Which radiology innovator is known as the father of the science of radiation protection?
Which theory best describes the free radical formation that is so injurious to living tissue?
What factor is most important when considering the biologic effects of radiation used in dentistry?
Limited area exposure
Which radiographic technique has less distortion and magnification and creates a more accurate image on film?
If the source-to-film distance is changed from 8 to 24 inches, the intensity of the beam becomes __________.
1/9th as intense
The greatest cause of human radiation effects in dental radiography involve _________.
Free radicals of water
Cell sensitivity to radiation is most pronounced when?
During mitosis, periods of increased metabolism and during embryonic development
As you go from a "D-speed" film to an "E-speed" film, the exposure time should be approximately ________.
The mA setting controls what?
Heat of the tube filament
Number of free electrons in the tube
number of photons ultimately produced
The density of the film
A bite wing film is exposed properly using an exposure setting of 1 second with the xray source 8 in from the patient. What time would be needed if the source was moved 16 inches away?
For optimal detection of incipient interproximal caries, what machine setting is preferable?
65 Kvp, 10 mA
The primary purpose of sodium thiosulfate is to ________.
Remove the silver bromide crystals that have not been developed and enhance contrast
For reducing scatter radiation, the collimation or restriction of the radiation beam at the patient's face should not exceed ___________.
Which of the following PID's will reduce scatter radiation most effectively?
Long, rectangular, lead lined
If a person who works with radiation and wears a film badge or TLD dosimeter and has radiographs taken on themselves as a patient, what should be done with the dosimeter during exposure?
Leave the badge outside of the room
If a machine operated with good radiographic results at a setting of 10mA and 12 impulses, what exposure time should be used if the machine is set to 12 mA?
What is the proper thickness of the lead lining in radiographic lead aprons and thyroid collars?
0.25 mm equivalent
A film that has turned brown over a span of one year may have resulted from __________.
Which film processing ingredients converts energized crystals into metallic silver?
What is the processing order that films undergo in an automatic film processor?
Developer, fixer, water, dry
What is the least likely to cause a fogged film out of
What radiopaque maxillary anatomic landmark is MOST LIKELY to be seen on a maxillary incisor periapical film?
Partially formed third molars on a panoramic radiograph indicate that the patient is MOST likely how old?
11-15 yrs old
A pt of record complains of temperature sensitivity in the maxillary right second molar region of the mouth. A CMRS was taken 2 years ago. Which radiograph should be prescribed?
A radiolucent shadow that obscures the apices of the maxillary dentition on a pano indicated that what error occurred?
The tongue was not touching the palate
On a mandibular molar film the most superior radiopaque anatomic landmark is the _____________.
External oblique ridge
The hamular process is observed on intraoral films in a view of the ____________.
Maxillary molar area
Which of the following combinations of structures appears radiolucent on a radiograph?
Nares, median suture, medullary spaces
The ALARA concept endorses the use of the __________ possible exposure of the patient and operator to x-radiation to produce a diagnostically acceptable radiograph.
When the raised dot is placed outward (convex), the left side of the mounted radiograph corresponds to the ____ side of the patient's oral cavity.
_______ radiation is radiation that has been deflected from its path during the impact with matter.
The ________ is a method for determining the relative location of an object hidden within the oral tissues.
Buccal object rule
The hydroquinone in the developer brings out the ____ tones, whereas the Elon in the developer brings out the _____ tones on a dental radiograph.
What are the purpose of the fixing solution in processing radiographs?
Harden emulsion & remove undeveloped silver halide salts
Increasing the milliamperage (mA) will cause _____________.
An increase in density; the film appears darker
Increasing the operating kilovoltage peak (kVp) will cause ___________.
An increase in density; the film appears darker
The rays that are most apt to be absorbed by the skin are xrays that are _______________.
Of long wavelength
The speed at which the electrons move across an xray tube is regulated by _____________.
Why is an increases target-film distance required in the paralleling technique?
To avoid image magnification
What is the relationship of the central ray to the film in the paralleling technique?
90 degrees to the film and the long axis of the tooth
A dental xray machine that is set at more than 70 kVp is required to have a total filtration of at least how many mm of aluminum?
If the temperature of processing solutions is slightly above normal, radiographs of desired density may best be obtained by __________.
Decreasing developing time
A breakdown of chemicals in the processing solution that results from exposure to air is termed _________.
The super concentrated solution that is added to the processing solution to compensate for the effects of oxidation is termed __________.
Arrange the following cells and tissues from MOST sensitive to LEAST sensitive to ionizing radiation:
Adult bone and nerve
Epithelium and muscle
Alimentary tract and immature bone
Blood forming cells and reproductive cells
1. Blood forming cells and reproductive cells
2. Alimentary tract and immature bone
3. Epithelium and muscle
4. Adult bone and nerve
A major difference between automatic and manual processing of radiographs is that automatic processing __________.
Requires special solutions at higher temperatures
What is the periapical lesion that is least likely to be seen on radiographs?
An acute alveolar abscess
The Coronoid Process
The marked prominence that appears on a maxillary molar periapical film as a triangular radiopacity superimposed over, or inferior to, the maxillary tuberosity region is
On intraoral radiographs, when the patient's right is on your left, this is called __________Mounting
The protective coating on the emulsion is softened by the ________and hardened by the __________
Digital radiography requires less radiation than conventional radiography because the;
Sensor is more sensitive to x-rays
The purpose of the aluminum filter is the x-ray tube head is to remove the ____energy, _____wavelength, least penetrating from the beam
Proper prescribing of radiographs
_____________ is an example of a patient protection technique used before x-ray exposure
PID (Position Indicating Device)
The _________ is an extension of the x-ray tube head and is used to direct the x-ray beam.
Long axis of the film
When using the bisecting technique, the imaginary angle that is bisected is formed between the long axis of the tooth and the;
On intraoral radiographs, when the patient's right is on your right, this is called __________ mounting
is that form of radiation that is in the environment and includes cosmic and terrestrial radiation
A concept of radiation protection that states that all exposure to radiation must be kept to a minimum is
With size 2 films, a total of ___________anterior film placements are used with the paralleling technique?
Reduce radiation to the tissues surrounding the area to be examined
Collimation of the x-ray beam is accomplished through the use of washers placed in the path of the primary beam of radiation. The primary purpose of the collimator is to:
The function of the lead diaphragm on the head of the x-ray machines is to:
Limit the size of the beam
Reduce radiation exposure to the patient
The intensifying screen used with Extraoral films functions to
In normal dental diagnostic procedures, the principal hazard to the operator is produced by
What is the operator distance, from the x-ray source recommended by the national bureau of standards
shows the complete image of the tooth, from Incisal edge to apex, the alveolus, supporting mesial and distal one and surrounding bone beyond the apex.
When using bisecting technique, when the palate is high or the floor of the mouth is deep, you would
Decrease vertical angulation
The disto buccal root of the tooth # 3 appears smaller than normal the causative factor is
Vertical angle to high-horizontal angle to far mesial
The principle reason for placing an aluminum filter in the primary beam or radiation
To obtain greater definition of the images of the teeth
A dentist using a film badge service to measure his radiation exposure gets a report from the film badge service stating the badge was exposed to 475 millirems in the previous mouth. The dentist should
Evaluate his x-ray procedures and take steps to reduce unnecessary radiation
Centric Ray or Central Ray
is the primary beam of radiation emanating from the aperture of the collimator of the x-ray tube head.
5 rem per year
The Maximum Permissible Dose (MPD) for each member of the dental staff must not exceed.
