 85%
the maximum energy for an exposure taken at 90 kVp would be ____
90 keV
the number of naturally occurring elements
92
What percent of the kinetic energy of projectile electrons is converted to heat?
99%
Effective Industrial dose
< .1%
Effective Occupational Dose
< .1%
energy range for coherent scatter
< 10 keV
Voltage ripple of high-frequency generator
<1%
_______ of the kinetic energy of electrons is converted into x-rays
<1%
symbol for atomic mass number
A
2How much kVp will you reduce when changing from a single phase to three phase equipment?
A 12% reduction
How much kVp will reduce when changing from a single phase to a high frequency equipment?
A 16% reduction
Understand continuous x-ray emission spectrum and discrete x-ray emission spectrum.
A continuous spectrum contains all possible values and a discrete spectrum contains only specific values.
What does a anode consist of?
A metal target made of a tungsten-rhenium allow embeded in a disk of molubdenum with a motor to rotate the traget.
transformers only operate on this type of current
AC
Transformers requires what type of current?
AC (alternating current)
What is the usual output of an electrical generator?
AC (alternating current)
What type of current do transformers operate on?
AC (alternating current)
an electronic device designed to terminate x-ray exposure after properly exposing an image receptor
AEC
this type of timer may not respond properly at low kVp
AEC
acronym for as low as reasonably achievable
ALARA
the rate of change of velocity with time
Acceleration
List the 3 inorganic compounds found in the body:
Acids Bases *Salts (electrolytes)
Name the 2 purines:
Adenine Guanine
List the 4 nitrogenous organic bases that compose the rungs of the ladder in a DNA macromolecule:
Adenine Guanine Cytosine Thymine
an alternative to a grid for reducing scatter and improving contrast.
Air gap technique
What does the acronym ALARA stand for?
As Low As Reasonably Achievable
What is the difference between filament current and tube current?
At low filament current, there is no tube current because the filament does not get hot enough for thermionic emission. Because of thermionic emission, a small change in filament current results in a large change in tube current.
What is the number of protons plus the number of neutrons and is represented by the letter A called?
Atomic mass
What contains protons (positive charges) and neutrons (no charge); contains most of the mass of an atom?
Atomic nucleus
What equals the number of protons in the nucleus, is represented byt the letter Z, and that determines the chemical element?
Atomic number of an atom
model of atom with a central nucleus and well defined electron orbital paths
Bohr's
In the diagnostic range, most x-rays are this type:
Bremsstrahlung
This type of x-rays have a range of energies and form a continuous emission spectrum
Bremsstrahlung
X-rays that are produced when a projectile electron is slowed by the electric field of a target atom nucleus
Bremsstrahlung
A projectile electron misses outer shell electrons in the target and moves in close to the nucleus is called what?
Bremsstrahlung (bremms) radiation
X-ray tubes used in these modalities generally have a much shorter life
CT interventional radiology
______ is a late effect of radiation exposure.
Cancer
an electrical circuit device that stores electric charge
Capacitor
6.The negative side of the x-ray tube is called ______ and has two main parts ________ and __________
Cathode, Filament, Focusing cup
This results when projectile electron interaction is sufficiently violent to ionize the target atom through total removal of an inner-shell electron.
Characteristic X-rays
These are emitted when an outer-shell electron fills an inner-shell void.
Characteristic x-rays
This type of x-rays have precisely fixed (discrete) energies and form a discrete emission spectrum.
Characteristic x-rays
What is emitted when an other-shell electron fills an inner-shell void?
Characteristic x-rays
Explain how characteristic radiation is produced?
Characteristic x-rays are emitted from heavy elements when their electrons make transitions between the lower atomic energy levels.
Who cut exposure time in half by exposing two glass plates with emulsion sides together, leading to the development of double-emulsion film?
Charles Leonard
What is energy resulting form a chemical reaction?
Chemical energy
type of chromosome anomalie that results when irradiation of individual chromatids occurs later in interphase, after DNA sythesis has taken place
Chromatid aberration
type of chromosome anomalie that results when irradiation occurs early in interphase, before DNA synthesis takes place
Chromosome aberration
Which of the 2 types of chromosome anomalies is the most detrimental?
Chromosome aberrations
List 3 types of transformers:
Closed-core transformer Autotransformer *Shell-type transformer
Which x-ray interaction with matter is not considered to be important in radiography
Coherent scattering
Which x-ray interaction with matter occurs with low-energy x-rays, causes an atom to become temporarily excited, and results in the x-ray losing no energy and changing direction less than 20 degrees
Coherent scattering
Of compton and photoelectric, even though both decrease as kV increases, which is more prevalent at higher kV?
Compton
Scatter radiation can add unwanted exposure to the radiographic image as a result of ___
Compton interactions
interactions with matter occurring in the diagnostic energy range
Compton scatter and photoelectric
Which specific scattering interaction causes an outer shell electron to be ejected from an atom
Compton scattering
What are the 3 ways to electrify an object?
Contact Friction *Induction
area occupied by workers trained in radiation safety procedures and wearing radiation monitoring devices
Controlled area
the transfer of thermal energy from one position to another by a moving fluid medium
Convection
three components of Natural environmental radiation
Cosmic rays - terrestrial radiation - internally deposited radionuclides
What are the 3 Natural sources of whole-body radiation exposure?
Cosmic rays Terrestrial radiation *Internally deposited radionuclides
type of tube Roentgen was experimenting with when he discovered x-rays
Crooke's tube
A step-down transformer is used in the filament protion of the x-ray circuit to increase what?
Current flow to the chathode
What are the 3 types of area monitoring instruments?
Cutie pie (Ionization chamber) Geiger-Muller Detector *Proportional counter
Name the 2 Pyrimidines:
Cytosine Thymine
What type of current does an x-ray tube require?
DC (direct current)
What is the prototype for mRNA?
DNA
What serves as a prototype for messenger RNA (mRNA)?
DNA
composed of two long sugar-phosphate chains, twisted in a double-helix configuration
DNA
known as the "master chemical" found mostly in the cell nucleus and contains all the information the cell needs to function; a radiation-sensitive target molecule
DNA
What are the 2 types of nucleic acids?
DNA (deoxyribonucleic acid) RNA (ribonucleic acid)
person noted as describing elements being composed of identical atoms
Dalton
HVL may be defined as the thickness of a designated absorber required to:
Decrease the intensity of the primary beam by 50% of its initial value
Lipids are also known as what ugly, 4 letter word?
Fats
Ovaries are most radiosensitive during:
Fetal growth Early childhood
steps down the voltage to approximately 12 V and provides the current to heat the filament
Filament Heating Isolation Step-down Transformer
3 areas in diagnostic imaging that provide the greatest occupational exposure to radiation for radiologic technologists
Fluoroscopy Portables *C-arm
What surrounds the filaments on three sides?
Focusing cup
What 3 things must the body provide to ensure efficient cell operation?
Food Oxygen *Water
Secondary quantities that are derived from a combination of one or more of the three base quantities
Derived Quantity
What is electron cloud?
Describe where electrons are when they go around the nucleus of an atom
an electrical device that contains two electrodes
Diode
Undirectional folw of electrons in an electrical conductor is called what?
Direct Current (DC)
Name 2 factors that do not affect radiation quality
Distance & mAs
created the Periodic Table of the Elements
Dmitri Mendeleev
his work occurred 50 yrs after Dalton's work
Dmitri Mendeleev
showed that if the elements were arranged in order of increasing atomic mass, a periodic repetition of similar chemical properties occurred
Dmitri Mendeleev
most damaging break that cuts DNA in half
Double-strand break
Planck's Quantum Equation
E = hf (where E is the photon energy, "h" is Planck's constant, and "f" is the photon frequency in hertz)
Einstein's mass-energy equivalence equation
E = mc^2
Einstein's Relativity Equation
E = mc^2 (E is the energy measured in joules, "m" is the mass measured in kilograms, and "c" is the velocity of light measured in meters per second)
develops and enforces regulations pertaining to the control of environmental radiation
EPA (Environmental Protection Agency)
TLDs are used to measure
ESE (Entrance Skin Exposure)
What does a mA meter do?
Measures tube current in milliamperes.
type of cell division in which 2 cell divisions occur and 4 daughter cells are formed
Meiosis
Who developed the Periodic Table of the Elements?
Mendeleev
List the 3 units common to the SI and MKS systems:
Meter Kilogram *Second
Intensity of radiation is measeured in what unit?
Milligray in air
Intensity of radiation is measured in what unit?
Milligray in air (also called xray quanity)
the process of somatic cell division wherein a parent cell divides to form two daughter cells identical to the parent cell
Mitosis
List the 2 types of cell division:
Mitosis Meiosis
List 3 types of carbohydrates:
Monosaccharide Disaccharides *Polysaccharides
What will happen to the KE of the projectile electron when it interacts with the tungsten atom of the target material?
Most of the KE will turn into heat
What is inducing current flow in a secondary coil by varying the current flow through a primary coil called?
Mutual induction
Name the 2 types of semiconductors:
N-type P-type
reviews ICRP recommendations and implements them into U.S. radiation protection policy
NCRP (National Council on Radiation Protection and Measurements)
What is energy resulting form the nucleus of an atom?
Nuclear energy
Neutrons and protons
Nucleons
"City Hall"; controls every organelle in the cytoplasm along with the process of cell reproduction; must function properly for a cell to accomplish its normal activities & be able to duplicate itself
Nucleus
What is the formula for average gradient
OD2 - OD1 / LRE2 - LRE1
Numerically describes the oxygen effect that states that when irradiated in an oxygenated state, biologic tissue is more sensitive to radiation than when exposed to radiation without oxygen
OER (Oxygen Enhancement Ratio)
Because radiographers produce radiographs of three-dimensional objects, some size distortion always occurs as a result of ____
OID (some part of the object is always farther away from the image receptor resulting is more size distortion)
monitors the workplace and regulates occupational exposure to radiation
OSHA (Occupational Safety and Health Administration)
Factor used to modify the shielding requirement for a particular barrier by taking into account the fraction of the x-ray unit's workload for which there is an occupancy beyond that barrier
Occupancy Factor
T represents
Occupancy factor
What rule states that the outer shell of an atom may not contain more then eight electrons?
Octet rule
What law states that voltage in the circuit is equal to the current X resistace?
Ohm's Law
describes the manner in which electric currents behave in an electric circuit
Ohm's Law
V=IR
Ohm's law
List 5 major controls on the operator's console:
On/off control kVp selection mA selection time selection *AEC
Protoplasm consists of these 2 types of compounds:
Organic Inorganic
Without oxygen, damage produced by the indirect action of radiation on a biologic molecule my be repaired, but when damage occurs through an oxygen-mediated process, the end result is permanent, or fixed.
Oxygen Fixation Hypothesis
What type of radiation is alpha particles (helium nucleus - two protons and two neutrons), and beta particles (electronlike particles emitted from the nucleus of a radioactive atom)?
Particulated radiation
Name 5 Clinical skills required by the ARRT:
Patient Care Radiation protection Equipment Operation Image Production *Radiographic Procedures
List 8 examples of voluntary motion:
Patient's age Breathing patterns Anxiety Physical or mental discomfort Excitability Fear of exam Unfavorable prognosis Mental instability
an arrangement of all known elements into rows and columns
Periodic Table of the Elements
List the 3 principal types of magnets:
Permanent magnets Electromagnets *Superconducting magnets
What is the smallest amount of any type of electromagnetic radiation, is also considered a bundle of energy called a quantum, travels at the speed of light, and travels in waves in a stright path?
Photon
the study of interactions of matter and energy in all their diverse forms
Physics
the constant of proportionality is know as this:
Planck's constant
a single-strand break in the ladderlike DNA molecular structure
Point mutation
the 2 radioactive elements discovered by Marie and Pierre Curie
Polonium and Radium
What type of charge is a proton?
Positive
What is the anode?
Positive electrode in the x-ray tube
7 Forms of Energy
Potential - Kinetic - Chemical - Electrical - Thermal - Nuclear - Electromagnetic
What is energy of position?
Potential energy
Both ____ and ____ determine the amount of magnification of the anatomic structures on an image
SID, OID
___ and ____ play an important role in minimizing the amount of size distortion
SID, OID
___________ must be done in a way to minimize occupational dose and evenly distribute occupational dose to keep individual radiation doses ALARA.
Scheduling of radiographers
barriers from leakage radiation and scatter
Secondary protective barriers
What are the two types of electromagnetic induction?
Self induction and mutual induction.
What is opposing voltage created in a conductor by passing alternating current through it called?
Self-induction
Material that may act as an insulator or conductor under different conditions called?
Semiconductor
a material that can conduct an electric current or not, depending on the voltage applied across that material
Semiconductor
SI unit of occupational dose
Sievert
the SI equivalent for rem
Sievert (Sv)
Representation of electron flow as alternating current is called what?
Sine wave
What is waves of electromatnetic radiation?
Sine waves
What is the simplest type of current, has voltage that flows as a sine wave, has voltage that begins at zero and peaks at full value a the the crest of the wave then returns to zero, reverses, and again peaks on the inverse portion of the cycle at the trough?
Single-phase, two-pulse alternating current
the mathematical or graphical description of a simple harmonic motion
Sinusoidal variation
What is added to the filaments in the cathode assembly to reduce vaporization and prolong tube life?
Small amount of thorium
List the 2 types of endoplasmic reticulum:
Smooth ER Rough ER
2 developments that transformed the use of x-rays into a valuable medical specialty
Snook transformer Coolidge tube
Stakes of wire coil through which electrical current flows, creating overlapping force field lines is called what?
Solenoid
Electron cloud near the filament is called?
Space Charge
Phenomenon of the space charge that makes it difficult for subsequent electrons to be emitted by the filament because of electrostatic repulsion is called?
Space charge effect
Quantities derived from the base quantities that are used only in specialty areas of science, such as the units used in radiologic science
Special Quantity
Transformer that decrease voltage from the primary to the secondary coil and increases current in the same proportion is called what?
Step-down transformer
Does a step-up transformer or a step-down transformer have more turns in the secondary coil than in the primary coil?
Step-up transformer
Transformer that increases voltage from the primary to the secondary coil and decreases current in the same proportion is called what?
Step-up transformer
What composes the rails of the DNA ladder?
