Radiology Flashcards
connects extension arm and tube head, can revolve 360
Yoke
Measures the amount of current passing through the wires of the circuits; determines the available number of free electrons at the cathode filament; determines the amount of xrays produced
mA
determines the speed of electrons traveling from cathode to anode; determines the PENETRATING ability of the xrays produced.
Kvp
a — kvp produces a radiograph with long scale contract; many shades of black to white
high
the timer regulates duration of the interval the current will pass through the xray tube. how many impulses?
60
electricity continuously flows in one direction. well suited for digital radiography
direct contact
the measurement of the number of electrons moving through a wire conductor
amerage
majority of dental x ray units operate in ranges from — mA to — mA
7-15
the electrical pressure between two electrical charges; the measurement of electrical force that causes electrons to flow through a conductor; in radiography, determines speed of electrons traveling from cathode to anode
voltage
the highest voltage to which the current in the tube rises during exposure; majority of dental x ray untis operate in range of 65 to 100 kvp
kvp
1 percent of — is converted to xray, 99 is loss to heat
energy
heat is carried away and absorbed by insulating oil
true
results in freed electrons to form cloud and hover around the filament wire recessed in the focusing cup until exposure button is pressed
thermionic emission
wavelengths and frequency are inversely related
true
xrays travel in — lines
have no charge
can cause latent image
straight
aka thompson scattering, low energy xray passes near atoms outer electron. it may be scattered without loss of energy, the xray is scattered and unchanged
coherent scattering
electromagnetic energy of xray is imparted in the form of kinetic energy causing the electron to fly from its orbit with considerable speed.
photoelectric effect
exposure is per —- in —- units
coulombs per kilogram, and roentgen
absorbed dose is per — and in — units
gray, rad
dose equivelent is — to — units
sievert, rem
occupational exposure limit is — mSv in one year
50, 5 rem
occupational lifetime exposure limit is — mSv times the number of an individuals age
10
pregnant dental personnel occupation exposure limit is
.5 mSV/month
general public is permitted — in one year
.5 rem or 5mSv
Lymphoid, organs, bone marrow, testes, and ovaries, small intestines, fetal cells
HIGHLY RADIOSENSITIVE
muscle, brain, spinal cord
low radio
reduces size of the xray beam impacts area of tissue exposed to primary xray beams reduces scatter
collimator
single most effective method of reducing radiation to patient
rectangular
rectangular collimation reduces patient exposure by
70 percent
must restrict x ray beam to — at the skin surface
2.75 inches
safety standards require equivalent of 1.5 mm aluminum for xray machines operating in ranges below 70 kvp and a minimum of 2.5 mm aluminmum for machines operating at or above 70 kvp
true
the longer the pid the less
radiation to the patient
lead apron must contain — mm of lead
.25
second most effective method of reducing radiation to patient
fast film
6 feet away at – – from head of patient
90 -135
sensitive to radiation, retain the latent image when exposed to xrays
silver halide crystals
the thicker the emulsion the faster the film.
the larger the crystal the faster the film
both true
inadequate rinsing during any technique results in film turning — eventually
brown
— or — watt incandescent white light with a safelight filter over it
7.5-15
safelight must be minimum of — from working area
4 feet
reduces exposed silver halide crystals to black metallic silver
developer
stops further film development, establishes the image perm. on the film, removes the unexposed silver halide crystals, hardens the emulsion
fixer
utilizing the occlusal radiographic technique along with parallel or bisecting the angle
right angle method
produces images by utilzing a narrow beam of xrays to image a curved layer of slice of tissue
tomography
the area between the xray source and the film where structures will be imaged clearly on the radiograph
focal trough
frankfort plane needs to be parallel to the
floor
chin to far forward
anterior teeth blurred and diminisehd
chin to far back
anterior teeth blurred and magnified
when the patients chin is tipped to low in pan xray the teeth on the anterior will be positioned closer to the film. the anterior teeth will appear blurry and magnified on the processed film
both false
which of the following would be best for imaging perio disease
periapical radiographs exposed using paralleling tech
when the automatic processor is working properly, how will an unexposed film exit the return chute?
a. wet and dark
b. dry and dark
c. wet and clear
d. dry and clear
dry and clear
where should the embossed identification dot be positioned when taking periapical radiographs
a. toward the midline of the oral cavity
b. toward the distal of the oral cavity
c. toward the palate of the floor of the mouth
d. toward the incisal or occlusal edge of the tooth
d
when viewing a radiographic film you identify the inverted y. what makes the y?
a. dense cartilage structure that seperates the right nasal fossa from the left
b. lateral wall of the nasal fossa and the anterior medial wall of the max sinus
c. delineation of the midline of the palate and the junction of the right and left maxilla
d. the opening that serves for the passage of nerves and blood vessels to max incisors
b
which of the following is a radiolucent image evident on max cent periapical film a. nasal fossa b. nasal septum c lingual foramen d.anterior nasal spine
a
which of the following removes the unexposed silver halide crystals from film emulsion during film processing
a. elon
b. hydroquinone
c. sodium thiosulfate
d. potassium bromide
c
why is f speed film recommended over d speed film
a. processess faster
b. exposes two films at once
c. greater sensitivity to radiation
d. more comy in patients mouth
c
which age of patient would be more sensitive to ionizing radiation a. 6. b. 16 c 30 d 60
a1