The following can produce a thin or light image on the x-ray film
Underexposure, Underdevelopment, Cold developing solution
In the placement of the dental periapical film, the border of the film packet should be parallel to the
True or False: The quantity often x-rays produced is controlled by Kilovoltage (Milliamperage)
True or False: All set of radiographs should be taken according to insurance coverage (every 3yrs)
True or False: If an exposed film is dark, to lighten the duplicate expose the duplicating film to the light longer
True or False: When using the bisecting method the object film distance is kept to a maximum (Minimum)
True or False: When using the bisecting techniques, the imaginary angle that is bisected is formed between the long axis of the tooth and the long axis of the film
True or False: The inverse square law is when the intensity of the radiation at a certain point distance from a point source of radiation is inversely proportional to the square of the distance from the radiation source.
Collimation of the x-ray beam is accomplished through the use of washers placed in the path of the primary beam of radiation. The primary purpose of the collimator is to:
Reduce radiation to the tissues surrounding the area to be examined
A beam of energy that has the power to penetrate substances and record image shadows on photographic film.
What can cause an overdeveloped film
excessive development time, inaccurate timer/thermometer, high developer temperature.
A replenisher is added to the processing solutions to
compensate for loss of solution strength, ensure uniform results between solution changes, compensate for the loss of volume of solutions, compensate for oxidation.
In film processing, the rinsing step is necessary because:
rinsing removes the developer from the film and stops the development process.
When intraoral images are impossible to obtain, the radiographer should
Use extraoral images to obtain diagnostic information.
Which intraoral film is used to examine the entire tooth (crown and root) and supporting bone?
The intensifying screen that emits green light and must be used with green sensitive film is
Rare earth screen
An adult comes in for a periodontal check up and doctor asks for 4 bitewings. what size film shoudl you use?
What controls the amount of contrast and also the amount of kinetic energy produced
KVP (Kilovoltage Peak)
The zone in which structures are clearly demonstrated on a panoramic radiographs is termed the
The imaginary line that passes from the bottom of the eye socket through the top of the ear canal is termed the
The midsagittal plane must be positioned perpendicular to the floor.
Both Panoramic or Intraoral Radiography
True or False: The preferred exposure method for intraoral digital radiography is the paralleling technique.
In the dental radiography, the term ____ is used to describe the mean energy or penetrating ability of the x-ray beam
True or False: The concept of paralleling is when the film is placed parallel to the long axis of the tooth and the primary beam of the x-rays is directed at a right angle to the long axis of the tooth.
Which of the following is the true of the bisecting technique
film is as close to the tooth as possible
The inverted Y is created by
the intersection of the anterior border of the maxillary sinus and the lateral wall of the nasal fossa
________is a rounded prominence of bone that extends posterior to the third molar region.
Cortical bone is
hard or compact bone, is the dense outer layer of bone, radiopaque, the inferior border of the mandible is composed of cortical bone.
Zygomatic process of the maxilla
is a bony projection of the maxilla that articulates with the zygoma, or malar bone.
ovoid or round radiolucent area located between the roots of the maxillary central incisors
a lesion characterized by a localized collection of pus around the apex of a nonvital tooth that results from pulpal death; appears radiolucent.
incipient interproximal caries
extends less than halfway through the thickness of enamel. Incipient means beginning to exist or appear.
moderate interproximal caries
extends less than halfway through the thickness of enamel but does not involve the DEJ.
advanced interproximal caries
extends to or through the DEJ and into the dentin but does not extend through dentin more than half the distance toward the pulp.
severe interproximal caries
extends through the enamel, through dentin, and more than half the distance toward the pulp
the surface of a tooth that is farthest from the midline of the dental arch, opposite to its mesial surface.
the surface of a tooth that is closest to the midline of the dental arch, opposite to its distal surface.
proximal surface (proximate surface)
the area where the mesial surface of one tooth touches the distal surface of another; called also contact area or surface.
the surface of a tooth that faces inward toward the tongue and oral cavity, opposite the vestibular surface; called also oral surface.
the cutting edges of the anterior teeth, the incisors and canines, which come into contact with those of the opposite teeth during protrusive occlusion. See also occlusal surface.
refers to tissues that invest and support teeth, such as the gingiva and alveolar bone.
absorb x-rays, and as a result, very little (if any) radiation comes in contact with the receptor. (amalgam, gold, etc.)
may vary in appearance from radiolucent to slightly radiopaque, depending on the density of the material. (porcelain, composite, acrylic)
alveolar bone loss
refers to loss of maxillary or mandibular bone that surrounds and supports the teeth
How many ounces of developer solution should added to the developer tank at the beginning of each day
How many ounces of fixer solution should added to the fixer tank at the beginning of each day
A Replenisher is
a super-concentrated solution that is added to the processing solutions to compensate for the loss of volume and strength that results from oxidation.
The process of informing the patient about the particulars of exposing dental radiographs termed
Paralleling technique is also known as
the extension cone paralleling (XCP) technique, right angle technique, and long cone technique.
film produced using 90 kVp and 0.25 seconds. what exposure time is needed to produce the same at 75 kVp ?
The total energy contained in the xray beam in a specific area at a given time is termed....
Which radiation occurs only at 70 kVp or higher ad accounts for a very small part of dental x-rays produced?
why is an increased target film distance required in the paralleling technique?
to avoid image magnification
The -----the crystals, the -------- the film speed
The larger the crystals , the faster the film speed
What regulates the flow of electrical current to the filament of the x-ray tube?
low -voltage circuit
Process by which unstable atoms undergo a spontaneous disintegration in an effort to attain a more balance nuclear state?(undergo decay trying
to become more balanced )
Who introduced paralleling tech. and exposed first dental radiograph in the US using a live person?
C. Edmund Kells 1896
The higher the speed of the film....
the faster the film exposure and the less radiation to patient
Chemical components that change when exposed to radiation or light are termed?
silver halide crystals- reduced to black metallic silver
Five Rules for Paralleling tech
Film Placement- most cover teeth to be examined
Film Position- parallel to the long axis
Vertical Angulation- CR directed perpend to film
Horizontal Angulation - CR directed thru contact-open
Film Exposure- center x-ray beam to espose film
Radiation that is capable of producing ions by removing or adding electrons to an atom.
# of wavelenths that pass a given point in a certain amount of time.
Low freq./ Long wavelength = decreased energy
High freq/ short wavelength= increase energy
x-ray photon is deflected form path during passage through matter
x-ray photon that has its path altered by matter
No change in atom occurs, NO ionization
What determines the speed of dental films?
size of crystals, thickness of emulsion, radiosensitive dyes
what causes film fogging
-old or contaminated processing solutions
-exposure to chemical fumes
what would cause a film to be too light
-depleted developer solution
-excessive fixation (takes all crystals off)
what would cause a film to be too dark
-developer is too strong
-not enough fixation
-exposure to white light
what would happen to a film that is placed in the fixer prior to development
blank or clear
(takes all of the crystals off)
what is reticulation
cracking of the emulsion caused by excessive temp diff. b/w any darkroom solutions
how would a film appear if submerged totally in the developer but not in the fixer
top of film delineated by a straight line then dark
film submerged totally in fixer but not in developer
part that was fixed but not developed would be clear
diff. b/w direct and indirect exposure sensor?
direct - directly obtaining a digital image by exposing intraoral sensor to x-rays to provide an image that can be viewed on a computer
indirect - photostimuable phosphor plate sensor technology, obtaining a digital image in which an exposed phosphor plate is placed into a scanner and then converted into a digital image
what projection would you take for a patient complaining of pain in the lower left molar area
left molar PA
what is the purpose of a pano
image the entire dentition, surrounding alveolar bone, sinuses, and the TMJ, examine large area of face and jaws, locate impacted teeth, retain root tips, evaluate trauma, lesions, and diseases, and assess growth and development
how do you differentiate b/w max and mand molar when mounting
- max molars have 3 roots, mand have 2 roots
-Photostimuable Phosphor Plate aka storage phosphor system
-indirect digital imaging
-captures analog data then processed in a laser scanning device
-light is then converted into electrical signal that the computer uses to create the digital image
what type of projection is used to visualize the crestol alveolar bone on a patient with moderate to severe bone loss
max. centrals anatomy
-nasal septum, ant. nasal spine, nasal fossa, median palatine suture, incisive foramen
what would cause increased magnification, decreased resolution and edge sharpness
increased focal spot size, decrease source-object distance, & increased object-film distance
according to principles of shadow casting, how should the film be placed in relation to the tooth?