Sugar-phosphate compounds
Name the 4 types of timing circuits:
Synchronous Electronic Timers mAs Timers *Automatic Exposure Control
Antibodies are produced when other lymphocytes in the body, known as _____________, detect the presence of molecules that do not belong to the body.
T lymphocytes
True or False: Cine procedures can result in the highest patient doses of all diagnostic procedures.
TRUE
True or False: It is important that all radiographers are conscientiously employing radiation protection practices.
TRUE
True or False: Radiographers should not be allowed to get a dose close to 5 rem annually.
TRUE
True or False: When the frame rate is higher when using cine film in fluoroscopy, the radiation dose to the patient is also higher.
TRUE
the concept that DNA is the irreplaceable master molecule that serves as the vital target necessary for the survival of the cell; if DNA dies, the cell dies
Target Theory
a mathematical relationship describing the reduction in radiation intensity with distance from a point source.
The Inverse Square Law
energy can be transformed into another form or into matter, but it cannot be created or destroyed
The Law of Conservation of Energy
the first description of an atom having a nucleus
The Rutherford atom
List 3 effects to the x-ray beam of added filtration:
a beam with higher energy greater penetrability *better quality
tube tanning
a brownish-golden film on tube glass resulting from filament vaporizing
This type of spectrum contains all possible values
a continuous spectrum
Oersted proved what?
a current produces a magnetic field
This type of spectrum contains only specific values.
a discrete spectrum
Because of thermionic emission, a small change in filament current results in this:
a large change in tube current
faraday proved what?
a magnetic field in motion could produce an electric current
A charged particle in motion creates
a magnetic field.
Who determines the specifications for protective structural shielding of radiographic imaging rooms?
a medical physicist
atoms grouped together with other atoms form this
a molecule
When does a negative charge occur?
a negative charge occurs when there are more electrons than protons
List the 3 components that form nucleotides:
a nitrogen-containing organic base a five-carbon sugar molecule (deoxyribose) *a phosphate molecule
Rutherford's experiments in 1911 showed that the atom was composed of
a nucleus with an electron cloud.
What is the sensing agent in pocket ionization chambers?
a positive and negative electrode (ion pairs)
When does a positive charge occur?
a positive charge occurs when there are fewer electrons than protons
this allows the voltage to be monitored before an exposure
a prereading kVp meter
single-phase power results in this
a pulsating x-ray beam
the electronic device that allows current flow in only one direction
a rectifier
What type of transformer is a high-voltage transformer?
a step-up transformer
a precision device designed to drive a shaft at precisely 60 revolutions per second
a synchronous motor
What is the usual form of added filtration?
a thin sheet of aluminum positioned between the protective x-ray tube housing and the x-ray beam collimator
visible light behaves like
a wave
A decrease in quantity. An increase in quality.
an increase in added filtration
An increase in quantity and quality.
an increase in kVp (voltage)
An increase in quantity. No change in quality.
an increase in mAs (current)
An increase in quantity and quality.
an increase in target atomic number
A decrease in quantity and quality.
an increase in voltage ripple
a quantum of electromagnetic energy that travels through space at the speed of light
an x-ray photon
contains considerably more energy than a visible light photon or an RF photon
an x-ray photon
Bit depth is determined by the ____
analog-to-digital converter
What is angled if an image has foreshortening
anatomic part
where radiation is made in the x-ray tube
anode
means "without oxygen"
anoxic
foreign objects such as bacteria and flu viruses
antigens
this means programmed cell death
apoptosis
What is the inherent filtration of tubes made of beryllium?
approx. 0.1 mm Al equivalent
What is the inherent filtration of a general purpose x-ray tube?
approx. 0.5 mm Al equivalent
What is the distance between the filament and the x-ray tube?
approx. 1 cm
How much does the voltage fall during capacitor discharge?
approximately 1kV/mAs
the autotransformer can be designed to step up voltage to this amount:
approximately twice the input voltage value
tungsten vaporization can cause this tube failure issue
arcing
An ___ is any unwanted image on a radiograph; something that should not have been there or is not actually part of the patients anatomy
artifact
Errors such as double exposing an image receptor or the improper use of equipment can result in image _____ and must be avoided
artifacts
For photoelectric absorption to occur, the incoming x-ray photon must be ___ to the binding energy of the inner shell electron
at least equal
Where do x-rays interact?
at the electron level, or nuclear level, ionizing an atom or ejecting a nuclear particle
Where does a pregnant radiographer wear her fetal dose monitor?
at waist level, underneath the lead apron
[a (not) + temon (cut)] and is used to describe the smallest part of the four substances of matter
atom
smallest part of an element
atom
smallest particle of an element
atom
the smallest particle of matter that has all the properties of an element
atom
sources of manmade ionizing radiation?
atomic fallout, smoke detectors, nuclear power plants, medical x-rays
sum of proton's and neutrons in an atom determine the atom's ______.
atomic mass
the way in which the mass of an atomic particle is expressed when precision is not necessary (system of whole numbers)
atomic mass units (amu)
Increasing target _____ _______ enhances the efficiency of x-ray production and the energy of characteristic and bremsstrahlung x-rays.
atomic number
protons in an atom determine the atom's _____.
atomic number
to change the discrete x-ray emission spectrum, one would need to change this
atomic number of target material
all matter is composed of this
atoms
the fundamental, complex building blocks of matter
atoms and molecules
Where is the radiographic x-ray tube located?
attached to an overhead movable crane assembly
What is the reduction in the energy or number of photons in the primary x-ray beam as it interacts with anatomic tissue
attenuation
the reduction in x-ray intensity that results from absorption and scattering
attenuation
the reduction of x-ray beam intensity because of absorption and scatter
attenuation
Creating a radiographic image by differential absorption requires that these processes occur ______, ______, and ______
attenuation, absorption, transmission
unlike charges
attract
what type of transformer has a single winding
autotransformer
The first component to receive power in the x-ray circuit is the:
autotransformer.
The slope of a straight line drawn between 2 points on the characteristic curve at ODs 0.25 and 2.0 above base and fog is called
average gradient
What is the most often used method to numerically specify image receptor contrast
average gradient
model of atom with hooks and eyes to account for chemical combination
dalton's
If you have greater voltage ripple, you will have a ____ in image quality
decrease
If you have greater voltage ripple, you will have a ____ in image quantity
decrease
effect of an increase in kVp on compton scatter
decrease
emission specturm: increase filtration
decrease amplitude and shift to right
major benefit of using high kVp
decrease patient dose
As x-ray wavelength increases, x-ray energy _____.
decreases
as the distance between the source and image increases, x-ray quantity at the image _____
decreases
as the wavelength of a photon increases, the energy of the photon ______
decreases
Increasing the pixel density and ______ the pixel pitch increases spatial resolution
decreasing
Scatter has the effect of _____ by masking the desired brightness or densities on the image and change the degree of differences
decreasing the contrast
Scatter ____ or ____ the visibility of anatomic structures
degrades, decreases
A device used to numerically determine the amount of blackness on a radiograph
densitometer
____ is the amount of overall blackness on the processed film image
density
Visibility of the recorded detail is achieved by the proper balance of _____ and _____
density (image brightness), contrast
secondary quantities that are derived from a combination of one or more of the 3 base quantities
derived quantities
this imaging modality is not a part of the electromagnetic spectrum
diagnostic ultrasound
What would be the most likely immediate response to a whole body dose of 200 rads?
diarrhea, nausea, and vomiting
The process of image formation is a result of _____ of the x-ray beam as it interacts with anatomic tissue
differential absorption
What is a process whereby some of the x-ray beam is absorbed in the tissue and some passes through the anatomic part
differential absorption
the difference in x-ray interaction by various body tissue
differential absorption
In digital imaging, the latent image is stored as ____ and must be processed by the computer for viewing on a display monitor
digital data
an electronic device that contains two electrodes
diode
rectification is accomplished with these
diodes
two poles
dipole
What is the relationship between the production of heat in the anode, x-ray tube current & kVp in the diagnostic range?
direct
Anode angle and effective focal spot size are directly or indirectly proportional?
directly
For any given radiologic examination, how is the number of x-rays that reach the image receptor related to both the x-ray tube current and the time that the tube is energized?
directly
What is the relationship between x-ray quantity and mAs?
directly proportional
Characteristic radiations have ______ emission spectrum.
discrete
___ results from the radiographic misrepresentation of either the size or shape of the anatomic part
distortion
increases in atomic number of the absorber ______ compton interactions
do not affect
Scientists use epidemiologic studies to formulate ________ estimates to predict the risk of ______ in human populations exposed to low doses of ionizing radiation.
dose-response, cancer
In the diagnostic range, a 15% increase in kVp is equivalent to _________ the mAs to obtain a given OD on the radiograph.
doubling
When did radiologists begin using film?
during World War I
During this portion of the AC waveform, the rectifier does not conduct and no electric current is allowed.
during the negative portion of the AC waveform
When does the rectifier allow electric current to pass through the x-ray tube?
during the positive portion of the AC waveform
artifact that appears as white dots or specks on a film
dust
artifact that may appear as a white line on a digital image
dust on the laser
_____ refers to the range of exposure intensities an image receptor can accurately detect
dynamic range
Ancient Greek scientists thought that all matter was composed of these 4 substances:
earth water air fire
the reason radiology is now considered a safe occupation
effective radiation protection practices
the primary difference between a proton and a neutron
electric charge
the movement of electrons between atoms
electric current
Mechanical motion produces electric current in the :
electric generator
which system of the processor powers the motors that turn the gears attached to the rollers?
electrical
Name 3 functions of the anode in an x-ray tube:
electrical conductor provides mechanical support for the target *is a good thermal dissipator
A transformer converts:
electrical potential to higher or lower intensity.
a naturally occurring force that exists all around us
electricity
form of energy created by the activity of electrons and other subatomic particles in motion
electricity
natural forces that are closely related to one another
electricity & magnetism
an object is said to be this if it has too few or too many electrons
electrified
study of moving electric charges
electrodynamics
the study of electric charges in motion
electrodynamics
a field or state of energy that is always present around us and exists over a wide range called an energy continuum
electromagnetic energy
the reduction in intensity that results from scattering and absorption
electromagnetic energy attenuation
The rotating anode is powered by __________________ ____________motor.
electromagnetic induction
a means of transferring electric potential energy form one position to another, as in a transformer
electromagnetic induction
an electric current is induced in a circuit if some part of that circuit is in a changing magnetic field defines ________
electromagnetic induction
oscillating electric and magnetic fields that travel in a vacuum with the velocity of light. Includes x-rays, gamma rays, and some nonionizing radiation (such as ultraviolet, visible, infrared, and radio waves).
electromagnetic radiation or radiation
this includes the entire range of electromagnetic energy
electromagnetic spectrum
describes how electrons are given electric potential energy (voltage) and how electrons in motion create magnetism
electromagnetism
the smallest unit of negative charge
electron
this determines how the atom reacts chemically
electron arrangement in shells
the energy required to maintain electrons in orbit about the nucleus
electron binding energy
this term is used when medical imaging systems are described
electron flow
What is increased by raising the kVp and why?
electron kinetic energy is increased because all electrons have the same mass
rotation of electrons on their axis
electron spin
a unit measurement of energy in radiology
electron volt (eV)
most exposure timers are this type and are controlled by a microprocessor
electronic timers
the most sophisticated, most complicated, and most accurate of the x-ray exposure timers
electronic timers
electrification is due to the movement of these
electrons
the smallest & lightest of the particles in an atom
electrons
the smallest units of electric charge
electrons and protons
What are cathode rays?
electrons emitted from the filament of an electronic vacuum tube (ex: an x-ray tube)
What is another term for mAs?
electrostatic charge
mAs is the same as
electrostatic charge
what part of the image intensifier accelerates electrons?
electrostatic focusing lenses
the force of attraction between unlike charges or repulsion between like charges, due to the electric field
electrostatic force
Why doesn't an electron spontaneously fly away from the nucleus of an atom?
electrostatic force of attraction, electron binding energy
study of stationary electric charges
electrostatics
the study of stationary electric charges
electrostatics
___ refers to images of objects that appear longer than the true objects
elongation
What are the two types of shape distortion
elongation, foreshortening
the atom is comprised mostly of this (similar to our solar system)
empty space
In order to create and display a radiographic image on film, an active layer or ____ is adhered to a sheet of ______
emulsion, polyester plastic
the ability to do work
energy
the ability to do work or physically influence surroundings because of position
energy
x-rays are identified by their
energy
x-rays are identified by:
energy
List 2 advantages of the addition of 1% to 2% thorium to the tungsten filament:
enhances efficiency of thermionic emission prolongs tube life
these proteins function as organic catalysts that affect the rate or speed of chemical reactions without being altered themselves
enzymatic proteins
cause an increase in cellular activity that in turn causes biochemical reactions to occur more rapidly to meet the needs of the cell
enzymes
quality control looks at ______
equipment
When the attenuated x-ray beam leaves the patient, the remaining x-ray beam is referred to as ______ or ______
exit radiation, remnant radiation
X-rays are attenuated ______ and generally reduced by approx. _____ for each 4 to 5 cm of tissue thickness
exponentially, 50%
matter that intercepts radiation and absorbs part or all of it is said to be this
exposed or irradiated
largest number of repeat exams are due to this type of artifact
exposure
motion, patient artifacts, and quantum mottle are examples of this type of artifact
exposure
how does AEC work?
exposure ends once a certain radiation level reaches the image receptor
A measurement of the amount and energy of the x-rays reaching an area of the film
exposure intensity (or intensity of radiation exposure)
What are the 2 principal measurements involved in sensitometry
exposure to the film, percentage of light transmitted through the processed film
this does not affect the rate of radioactive decay
external factors (ie. heat, high pressure, strong magnetic fields)
the time it takes to end an exposure is termed this
extinction time
a capacitor discharge system in which the exposure begins at maximum mA, and the mA drops as the anode heats.
