ch 1-4 Flashcards
A transformer is used to step up or step down electricity; it receives:
High voltage and low amperage
In x-ray technology, potential difference refers to the difference between:
The charge between the cathode and the anode of the x-ray tube
The purpose of a transformer is to
Increase the voltage in a step-up transformer
Rectifiers are used in the x-ray circuit to ensure that:
The current flows through the x-ray tube in a continuous direction
The high-frequency x-ray unit is _________ efficient than a/an __________ unit.
more, single-phase
The cathode in the x-ray tube is a coiled _________. It is made of ______________.
wire, tungsten
The filament circuit is used to:
Send voltage to the cathode to heat it
The anode rotates in order to:
. Dissipate the heat emitted in the production of x-rays
X-rays are produced when ________ electrons are attracted to _______________ by an electromagnetic force.
negative, a positive anode
Heat builds up on the anode and must be dissipated by:
A rotating anode and a tungsten alloy target
The rotor circuit is responsible to activate:
The rotating anode
The exposure switch must ____________ and _________________.
terminate when the exposure is complete, must not reexpose until the switch is released and reactivated
The line voltage compensator is situated_______ and controls the ________.
on the incoming line; incoming voltage
A ground wire is installed in every generator. Which of the following statements is correct?
It provides an alternative route for the electricity.
Direct current is necessary to produce x-rays; the current must flow through the x-ray tube:
From the cathode to the anode without interruption
produces one positive pulse and then one matching negative pulse; An electric current that reverses its direction many times a second
alternating current
The strength of an electric current, measured in amperes
amperage
An electrode with a positive charge; An electrode with a positive charge
“Positive Andy”
Anode
Because of the angle of the anode target, the x-ray beam has greater intensity on the cathode side of the tube, with the intensity diminishing toward the anode side. Used when a patient is thicker on one side of its anatomy
Anode Heel effect
Occurs during the production of x-rays when a projectile electron completely avoids the orbital electrons of the tungsten atom and travels very close to its nucleus. The very strong electrostatic force of the nucleus causes the electron to suddenly ‘slow down’. As the electron loses energy, it suddenly changes its direction and the energy loss then reappears as an x-ray photon.
Bremsstrahlung radiation
A negatively charged electrode within the x-ray tube. It comprises a filament and a focusing cup.
cathode
Produced when a projectile electron interacts with an electron from the inner (K) shell of the tungsten atom. When the K-shell electron is ejected from its orbit; an outer shell electron drops into the open position and thereby creates an energy difference. The energy difference is emitted as an x-ray photon.
characteristic radiation or interactions
A course or pathway through which an electrical current passes
circuit
An automatic safety device for stopping the flow of current in an electrical circuit
circuit breaker
An electric current flowing in one direction only.
ex: flashlight
direct current
The switch that generates the power to the x-ray tube. A remote-control device that permits current to flow through the circuit.
exposure switch
what are the two stages of the exposure switch
The first stage activates the rotating anode and boosts the filament circuit. The second stage activates the exposure, and x-rays are produced.
A coiled tungsten wire that is the source of electrons during x-ray production. Part of the cathode, has two sizes
Filament
The physical area of the target that is bombarded by electrons during x-ray production
focal spot
When the anode is bombarded with radiation, it becomes very hot. This can expand the size of the anode and therefore decrease sharpness.
Focal spot bloom
X-rays are described as:
Invisible, but they travel in straight lines at the speed of light
An element is the smallest part of a substance. Which of the following statements is true?
a. The element is combined with a proton.
b. The smallest part of an element is an atom.
c. The element is composed of neutrons and particles.
d. Electrons circle the element in random order.
b. The smallest part of an element is an atom.
The electrons are held in place by:
The positive charge of the protons
On the table of the elements:
The elements are arranged in specific groups.
. Matter and energy are basic to every substance on earth. Which of the following statements is true?
a. The principle characteristic of matter is mass or weight.
b. The principle characteristics of energy are time and space.
c. Matter represents motion and frequency.
d. Energy cannot be created out of atoms and molecules.
a. The principle characteristic of matter is mass or weight.
The electromagnetic spectrum represents:
The vast spectrum from x-rays to radiowaves
Energy can be represented by both:
b. Waves and frequencies
A sinusoidal wave represents x-ray energy as waves. Which of the following statements is true?
a. It contains the energy of the x-ray beam.
b. It is an uneven wave so cannot be measured.
c. It has frequency and amplitude in its definition.
d. It represents the motion of the x-ray timer.
c. It has frequency and amplitude in its definition.
Energy as particles is represented as:
Waves with frequencies and structure
Photons are described as:
Electromagnetic radiation that has no electrical charge
Radiation workers should always reduce radiation doses by following the:
ALARA principle
The radiation dose that workers are subjected to today is ________ than the ______doses of early researchers.
far less, high
When radiation strikes a cell, the most vulnerable area is the:
DNA
If there is damage to the DNA, one of the outcomes is:
Cell death from damage to the entire cell
Late-occurring effects are evident long after the damage has occurred. They are:
Stochastic effects
Radiation exposure to veterinary workers is usually due to:
Scattered and secondary radiation
Isotopes are variants of elements. They have differing numbers of:
neutrons
Linear energy transfer is defined as:
The ability of radiation to transfer energy into tissue
X-rays and gamma rays have:
Low LET with higher penetrability
Bone is much denser than fat so it absorbs more radiation than fat. (t/f)
true
Three methods of radiation protection are:
Time, distance, and shielding
The most susceptible tissue is tissue that is rapidly dividing; which of the following is true?
a. Postpubertal adolescents would be highly affected.
b. Prepubertal children would be most affected.
c. This includes the healing of surgical wounds.
d. This includes the tissue in a 2- to 10-week fetus.
d. This includes the tissue in a 2- to 10-week fetus.