according to principles of shadow casting, how should the central beam be directed
perpendicular to the tooth and film
what periapical technique offers the best diagnostic quality?
paralleling; meets more principles of shadow casting
how is vertical angulation established with the bisecting technique
beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film
how is vertical angulation established with the paralleling technique
perpendicular to the film, parallel to the bite portion of the stabe
how does packet placement differ b/w bisecting and paralleling
-bisecting - packet is as close to tooth as possible, but not parallel
-parallel - packet is parallel to tooth, further away
what is the best method of reducing radiation to the patient
rectangular collimation and fast film speed
what is inherent filtration
produced by internal barriers in tube head
(ex: glass and insulating oils)
how should the frequency of radiographic exposures be determined
depends on the needs of the patient, established after intraoral exam
how does the reproductive capacity of a cell correlate with radiosensitivity
rapidly producing cells are more sensitive to radiation
how are x-rays formed in the tubehead
-turn on machine
-press exposure button
-filament heats up/thermoionic emmision
-electron cloud is formed
-electrons flow from cathode to anode
-electrons strike target
-energy is converted into x-rays and heat
list the properties of x-rays
-travel in straight lines
-travel and speed of light
-interact w/ matter causing ionization
-can penetrate opaque tissues and structures
-can effect photographic film emulsion
-can effect biologic tissue
what are occlusal radiographs used to diagnose
-locate retained roots
-locate unerrupted or impacted teeth
-evaluate for diseases and lesions
-locate foreign bodies
-reveal presence of salivary stones (sialothiths)
-aid in evaluating fractures
-size and shape of tori
-aid in examining patients with trismus (patient can only open mouth a few mm)
-evaluate borders of sinus
-examine cleft palates
-substitute for PA's for young children or patient who can't tolerate
how does exposure time for edentulous patients compare to dentulous patients
1/5 exposure time for edentulous
if the kVp is increased from 75-90, what must be done to achieve a radiograph of comparible density
-decrease mA & time
if the source-object distance is cut from 16 to 8 , what must be changed to compensate
method should be compensated for bisecting or paralleling
You take a radiograph using 10 mA 30 impulses and 90 kVp, your dentist wants a radiograph with increased contrast and equal density. What settings would you use?
decrease kVp by 15 and double exposure time
10 mA 60 impules 75 kVp
what are the short term effects of radiation exposure
erythema, vomitting, nausea, hemorrage, diarrhea, hair loss
what are the long term effects of radiation exposure
cancer, cateracts, embryologic defects, genetic mutations, low birth weight
what exposure is taken to determine jaw relationships in ortho treatment planning
what is the purpose of taking radiographs of an edentulous patient
-detect pathological lesions
-establish position of mental foramen
-establish position of mand canal
-determine quality & quantity of alveolar bone present
what exposure would be useful in identifying salivary stones in the submandibular gland
what are common sources of background radiation
cosmic , naturally occuring radiation from earth, radiation for radioactive materials
how are indirect exposure films exposed
x-rays hit phosphor screen creating florescent light that exposes the film
what is the bremsstrahlung radiation
aka general radiation; stopping or slowing of the electrons of the cathode stream as they collide with the nuclei of the target atoms
what is characteristic radiation
a form of radiation originating from an atom following removal of an electron or excitation of an atom
what is the major diff. b/w particulate and electromagnetic radiation
-particulate radiation: made of protons, neutrons, electrons and alpha and beta particles; has mass
-electromagnetic radiation: made of photons; no mass
which radiographic technique records the most accurate image of crowns, roots, and supporting structures in a selected area?
periapical examination, paralleling technique
A patient complains of pain in the upper molar region. What radiographic exposure should be made?
in the darkroom, you unwrap a film and place a coin on top of the film for several minutes. when you process the film, you notice a slight, well-defined white circle on the film. what does this mean?
failed safelight test, suggesting that the safelight conditions in the darkroom are fogging the film
what would cause a properly exposed film to appear dark?
-temp. too high
-time too long
-developer concentration too high
-accidental exposure to light
what are automatic processors faster than manual processing?
b/c of its stability to produce a large volume of radiographs in a short amount of time
when looking at radiographs that were taken several years ago, you notice a brownish stain which makes interpretation difficult. what caused this?
insufficient or improper washing
what is thermionic emission
release of electrons when a material such as tungsten is heated to incandescence.
electrons are boiled off from the cathode filament in the x-ray tube when electric current is passed through it
what parts of the x-ray machine are included in the anode circuit
what factors would decrease edge sharpness and increase magnification
far object-image receptor distance
you process a set of BW's in the automatic processor. three of the BW's are of good quality, but fourth is completely blank. what probably caused this?
no exposure to x-rays,
malfunction of x-ray machine,
or processing errors
what looking at manually processed films, you notice small black spots on the films. what caused those spots?
premature contact w/ developing chemicals.
drops of developer or fixer that splash onto the work area and came in contact with the film.
when mounting a FMS, you notice that one film is blank. another film is dark, the teeth look strange, and it is difficult to determine what film it is. what do you think happened?
dark film is from over exposure and improper packet placement for strange looking teeth and not being able to determine what film is
your dentist asks you to take a FMS on a 65 yr old edentulous patient. how many exposures will you take? which exposures are not necessary? what intraoral technique will you use? what might be better than a FMS?
-take 14 radiographs
-omit the BW
-paralleling should be technique of choice
-panoramic might be better than FMS
when viewing a periapical radiograph, you notice that the image of the tooth is extremely long and well defined; however the apices are missing. what technique was used to take the radiograph? what caused the roots to appear long?
-bisecting was used b/c of the distortion of the elongated root
-the roots appeared long b/c the vertical angulation was inadequate
how does resolutiong and detial of a panoramic radiograph compare with that of PA's and BW's
not as sharp and detailed as the intraoral image
what must a patient remove before taking a PANO
oral piercings, earings, glasses, necklaces, facial piercings, hair pins, hearing aids, dentures, and retainers
when mounting dental radiographs, what is the best way to differentiate max and mand films?
-max teeth are longer
-max molars have 3 roots, mand molars have 2 roots
-most roots curve toward the distal
-occlusal plane is straight or curved slight towards distal
when interpreting radiographs, you notice a radiopaque extension or spur off the proximal surface of #30. what do you think this is?
the mental ridge
in which area of the tooth is interproximal caries often seen
located on the tooth surface that contacts the adjacent tooth
when using D speed film, you use 50 impulses of radiation. how many impulses would you use with E speed film?
which dose of radiation is more biologically damaging
chronic low-level exposures/long term dose; causing cancer, cataracts, low birth weight, genetic mutations, and embryological defects
when manually processing dental film, you notice the temp. has gotten warmer as the day progressed. how should the developing time be changed?
higher temp. increases film fog, so radiographer should consult a time-temp. development chart to adjust developing time appropriately; developing time will decrease
what is the best method of protecting the thyroid gland from radiation?
