Technique, Physics Flashcards
Lead foil screens are used in radiography:
☑️To improve the quality of the radiograph by preferentially reducing the effect of scatter radiation
☑️To reduce the exposure time
The sharpness of the outline in the image of the radiograph is a measure of:
Radiographic Definition
If a piece of lead 1/2-inch this is placed in the path of a beam of radiation emanating from cobalt-60, it will reduce the dose rate at a given location by:
One half
Two X-ray machines operating at the same nominal kilovoltage and milliamperage settings:
May give not only different intensities but also different qualities of radiation
If a fluorescent screen is accidentally exposed to unattenuated X-rays, which of the following occurs:
The screen is essentially undamaged
Movement, geometry, and screen contact are three factors that affect radiographic:
Unsharpness
An ______ is a charged part of an atom that can have either a +/- charge
Ion
When doing gamma-ray radiography with high-intensity emitters, the sources are best handled:
By remote handling equipment
A graph showing (logarithmic scale) the relation between material thickness, kilovoltage, and exposure time is called:
Exposure chart
Atoms that have the same atomic number but different atomic mass number.
Isotopes
The addition or removal of electrons is called.
Electrification
Atoms that have the same atomic number and the same atomic mass number.
Isomers
The force that keeps an electron in orbit.
Centripetal force
) It is the quantity of matter described by its energy equivalence.
Mass
The unit of the quantity of radioactive material.
Curie
Energy emitted and transferred through space.
Radiation
By using a___________ transformer, the incoming voltage can be adjusted in order to heat the filament of an x-ray tube; is about ________volts
Step Down, 10-12 volts
Which meter registers indicating x-ray exposure?
Milliamp meter
Which of the following applies to the filament transformer?
A step down transformer is needed
The purpose of the circuit breaker is to
Prevent overloading
The source of electrons is the
Cathode, filament
The positive end of the tube is referred to as the
Anode, focal spot
The most sensitive cells to ionizing radiation are
Reproductive cells
The best type of xray to penetrate body tissue is
Hard rays, short wavelengths
Milliamperage controls
Heating of the cathode
The portion of the target that is struck by electrons is called the
Focal spot
Filtration of the xray beam protects the patient by
Eliminating weak wavelength xrays from the xray beam
The term used to express the number of curies of radioactivity per gram or ounce of source weight is:
Specific activity
An advantage of the pocket dosimeter type of ionization chamber used to monitor radiation received by personnel is:
It provides an immediate indication of dosage
White crescent-shaped marks on an exposed X-ray film are most likely caused by:
Crimping film before exposure
As a check on the adequacy of the radiographic technique, it is customary to place a standard test piece on the source side of the specimen. This standard test piece is called a:
Penetrameter
The intensity of X or Gamma radiation is measured in:
Roentgens per unit of time
Film graininess greatly affects the amount of __________ on a radiograph.
Definition
☑️ Film graininess affects definition, whenever penumbra can be reduced it will also improve the definition
When referring to a “2T” or “4T” hole in the ASTM penetrameter, the T refers to:
The penetrameter thickness
As the kilovoltage applied to the X-ray tube is raised:
X rays of shorter wavelength and more penetrating power are produced
The accidental movement of the specimen or film during exposure or the use of a focus-film distance that is too small will:
Result in a unsharpness or the radiograph
True or False
The term ‘’ absorption’’ refers to the ability of a material to permit X-rays to penetrate without loss of energy.
False
☑️absorption is dependent upon the thickness and density at that point.
absorption- the ability of the specimen to BLOCK the PASSAGE of X-RAYS through the material.
The purpose of agitating an X-ray film during development is to:
Renew the developer at the surface of the film
Amount of energy deposited per unit mass (J/kg)
Absorbed dose
Frequency and wavelength are ________________ to each other.
Inversely proportional
The activity of the developer solution is maintained stable by:
Addition of Replenisher
Cobalt 60 used in nondestructive testing emits:
Gamma Rays
When the minute silver grains on which the xray film image is formed group together in relatively large masses, they produce a visual impression called
Graininess
Term used to describe the loss of excess energy by the nucleus of radioactive atoms is called
Decay (disintegration)
A large source can be compensated by:
Increasing the source-to-specimen distance.
A radioactive source with an activity of one curie has:
3.7 x 10^10 disintegrations per second taking place
Unit of absorbed dose
rad
Atomic mass number represents
Number of protons and neutrons in the nucleus
It is a type of radiation that is capable of removing an orbital electron from the atom with which it interacts.
Ionizing Radiation
SI Unit for radiation exposure to air is
Air Kerma
Largest source of natural environmental radiation
Radon
Smallest particle of an element
Atom
What process by which xray are produced?
Bremstrahlung and Photoelectric
Unit of current
Ampere
A cathode is a filament composed of
Tungsten
The time period between the effects of cumulative radiation and visible tissue damage is the
Latent Period
To avoid exposure to the secondary radiation , the operator should stand
At least 6 feet from the xray head
Film speed is determined by the
Size of the silver bromide crystal
The radiographic film is covered with an emulsion of
Silver Bromide Crystal
A material substance that does not stop or absorb xrays is known as
Radiolucent
A latent image is
Composed of energized silver halide crystals
Black lines across the film may be result of
Excessive bending
As the target-film distance is increased, the
Less distortion
If a film is exposed on the wrong aide, the result would be
A herringbone pattern
The difference in density in various regions of a radiograph is called
Contrast
The developing solution should
Always be covered
Films left overnight in the fixer
Will be clear
The fixing solution is
Acidic
Fixing the film
Removes the unaffected silver salts
For the developing solutions to work, the solution must be
Basic
Reticulation is
Cracking of the film emulsion
Air gap technique
☑️reduces scatter ☑️increases contrast ☑️IP 10-15 cm away from pt ☑️mAs increase 10% for every cm gap ☑️Not effective with high kV
Energy is measured in
Joules or electron volts
Removal of electeon from an atom
Ionization
Exposure is measured in unit of
Gray
When were x-rays discovered?
Nov 8, 1895
Defined as an instantaneous production of the light only during an interaction between a type of energy and some element or compound
Fluorescence
Fluorescent material that glowed when tube is energized
Barium platinocyanide
Xrays used in radiography have wavelengths that are measure in
Angstroms
Unit of Frequency
Hertz
Xrays used in radiography have wavelenth from
0.1 to 1 A