falling-load generator
T/F: If a scattered photon strikes the image receptor it contributes useful information about the anatomic area of interest
false
T/F: If all other factors remain the same, increasing the exposure intensity will decrease the optical density
false (increasing exposure intensity will increase OD)
T/F: Quantity has more effect on the brightness of a digital image because of computer processing
false (it has less effect)
T/F: Proper film processing is not required for optimal image receptor contrast
false (it is required for optimal contrast)
T/F: A smaller bit depth allows a greater number of shades of gray to be displayed
false (larger bit depth = more shades of gray)
T/F: Fewer x-rays are needed to produce a radiographic image for a thicker anatomic part
false (more are needed for thicker, less are needed for thinner)
T/F: Radiographic images of objects are never magnified in terms of the true object size
false (they are always magnified)
T/F: Film graininess and screen structure mottle are the result of using the wrong technique
false (they are inherent to the screen-film image receptor and are not under the control of the radiographer)
The stem cells of the ovaries multiply during _______.
fetal growth
physicists use this term to describe the interactions among different energies, forces, or masses that can otherwise be described only mathematically
field
this circuit provides electrons for tube current
filament
where electrons are boiled off
filament
a step down transformer is used in what part of the circuit?
filament circuit
the focal spot selector is located in this portion of the x-ray circuit
filament circuit
where would a step down transformer be located in an x-ray circuit?
filament circuit
This controls the filament temperature
filament current
X-ray tube current is adjusted by controlling the _______ _________.
filament current
Name the 2 primary parts of the cathode:
filament focusing cup
this determines the number of electrons emitted by the filament
filament temperature
What are 5 types of image receptors
film and intensifying screens, CR cassettes, indirect DR panels, direct DR panels, fluoroscopy image intensifiers
____ refers to the distribution in size and space of silver halide grains in the film emulsion
film graininess
developed in 1898 by Thomas Edison
fluoroscopy
the production of continuous x-ray images in real time using a special x-ray imaging system, the fluoroscope, with continuous low mA
fluoroscopy
The _________ is the source of radiation in the x-ray tube.
focal spot
where electrons strike the target to make x-rays
focal spot
____ is caused by the effective size of the focal spot
focal-spot blur
what keeps the electrons together in a cloud near the filament
focusing cup
Scatter radiation creates unwanted exposure on the image called ____
fog
The development of silver grains in the film emulsion that contain no useful information
fog density
mass x distance
force
Measurement standards of work is:
force applied on an object over a distance
____ refers to images that appear shorter than the true objects
foreshortening
RF is identified by its
frequency
RF is identified by:
frequency
number of wavelengths that pass a point of observation per second
frequency
rate of rise and fall of a sine wave
frequency
the number of wavelengths passing a point per second
frequency
the number of wavelengths that pass a point of observation per second
frequency
The important properties of the sine wave model of electromagnetic energy:
frequency (f) and wavelength (represented by the Greek letter lambda)
List the 4 properties of electromagnetic energy:
frequency wavelength velocity amplitude
List the 4 properties of photons:
frequency wavelength velocity amplitude
What are the methods of electrification?
friction, contact, and induction
a form of voltage rectification that rectifies the entire AC waveform
full-wave rectification
What type of voltage generation is used in almost all stationary x-ray imaging systems?
full-wave rectification or high-frequency voltage generation
how does something become electrified?
gains excess electrons
the type of radioactivity that has no mass or charge
gamma rays
these come from inside the nucleus of a radioactive atom
gamma rays
this type of radioactivity is hard to stop
gamma rays
a specific sequence of base pairs in a chromosome
gene
device that uses mechanical motion to create electrical energy
generator
segments of DNA that serve as the basic units of heredity
genes
All our genes together are known as our ________.
genome
individual male and female reproductive cells
germ cells
In Roentgen's time, what was used instead of an image receptor?
glass plates
the primary energy source for the cell
glucose
The occupational risk for monitored radiographers may be compared with occupational risk for persons employed in other industries generally considered safe such as:
government and trade
a major source of radon
granite
Si unit of radiation in air
gray in air
In digital imaging, the number of different shades of gray that can be displayed is called
grayscale
The fewer the photons reaching the imaging receptor to form the image, the ____ the quantum mottle visible on the digital image
greater (and vice versa, more photons = less mottle)
What is the result of less voltage ripple?
greater radiation quantity and quality
How hot did the overheated coolant get in the Three Mile Island disaster?
greater than 5000 degrees F
person noted as describing atoms as being made of four different elements in varying quantities (earth, water, air, and fire)
greeks
x-ray tubes that are designed to be turned on and off very rapidly
grid-controlled tubes (ex: portable capacitor discharge imaging systems, digital radiography & cineradiography)
This timer will terminate an exposure after a prescribed time, usually approximately 6 s.
guard timer
artifact that is evenly spaced parallel to the path of film travel
guide shoe mark
In radiography, the quality of x-rays is measured by the
half value layer (HVL)
the best method for specifying x-ray quality
half value layer (HVL)
the thickness of absorbing material necessary to reduce the x-ray intensity to half of its original value
half value layer (HVL)
kink marks, static, and cassette marks are examples of this type of artifact
handling and storage
classifications of artifacts
handling/storage, processing, exposure
Adding filtration is sometimes called this because of the relative increase in average energy.
hardening the x-ray beam
What is the material that is sometimes used for special purpose tubes, such as those used in mammography?
beryllium (Z=4)
type of radioactivity that consists of a particle that is the same as an electron
beta particles
What is the turns ratio of a high-voltage transformer?
between 500:1 and 1000:1
a step up transformer is used in what part of the circuit?
between low and high voltage/between primary and secondary sides
Where is the prereading voltmeter located?
between the autotransformer and high-voltage transformer
Where is the timer located?
between the autotransformer and the high-voltage transformer
where would a step up transformer be located in an x-ray circuit
between the primary and secondary sides
as the angle of a target gets bigger, the effective focal spot will get ______
bigger
each electron shell is representative of this within the atom
binding energies of electrons
the term applied to the chemistry of the body
biochemistry
Each pixel also has a _______, or number of bits that determines the amount of precision in digitizing the analog signal and the number of grays that can be displayed in the image
bit depth
The dark densities on a processed film are created when the exposed crystals are converted to
black metallic silver
People who were employed painting radium watch dials later showed excess risk for _____ cancer.
bone
The resultant x-rays are called ______________ x-rays because they are produced by the slowing (braking) of projectile electrons.
bremsstrahlung
continuous x-ray emission spectrum is from _____ radiation
bremsstrahlung
interaction at the anode where electron interacts with nuclear field and slows
bremsstrahlung
____ is the amount of luminance (light emission) of a display monitor
brightness
Quantum mottle (noise) is visible as _____ or _____ fluctuations on the image
brightness, density
Visibility of the recorded detail refers to ____ or _____
brightness, density
Because of variations in power distribution to the hospital and in power consumption by various sections of the hospital, how much may the voltage provided to an x-ray unit vary?
by as much as 5%
How is the x-ray tube current adjusted?
by controlling the filament current
How are x-rays produced?
by the acceleration of electrons from the cathode to the anode - DC (direct current) only
How are fluoroscopic tables identified?
by their degree of tilt
velocity of electromagnetic radiation
c
The Electromagnetic Wave Equation:
c = frequency x wavelength
KE of random motion of molecules
heat
the kinetic energy of electrons is converted into mostly _____ in the x-ray tube
heat
List 3 functions of mineral salts:
help produce energy aid in conduction of nerve impulses *prevention of muscle cramping
Some radiation victims of ____ syndrome may recover completely.
hematologic
The chest is composed of tissues that vary greatly in the way they attenuate the x-ray beam, such as ribs, air filled lungs, and heart, which creates ___ subject contrast
high
A film with only a few densities that have great differences among them is said to have ____
high contrast
this increases the average energy of the beam, increasing forward scatter
high kVp techniques
What reduces quantum mottle
high mAs, low kVp, slower image receptors
what makes a good contrast agent?
high mass density, high atomic number
lose energy more rapidly than low-LET radiation because the produce much more ionization per unit of distance traveled
high-LET radiation
x-rays with high penetrability are termed this
high-quality x-rays
mA meter is located in this part of the x-ray circuit
high-voltage
responsible for increasing the output voltage from the autotransformer to the kVp necessary for x-ray production
high-voltage generator
What are the 3 parts of the high-voltage generator?
high-voltage transformer filament transformer *rectifiers
Numbers ____ than the par speed refer to fast image receptors
higher
The farther to the right a spectrum is, the ______ the effective energy or quality of the x-ray beam.
higher
The larger the area under the curve, the ______ is the x-ray ________.
higher, intensity or quantity
The x-ray beam generated by the circuit with the ________ voltage ripple has the lowest quantity and quality.
highest
Measurement standards of velocity (speed) is:
how fast an object is moving
means "low oxygen"
hypoxic
Differences in brightness or density in a radiographic image is called
image contrast
____ contributes no useful diagnostic information and serves only to detract from the quality of the image
image noise
What do you call the device that receives the radiation leaving the patient
image receptor (IR)
Greater pixel density provides ______ spatial resolution
improved
Where is the filament contained?
in the focusing cup
Where are rectifiers located?
in the high voltage section
Computer processing time, network transmission time, and digital storage space ___ as the matrix size increases
increase
emission spectrum: increasing mAs
increase amplitude
emission spectrum: increase atomic number of target material
increase amplitude and shift to right
emission spectrum: increasing kV
increase amplitude and shift to right
ways to increase efficiency of x-ray production
increase kV, increase atomic number of target material, use equipment with least voltage ripple
as voltage is _____, amperage decreases
increased
What does added filtration result in?
increased HVL
Using a radiographic grid results in:
increased contrast more gray tones on the radiograph *Increased patient dose
What is the result of increased kVp? (pg 157, 2nd paragraph)
increased quality, HVL, and a more penetrating x-ray beam
Using the magnification mode in flouroscopy _______ patient dose.
increases
When photo wavelenghts decrease what happens to photo energy?
increases
With increasing kVp, the efficiency of x-ray production does this
increases
as the frequency of a photon increases, the energy of the photon _____
increases
increases in atomic number of the absorber _____ photoelectric interactions
increases
increases in mass density of the absorber _____ Compton and Photoelectric interactions
increases
As SID ____, size distortion decreases and as SID ____, size distortion increases
increases, decreases
The efficiency of x-ray production is _______ of the tube current.
independent
Anode angel and heel effect is directly or indirectly proportional
indirectly
the ability to transfer energy from one object to another without touching
induction
the x-ray tube is an example of this type of motor
induction
consists of photons with wavelengths longer than those of visible light but shorter than those of microwaves
infrared light
When the excited outer-shell electrons return to their normal energy level, what type of radiation do they emit?
infrared radiation
sunlight contains these 2 types of invisible light:
infrared ultraviolet
List 3 types of filtration
inherent added *compensating filters
filtration of useful x-ray beams provided by the permanently installed components of an x-ray tube housing assembly and the glass window of an x-ray tube
inherent filtration
What are the 2 components of filtration of diagnostic x-ray beams?
inherent filtration added filtration
What is the principal disadvantage of a three-phase x-ray apparatus?
initial cost
the time it takes to start an exposure is termed this
initiation time
During photoelectric absorption an electron is ejected from the _____ shell and is replaced by an electron from a(n) ______ shell
inner, outer
materials that do not have any free electrons & do not make good conductors for electrical currents
insulators
determining the total number of x-rays emitted from an x-ray tube by adding together the number of x-rays emitted at each energy over the entire spectrum
integration
To reduce patient exposure, the film is placed between 2 _______, which convert the exit radiation intensities into visible light that exposes the crystals in the emulsion
intensifying screens
Where does lower-energy electromagnetic radiation interact?
interacts with molecules, cells, and larger objects in a way that will usually elevate the temperature of the object
natural metabolites such as potassium-40
internally deposited radionuclides
How are frequency and wavelength related?
inversely
How is electromagnetic energy (radiation) intensity related to the square of the distance from the source?
inversely
Latitude and contrast are ____ proportional
inversely
X-ray intensity varies _______ with the square of the distance from the x-ray tube target.
inversely
frequency is _______ proportional to wavelength
inversely
What is the relationship between x-ray energy and its wavelength?
inversely proportional
at a given velocity, wavelength and frequency are:
inversely proportional
for electromagnetic energy, frequency and wavelength are:
inversely proportional
electron removed from atom and atom it originated from
ion pair
the ejected electron and the resultant positively charged atom
ion pair
What is the actual giving up or taking on of electrons causing the atom to assume a net charge (positive or negative)
ionization
The negative side of the x-ray tube is called ______ and has two main parts __________ and __________.
cathode, filament, focusing cup
The smallest unit of protoplasm capable of independent existence is the ______.
cell
Name some uses of microwaves:
cell phone communication highway speed monitoring medical diathermy hot dog preparation
What was substituted for glass when radiologists began using film?
cellulose nitrate
removal of an electron from an atom
ionization
the removal of an electron from an atom
ionization
pairs of small, hollow, cylindrical structures believed to play a part in the formation of the mitotic spindle during cell division; contain the centrioles
centrosomes
prupose of a transformer
change electric potential intensities
Faraday's experiments proved that a current could be induced by a magnetic field only if the field is:
changing.
discrete portion of x-ray emission spectrum is from _____ radiation
characteristic
interaction at the anode where electron interacts with inner shell electron
characteristic
two interactions that occur at the anode to produce radiation
characteristic and bremsstrahlung
The relationship between optical density and radiation exposure is called
characteristic curve
new substance that is formed when two or more atoms of different elements combine
chemical compound
The Z number determines this about the atom
chemical element
Low doses of radiation have been shown to cause _________.
chromosome damage
tiny rod-shaped bodies composed of protein and DNA
chromosomes
interaction where no ionization takes place and results in an atom releasing an energy photon of equal energy in a different direction
coherent
no ionization takes place in which of the radiation interactions with matter
coherent
five interactions in matter
coherent scatter, compton scatter, photoelectric absorption, pair production, photodisintegration
the procedure of confining the x-ray beam to the area of anatomic interest to limit patient radiation dose
collimation
List 8 physical properties of elements that describe the material as it is
color brittleness malleability electrical conductivity density hardness melting & boiling temperature tendency to dissolve in liquids
unit of electric charge
coloumb
used to change DC to AC in a motor
commutator ring
used to make a uniform density on a radiograph for a non uniform part thickness
compensating filter
any quantity of one type of molecule
compound
What increases as the number of x-rays in the beam increases?