thyroid collar, lead and lead-equivalent sprons are availaable with or without an attached thyroid collar
when should radiographs be taken on a pregnant patient
only when necessary to help the dentist diagnose and treat oral diseases; elective xrays should be postponed until after delivery
what is the area of the skull that is in focus on a pano
patient's dental arches; maxilla and mandile
what quality control procedures should be performed on xray cassettes
periodically examining cassettes and intensifying screens; extra oral cassettes should be checked for warping and light leaks
an insurance company requests a patient's radiographs when examining a dental clain. you only have one copy of the radiographs. what should you do
duplicate, which will go to the insurance comp.; office keeps best copy
when duplicating radiographs, what side of the duplicating film is in contact with the radiograph to be duplicated
the emulsion side of the film is placed against the orginal radiograph with the nonemulsion side up
when viewing a duplicated radiograph, you notice that the duplicate is too dark. what should you do to duplicating time to lighten the film
increase the exposure time
your dentist recommends that a patient have xrays taken, bu the patient refuses. what should be done
document patient's refusal and have them sign
what can be done to minimize gagging when taking radiographs
do not suggest gagging, emphasize, use power of suggestions, apply distractiong techniques, give patient breathing instructions, reduce tactile stimuli, being exposures in the ant. region, place image receptor firmly and expertly, confuse the senses, utilize special products; substitute extraoral as needed
what info should be recorded on the dental radiographic mount
patient's name, date, and other pertinent info
when viewing a radiograph, the tooth looks normal in size and shape; however, there is a large blank space at the incisal edge and the apices are missing. what caused this error
large blank space is due to reversed image error or chemical contamination
missing apices is due to inadequate VA
what causes teeth to appear very short and distorted
excessive VA w/ PID positioned too steep enough away from zero degrees
how are stabe film holders sterilized b/w uses
sterilize film holder devices or discard disposable image receptor holding devices
when taking a paralleling radiograph of a patient with palatal tori, where is the film places
on the back side of the tori
what would cause the radiographic image to be blurred
movement caused by the patient, slippage of the image receptor, or vibration of the tube head
what can be done to increase the life span of processing solutions
reg. replenishment and changing out expired solutiong with fresh chemicals at reg. intervals; monitor strength of chemicals on a daily basis
what can be done to prevent air bubbles from being trapped on the surface of films during manual processing
gently agitating the hanger up and down a few times
you notice that the xrays you process are becoming successively lighter than the quality control film you compare it to. what should you do
check the processing chemical, particularly the developer
what radiographs are used to determine if a foreign object is located facially or lingually
you notice on a PANO that the ant. teeth appear narrow and out of focus. what caused this
patient positioned too far foward in the focal trough
using a 16 inch cone focal-film distance, the diameter of the beam measured at the patient's face should be no larger than
when taking a radiograph, you pull the end of the PID away from the patients face about 6 inches. how will this affect the radiographic image and patient exposure
lighter image, patient exposed to larger beam which will increase exposure
what factors affect the sharpness of the radiographic image
focal spot size, target-image receptor distance, object-image receptor distance, motion, screen thickness, screen-film contact, and crystal/pixel size of intraoral image receptors
what is the max. permissable fose for radiation workers in systeme interventional units
50 mSv (5rem)
after processing exposed dental film, you notice dark spots on the film. what caused this
premature contact with developer
on a mandibular molar PA , where is the mylohoid ridge located
highest of the 2 ridges, about the level of the cervical 3rd, behind the 2nd and 3rd molars
when taking a PANO radiograph, the patient is placed too far into the machine. how will the radiograph appear
all of the ant. teeth will appear blurred and narrowed in width
when viewing a PANO, you notice that the right TMJ is magnified, bu the left TMJ is normal. what caused this error
patient positioned too far to the left
when viewing a PANO, you notice that a lot of spine shows on both side of the film, what caused this
positioning the arches too far foward
how can you differentiate the zygoma from the max sinus in a max posterior PA
zygoma will be radiopaque, max. sinus will be a large area of radiolucency
you notice that a radiograph taken several months ago is brown and spotted. what happened
insufficient or improper washing
when processing, two films overlap in the developer, but not in the fixer. how would the films appear
clear/blue in the area of overlap b/c fixer will not remove all crystals
you process four BW films. three of the films appear normal, but one is clear. what happened
didn't push button completely
when taking a radiograph, you pulls the cone out about 6 inches from the patient's face. what is the result
increase the area of radiation exposure
how does reducing exposure to the patient benefit the operator
the less the patient is exposed, the less the operator is exposed
what is the major use of cross sectional occlusal radiograph
provides more info. about the location of tori, impacted and malpositioned teeth and the calcification of soft tissues
what is the major use of topographical occlusal radiographs
images conditions of the teeth and supporting structures when a larger area than a PA is needed; provides more info. than a PA about the alveolar crest and apical areas
how often should an FMS be taken on an adult with no significant medical history
take FMS on all new patients; recall adults with no sig. med. history only require BW and PA, if indicated
what are three types of image receptors used in digital radiography
list the cells from most sensitive to least sensitive
white blood cells
red blood cells
immature reproductive cells
connective tissue cells
when viewing a molar BW, what should be on the distal of the film
the most distal tooth should be captured in full as well as a few mm of bone level behind the most distal tooth
your film badge report shows that you have received a small amt. of radiation. what should you do
stop taking xrays and evaluate all equipment and techniques to ensure safety
you change you kVp from 90 to 70 and leave all other factors the same. what is the result
the wave length will be shorter, the quality and energy of the beam will be higher and the contrast will be lowe.
the image will also have a higher density
you change from an 8 inch to an 16 inch focal film distance. how is the intensity of the beam affected
1/4 as intense
how often must you replenish the solutions in an automatic processor
for every 30 films processed 6-8 oz should be taken out and replaced with fresh solution
what is the purpose of replenishing the developer solution
maintain acidity & alkalinity & prevent oxidation,
what size and how is the film places when taking a molar PA in the mixed dentition
#1 or #2
placed so the edge of the receptor lines up behind the distal of the canine before the eruption of the permanent 2nd molar;
after the eruption of the perm. 2nd molar, 2 posterior PA's should be taken per quadrant
Movement if electrons (-) along a wire toward a (+) charge which changes direction ____times per second. Many x-ray machines produce __ bursts or impulses of radiation per second. This electricity is called _____.
This term describes the number of electrons flowing. Counting electrons.
This term describes the "potential differences" between the (-) and (+) and therefore, the speed of force of the moving electrons toward the (+) charge.
Which ones have no effect on the energy of the beam?
b.) Exposure Time
d.) Aluminum filtration
b.) Exposure Time
The number of photons increase or decrease with mA?
To produce quantity or quality or both?
Number of photons increase or decrease with exposure time?
Does exposure time affect quantity or quality or both?
The number of photons increase or decrease with kVp?
Does kVp affect quantity or quality or both?
increase, Both quantity and quality
kVp: Shorter the wavelengths:
A.) More penetration
B.) Less penetration
C.) Does not make penetration
A.) More penetration
Number of photons increase of decrease with Aluminum filtration?
Does aluminum filtration affect quantity or quality or both?
decrease, Both quantity and quality
This removes softer dangerous photons and hardens the beam. (Strong photons pass)
Number of photons increase or decrease as beam spreads with Distance?
Does Distance affect quantity or quality?
Density is affected by which of the following:
B.) exposure time
A, B, C, D, E
The film is more black as we decrease exposure time. True or False
False. Increase exposure time and the film is more black.
The film density is decreased with distance and aluminum and they are both considered the short scale.
A.) Both sentences are true
B.) First Sentence is True, second is false
C.) Both are false
D.) First sentence is false, second is true.
B. Distance is part of the short scale (More black)
Aluminum is part of the long scale (More grays)
Area of sharpness means:
a.) small focal spot
b.) large target to film distance
d.) film and tooth parallel
All of the following produce the sharpest images with the least magnification except:
A.) Small Focal Spot
B.) Short object to film distance (OFD)
C.) Large target to film distance (TFD) or (SFD)
D.) Film and tooth parallel
E.) Large Focal Spot
F.) Beam perpendicular to film
E. Large focal spot
A hygienist is taking a second radiograph of a two-rooted tooth. On the second radiograph, the tube head was moved more distally, and one of the roots appears to have also moved more distally than the other root. Was the root that moved distally a buccal or a lingual root?