Shielding of radiography rooms is essential in all installations; which of the following is true?
a. Most radiation therapy suites are excused from this regulation.
b. This applies to all imaging suites where ionizing radiation is used.
c. This applies to only dental and nuclear medicine suites.
d. This applies to only units that use over 90 kilovolts.
b. This applies to all imaging suites where ionizing radiation is used.
. Leaded aprons are composed of thin sheets of leaded rubber; which of the following is true?
a. The rubber is flexible and not likely to split if folded.
b. The rubber is heavy and does not react to bending or splitting.
c. The sheets of rubber are fragile and will split apart over time.
d. The leaded apron should be hung up when not in use.
d. The leaded apron should be hung up when not in use.
Radiation dosimeters must be issued to every radiation worker; which of the following is true?
a. Personal dosimeters should be hung in the x-ray room when not in use.
b. These are personal dosimeters and must not be shared with other workers.
c. They can be shared by people who job-share.
d. They should be taken home at the end of each shift to ensure they are safe.
b. These are personal dosimeters and must not be shared with other workers.
The radiation worker is described as:
A worker who works with radiation during his or her normal duties
An employer is legally bound to instruct new employees that:
There is equipment that produces radiation on site
An employer is legally bound to instruct new employees that:
There is equipment that produces radiation on site
When maximum doses allowed are listed, there is no discrimination between men and women of reproductive age. (t/f)
true
There are two completely separate components to an imaging system; they are:
. X-ray generator and imaging receptor
It is very important that the x-ray generator is the latest model available (t/f)
false
A good technique chart and knowledge of image production is essential because:
Setting correct technical factors is essential to good imaging
The x-ray cassette is a sophisticated film holder. Which of the following statements is true?
a. It can be made of any plastic as long as it is bendable.
b. It must be sturdy and have a strong reliable closure.
c. The film can be held loosely in place as long as it is light-tight.
d. The intensifying screens are placed in the cassette by the technician.
b. It must be sturdy and have a strong reliable closure.
The front of the x-ray cassette:
Must be radiolucent and free of artifacts
The purpose of an intensifying screen is to:
Convert the primary x-ray beam to light photons
The intensifying screen is composed of a __________ and a(n) ____________.
base, emulsion layer
Conversion efficiency is ________ at which the x-ray photons are converted _____.
the speed, to light
Screen speed is defined by the:
Conversion efficiency of the phosphor
Rare earth elements are so named because they are _______ and ________ efficient than standard phosphors.
difficult to mine from the earth, more
The density chosen to represent a midline density is:
1.0
The intensification factor is the ______ necessary to produce an image ______ screens vs. the exposure necessary to produce the image _____ screens.
exposure, with, without
Imaging relies on a sound knowledge of the colors of the rainbow; the following is true:
a. It doesn’t matter because we can’t see color in the dark.
b. Ultraviolet, on the outside of the curve, cannot be affected by infrared.
c. Ultraviolet is in the middle of the curve; infrared is on the outside of the curve.
d. The color of the light that film emulsion reacts to must match the screen color.
The color of the light that film emulsion reacts to must match the screen color.
The introduction of green light–emitting screens:
a. Was a natural progression in screen technology but created confusion
The green-receiving film will “see” blue light:
But needs the green light to produce an optimum image
Knowledge of the system speed is critical to produce the correct amount of radiation:
b. To optimize imaging and produce a diagnostic radiograph
Luminescence is the reaction of the screen to the photons; the reaction is called:
a. Fluorescence
If the screen continues to emit light after the photon source is removed, the effect is called:
a. Phosphorescence
A knowledge of screen color and speed assists in optimizing imaging and ensuring uniformity of images. (t/f)
true
The film base Mylar was produced in response to:
A need for a stable, nonflammable, nontearable support for the emulsion
Two types of film are ________ emulsion and ________ emulsion film.
d. double-, single-
Screen speed is determined by the _____ of the emulsion and the ____ of the silver halide crystals.
thickness, size
Film emulsion is composed of mainly:
a. Silver iodide crystals and gelatin
The supercoat is an added top layer that:
Protects the emulsion during processing
The lattice network is so named because:
. A confluence of sensitivity specks will make up the beginning of the image
The combination of the color of the film base and the initial aging of the film:
c. Is called base + fog
If a film is exposed to alternative energy, it will acquire a density before exposure. Which of these statements is true?
a. This may be caused by heat, light, or chemical fumes.
b. This density does not affect the overall image.
c. Film fog is a natural part of imaging.
d. Fogging a film is not important in image production.
a. This may be caused by heat, light, or chemical fumes.
The following factor distinguishes a fogged film as opposed to overexposed film.
d. The density does not change if the technique is altered.
Blue-receiving film is physically ______; green-receiving film is physically _______.
a. green, violet
The following method is used to determine the color of the screens in order to use the correct film:
The cassette is placed open on the table and exposed to radiation.
White box film is so called because:
It did not meet the quality control standards of the parent company
New unused boxes of film should be stored:
a. Upright in an area unaffected by radiation and heat
X-ray film has an expiration date, which should be:
d. Noted and adhered to by the facility staff
The standard film sizes are important to the ordering process because:
The film sizes are critical to the size of the cassette