ionization of air increases
any electromagnetic or particulate radiation that has sufficient energy to remove an electron from an atom
ionizing radiation
backscatter is caused by this interaction
compton
interaction responsible for occupational dose
compton
What are the 2 types of digital radiographic systems in use today
computed radiography (CR), digital radiography (DR)
electric charge distribution is ______________ in a conductor
concentrated along the sharpest curvature
any type of radiation that is capable of removing an orbital electron from the atom with which it interacts
ionizing radiation
What material that allows the free flow of electrons?
conductor
materials that have free electrons & allow electrical current to flow easily
conductors
Electrification can be created by these 3 methods:
contact friction *induction
Brems x-rays have _______ emission spectrum.
continuous
an uninterrupted (continuous) ordered sequence
continuum
an uninterrupted continuous ordered sequence
continuum
A system that can digitize a greater number of shades of gray has better ________
contrast resolution
The ability of an imaging receptor to distinguish between objects having similar subject contrast is called
contrast resolution
What is anode mode of ?
copper and molybdenum metal
Name the 3 most common anode materials:
copper molybdenum *graphite
particulate and electromagnetic radiation emitted by the sun and stars
cosmic rays
List several drawbacks of film-screen imaging
costs (film, equipment, processing, maintenance), chemical processing, artifacts from handling and processing, required frequent quality control procedures, image cannot be adjusted, cannot be electronically stored, duplicated, displayed, or transmitted, archives consume significant space, easy to lose films
the fundamental unit of electric charge
coulomb
electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance between them
coulomb's law
Once a radiographer declares her pregnancy, she will receive _______ and _________.
counseling...and an additional dosimeter
a single excessive exposure will damage the x-ray tube in this way
cracking of the anode
The film emulsion is made of
crystals suspended in gelatin
unit for radioactivity
curie
site of all metabolic functions of the cell
cytoplasm
damages living systems by ionizing (removing electrons from) the atoms comprising the molecular structures of these systems
ionizing radiation
atom with same atomic number but different atomic mass numbers
isotope
atoms that have the same number of protons but differ in the number of neutrons; they behave in the same way during chemical reactions
isotopes
When x-rays are produced, how are they emitted?
isotropically, with equal intensity in all directions
What does added filtration do?
it attenuates x-rays of all energies emitted, but it attenuates a greater number of low-energy x-rays than high-energy x-rays
the discovery of the neutron explained this
it explained the large masses of the elements compared to their number of charges
energy of a photon is directly proportional to
it frequency
When the voltage is increased, what happens to the current?
it is decreased proportionately
List the reasons aluminum is usually chosen as the material for an x-ray filter:
it is efficient in removing low-energy x-rays through the photoelectric effect it is readily available inexpensive it is easily shaped
When the voltage is decreased, what happens to the current?
it is increased proportionately
What is the advantage of adding filtration to the useful x-ray beam?
it reduces patient dose
With age, does inherent filtration tend to increase or decrease? ...why?
it tends to increase because some of the tungsten metal of both target and filament is vaporized and is deposited on the inside of the window (tube tanning)
SI unit for work
joule
energy is expressed in
joules
the way in which a unit of energy is measured in the International System (SI)
joules (J)
unit of measurement for electricity
joules or electron volts
The average energy of an x-ray beam is expressed as ___
kEv
What determines the quality of the x-ray beam
kV
differential absorption is dependent upon this
kV, Z number, mass density
controlling factors of beam quality
kV, filtration
controlling factors of beam quantity
kV, mAs, filtration
Our primary method of controlling contrast is
kVp
Quality is determined by _____
kVp
this determines the quality of the x-ray beam
kVp
What is the unit of measure of the secondary voltage?
kVp (kilovolt peak)
Name the factors that affect x-ray quality
kVp Filtration
x-ray quantity is proportional to...
kVp^2
LET is usually described in what unit over what length?
keV per micron
When the electron from the filament interact with the anode the __________ energy of the electrons are converted to ___% of ______energy and ___% of ________energy
kenetic, 99, heat, 1, x-ray
SI unit for mass
kg
Measurement standards of mass is:
kilogram
the scientific unit of mass
kilogram
unit of mass
kilogram (kg)
unit of measure that is the mass of 1000 cm^3 of water at 4 degrees C.
kilogram (kg)
the energy of motion and the function of an object's mass and velocity
kinetic energy
artifact caused by sharp bending/creasing of the film
kink mark
wavelength is represented by this greek letter
lambda
In the straight-line portion of a characteristic curve, small changes in exposure result in _____ changes in OD
large
Digital image quality is improved with a ____ matrix size that includes a ____ number of smaller pixels
larger, larger
The radiation that exits the patient interacts with the image receptor to form the _____ image, which must be processed to be visible
latent
There is usually a ____ before the symptoms of acute radiation syndromes appear.
latent period
The range of exposures over which the image receptor responds with ODs in the diagnostically useful range
latitude
The shorthand for determining speed is to choose the one on the ____
left
What is the maximum leakage allowed from the x-ray tube housing?
less than 100 mR/hr at 1 meter from the source
High speed IRs require ____ exposure (mA) which results in fewer x-ray photons being able to produce ______ scatter, decreasing personnel exposure.
less; Compton
Ankylosing spondylitis patients treated with radiation showed an increased incidence of ______.
leukemia
One major deficiency of film-screen imaging is
limited dynamic range
measures the voltage provided to the x-ray imaging system and adjusts that voltage to precisely 220V
line compensator
The x-ray intensity is lower on the anode side of the tube because of the _____.
line focus principle
varying power supplies to the x-ray circuit will be corrected by what component of the circuit?
line voltage compensator
today, these make it possible to produce x-rays of considerably higher energies than gamma ray emissions
linear accelerators
Studies of A-bomb survivors indicate that leukemia has a _______ dose-response relationship to radiation..
linear, nonthreshold
mAs is directly related to output intensity
linearity
TLDs contain the sensing material, _______, which responds to ionizing radiation in a similar manner as _____.
lithium fluoride; human tissue
Exposure values for a characteristic curve are presented in a _______ fashion
logarithmic
Which contrast scale is generally considered to be the most useful in diagnostic radiography because it offers more information and demonstrates many different tissues at once
long scale (low contrast)
What are several terms used for a large number of narrowly varying tonal values
long scale, low contrast, elephant
Low contrast is also called
long-scale contrast
What overall effects do Compton scattering have on an x-ray photon
loss of energy and change of direction
The abdomen is composed of tissues that attenuate the x-ray beam similarly, such as the stomach, kidneys, intestines, and pancreas, which creates ___ subject contrast
low
circuits on the operating console are _____ voltage
low
A film with a large number of densities that vary only a little is said to have ____
low contrast
Point mutations commonly occur with ________ radiation.
low-LET
Point mutations commonly occur with this type of radiation
low-LET radiation
Elements of low atomic number produce ________ characteristic x-rays.
low-energy
x-rays with low penetrability are termed this
low-quality x-rays
kVp meter is located in this part of the x-ray circuit
low-voltage
Numbers ____ than par speed refer to "detail" image receptors
lower
The most radiosensitive cells in the hematopoietic system of the human body are the _____.
lymphocytes
white blood cells involved in the body's immune reactions
lymphocytes
these are called suicide sacks
lysosomes
SI unit for velocity
m/s
SI unit for acceleration
m/s(squared)
The quantity of x-rays in the primary beam is controlled by the ____
mA
What is the unit of measure of the secondary current?
mA (milliamperes)
Placed in the tube circuit, connected at the center of the secondary winding of the high-voltage step-up transformer in series with the x-ray tube. This reduces the possibility of shock.
mA meter location
For three-phase and high-frequency, kW =
mA x kVp / 1000
Quantity of radiation is determined by ____
mA x time (mAs)
Doubling the exposure can be achieved by doubling the ____
mAs
When SID is increased, what must be increased by SID^2 to maintain constant exposure to the image receptor?
mAs
a measure of the total number of electrons that travel from cathode to anode to produce x-rays
mAs
beam quantity is directly proportional to
mAs
What provides the safest tube current in the shortest time possible?
mAs Timer
Name the factors the affect X-ray quantity
mAs kVp Distance Filtration
monitors the product of mA and exposure time and terminates exposure when the desired mAs value is attained
mAs timer
used on falling-load and capacitor discharge imaging systems
mAs timers
What are the five factors that affect the x-ray emission spectrum?
mAs, kVp, Added filtration, Target material, and Voltage waveform.
a measure of the number of ion pairs produced in air by a quantity of x-rays
mGya
Quantity is expressed in _____
mR
Name 3 ways to express x-ray intensity
mR/s mR/min. *mR/mAs
leaves the cell nucleus and directs the process of making proteins out of amino acids in the cytoplasm
mRNA
Energy field surrounding an electrical charge in motion is called what?
magnetic field
What can magnetize a ferromagnetic material, such as iron?
magnetic field
induction motors use this to operate
magnetic field
ability of a material to attract the lines of magnetic field intensity
magnetic permeability
Every magnet has a north and south pole which these poles are called what?
magnetic poles
degree to which material can be magnetized
magnetic susceptibility
Magnification is expressed by the
magnification factor (MF)
Radiographic examinations where magnification is desirable and is carefully planned into the examination is called
magnification radiography
List the 3 geometric factors that affect radiographic quality
magnification, distortion, focal-spot blur
the quantity of matter as described by its energy equivalence
mass
this is determined by the object's energy equivalence
mass
base quantities in mechanical physics
mass, length, time
basic quanities in mechanical physics
mass, length, time
A digital image is recorded as a ____ or combination of rows and columns of pixels
matrix
anything that occupies space; the material substance with mass of which physical objects are composed
matter
has mass and energy equivalence; may also have electric charge
matter
the strangest property associated with matter and energy
matter and energy are interchangeable
What is a radiographic rating chart used for?
maximum exposure times
high-voltage generator power =
maximum x-ray tube current (mA) at 100 kVp and 100 ms
What contributes to the increased usage of medical radiation exams?
medicolegal considerations - physicians relying more on radiological diagnoses to assist them in patient care
Measurement standards of length is:
meter
SI unit for length
meter
unit of measure based on the speed of light
meter
unit of measure that is based on the speed of light
meter
The size of a pixel is measured in ____ (0.001 mm)
microns
these frequencies vary according to use but are always higher than broadcast RF and lower than infrared
microwave frequencies
very-short-wavelength RF
microwave radiation
the x-ray tube current, crossing from cathode to anode, is measured in this unit of measure:
milliamperes (mA)
the result of a falling load generator
minimum exposure time
____ artifacts are of less density than the area of the image immediately surrounding them
minus-density
"Powerhouse of the cell" ("Power Plant") that supplies energy for the cell; the greatest number of these are found in cells exhibiting the greatest activity
mitochondria
the powerhouse of the cell
mitochondrion
When two or more atoms are chemically united, they form a what?
molecule
smallest particle of a compound
molecule
combination of two or more types of atoms of various elements
molecules
Digital image receptors are _____ sensitive to scatter radiation than film because they can detect low levels of radiation intensity
more
Voltage waveforms of three-phase or high-frequency operation result in _____ _______ x-ray emission than those of single-phase operation.
more intense
When there is ____ forward scatter and ____ side scatter, chances of occupational exposure will be reduced.
more; less
What is the number one enemy of recorded detail
motion
The loss of radiographic quality due to movement of the patient or the x-ray tube during exposure is called
motion blur
device that uses electrical energy to create mechanical motion
motor
1/1000 of a rem
mrem
Give an example of a golgi apparatus product:
mucus
Transformers operates on the principle of mutual induction or self induction?
mutual induction
Two main categories of radiation
natural environmental radiation & man-made radiation
electrical charge of an electron
negative
In their normal state, atoms are electrically...
neutral
British units of weight
newton and pound
A change in kVp has ___ effect on the position of the discrete x-ray emission spectrum.
no
Can grid be used to prevent off focus radiation from reaching the film?
no
The radiographic beam should be collimated so that it is:
no larger than the image receptor
Skin effects from localized doses of radiation follow a _______ dose-response relationship.
non-linear, threshold
How many excess cancer deaths are expected in the future due to the Three Mile Island accident?
none
Death from acute radiation exposure follows a ____, ____ dose-response relationship.
nonlinear, threshold
If the object plane and the image plane are _____, distortion occurs
not parallel
the energy required to hold nucleons together as a nucleus
nuclear binding energy
an example of converting matter into energy
nuclear fission
the basis for generating electricity
nuclear fission
these are composed of quarks that are held together by gluons
nucleons (protons and neutrons)
smaller structures that make up nucleic acids
nucleotides
gamma rays are produced in this part of the atom
nucleus
If the image size, SID, and SOD are known, the object size can be calculated as
object size = image size x SOD/SID (image size times SOD over SID)
Distortion depends on what 3 things
object thickness, object position, object shape
How is an object charged?
objects are charged by adding or removing electrons
unit of electric resistance
ohm
serves as both an insulator against electric shock and as a thermal cushion to dissipate heat
oil contained in the protective housing
Where is the mAs timer located?
on the secondary side of the high-voltage transformer
the atomic mass # of each type of nucleon is
one (1)
the distance traveled by light in 1/299,792,468 second
one meter
Which x-rays of tungsten are the only ones useful for imaging?
only the K-characteristic x-rays
The numeric calculation that compares the intensity of light transmitted through an area on the film to the amount of light originally striking the area
optical density
xrays are produced in this part of the atom
orbital shells
when you check a radiologist report for actually matching the patient's diagnosis
outcome assessment
what part of the image intensifier changes electrons into light photons?
output phosphor
The presence of ______ in biologic tissues makes the damage produced by free radicals permanent.
oxygen
an example of converting energy into mass
pair production
When expressing speed as a number, 100 is called the
par speed
Which type of circuit do the following laws apply: total R=1/R1+1/R2+1/R3; total I= I1+I2+I3; total V=V1=V2=V3
parallel
x-rays behave as though they are
particles
What advantage does increasing kVp by 15% and reducing the mAs by half have?
patient dose is reduced significantly
What is increased as the energy of an x-ray beam is increased?