If the cone length is changed from 8 to 16, the original dose ______by factor of 4.
(The answer is always 4xs more or less)
(Think of it like this: If the number goes from low to high like 8 to 16, the number decreases. It's the opposite of what you would think.)
What opaque area is indicated:
A.) Pulp Chamber
B.) Periodontal Ligament Space
C.) Lamina Dura
C.) Lamina Dura
A film comes out of the machine and it is all white. What most likely happened?
A.) Cone cut
B.) Backwards film placement
C.) Developer first
D.) Fixer first
D.) Fixer first, unexposed. Fixer removes unexposed, undeveloped crystals. No energy took place.
A film comes out of the machine and it is all black. What most likely happened?
A.) Someone opened the film packet exposing the film to light
B.) Fixer first
C.) Cone cut
A.) Exposed film
Pano Errors: When the anterior teeth are blurred and thin, what happened?
A.) Too Far posterior
B.) Too Far Anterior
C.) chin too high
B.) Too far anterior
Pano Errors: When the anterior teeth are blurred and wide what happened?
A.) Too far posterior
B.) Too far anterior
C.) Nothing is wrong
A.) too far posterior
Pano Errors: When there is a reverse curve of occlusion; condyles off side of image. (frown) This is the result of:
A.) Patients chin too high
B.) Patients chin too low
C.) The patient sneezed
A.) Chin too high
Pano Errors: When the condyles are off the top of the image, this is a result of:
A.) Chin too high
B.) Chin too low
C.) Imposing air space
B.) Chin too low
Pano Errors: When the tongue is not placed against the palate, what happens the pano?
A.) Becomes too dark
B.) Becomes too light
C.) Imposing air space
D.) Spinal Shadow
C. Imposing air space
Pano Errors: When the patient slumped forward at an angle, what is the result:
A.)Imposing air space
B.) Imposing Spinal Shadow
C.) Imposing condyle space
B.) Imposing spinal shadow
Discolored film is due to all except:
a.) exhausted developer
b.) exhausted fixer
c.) poor replenishment
d.) poor wash
A.) exhausted developer. Exhausted fixer or poor replenishment after time, problem is poor wash is the cause.
This removes undeveloped, unexposed crystals.
C.) Film Emulsion
This only turns exposed crystals to metallic silver.
C.) Film Emulsion
Most common mechanism of damage in humans. Free radicals of water is called:
Hydrolysis (Breaking down water molecules causes the most damage.)
Biological sensitivity to radiation:
Rapid turnover or __1___ rate of cells increases tissue damage. Undifferentiated cells have __2___damage
1.) Meiosis or Mitosis
2.) Increased or decreased
_____are more sensitive to radiation due to rapid cell mitosis associated with their growth.
_____effects are only those that can be passed o future generations.
B.) Genetic. (Anything else is somatic)
Adverse reactions of the body to x-radiation never return exactly to orginal state, therefore, accumulating to some degree over a lifetime is called:
Gonadal exposure for the average complete mouth series is equal to ____days to ______ of normal background whole body radiation.
3 days to one week
What has the highest tissue sensitivity to radiation?
A.) Mucous Membranes
C.) Reproductive tissue
C.) Reproductive tissue
Name three tissues that have the highest sensitivity to radiation.
Reproductive tissue, lymphoid tissue, bone marrow
Name three tissues that have medium sensitivity to radiation.
Growing cartilage, growing bone, salivary glands
Film speed is the most effective method of protection. Each alphabetical film group is ___ times faster than the previous film group and needs half as much radiation exposure.
2 times faster. Ex: D-speed needs half as much exposure as C-speed and E-speed or E-plus needs half as much as D-Speed.
Panoramic intensifying screens reduce the amount of radiation (3-4 BWX) to the patient or the clinician?
To the patient
Beam size at the patient's face can be no larger than ____inches. _______ reduces patient's dose.
The rectangular collimation reduces the area of patient's skin surface exposed by __% to ___% over round
With aluminum filtration: Must have at least ___mm of total aluminum filtration for up to and including 70kVp. Requires 2.5mm if machine can function above ___kVp.
Wall is mandatory if operator cannot stand at least ___ft from the scatter source(measured from the patient's head).
Lead apron absorbs ___% of the scatter that would have reached the reproductive tissues. Lead equivalent of ____mm
According to the MPD, the maximum amount of radiation a non occupational person may receive in one year is:
A.) 5 Sv/year
B.) 4 mSv/year
D.) .005 Sv/year
According to the MPD, the maximum amount of radiation an non-occupational person may receive in one year is:
A.) .05 rem/year
B.) .005 rem/year
C.) .5 rem/year
D.) 5 rem/year
C.) .5 rem/year
According to the MPD, the maximum amount of radiation an occupational person may receive in one year is:
A.) 5 rem/year
B.) 400 rem/year
C.) .5 rem/year
D.) .005 rem/year
A.) 5 rem/year
According to the MPD, the maximum amount of radiation an occupational person may receive in one year is:
A.) .005 Sv
B.) .05 Sv
C.) 4 Sv
D.) 5 Sv
B.) .05 Sv/year
All of the forms of energy comprising the electromagnetic family behave similarly except for which characteristic:
A.) all cause ionization of tissues
B.) all can produce "shadows"
C.) all travel in straight lines
D.) all travel at the speed of light
How many impulses equal a 1/4 second exposure time?
a.) 6 impulses
b.) 10 impulses
C.) 15 impulses
X-rays are generated when a stream of electrons traveling from one side of an x-ray tube is suddenly stopped by its impact on the:
a.) filament cup
b.) tungsten target of the anode
c.) tungsten target of the cathode
d.) the aluminum filter
As you go from a D speed to an E speed film, the exposure time should be approximately:
c.)cut to 1/4
The mA setting controls which item(s) below:
a.) thermionic emission
b.) number of free electrons in the tube
c.) number of protons ultimately produced
d.) the density of the film
e.) contrast of the film
A, b, c, d
Which of the following reduces the percentage of low energy x-rays in the beam?
b.) aluminum filtration
The mean penetrability of an x-ray beam is related to all in the list below except:
If radiology technician received a dose of 3 sieverts standing 4 feet from the source of radiation during an exposure, how many Sieverts would he receive during the same exposure standing 2ft away?
a.) 1.5 sieverts
b.) 6 sieverts
c.) 12 sieverts
d.) 27 sieverts
A bitewing film is exposed properly using an exposure setting of 1 second with the x-ray source 8 inches from the patient. What time would be needed if the source was moved 16 inches away?
a.) 1/2 sec
c.) 2 secs
d.) 4 secs
For optimal detection of incipient interproximal carious lesions (high contrast), which of the following machine settings is preferable?
a.) 90 kvp, 10 mA
b.) 85 kvp, 10 mA
c.) 75 kvp, 5 mA
d.) 65 kvp, 10 mA
Which of the following factors control the quality of the x-ray beam and thus film contrast?
a.) exposure time
b.) aluminum filtration
If a machine operated with good radiographic results at a setting of 15mA, 90kvp and 8 impulses, what exposure time should be used if the machine is changed to 10mA and 90 kvp?
a.) 120 impulses
Increasing the kvp results in:
a.) a long scale of contrast
b.) a short scale of contrast
c.) neither, it would have no effect
Image magnification results from decreased:
a.) target size
b.) target film distance
c.) object film distance
Exposure time and mA control:
a.) quality of the beam
b.) photon wavelength
c.) number of x-rays produced
d.) cross section of the beam
GBX II filters are needed for extraoral radiographs due to:
a.) double emulsion on film
b.) thicker emulsion
c.) larger film surface area
d.) film is more sensitive
The optimum operating temperature for dental automatic processors is:
a.) 68 degrees F
The primary purpose of sodium thiosulfate is to:
a.) preserve the image
b.) allow further blackening of the film
c.) remove the silver bromide crystals that have been developed
d.) remove the SBC that have not been developed
Films not fixed for a long enough period of time will appear:
a.) to have black lines running through them
b.) to be brittle
c.) to have a brown tint
For reducing scatter radiation, the radiation beam at the patient's face should not exceed:
a.) 2.75 in
The minimum total aluminum filtration on a dental x-ray machine capable of operating at 70kVp and above is:
a.) 2.0 mm Al.
b.) 2.5 mm Al
Match cells to their sensitivity to radiation damage:
a.) Sperm cells 1.) radiosensitive
b.) spinal tissues 2.) radioinsensitive
d.) mature bone
According to the NCRP, the maximum amount of radiation an occupationally exposed person may receive in one year is:
a.) 5 Sv
d.) .05 Sv.
According to the NCRP, the maximum amount of radiation an occupationally exposed person may receive in one week is:
a.) 50 rem
b.) 5 rem
c.) 100 mrem
d.) 10 mrem
If an operator can stand 6 feet or more away from the ousrce of radiation scatter and out of the primary beam, no barrier wall is necessary.
Rank the following PIDs in order of safety provided from most safe to least safe.
a.) long, round
b.) short, round
c.) long, rectangular, led lined
d.) long, rectangular
An ill defined radiolucency with a calcification at the apex of a vital root tip is:
a.) a traumatic bone cyst
b.) benign cemmental dysplasia (cementoma)
c.) osteogenic sarcoma
d.) condensing osteitis
What is the proper thickness of the lead lining in radiographic lead aprons?
a.) .1 mm equivalent
Intensifying screens in panoramic cassettes are necessary to:
a.) increase sharpness
b.) decrease magnification
c.) increase film detail
d.) reduce patient exposure
A film that has turned brown after the span of one year may have resulted from:
a.) insufficient wash
b.) extremely high developer temp
c.) fixing before developing
d.) the radiograph has simply aged and turned with time and is normal
What is the most radiolucent dental material seen on dental radiographs?
b.) gutta percha
d.) aluminum temporary crowns
What is the earliest clinical sign of an over exposure to x-radiation?
a.) loss of hair
b.) breakage of chromosome bonds
c.) mucosal sloughing
The greatest cause of human radiation effects in dental radiography involves:
a.) lysis of proteins
b.) destruction of enzymes
c.) free radicals of water
Cell sensitivity to radiation is most pronounced except:
a.) during mitosis
b.) during periods of increased metabolism
c.) during embryonic development
d.) in mature bone
Tissue damage increases with decreased:
a.) exposure dose
b.) body coverage
c.) cell differentiation
d.) mitotic rate
What is the effect of excessive vertical angulation?
In bisecting the angle technique, the central ray is directed perpendicular to:
a.) the film
b.) the long axis of the tooth
c.) an imaginary line bisecting the film and tooth
d.) the patient's Frankford Plane
A panoramic image with a jack o lantern or extreme smile results from:
a.) chin too low
b.) chin too high
c.) patient placed too far anteriorly
d.) patient placed too far posteriorly
All can create film fog except:
a.) light leaks
b.) proper refrigeration
d.) faulty safelight
Lisa deceided to change xray machines in her new operatory. The old machine had an 8" PID and was set at 26 exposure time and due to the knobs being broken she could not change it. If she decided to go to a 16" PID and a fully functioning xray machine, what would happen to the intensity if set at proper exposures?
a.) The intensity stays the same, but the exposure time would alter the density
b.) The intensity is directly proportional to a factor of 4 per every exposure time, thus meaning it is increased by 4.
c.) The exposure time is decreased by 4
d.) The intensity would be decreased by 4
D. Dont pay attention to the rest of the garbage. It is only asking about intensity and when the cone size is doubled, then the intensity is decreased by 4.
Which of the following has no antibody production associated with it?
a.) Type I
e.) none of the above, they all do
D, Type IV or delayed hypersensitivity is the only reaction that does not have an associated antibody. Primary antibodies are
Type II= IgG or IgM
Type III= IgG
Identify which of the following is not a type of particulate radiation:
a.) alpha particles
Identify the reduction in exposure time when changing from D speed film to E speed film:
a.) reduce exposure by 1/8
b.) reduce by 1/4
c.) reduce by 1/2
d.) reduce by 1/3
Angela is manually developing radiographs and does not notice a difference in solution temps. Identify the error that Angela would cause when a film is subjected to sudden temp changes (such as between developer and water bath)
a.) reticulation of emusion
b.) brown yellow stains
c.) fixer spots
d.) static electricity
Fluorescent light and xrays produce the latent image on intraoral radiographs. The visible image on an extraoral film is the result of chemical processing of the exposed film.
a.) The first statement is True, the second is false
b.) The first statement is false, the second is true
c.) Both statements are True
d.) Both statements are False
Model plaster or stone is sifted into the water before mixing in order to:
a.) retard setting time
b.) prevent entrapment of air
c.) dissipate heat
d.) avoid distortion of final product
Approved fluoride components found in over the counter dentrifices include:
a.) sodium fluoride
b.) stannous fluoride
c.) sodium momofluorophosphate
d.) acidulated phosphate fluoride
2.) a and d
3.) d only
4.) d only
5.) all the above
Acquired pellicle is initally derived from:
b.) tooth structure
c.) bacterial products
d.) dietary components
When a patient protrudes his tongue, deviation to the right side is noted. This suggests a disturbance in motor function of which of the following cranial nerves?
D. Cranial Nerve 12 - Hypoglossal
Dilated pupils occurs in what drugs?