penetrability
refers to the ability of x-rays to penetrate deeper in tissue
penetrability
kVp settings on teh operator console controls this in the x-ray beam
penetrability/energy of the beam
Quality is energy, is _____, is electromotive force
penetrating ability
What is visibility dependent on
penetration, density (brightness), contrast
The blurred outer portion of the image is called the ____
penumbra
quality assurance looks at ______
people
The presence of oxygen in biologic tissues makes the damage produced by free radicals _______ because oxygen reacts w/free radicals to produce __________ compounds.
permanent....peroxide
What part of the image intensifier changes light photons into electrons?
photocathode
interaction responsible for patient dose
photoelectric
Which interaction creates the white or clear areas (more brightness or low density) on the image
photoelectric absorption
What is the complete absorption of an x-ray and ejection of an electron called if it occurs in the diagnostic range
photoelectric effect
During complete absorption, what is the ejected electron called
photoelectron
any quantum of electromagnetic radiation
photon
smallest part of electromagnetic energy
photon
the smallest quantity of any type of electromagnetic energy
photon
the smallest quantity of any type of electromagnetic radiation; it may be pictured as a small bundle of energy, sometimes called a quantum
photon
How is the energy of a photon related to its wavelength?
photon energy is inversely proportional to photon wavelength
artifact that repeats every 3.14" perpendicular to the path of film travel
pi line
tool to measure focal spot size
pin hole camera, star pattern, slit camera
The number of pixels per unit area
pixel density
The distance measured from the center of a pixel to an adjacent pixel
pixel pitch
___ artifacts are greater in density than the area of the image immediately surrounding them
plus-density
What are the two classifications of artifacts
plus-density, minus-density
electrical charge of a proton
positive
Positively charged beta particle
positron
what does voltage measure?
potential energy
rate of doing work
power
the product of voltage and current; expressed in Watts
power
Give an example of a source of alternating current:
power plants a wall plug outlet
the kV meter is on the ____ side of the x-ray circuit
primary
Film must be _____ before it is looked at
processed chemically
emulsion pickoff, curtain effect and chemical fog are examples of this type of artifact
processing
Immediately following a whole body dose of 1000 rads, the victim would experience ______.
prodromal symptoms
Electrons traveling from cathode to anode constitute the x-ray tube current and are sometimes called this:
projectile electrons
A change in mA or mAs results in a ________ change in the amplitude of the x-ray emission spectrum at all energies.
proportional
guards against excessive radiation exposure and electric shock
protective housing
essential for growth, the construction of new body tissue, and the repair of injured or debilitated tissue
proteins
the most elementary building blocks of cells
proteins
the smallest unit of positive charge
proton
List the 3 fundamental particles of an atom
protons neutrons *electrons
the chemical building material for all living things
protoplasm
What do you call the penetrating ability of the x-ray beam
quality
The primary factor that affects the amount of brightness or density produced in an image is the ____ of radiation reaching the image receptor
quantity (amount)
mA setting on the operator console controls this in the x-ray beam
quantity of electrons emitted through thermionic emission
a term that means "a small bundle of energy"
quantum
details of atomic structure are most accurately described by this atomic model
quantum chromodynamics (QCD)
____ refers to the random nature by which x-rays interact with the image receptor
quantum mottle
Radiographic mottle is made up of what 4 things
quantum mottle, film granularity, screen structure mottle, scatter radiation
unit for patient dose
rad
how does an x-ray tube cool primarily (what method is used)?
radiation
the transfer of energy
radiation
the transfer of energy from one area or medium to another
radiation
the branch of biology concerned with the effects of ionizing radiation on living systems
radiation biology
the amount of energy transferred to electrons by ionizing radiation
radiation dose
demonstrated graphically through a curve that maps the observed effects of radiation exposure in relation to the doses of radiation received
radiation dose-response relationship
What is another name for x-ray intensity or x-ray quantity?
radiation exposure
What do scattered photons contribute to if they do not strike the image receptor
radiation exposure (to the patient if they don't leave the patient and anyone nearby if they do leave the patient)
The amount of optical density created on the film after processing is primarily determined by
radiation exposure to the image receptor
A growing body of radiobiologic evidence suggests that a little bit of radiation is good for you. A little radiation may stimulate hormonal and immune response to other toxic environmental agents. We refer to this as _______.
radiation hormesis
A theory which presents low doses of radiation providing beneficial health effects is:
radiation hormesis
refers to the penetrability of the x-ray beam and is expressed in kVp or HVL
radiation quality
refers to the number of x-rays or the intensity of the x-ray beam & is usually expressed in mR or mR/mAs
radiation quantity
Although the computer can adjust for low and high exposure technique errors, the ____ is still responsible for selecting techniques that produce acceptable image quality while maintaining patient exposure as low as reasonably achievable
radiographer
Factors that affect x-ray beam quality also influence this
radiographic contrast
____ is the umbrella term for the amount of noise seen in an image
radiographic mottle
The two general types of x-ray exams
radiography and fluoroscopy
structures that transmit x-rays are called this:
radiolucent
structures that absorb x-rays are called this:
radiopaque
the first decay product of radium
radon
the largest source of natural environmental radiation
radon
Measurement standards of acceleration is:
rate of change of speed per unit of time
Measurement standards of power is:
rate of doing work (measured in watts)
Magnification is calculated as the
ratio of image size to object size (MF=image size/object size)
same mAs selected with different mA stations should still yield the same mR
reciprocity
The law that states that the OD will be the same if the mAs value is constant regardless of the exposure time
reciprocity law
An image with increased contrast resolution increases the visibility of ____
recorded detail
___ refers to the distinctness or sharpness of the structural lines that make up the recorded image
recorded detail
process of converting AC to DC
rectification
the process of converting AC to DC
rectification
these convert AC to DC
rectifiers
Anything that you do to ____ ____ when taking a radiograph, will also lower occupational exposure.
reduce scatter
What technique should be used to maintain a constant exposure of the image receptor and constant radiographic optical density if kVp is increased by 15%?
reduce the mAs by 1/2
What is the disadvantage of increasing kVp by 15% and reducing the mAs by half?
reduced image contrast
What is the disadvantage of x-ray beam filtration?
reduced image contrast caused by beam hardening
Adding filtration to an x-ray tube results in ______ x-ray intensity but ______ effective energy.
reduced, increased
When distance is doubled, intensity of x-ray beam is ______ by _______.
reduced; factor of four
return or reentry of an x-ray
reflection
the deviation in the course of visible light when they pass from one transparent medium to another
refraction
What is the traditional unit of measure for Equivalent Dose (EqD)?
rem
unit for occupational dose
rem
the unit of occupational radiation exposure
rem or (Sv)
The light or clear areas on the film result from _____ during processing
removal of unexposed crystals
A _______ looks at repeated radiographs to determine the cause of repeat.
repeat analysis program
like charges
repel
which system of the processor allows for chemistry to stay fresh?
replenishment
same mAs used on the same tube should yield the same mR output
reproducibility
The ability to image 2 separate objects and visually distinguish one from the other
resolution
What are 3 interrelated characteristics of radiographic quality
resolution, noise, speed
Limiting _____ limits occupational exposure.
retakes
unit for radiation in air
roentgen
Radiation exposure is measured in this:
roentgens (R)
rating charts for x-ray tubes demonstrate this
safe exposure times
Filament current that has risen to its maximum value because all available electrons have been used is called?
saturation current
filament current that has risen to its maximum value because all available electrons have been used
saturation current
Radiographic film images are typically described by their _____, or the range of densities visible
scale of contrast
our greatest source of radiation exposure
scatter radiation
In which type of interaction are incoming photons not absorbed but instead lose energy during interactions with atoms comprising the tissue
scattering
___ is similar to film graininess but refers instead to the phosphor of the radiographic intensifying screen
screen structure mottle
Measurement standards of time is:
second
SI unit for time
second
the standard unit of time based on the vibration of atoms of cesium
second (s)
the mA meter is on the ____ side of the x-ray circuit
secondary
mRNA transfers its genetic code to ____.
tRNA
Anatomic tissues are typically ranked based on their attenuation properties. List the following substances in order from most radiopaque to most radiolucient: fat, bone, air, muscle, and teeth
teeth, bone, muscle, fat, air
which system monitors and adjusts the temperature of the processor chemistry?
temperature control system
results from deposits of uranium, thorium, and other radionuclides in the Earth
terrestrial radiation
What does the kinetic energy formula indicate about the relationship between mass & velocity?
that the velocity is much more important than mass
the first heated filament x-ray tube was developed by a physicist, William Coolidge, in 1913
the Coolidge Hot Cathode Tube
Compensating for a change in SID by changing mAs by the factor SID^2 is known as
the Square Law
the first ancient people to describe photons
the ancient Greeks
Name the positive side of the x-ray tube:
the anode
conducts electricity and radiates heat and contains the target
the anode
List the internal structures of the x-ray tube:
the anode the cathode
In a graph, the total number of x-rays emitted is equivalent to...
the area under the curve of the x-ray emission spectrum
What determines the chemical properties of an element?
the arrangements of electrons in the outermost shells
the basic building block of matter
the atom
the building block of the radiographer's understanding of the interaction between ionizing radiation and matter
the atom
the superscript in each block of the Periodic Table of Elements represents this
the atomic number
What unique characteristic of the TLD dosimeter makes it the most reliable?
the atomic number of lithium fluoride is most similar to human tissue
this has a single winding and is designed to supply a precise voltage to the filament circuit and to the high-voltage circuit of the x-ray imaging system
the autotransformer
Name the 2 primary parts of the diagnostic x-ray tube:
the cathode and the anode
method of displaying the sensitivity of a particular type of cell to radiation
the cell survival curve
What determines the type of ER in a cell?
the cell type
What is responsible for most of the heat generated in the anodes of x-ray tubes?
the constant excitation & return of outer-shell electrons
the fundamental unit of electric charge
the coulomb
The characteristic x-ray has energy equal to this:
the difference in the binding energies of the orbital electrons involved
What helps shield the earth from cosmic rays?
the earth's atmosphere and magnetic field
this governs the interaction of electrostatic charges, the magnetic field, and the interaction of magnetic poles
the electric field
The smallest unit of electric charge
the electron
What is the projectile in an x-ray tube?
the electron
has one unit of negative charge
the electron
unit of energy used to describe x-rays
the electron volt (eV)
the subscript in each block of the Periodic Table of Elements represents this
the elemental mass
What is the main advantage of full-wave rectification?
the exposure time for any given technique is cut in half
the x-ray tube current is controlled through
the filament circuit
this governs the interaction of different masses
the gravitational field
the unit of frequency that is used to describe radio waves
the hertz
Name the 3 primary parts of a high-voltage generator:
the high-voltage transformer the filament transformer *rectifiers
As electron energy is increased, what is also increased?
the intensity (quantity) and the energy (quality) of the x-ray beam
describes the relationship between radiation intensity and distance from the radiation source
the inverse square law
this is placed across the output terminals of the autotransformer, and therefore actually reads voltage
the kVp meter
Planck's constant is symbolized by
the letter "h"
measures the voltage provided to the x-ray imaging system and adjusts that voltage to precisely 220V
the line compensator
Optical density is defined as
the logarithm of the inverse transmittance
1/1000 of a rad, where the rad is 100 ergs of energy absorbed per gram of tissue
the mrad
part of the atom that contains nearly all the mass of the atom
the nucleus
In the Periodic Table, what do the rows relate to?
the number of electron shells present
In the Periodic Table, what do the columns relate to?
the number of electrons in the outermost shell
in the normal atom, the number of electrons is equal to
the number of positive charges in the nucleus
this ultimately determines the chemical behavior of an atom (chemical element)
the number of protons the atom contains
if the count rate has fallen by half, this has also fallen by half
the number of unstable atoms
the count rate coming from a radioactive source depends on the number of this
the number of unstable atoms it contains
What is the primary function of the oil in the high-voltage section of the generator?
the oil is used primarily for electrical insulation
this allows the radiologic technologist to control the x-ray tube current and voltage so that the useful x-ray beam is of proper quantity and quality
the operating console
used to control the voltage applied to the x-ray tube, the current through the x-ray tube, and the exposure time
the operating console
has one unit of positive charge
the proton
Increasing the kVp peak increases...
the quality of an x-ray beam
What does increasing filtration increase?
the quality of an x-ray beam
What does increasing filtration decrease?
the quantity of an x-ray beam
The cumulative effective dose limit for a radiographer cannot exceed:
the radiographer's age x 1rem or age in years x 10mSv
What speed do x-ray photons travel at?
the speed of light
The external structure of the x-ray tube consists of these 3 parts:
the support structure the protective housing *the glass or metal enclosure
the number of electrons emitted by the filament is determined by this
the temperature of the filament
When using AEC, how should the electronic timer be set in case the AEC fails to terminate?
the timer should be set to 1.5 times the expected exposure time as a backup timer in case the AEC fails to terminate
x-rays emitted through the window are called this
the useful beam
this extremely small segment of the electromagnetic energy continuum is the only one that is naturally apparent to us
the visible light segment
Name 3 things the operating console controls:
the voltage applied to the x-ray tube the current through the x-ray tube *the exposure time
Some regions of the EM spectrum behave like waves and some regions behave like particles in their interaction with matter. This phenomenon is called:
the wave-particle duality of EM radiation
this provides for low inherent filtration
the window
the penetrability of an x-ray beam is called this
the x-ray quality
the intensity of the x-ray beam is called this
the x-ray quantity
What is the only difference between the primary and secondary waveforms?
their amplitude
the only difference between atoms of different elements in the late 1800's
their mass
objects in motion have kinetic energy proportional to this
their mass and to the square of their velocity
the only difference between x-rays and gamma rays
their origin
What is the difference between x-rays and gamma rays?
their origin: X-rays are emitted from the electron cloud. Gamma rays are emitted from the nucleus.
The binding energies, or energy levels, of electrons, are represented by
their shells.
cooling charts for x-ray tubes demonstrate this
thermal capacities and heat dissipation characteristics
refers to the "boiling off" of electrons from the filament
thermionic emission
the release of electrons from a heated filament
thermionic emission
the wavelength differences between a photon of x-radiation and a photon of visible light result in this difference between them
these differences result in differences in the way these photons interact with matter
What units, both traditional & SI, are used to measure occupational and non-occupational dose limits?
these dose limits are expressed as EfD, and stated in Sieverts (Sv) and rem
List 3 advantages of carbon fiber tabletops:
they are strong absorb little x-radiation *contribute to reduced patient dose
What is the only way the photons of various portions of the electromagnetic spectrum differ?
they differ only in frequency and wavelength
the ionizing strength of beta particles in comparison with alpha particles
they do around 1/20th of the damage done by the same dose of alpha particles
What happens when the projectile electrons hit the heavy metal atoms of the x-ray tube target?
they transfer their kinetic energy to the target atoms
What factors affect x-ray beam attenuation
thickness, atomic number, and density of the anatomic part and energy of the x-ray beam
The absorption characteristics of the anatomic part are determined by its ____, ____, and ____
thickness, atomic number, tissue density
What tissue characteristics contribute to subject contrast
thickness, density, effective atomic number (same ones that affect attenuation and absorption)
model of atom described similar to plum pudding
thomson's
What are filaments usually made of?
thoriated tungsten
to figure HU for a ______ phase gnerator, multiply 1.4 x kvp x ma x s
three
With this type of power, multiple voltage waveforms are superimposed on one another, resulting in a waveform that maintains a nearly constant high voltage
three-phase power
Radiation induced skin cancer in radiotherapy patients has occurred with a _______ dose-response.
threshold
a point at which a response or reaction to an increasing stimulation first occurs
threshold
People who had radiation treatments to their thymus gland as children later showed excess risk for ______.
thyroid cancers
Name the primary function of an x-ray imaging system
to convert electric energy into electromagnetic energy
What is the important role of neutrophils?
to fight infection
Primary Function of the X-ray Imaging System
to provide a controlled flow of electrons intense enough to produce an x-ray beam appropriate for imaging
the function of the x-ray imaging system:
to provide a controlled flow of electrons intense enough to produce an x-ray beam appropriate for imaging
What is the purpose of the metal filter that is positioned in the useful beam in an x-ray imaging system?
to reduce the number of low energy x-rays
State the primary purpose of adding filtration to an x-ray beam.
to remove selectively low-energy x-rays that have little chance of getting to the image receptor
The bottom portion of a characteristic curve which shows only small change in OD is called the
toe
Individuals that are restraining patients should be positioned so that their _____ is not hit by the primary beam.
torso
transformer uses self induction or mutual induction to _____
transform electrical energy into higher or lower intensities
If the incoming x-ray photon passes through the anatomic part without any interaction, what is it called
transmission (more specifically direct transmission)
The ratio of the 2 intensities used to calculate optical density is called
transmittance
3 degrees of interaction between light and an absorbing material:
transparency (transmission) translucency (attenuation) *opacity (absorption)
what system of the processor gets a film from latent to manifest image?
transport
List 3 functions of water:
transports materials to and from cells acts as a solvent for regulation of acids, bases and salts *maintains body temperature
T/F: A densitometer calculates optical density
true
T/F: A quality radiographic image accurately represents the anatomic area of interest
true
T/F: A radiographic image cannot be an exact reconstruction of the anatomic structure because some information is always lost during the process of image formation
true
T/F: A small anatomic structure is best visualized when its brightness or density varies significantly from the background
true
T/F: Anatomic tissues that vary in absorption and transmission create a range of brightness or shades of gray
true
T/F: Because the digital image is processed and reconstructed in the computer as digital data, its grayscale or contrast can be altered
true
T/F: Each pixel is recorded as a single numeric value, which is represented as a brightness level on a display monitor
true
T/F: In order to evaluate other attributes of radiographic quality, such as contrast and sharpness, the image must have sufficient brightness or density to visualize the anatomic area of interest
true
T/F: Shape distortion can be used to our advantage in particular projections or positions, for example to eliminate superimposition
true
T/F: Speed = 1/exposure in roentgens to produce an OD of 1.0 plus base + fog
true
T/F: The imaging process makes it impossible to produce a radiographic image without some degree of unsharpness (blurring)
true
T/F: The secondary x-ray created during photoelectric absorption has very low energy and is unlikely to exit the patient
true
T/F: Tissue composed of a higher atomic number, such as bone, attenuates the x-ray beam more than tissue composed of a lower atomic number, such as fat
true
T/F: When the image is distorted, spatial resolution or recorded detail is also reduced
true
T/F: X-ray beam attenuation is decreased with a higher energy x-ray beam and increased with a lower energy x-ray beam
true
T/F: the best source for exposure technique is an exposure technique chart made and calibrated for the x-ray unit being used
true
T/F: the quality (contrast) of the radiographic image is compromised if scattered photons strike the image receptor
true
T/F: the various shades of gray recorded in the radiographic image make anatomic tissues visible
true
T/F: If 2 image recepters were compared and A was twice as fast as B, then A would require half the mAs of B to produce a given OD, but the image on A might be of poor quality because of increased radiographic mottle
true (twice the speed requires half the mAs, but faster speed generally creates more noise)
electrons boiled off of the filament and being attracted to tungsten plating the inside of the x-ray tube
tube arcing
What is angled if an image has elongation
tube or IR
What is the most common cause of tube failure?
tube tanning - tungsten vaporization with deposition on the inside of the glass enclosure
Shape distortion occurs when one of these three things are angled
tube, anatomic part, image receptor
What are the filaments made of ?
tungsten
term used to describe the ratio of the number of secondary windings to the number of primary windings
turns ratio
located in the electromagnetic spectrum between visible light and ionizing radiation
ultraviolet light
The detailed, sharp inner portion of the image is called the ___
umbra
Where is the fluoroscopic x-ray tube usually located?
under the examining table
Limited dynamic range makes film very sensitive to ______ and restricts ____
underexposure or overexposure, visibility of structures that differ greatly in x-ray attenuation
electric charge distribuition is ______ in a diffuse nonconductor
uniform
How do you minimize motion blur
use shortest exposure time possible, restrict patient movement, use large SID, use small OID
How do you minimize focal-spot blur
use smallest focal spot, use smallest OID possible, use largest SID possible
How do you minimize magnification
use the largest SID possible, place the object as close to the image receptor as possible
The Wave Equation:
v = frequency x wavelength
an old-fashioned rectifier was called this
valve tube
What is constant with all electromagnetic energies?
velocity
the rate of change of position with time, sometimes called speed
velocity
The 3 wave parameters needed to describe electromagnetic energy:
velocity frequency *wavelength
derived quantities in mechanical physics
velocity, acceleration, momentum, work, volume
The ____ of the anatomic structures and the ____ of their structural lines recorded (sharpness) determine the overall quality of the radiographic image
visibility, accuracy
occupies the smallest segment of the electromagnetic spectrum
visible light
the only portion of the electromagnetic spectrum we can sense directly
visible light
3 regions of the electromagnetic spectrum most important to radiologic science:
visible light x-radiation *radiofrequency
the unit of electric potential
volt
unit of electric potential
volt
this is required to ensure that electrons flow from cathode to anode only
voltage rectification
means of characterizing voltage waveforms
voltage ripple
the fluctuation in the voltage applied to the x-ray tube expressed as a percentage of peak kilovoltage
voltage ripple
What is the unit of measure of the primary voltage?
volts (V)
the step up transformer changes _____ into _____
volts; kilovolts
Name 2 mathematical formulas that describe how electromagnetic energy behaves
wave equation inverse square law
Maximum x-ray energy is associated with the minimum x-ray ________.
wavelength
What is the distance between the peaks of waves called?
wavelength
distance from one crest to another
wavelength
the distance from one crest to another, from one valley to another, or from any point on the sine wave to the next corresponding point
wavelength
visible light is identified by its
wavelength
visible light is identified by:
wavelength
determined by the force of gravity
weight
During the latent period, the radiation victim experiences _____.
well-being
the 4 basic essences the Greek scientists thought that could change the 4 basic substances
wet dry hot cold
When is a small focal spot used?
when better spatial resolution is required
When is a large focal spot used?
when large body parts are imaged, and when other techniques that produce high heat are required
When do photons interact with matter most easily?
when the matter is approximately the same size as the photon wavelength
When does complete absorption occur
when the x-ray photon has enough energy to eject an inner-shell electron
List 6 chemical properties of elements
whether a material will react w/another material rate of reaction with that material Amt of heat produced by the reaction w/material At what temperature it will react In what proportion it reacts Valence of elements
A unique characteristic of digital imaging receptors is their _____ dynamic range
wide
x-rays are emitted through this special section of the x-ray tube:
window
How accurate should the collimator be?
within 2% of SID
the force applied to an object multiplied by the distance over which it is applied
work
Here, the relative number of x-rays emitted is plotted as a function of the energy of each individual x-ray and x-ray energy is the variable that is considered.
x-ray emission spectrum
The minimum wavelength of x-ray emission corresponds to the maximum ______, and the maximum x-ray energy is numerically equal to the __
x-ray energy, kVp
the number of x-rays in the useful beam
x-ray quantity
The 3 Main Components of an x-ray imaging system:
x-ray tube operating console *high-voltage generator
What are the 3 principle parts of the X-ray imaging system?
x-ray tube operating console *high-voltage generator
these are emitted from the electron cloud of an atom that has been stimulated artificially
x-rays
List 2 examples of low LET radiation:
x-rays Gamma rays
What is the charge of an x-ray photon?
x-rays have no electric charge
What is the mass of an x-ray photon?
x-rays have no mass
What is leakage radiation?
x-rays that escape throught the protective covering.
List 3 examples of electromagnetic energy:
x-rays visible light *radiofrequencies
What happens to the x-ray beam when you increase the kV by 15%
you get the effect of the mAs doubling (increase in density)
the atomic mass number of an electron
zero
What is the advantage of having a metal envelope instead of a glass x-ray tube?
• Able to provide constant electric potential between the electrons of the tube current and the envelope. • Have longer life • Less likely to fall
What is the function of protective housing?
• Prevents unnecessary radiation exposure to the patient and radiographer • Protects from electric shock • Provides mechanical support for the tube and protect from damage • Reduces the level of leakage radiation to less than 100 mR/Hr at 1 meter from the tube
What are the two types of anode?
• Stationary anode • Rotating anode
1 Gray is equivalent to
100 rad
What is the usual tube current range for diagnostic x-ray systems?
100 to 1200 mA
Voltage ripple of single-phase generator
100%
What percent voltage ripple does single-phase power have?
100%
The intensity of radiation scattered at 90 degrees at a distance of 1 m from its source is reduced by a factor of ______ relative to the primary radiation for a field size of 8"x8".
1000
instant death of large numbers of cells occurs at this irradiation dose:
1000 Gy
What is the maximum permitted equivalent dose in a controlled area?
1000 microSv (100 mrem)
the associated wavelength for x-ray energy
10^-10 to 10^-14 m
the range of x-ray photon frequency
10^18 to 10^22 Hz
the number of elements that have been identified today
112
Source to skin distance for all mobile exams should not be less than ___ inches.
12 inches
When using a high-frequency generator, how much reduction in kVp would be required to produce the same image receptor exposure when operated at the same mAs as single phase?
12 kVp
minimum source to skin distance for mobile fluoroscopy unit
12"
Effective dose from Nuclear Medicine
12%
To produce results similar to single-phase equipment, a ____ reduction is required on three-phase equipment.
12%
a full wave rectified single phase generator would have how many x-ray beam pulses per second?
120
How many times per second does the voltage swing from zero to maximum potential under single-phase full-wave rectification?
120 times per second
If the peak energy is ____ kVp, the primary protective barrier in a typical installation consists of ___ inch of Pb and extends ___ ft upward from the floor when the x-ray tube is ____ ft from the wall in question.
130; 1/16; 7; 5-7
Voltage ripple of three-phase, six-pulse generator
14%
What percent voltage ripple does three phase, six pulse power have?
14%
Characteristic x-ray emission spectrum for tungsten contains ____ different x-ray energies.
15
Source to skin distance for all exams with stationary x-ray equipment should not be less than _____ inches.
15 inches
Dose limit to lens of eye for occupational workers
15 rem
minimum source to skin distance for stationary/fixed fluoroscopy unit
15"
At 100 kVp, approx. _____ of the x-ray beam is Characteristic, and the remaining is Bremsstrahlung.
15%
What percentage of proteins are contained in the cell?
15%
What is the normal platelet count for adults?
150,000 to 300,000
High-frequency generators produce approx. the equivalent of a ____ increase in kVp, or slightly more than a doubling of mAs over single-phase power.
16%
A 14-bit depth can display ____ shades of gray
16,384
What object prohibits the flow of electrons?
Insulator
a cross-link formed between 2 places on the same DNA strand
Intra-strand cross-link
What is the relationship between frequency and wavelength with EM radiation?
Inverse - Higher frequencies are associated with shorter wavelengths and higher energies
The force of attraction between poles is governed by what law?
Inverse square law
What law governs the intensity of x-radiation, and states that the intensity of the x-ray beam is inversely proportional to the square of the distance between the source of the x-rays and the object?
Inverse square law
Removal of an electron form an atom is called?
Ionization
What is electromatgnetic radiation that is able to remove an electron from an atom?
Ionizing radiation
What do you understand of the term intensity?
Is it the energy of the x-ray beams or the number of x-rays?
What is attenuation?
Is the reduction in x-ray intensity that result from absorption and scattering.
What is half life of a radioisotope?
Is the time required for a quantity of raiocactivity to be reduced to one-half its original value.
What is characteristic radiation?
Is when electrons jump from the outer shell to the inter-shell
these have the same atomic mass number but different atomic number
Isobars
these have the same atomic number and same mass number
Isomers
these have the same number of neutrons
Isotones
A atom with the same number of protons but different number of neutrons is called what ?
Isotopes
these have the same number of protons
Isotopes
Explain the production of Bremstrahlung x-rays?
It gets close to the nucleus then slows down and moves into a new direction.
What is half value layer (HVL)?
It is the thickness of absorbing material necessary to reduce the x-ray intensity to half its original value.
What happens when a bar magnet is heated to a very high temperature?
It loses its magnetic properties
What is the function of the focusing cup?
It's a metal shroud that surrounds the filament.