shock, heart failure, and other emergencies and in the use of hallucinogens and amphetamines, LSD, cocaine, or marijuana
Pick out the Suprahyoid muscles:
a, c, d, g "Don't Get So Mad"
Pick out the Infrahyoid muscles:
a, c, d, e "TOSS"
the production of ions, the process of converting an atom into an ion, deals only with energy to overcome the electrostatic force that binds the electron to the nucleus, resulting in the formation of a positive atom and a dislodged negative electron
the use of absorbing materials (ex. aluminum) for removing the low-energy x-rays from the primary beam
a flexible lead shield used to protect the patients reproductive and blood forming tissues from scatter radiation
the restriction of the size and shape of the x-ray beam in order to reduce patient exposure
a concept of radiation protection that states that all exposure to radiation must be kept to a minimum, or "as low as reasonably achievable"
the pattern of stored energy on the exposed film; the invisible image produced when the film is exposed to x-rays and that remains invisible until the film is processed
the amount of time that lapses between exposure to ionizing radiation and the appearance of observable clinical signs
one of the interactions of x-radiation with matter in which the x-ray photon collides with a loosely bound, outer shell electron and gives up part of its energy to eject the electron from its orbit. the x-ray photon loses energy and continues in a different direction at a lower energy level
a device that transfers x-ray energy into visible light; the visible light in turn , exposes the screen film, these screens intensify the effect of x-rays on the film, with its use less radiation is required to expose screen film, and patient is exposed to less radiation
a term describing images of teeth that appear too short; it is a result of excessive vertical angulation
a term describing images of teeth that appear longer than the actual teeth; it is the result of insufficient vertical angulation
the penetrating x-ray beam produced at the target of the anode and that exits the tube-head
a form of radiation that occurs when speeding electrons slow down because of their interactions with the tungsten target in the anode - AKA- Bremstahlung or braking radiation
a form of radiation that occurs when a high speed electron dislodges an inner shell electron from an atom, causing excitation, or ionization of the atom
the propagation of wavelike energy through space or matter, the propagated energy is accompanied be electric and magnetic fields, thus the term electromagnetic. examples: cosmic rays, gamma rays, x-rays, ultraviolet rays, visible light, infrared light, radar waves, micro waves, and radio waves
radiation capable of producing ions; includes particulate or electromagnetic radiation
tiny particles of matter that possess mass, travel in straight lines, and also travel at high speeds
a form of secondary radiation; results from x-ray beam that has been deflected from its path by the interaction with matter
radiation created when the primary beam interacts with matter; it is less penetrating than primary radiaiton
how sharply dark and light areas are differentiated or separated on an image; the difference in the degrees of blackness (densities) between adjacent areas on a dental radio graph
long scale of contrast
a term describing an image with many densities, or many shades of gray; it results from the use of a higher kilo-voltage range
short scale of contrast
a term describing an image with only two densities, areas of black and white; it results from a lower kilo-voltage range
a term describing an image with many very dark areas and very light areas and few shades of gray
the portion of an image that is dark or black; this structure readily permits the passage of the x-ray beam and allows more x-rays to reach the receptor
the portion of an image that is light or white, this structure is one that resists the passage of the x-ray beam and limits the amount of x-rays that reach the receptor
the maximum of peak voltage that is used during an x-ray exposure. Low kVp=short scale=high contrast
High kVp=long scale=low contrast
determines the energy and the penetrating power of radiation. Shorter wavelengths=more penetrating power
Longer wavelengths=less penetrating and more likely to be absorbed by matter
is used to describe the mean energy or penetrating ability of the x-ray beam- the quality, or wavelength and energy of the x-ray beam is controlled by kilo-voltage
a measurement of force that refers to the potential difference between two electrical charges. Voltage= determines the speed of electrons that travel from the cathode to anode, When the voltage is increased- the speed of the electrons increases, the electron strikes the target with greater force and energy, resulting in a penetrating x-ray beam with a short wavelength
the unit of measurement used to describe the potential that drives an electrical current through a circuit
can be adjusted according to the individual diagnostic needs of the patient. the use of 85 to 100 kV produces more penetrating x-rays with greater energy and shorter wavelengths, 65 to 70 kV produces less penetrating dental x-rays with less energy and longer wavelengths. A higher kV should be used when the examined area is dense or thick
determines the amount of electrons passing through the cathode filament, an increase in he number of electrons available to travel from the cathode to the anode results in the production of an increased number of x-rays
the unit of measure used to describe the number of electrons or current flowing through the cathode filament
what exposure time is measured in, because x-rays are created in a series of bursts and pulses rather than in a continuous stream, 1 impulse occurs every 1/60 of a second, or 60 impulses occur in 1 second
this regulates the temperature of the cathode filament. if it is increased the temp of the cathode filament increases, and consequently the number of electrons produced increases. an increased number of electrons that strike the anode increases the number of x-rays emitted from the tube head.
an increase in mA increases the overall ______ of a radio graph and results in a darker image.
milliamperage and _______ are inversely related, when altering the mA, this must be adjusted to maintain diagnostic density of an image. increase mA-descrease___, decrase mA-increase____
is described as the product of the quantity (# of x-ray photons) and quality (energy of each photon) per unit of area per unit of time exposure. it is affected by kVp, mA, Exposure time, and distance.
inverse square law
the intensity of radiation is inversely proportioned to the square of the distance from the source of radiation. "inversely proportional" means that as one variable increases, the other decreases.
the number of wavelengths that pass at a given point in a certain amount of time. this and wavelength are inversely related, ____ increased= short wavelength, decreased ___= long wavelength.
these can be added to the tube head in 0.5mm increments, the purpose is to filter out the longer wavelengths, low-energy x-rays from the x-ray beam. the low-energy longer wavelength x-rays are harmful to the patient and are not useful in diagnostic radiology
dental x-ray machines operating at or below 70 kVp require a minimum of 1.5mm of aluminum filtration, machines operating above 70 kVp require a minimum of 2.5mm aluminum filtration.
when using a _____ _____, federal regulations require that the x-ray beam be collimated to a diameter of no more than 2.75 inches as it exits from the PID and reaches the patients skin.
this is approximately 0.5-1.0mm of aluminum**this does not meet regulated standards by state and federal law**
maximum permissible dose
MPD- the maximum dose equivalent that a body is permitted to receive within a specific period, it is the dose of radiation that a body can endure with little or no injury.
0.1/rem/year = 0.001/Sv/year
maximum permissible dose for non-occupationally exposed persons, or pregnant women who are occupationally exposed
maximum accumulated dose, this is the maximum dose of radiation that a person can be exposed to in a lifetime. formula=MAD=(N-(persons age in years)-18) X 5 rems/year,
MAD=(N-18)X 0.5 Sv/year
radiographer must maintain a distance of at least _____ from the x-ray tube head, or stand behind a protective barrier wall
radiographer must position themselves at a _______ angle to the primary beam, for protection
law of B & T
the faster the reproductive rate of the cells and tissues, the more sensitive they are to radiation, the more specialized the cells and tissues are the less sensitive to radiation they are
period of injury
this occurs after the latent period, following exposure to radiation, can include a variety of cellular injuries
a chemical solution used in processing; removes the unexposed silver halide crystals and creates white or clear (radiopaque) areas on film
a chemical solution used in film processing that distinguishes between exposed and unexposed silver halide crystals and makes the latent image visible.
the temperature for developer solution for manual processing is ____ degrees, and ______ degrees fro automatic processing
the bisecting technique
this is based on a geometric principle of bisecting a triangle, the angle formed by the long axis of the teeth and the film is bisected, and the x-ray beam is directed perpendicular to the bisecting line, (perpendicular means at a right angle to the film)
this is an error made during processing caused by nail pressure to film,or possibly light or saliva leaks through the film packets
a clear unexposed area on a dental radiograph that occurs when the PID is misaligned and the x-ray beam is not centered over the film
where the nasal fossa intersects with the maxillary sinus, usually near the lateral incisor or canine
the most radiopaque and most calcified substance in the body, followed by cementum, and dentin
identical copy of an extra/intra oral radio graph, this requires the use of a film dupilcator, a light source that is commercially available from the manufacturers, it provides a diffused light source that evenly exposes the special duplicating film
film speed change problem formula
with each change in speed, the exposure time needed halves, with each decrease in speed, the exposure time needed doubles. A_F film speeds A=slowest, F=fastest.
exposure time change problem formula
(new) exposure time = (new) distance
(old) exposure time = (old) distance
blurry film- little bit of exposure to the whole film, possible causes= incorrect filter, improper safe-light, incorrect bulb, or incorrect distance
differences in direct and indirect exposure
direct exposure film is exposed by x-rays, and indirect exposure film is exposed by florescent light from intensifying screens
helps protect the x-ray from scatter radiation, it has a herringbone imprint on it so it can detect if film was exposed backwards
black paper of film
goes around the front and back of film and helps protect the film from light and moisture if there is a leak in the outer wrapper
when x-rays hit the crystals it ____ them, where the x-rays are blocked the crystals did not get ____. when processed the crystals that are ____ are radiolucent, and the ones not _______ are wiped away from fixer, these are radiolucent.
description of latent image production
once the film is exposed, the crystals that are energized (the ones holding the image by holding the energy), the films have been exposed but they have not been processed yet
used to show the crowns of teeth, alveolar crest, and the interproximal area- taken once a year
lateral oblique mandible
used to view the mandible from the canine region posteriorly to the body and ramus
reveals the relationship of the head of the mandibular condyle in relation to the glenoid fossa of the temporal bone
revelas the entire skull in the posteroanterior plane; often used as a supplement to the lateral skull survey
The transfer of energy from an x-ray beam to the atoms or molecules of the matter through which it passes. The process whereby radiation is stopped and reduced in intensity as |t passes through matter. Lead, which is denser than most materials, is one of the best absorber of x-rays.