What is the light transmittance formula
It/Io x 100 (It = amount of light transmitted, Io = amount of original light incident on the film)
he concluded that electrons were an integral part of all atoms
J.J. Thomson
he described the atom as looking something like a plum pudding, where the plums represented negative electric charges
J.J. Thomson
he investigated cathode rays (electrons) in the late 1890's
J.J. Thomson
the person that discovered electrons in 1897 and come up with the "plum-pudding" model of the atom
J.J. Thomson
he discovered the neutron
James Chadwick
In the late 19th century, he showed that visible light has both electric and magnetic properties
James Clerk Maxwell
he heavily researched color blindness
John Dalton
showed that the elements could be classified according to integral values of atomic mass; a unit of atomic weight was called a "dalton" for many years
John Dalton
the "Father of Modern Atomic Theory"
John Dalton
What are the Maximum Number or Electrons that can occupy each electron shell?
K = 2 L = 8 M = 18 N = 32 O = 50 P = 72 Q = 98
9. There are many characteristic radiations (K, L, M, and N). Which characteristic radiation is useful for imaging? Why?
K is the stronger shell for penetration.
innermost electron shell
K shell
the only characteristic x-rays of tungsten with sufficient energy to be of value in diagnostic radiology
K x-rays
x-rays that result from electron transitions into the K shell are called this:
K x-rays
name the orbital shells from innermost to the fourth outer shell
K, L, M, N, O . . .
What is its equation for kinetic energy?
KE = ½ mv2
What is energy of motion?
Kinetic energy
State the formula for the relationship between mass & velocity as it affects kinetic energy
Kinetic energy = 1/2 mass x (velocity)^2
What are the factors that affect x-ray quality?
Kvp more filter
states that the most pronounced radiation effects occur in cells having the least maturity and specialization, or differentiation; the greatest reproductive activity; and the longest mitotic phase
Law of Bergonie and Tribondeau
states that energy can be neither created or destroyed
Law of Conservation of Energy
states that matter can be neither created or destroyed
Law of Conservation of Matter
What law states that energy connot be created or destroyed and only changed in form?
Law of conservation of energy
What law states that matter connot be created or destroyed and only changed in form?
Law of conservation of matter
What law states that unlike charges attract, and like charges repel;electrostatc charges reside on the outer surface of a conductor and are concentrated at the area of greaest curvature: only negative charges move?
Laws of electrostatics
What law states like poles repel, and unlike poles attract?
Laws of magnetics
X-rays that leak through the protective covering is called what?
Leakage radiation
What are the 3 fundamental units of measurements?
Length (meters) Mass (kg) *Time (seconds)
a method of adjusting the voltage to the x-ray imaging system to a constant value, in response to changes in voltage supplied by the power company
Line compensation
What keeps incoming voltage to the Radiology Department adjusted to proper value?
Line voltage compensation
The larger the actual focal spot, the greater the heat capacity; the smaller the effective focal spot, the greater the raiographic image sharpness. What is this effect called?
Line-focus principel
average energy deposited per unit length of track
Linear Energy Transfer (LET)
What is the sensing agent in a TLD?
Lithium fluoride
Carbohydrates are most abundant in which tissues?
Liver tissue Muscle tissue
What is the optical density formula
Log10 Io/It (log base10 of Io over It)
List 3 examples of Derived Quantities:
Volume Density *Velocity
What is the chemical symbol for Tungsten?
W
What are the most important inorganic compounds?
Water Mineral salts
unit of power
Watt
What is the concept called that although x-ray photons exist as waves, the exhibit properties fo particles.
Wave-particle duality
principle that states that both wave and particle concepts must be retained, because wave-like properties are exhibited in some experiments and particle-like properties are exhibited in others
Wave-particle duality
What is the relationship between anode angle and effective focal spot size?
When the target angle is made smaller, the effective focal spot size also is made smaller.
What is a 15% rule?
When you increase. kVp 15% you double the mAs.
W represents
Workload
radiation output weighted time during the week that the unit is actually delivering radiation
Workload
Name 5 things designed to minimize radiation exposure to the patient and the operator.
X-ray beam filtration X-ray beam collimation Protective apparel and barriers Fluoroscopic cumulative timer *Protective tube housing
the only forms of electromagnetic radiation with sufficient energy to ionize
X-rays - gamma rays - ultraviolet light
List 4 Examples of electromagnetic radiation:
X-rays Gamma rays Visible light Radio waves
One of the substantive statements of Planck's Quantum Theory
X-rays are created with the speed of light (c), and they exist with velocity (c) or they do not exist at all.
What is off focus radiation?
X-rays produced in the anode but not at the focal spot.
symbol for atomic number
Z
electrons have a negative charge, and are surrounded by a kind of invisible force field called this
an electrostatic field
each block on the Periodic Table of the Elements represents this
an element
also referred to as saccharides; make up about 1% of cell content
carbohydrates
the basic constituent of all organic matter
carbon
Focal-spot blur is greater on the ___ side of the image
cathode
the negative side of the x-ray tube
cathode
which side of the beam is "hotter"
cathode
which way do electrons flow in the x-ray tube?
cathode to anode
Spatial resolution is dependent on having some ____ between separate objects
space
No more electrons can be boiled off of the filament because of this phenomenon
space charge
electron cloud around the filament
space charge
this makes it difficult for subsequent electrons to be emitted by the filament because of electrostatic repulsion
space charge effect
___ refers to the smallest object that can be detected in an image
spatial resolution
The accuracy of the anatomic structural lines recorded in the radiographic image is determined by its ____ and _____
spatial resolution, recorded detail
Diagnostic quality is achieved by maximizing the amount of _____ or _____ and minimizing the amount of _____
spatial resolution, recorded detail, distortion
The accuracy of the structural lines is achieved by maximizing the amount of ____ or ____ and minimizing the amount of _____
spatial resolution, recorded detail, distortion
additional quantities that are designed to support measurement in specialized areas of science and technology
special quantities
____ is calculated by determining the film curve which reaches its speed point (1.0 OD above base + fog) with the least amount of exposure
speed
Name the 2 types of anodes:
stationary rotating
The ________ is outside the glass envelope.
stator
The destruction of ____ cells in the intestinal lining causes death from GI syndrome.
stem
if there are more windings on the primary side versus the secondary side of a transformer, you have a ________ transformer
step down
Does a step-up transformer or a step-down transformer have more turns in the primary coil than in the secondary coil?
step-down transformer
necessary for the filament circuit to decrease voltage & increase amperage
step-down transformer
necessary for the high-voltage circuit to increase voltage
step-up transformer
type of transformer in which the secondary voltage is higher than the primary voltage because the number of secondary windings is greater than the number of primary windings
step-up transformer
A _____ effect increases in incidence but not severity as the dose increases.
stochastic
Artifacts specific to film-screen imaging are typically a result of film _____, ____, and _____
storage, handling, chemical processing
The area between the toe and the shoulder on a characteristic curve is called the
straight-line portion
Which portion of the characteristic curve represents the useful densities in the image
straight-line portion
proteins such as those found in muscle that provide the body with its shape and form and are a source of heat and energy
structural proteins
particles that are much smaller than the atom
subatomic particles
The absorption characteristics of the anatomic tissue radiographed is called
subject contrast
the property of some materials to exhibit no resistance below a critical temperature
superconductivity
What type of cell is the most radiosensitive?
Lymphocytes
"Garbage disposal", "Suicide bags", "Digestive bags"
Lysosomes
Magnification can also be calculated as
MF=SID/SOD
The 3 Systems of Measurement
MKS CGS *British
an accumulation of many atomic magnets with their dipoles aligned
Magnetic domain
3 Characteristics of ionizing radiation that vary among the different types of radiation and determine the extent to which different radiation modalities transfer energy to biologic tissue:
Mass Charge *Energy
3 base quantities that are the building blocks of all other quantities
Mass Length *Time
What has form or shape and occupies space?
Matter
a German physicist whose mathematical and physical theories synthesized our understanding of electromagnetic radiation into a uniform model
Max Planck
he received the Nobel Prize in 1918
Max Planck
What results in emission of alpha particles, beta particles, and usually gamma rays?
Radioactive decay
What are the 3 imaging windows of the electromagnetic spectrum and what unit of measure is applied to each?
Radiofrequency (Hz) Visible light (meters) *X-radiation (electron volts)
characteristic of materials that allow x-rays to penetrate with a minimum of attenuation; they are nearly invisible on radiographs
Radiolucency
What is the second leading cause of lung cancer in the U.S.?
Radon
What naturally occuring radiation source is responsible for dosing to lung?
Radon 222 gas
What process changes alternating current to direct current?
Rectification
the process of changing alternating current and voltage into direct current and voltage
Rectification
What does the G.mA control (filament circuit)?
Regulates the nimber of electrons available at the filament to produce x-rays
the unit used to express the quantity of radiation received by radiation workers & populations
Rem
5 Electrostatic Laws
Repulsion-Attraction Coulomb's Law Distribution Concentration *Movement
believed to be the way in which 95% of single-chromosome breaks mend
Restitution
List 4 consequences to the cell from structural changes in biologic tissue:
Restitution Deletion Broken-end rearrangement Broken-end rearrangement without visible damage to the chromatids
"Protein Factories"; they are attached to & are part of the rough ER
Ribosomes
the unit of measure of radiation in the air; applies only to x-rays & gamma rays & their interaction with air
Roentgen (R)
unit that applies only to x-rays and gamma rays and their interactions with air
Roentgen (R)
Who coined the terms "alpha particles", "beta particles" & "gamma rays"?
Rutherford
person noted for introduction of a nuclear model where the atom had a small dense positively charged center surrounded by negative charged cloud of electrons
Rutherford
A change in kVp affects both the ______ and the _____ of the x-ray emission spectrum.
amplitude, position
How much added filtration does the collimator provide? ...why?
an additional 1 mm Al equivalent that results from the silver surface of the mirror in the collimator
True or False: Atoms can be ionized by changing the number of positive charges.
False - positive charges do not move, but are confined to the nucleus
What year did Roentgen discover x-rays?
1895
What year did Roentgen win his first Nobel Prize in physics?
1901
The Snook transformer was developed in this year
1907
The Coolidge hot-cathode x-ray tube was introduced this year
1913
Unprotected head, neck & lenses of the eye receive how much more exposure than the protected body trunk?
10 to 20 times
What is the RPM of high speed anode?
10,000 rpm
In abdominal imaging, the entrance skin dose is approx _______times the exit dose in radiography or fluoroscopy.
100
the time it takes for the radioactivity to fall by half
"half-life"
For single-phase, kW =
(0.7) [mA x kVp / 1000]
The maximum allowable radiation leakage from the tube housing is:
100 mR/hr at a distance of 1 meter from the source
What is the weekly Maximum Permissible Dose for a controlled area?
100 mrem
energy range for pair production
1.02 MeV
Control booth glass windows typically contain ____ mm Pb equivalent.
1.5
What is the Background Equivalent Radiation Time for a patient receiving an Upper GI series?
1.5 years
How many mill roentgens is one roentgen?
1/1000
1 AMU is equal to
1/2 the mass of a carbon-12 atom
Exposure time must be below __ of a second for abdominal x-ray to prevent motion blurring by peristalsis
1/20
In the Bremsstrahlung x-ray emission spectrum, the highest number of x-rays have approx. ____ the maximum energy.
1/3
Most doors to x-ray imaging rooms contain ____ inch of Pb and must be closed when radiographic exposures or fluoroscopy is taking place.
1/32
Secondary protective barriers consist of ____inch Pb.
1/32
Exposure time must be below __ of a second for chest x-ray or the heartbeat will cause blurring
1/60
Gonadal responses to radiation have been observed at doses as low as _____ rads.
10
energy range for photodisintegration
10 MeV
Current federal standards limit entrance skin exposure rates of general-purpose intensified fluoroscopic units to a maximum of _____ per minute.
10 R
What is the Background Equivalent Radiation Time for a patient receiving a chest radiograph?
10 days
When using three-phase operation, how much reduction in kVp would be required to produce the same image receptor exposure when operated at the same mAs as single phase?
10 kVp
the x-ray energy ranges
10 keV to 50 MeV
What is the lowest reading on a film badge?
10 mRem = .01 rem = .1mSv
Name 3 things that may be given out when an unstable nucleus decays
Alpha particle Beta particle *Gamma ray
List 4 examples of high LET radiation:
Alpha particles Ions of heavy nuclei Low energy neutrons Charged particles released from interactions between neutrons and atoms
Electrical circuit in which the current of electrons oscillates back and forth is called what?
Alternating current (AC)
What are OSL filters made of?
Aluminum Copper *Tin
What type of metal filters are in a film badge?
Aluminum or Copper
What is the sensing agent in OSL dosimeters?
Aluminum oxide
What is the tube housing made of?
Aluminum with lead lining
Watts =
Amps x Volts
The positive side of the x-ray tube is called?
Anode
What is it called when partial absorption of the energy of an x-ray beam as it traverses an object?
Attenuation
a device that measures the quantity of radiation that reaches the image receptor and automatically terminates the exposure when the image receptor has received the required radiation intensity
Automatic Exposure Control (AEC)
What is used to provide consistency of radiographic quality?
Automatic exposure contral (AEC)
Transformer that contains an iron core and a single winding of wire is called what?
Autotransformer
a type of transformer having a single winding
Autotransformer
an iron core transformer with only one winding
Autotransformer
Antibodies are molecules produced by specialized cells in bone marrow called __________.
B lymphocytes
What produces antibodies?
B lymphocytes
A phosphor that glows when excited with x-rays. The phosphor with which Roentgen was experimenting when he discovered x-rays.
Barium Platinocyanide
the 3 fundamental units of measurements
Base Quantity
Use factor is also called
Beam direction factor
Where is the mA meter located?
Between the rectifier and x-ray tube
the energy that causes electrons to move in a conductor; measured in volts (V)
Electric potential
Electric current (A) through a potential (V)
Electric power
What is the path along whtich electrons flow called and may be wired as series circuits or parallel circuits?
Electrical circuits
What is movement of electrons along a conductor or pathway (electrical circuit), and measures in ampres?
Electrical current
What is energy resulting from movement of electrons?
Electrical energy
What is the divice that converts mechanical energy to electrical energy called?
Electrical generator
What is the device called that converts electrical energy to mechanical energy?
Electrical motor
What is measured in ohms?
Electrical resistance
What is movement of electrons betwee objects called?
Electrification
What is it called when electrical charges are in motion?
Electrodynamics
the study of electric charges in motion
Electrodynamics
Current-carrying coil wrapped around a ferromagnetic core
Electromagnet
Solenoid with an iron core that concentrates the magnetic field is called wihat?
Electromagnet
What ies energy that is emitted and transferred through matter?
Electromagnetic energy
What is it called when a process of causing an electrical current to flow in a conductor when it is placed within the magnetic field of another conductor?
Electromagnetic induction
the wide range of electromagnetic radiation described by its frequency, wavelength, or energy
Electromagnetic spectrum
What is it called when movement of electrons in a conductor produces a magnetic field around the conductor (a coiled conductor, through which an electrical current is flowing, has overlapping magnetic fields)?
Electromagnetism
What is measured in volts, and is the force with which electrons move in an electrical circuit?
Electromotive force (EMF)
What is it called where electrons are when they go around the nucleus of an atom?
Electron Cloud
What is space charge?
Electron cloud near the filament
What contains orbital electrons (negative charges), is represented by the letters K, L, M, N, O, P, and Q, is in a stable atom, and the nimber of electrons and protons is equal?
Electron shells
What is the force called that holds electrons in orbit around the nucleus?
Electron-binding energy
What type of timer is contained in most radiographic equipment?
Electronic timer
Stationary electrical charges (static electricy) called?
Electrostatics
stationary electric charges
Electrostatics
What does the tube housing do?
Encases the x-ray tube
What is the amount of matter in an object; generally considered the same as weight?
Energy
What is meant by x-ray quality? (Energy or quantity)
Energy... The ability of x-rays to penetrate deeper into tissue.
when natural sources of radiation become increased because of accidental or deliberate human actions such as mining, they are termed this
Enhanced Natural Sources
science that deals with the incidence, distribution, and control of disease in a population
Epidemiology
type of highly radiosensitive cells found in the lining of the intestines, the mucous lining of the respiratory tract, pulonary alveoli and lining of blood & lymphatic vessels
Epithelial tissue
a radiation quantity used for radiation protection purposes when a person receives exposure from various types of ionizing radiation; this quantity attempts to numerically specify differences in biologic harm that are produced by different types of radiation
Equivalent Dose (EqD)
he called the center of the atom the nucleus
Ernest Rutherford
he coined the terms alpha particles, beta particles, and gamma rays
Ernest Rutherford
he disproved Thomson's atomic model in 1911
Ernest Rutherford
he introduced the nuclear model
Ernest Rutherford
List the 4 Special Quantities of Radiation Measurement:
Exposure Dose Effective dose Radioactivity
This agency regulates the design and manufacture of x-ray equipment
FDA
regulates the design and manufacture of products used in the radiation industry
FDA (U.S. Food and Drug Administration)
What is a modern generator that take s advantage of exremely short time capabilites and tube hear-loading potential?
Falling load gen4erator
X-ray quantity is proportional to the kVp. True or false?
False
True or False - Electromagnetic radiation travels at the speed of light (186,000 miles per hour).
False - its 186,000 miles per second
What is the number of wavelenghts passing a given point per unit time and is measured in hertz (Hz) called?
Frequency
X-ray beam quality can be identified most appropriately by its
Half value layer (HVL)
a condition in which the voltage is not allowed to swing negatively during the negative half of its cycle
Half-Wave Rectification
the German physicist that developed the first reliable detector for ionizing radiation
Hans Geiger
a form of ionizing electromagnetic radiation emitted from the nucleus of a radioactive atom
Gamma ray
What are electromagnetic rays called that are produced in the nucleus of radiactive atoms?
Gamma rays
Units of magnetic intensity
Gauss & Tesla
What does GSD stand for?
Genetically significant dose
the average gonadal dose given to members of the population who are of childbearing age
Genetically significant dose (GSD)
"Carbohydrate-producing and-packaging factory"
Golgi Apparatus
SI unit of patient dose
Gray
the SI equivalent for rad
Gray (Gy)
Cytosine always bonds with ________.
Guanine
What are 2 other names for a characteristic curve
H&D curve, sensitometric curve
What is the best method to specify x-ray quality?
HVL is most appropriate.
What is the function of oil inside the protective housing?
Helps the cooling of the tube.
he shared the 1903 Noble Prize for Physics with Marie and Pierre Curie
Henri Becquerel
High frecuency generators poduce what?
High-frequency electricity (thousands of hertz)
type of generator that produces a nearly constant potential voltage waveform, improving image quality at lower patient radiation dose
High-frequency generator
the international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings
Human Genome Project
Why is electrification easier in dry Phoenix than in humid Houston?
Humidity allows excess electrons to attach to water molecules in the air.
Who first described the characteristic curve relationship
Hurter and Driffield
makes recommendations on occupational and public dose limits
ICRP (International Commission on Radiological Protection)
List 7 Cellular Effects of Irradiation:
Instant death Reproductive death Programmed cell death (Apoptosis) Mitotic death Mitotic delay Interference with function *Chromosome breakage
How can you increase the kinetic energy of electrons travelling from filament to anode?
Increase KVP
The property of matter that acts to resist change in its state of motion as described in Newton's first law
Inertia
Which interaction produces characteristic radiation? (Inner shell or outer shell?)
Inner shell
what part of the image intensifier changes x-ray photons into light photons?
Input phosphor
the watchdog of the nuclear energy industry; it controls the manufacture and use of radioactive substances
NRC (Nuclear Regulatory Commission)
What type of charge is a Electron?
Negative
What is a Cathode assembly?
Negative elecrode in the x-ray tube
What type of charge is a neutron?
Neutral
SI unit for force
Newton
the force on an object is equal to its mass multiplied by its acceleration
Newton's Second Law of Motion
he developed the concept of the atom as a mini solar system
Niels Bohr
he improved Rutherford's nuclear model in 1913
Niels Bohr
his nuclear model was a miniature solar system in which the electrons revolved about the nucleus in prescribed orbits or energy levels
Niels Bohr
What composes the steps or rungs of the DNA ladder?
Nitrogenous bases
What indicates the kilovoltage that will be flowing through the tube oned the exposure is made?
Prereading voltmeter
The shell number of an atom is called
Principle Quantum Number
What are the 3 Electron-Target Interactions?
Production of heat Characteristic *Bremsstrahlung
List the fundamental particles of an atom:
Protons Neutrons *Electrons
Name 5 Personal skills required by the ARRT:
Provide instructions to the patient Position Patient Prepare the patient Confirm patient identity *Observe and monitor vital signs
a single unit of electromagnetic radiation
Quantum
describes the relative capabilities of radiation with differing LETs to produce a particular biologic reaction
RBE (Relative Biologic Effectiveness)
covers a considerable portion of the electromagnetic spectrum and has relatively low energy and relatively long wavelength
RF (radio frequency)
What is another name for single-strand DNA?
RNA
responsible for developing a radiation safety program for the health care facility; he or she maintains personnel radiation-monitoring records and provides counseling in radiation safety
RSO (Radiation Safety Officer)
the unit most often used when describing the quantity of radiation received by a patient
Rad
time required to reduce radioactivity to half its original value
Radioactive Half-life
Which has the greater magnitude? Protons or electrons?
The electric charges associated with an electron and a proton have the same magnitude but opposite signs.
How is the energy of a photon and its frequency related?
The energy of a photon is directly proportional to its frequency.
How is the energy of a photon related to its frequency?
The energy of a photon is directly proportional to its frequency.
A step-up transformer is used in the x-ray circuit to increase what?
Voltage to the kilovoltage level for x-ray production
What is the role of magnetism in the study of x-ray imaging?
The high voltage generators in x-ray imaging systems are magnetic devices.
What is x-ray quantity mean?
The intensity of the x-ray beam of an x-ray imaging system
What is x-ray quantity means?
The intensity of the x-ray beam of an x-ray imaging system.
At what distance from the source can the inverse square law be applied?
The inverse square law can be applied to distances greater than seven times the longest dimension of the source.
What is heat energy resulting form movement of atoms of molecules?
Thermal energy
What changes electrical voltage and current into higher or lower values?
Transformer
True or False - Thicker part of the body must be place under the cathode side of the x-ray tube.
True
True or False - Travel at the speed of light is constant regardless of wavelength or frequency.
True
True or False - Wavelength and frequency of electromagnetic radiation are inversely proportional?
True
True or False: A cell placed in water without salts would die.
True
True or False: An ion pair is formed when an electron is removed from an atom by ionizing radiation.
True
True or false - X-rays and gamma rays differ only in their origin.
True
List 5 Factors That Affect the Size and Relative Position of X-ray Emission Spectra:
Tube current (mA & mAs) Tube voltage (kVp) Added filtration Target material *Voltage waveform
What contains oil in which the x-ray tube is immersed to assist with cooling and additional electrical insulation?
Tube housing
What supports and protects the tube, restricts leakage radiation during exposure, and provides electrical insulation?
Tube housing
Relationship between filament current and tube current depends on what?
Tube voltage
The filament of an x-ray tube is made of _________ metal.
Tungsten
Area frequented by general public
Uncontrolled area
What is roentgen (R)?
Unit of exposure
What is roentgen?
Unit of exposure, which is the measure of the ionization produced in air by x or gamma radiation.
List the 4 laws of electrostatics:
Unlike charges attract, like charges repel Coulomb's Law of Electrostatic Force Electrostatic force follows the inverse square law Electric charges are uniformly distributed except at regions of high curvature where they concentrate
Proportional amount of time during which an x-ray beam is energized or directed toward a particular barrier.
Use factor
U represents
Use factor
Ohm's Law
V = I R
The Ohm's Law Formula
V = IR
Ohm's law
V=IR
What is the wave equation?
Velocity = frequency x wavelength
The 9 categories of Mechanics
Velocity Acceleration Newton's Laws of Motion Weight Momentum Work Power Energy *Heat
a narrow region in the middle of the electromagnetic spectrum extending from approx. 400 nm (blue) to 700 nm (red)
Visible light
What is the distance between the cathode and the anode?
about 1 cm
What 2 distinct processes occur during beam attenuation
absorption, scattering
QC program includes:
acceptance testing, performance monitoring, and maintenance
how do you calculate atomic mass
add protons and neutrons
another word for oxygenated
aerobic
describe the way in which elements in a group on the periodic table react chemically
all elements in a group react chemically in a similar fashion & have similar physical properties
fast-moving particles capable of ionization
alpha & beta particles
composed of 2 protons and 2 neutrons and carries an electric charge of plus 2
alpha particle
most damaging form of ionizing radiation
alpha particle
the nucleus of the helium atom - two neutrons and two protons
alpha particle
this type of particle is easy to stop
alpha particle
type of ionizing radiation that travels the least distance
alpha particle
this type of radioactivity has a low penetrating power, a short range in air and can be stopped by a sheet of paper
alpha particles
type of radioactivity that has 2 protons & 2 neutrons
alpha particles
unit of electric current
amp
What is the unit of measure of the primary current?
amperes (A)
the filament current, which controls the filament temperature, is measured in this unit of measure:
amperes (A)
What is wave hight called?
amplitude
one-half the range from crest to valley over which the sine wave varies
amplitude
what changes about the voltage waveform from primary to secondary side of the x-ray circuit
amplitude
the substance that coated the plate that fluoresced when Roentgen discovered x-rays
barium platinocyanide
Optical density inherent in the base of the film
base density
Give examples of good sources of direct current:
batteries solar cells fuel cells some types of generators
what would provide a DC?
battery
this increases the number of high energy x-rays in the beam by removing the lower-energy nonpenetrating x-rays.
beam hardening
HVL is a measurement of
beam quality
as the peak of the x-ray emission spectrum moves to the left, what is affected? How?
beam quality decreases
Why is Characteristic radiation called "characteristic"?
because it is characteristic of the target element
this is why alpha particles are so dangerous
because they ionize so strongly; if ingested in your body, they can ionize atoms in the cells of your body
What is the radon limit established by the EPA?
below 4 picocuries per liter (pCi/L)
SI unit of radioactivity
bequerel
electromagnetic wave equation
c=frequency x wavelength
E=mc(squared) can be used in radiology for what purpose
calculating mass equivalence of x-ray photons
List several ways digital imaging has overcome the limitations of film imaging
can be quickly electronically processed, displayed, stored, duplicated, and transmitted, has greater dynamic range and contrast resolution
types of induction
self, mutual
a material that under some conditions behaves as an insulator and in other conditions behaves as a conductor
semiconductor
this class of materials lie between the range of insulators and conductors in their ability to conduct electricity and serve a the basis for today's solid-state microchip marvels
semiconductors
The ability of an image receptor to respond to a low x-ray exposure is a measure of its
sensitivity
What 2 items are needed to construct a characteristic curve
sensitometer, densitometer
The study of the relationship between the intensity of exposure of the film and the blackness after processing is called
sensitometry
Which type of circuit do the following laws apply: total R=R1+R2+R3; total I= I1=I2=I3; total V=V1+V2+V3
series
A radiograph is similar to a ____ because both light and x-ray photons travel in straight lines
shadowgraph
Unequal magnification of different portions of the same object is called
shape distortion
What are several terms used for a small number of widely varying tonal values
short scale, high contrast, zebra
High contrast is also called
short-scale contrast
The top portion of a characteristic curve which shows only small change in OD is called
shoulder
What is the SI unit of measure for Equivalent Dose (EqD)?
sievert (Sv)
variations of amplitude over time
sine waves
to figure HU for a _________phase generator, multiply kVp x mA x s
single
this term means "simple motion; a sine wave"
sinusoidal
An increase in the image size of an object compared with its true or actual size
size distortion (or magnification)
Which focal spot produce high special resolution, Small or large?
small
The greater the number of pixels in an image matrix, the ____ their size
smaller
the effective focal spot is ____ than the actual focal spot
smaller
List 3 advantages of high-frequency generators over 60 Hz high-voltage generators
smaller less costly *more efficient
List 7 uses of Radioactivity
smoke detectors thickness control sterilizing radioactive dating radioactive tracers checking welds *cancer treatment
Why does the glass envelope contain a vacuum?
so that the electrons form the filament do not collide with atoms of gas.
List 2 examples of electrolytes:
sodium (Na) potassium (K)
magnet created by a coil of wire with a current passing through it
solenoid
What has replaced the original diode rectifiers that were vacuum tubes called valve tubes?
solid-state rectifiers made of silicon