(differential, rare earth screen, specific rate of, visible light)
Sheets of metal (usually aluminum or its equivalent) which are placed in the direct path of the x-ray beam.
A round/circular metal tube/shield attached to the X-ray tube housing or placed in front of the x-ray tube to limit the size of the x-ray beam to a predetermined size and shape.
An acronym for As Low As Reasonably Achievable, economic and social factors being taken into consideration. Relates to radiation dose to the patients, the public, and occupationally exposed individuals.
The thickness of aluminum affording the same attenuation, under specified conditions. Relates to radiation dose to the patients, the public, and occupationally exposed individuals.
A positive electrode, also referred to as a target, toward which electrons are accelerated from the cathode. The target is usually composed on tungsten.
Any density or mark on a radiograph that is caused by something not belonging to the part of being x-rayed.
The process by which an x-ray beam of radiation is reduced in intensity by absorption or scattering when passing through material.
Primary Radiation or X-ray Beam
That part of the radiation which passes through the window, aperture, cone, or other collimating device of the tube housing. Also called "useful beam."
A negative electrode; electrode in the x-ray tube from which electrons are emitted. It consists of one or two filaments and focusing cup.
A type of input-output "curve" used to express the change in density with the change in radiation dose exposure of the photographic or x-ray film. The slope of the straight line port/on in this curve is called "gamma."
Irradiation which is spread out over a period of years. Those who are occupationally exposed to radiation can suffer from chronic exposure.
A device for restricting/confining/limiting a beam of radiation within an assigned solid angle.
Compton Scatter Radiation
The incident radiation has sufficient energy to dislodge a bound electron, but attacks a loosely bound electron, dislodges the electron and the remaining radiation energy proceeds in a different direction as scatter radiation. This kind of radiation is the main process responsible for the dose of radiation the patient receives during a radiographic procedure.
A round/circular metal tube/shield attached to the x-ray tube housing or placed in front of the x-ray tube to limit the size of the x-ray beam to a predetermined size and shape.
In radiology, _______ is defined as the difference in density between light and dark areas on the processed film.
An instrument used to measure film density which is degree of blackening of film by measuring the ratio of the light intensity incident on the film to the light intensity transmitted by the film.
A device designed to measure the optical density of an exposed and processed film. It can measure the density of the individual steps on films exposed in this device, and is commonly used for daily processor quality control.
Refers to the sharpness of structure lines or contour lines on the processed film.
The chemical solution (alkaline) use in film processing that makes the latent image visible.
Used to maintained the proper alkalinity, chemical activity, and level of solution in the developer tank.
Diagnostic Type Tube Housing
Means any x-ray tube housing so constructed that the leakage radiation at a distance of one meter rom the target cannot exceed 100 millirads in one hour when the tube is operated at any of its specified ratings.
A plate, usually lead, with a central aperture so placed as to restrict the useful x-ray beam.
A general term denoting the quantity/amount of radiation or energy absorbed per unit mass. For special purposes it must be appropriately qualified.
Means the product of the absorbed dose in tissue, quality factor, and all other necessary modifying factors at the location of interest. The unit of dose equivalent are the rem and the Sievert (Sv). 1 rem= 0.01 Sv.
Devices designed to be worn or carried by an individual for the purpose of determining the dose equivalent received for example:
film badge, pocket chamber, pocket dosimeter, ring badges, thermoluminescent (TLD) badges, etc.
The sensitive layer of photographic or x-ray film containing a silver compound in a layer of gelatin.
The sensitive layer of photographic or x-ray film containing a silver compound in a layer of gelatin.
Exposure or Irradiation Time
The time interval in a radiological examination within which x-rays are incident upon the body part under examination.
A personnel monitoring device which measures radiation exposure and is used for personnel monitoring.
A relative exposure number needed to produce a density of 1/0 above gross fog-used for screen type, dental and medical x-ray films.
Means material placed in the primary or useful x-ray beam to absorb preferentially the less penetrating radiations. The use of appropriate filtration prevents the patient from receiving unnecessary radiation dose.
Filter in the x-ray tube and its housing such as the glass envelope (window) through which the X-ray beam passes.
A chemical solution (acidic) which removes the unexposed and underdeveloped silver halide crystals from the film so it will not discolor or darken with age or exposure to light. Also hardens the gelatin containing the black metallic silver so film may be dried and resist damage from abrasions.
The inadequate removal of fixer from the film by the water in the wash tank of the processor; causes eventual brown discoloration of the radiograph.
A small area on the target of the anode toward which the electrons from the focusing cup of the cathode are directed. X-radiation originates here.
Effective Focal Spot
The apparent size of the radiation source when viewed from the central axis of the useful beam.
Fog or Fogging
A cloudy appearance of the finished radiograph caused by several factors such as old or contaminated processing solutions, exposure to chemical fumes, faulty darkroom safelight, or scatter radiation.
Unsharpness of the recording image due to the combined optical effect of finite size of the radiation source and geometric separation of the anatomic area of interest from the image receptor and the collimator.
Devices used during radiographic procedures to protect the reproductive organs from exposure to the useful x-ray beams.
The SI unit of absorbed dose equal to an energy deposition of 1 joule/kg = 10,000 ergs/gm (1__-100rads).
The science of protecting human beings from injury by radiation, and promoting better health through beneficial applications or radiation. (Also called Radiological Health).
The location where one or more reportable sources of radiation are processed (located).
Devices which increase the brightness of the image produced by the action of x-rays upon a phosphor.
An atom or molecule which has one or more of its surrounding electrons separated from it and therefore carries a positive electric charge, or a free electron carrying a negative electrical charge.
An x-ray measuring device in which gas is ionized in proportion to the quality of x-ray energy passing through the chamber.
The process whereby one or more electrons is removed from a neutral atom by the action of radiation (the conversion of atoms to ions).
Kilovolt Peak (kVp)
A unit of maximum or crest value of electrical potential difference between the anode and cathode of an x-ray tube; determines the penetrating ability of x-rays and revers to the "quality" of x-rays.
Means all radiation coming from within the x-ray tube housing except the useful beam.
A blood disease which is characterized by overproduction of white blood cells. It may result from overexposure of the bone marrow to radiation.
The ratio of image size to object size. The image may be larger than, smaller than, or equal to the object; so magnification can be greater than, equal to, or less than 1.
Milliampere (mA) multiplied by the time during which the beam strikes an object (measured in seconds) is _________ and is a measure of the "quality" of x-rays.
A transformation of the gene which may be induced by radiation and may alter characteristics of the offspring.
Means the dose received by any individual in the course of employment. Exception: Radiation dose received for the operator's own personal medical and dental diagnosis or therapy.
The area where the control panel for the operation of an X-ray machine is located. It should be behind a protective barrier either in a separate room, in a protective booth, or behind a shield which will intercept the useful beam and any radiation which has been scattered only once.
A means used to indicate the direction of the useful beam and to establish the minimum source-surface distance. It may be a cylinder or a cone and must be open ended.
A term used to describe the penetrating power of x-rays and is related to the energies of the photons in the useful or primary x-ray beam.
Quality Assurance (QA)
A management tool that includes policies and procedures designed to optimize the performance of facility personnel and equipment.
1. Quality control (QC)
3. Education of personnel
4. Preventive maintenance methods
QA includes all of the following:
utilizing ionizing radiation, this technique involves making shadow images on photographic emulsions. The image is the result of differences in attenuation of the radiation as it passes through the object in its path.
The dose equivalent in rems is equal to the absorbed dose in ____ multiplied by the quality factor (1 rem - 0.01 Sievert).
Additional radiographs taken because of technical or mechanical error. These lead to increased radiation exposure for the patient and the radiation worker and should be avoided.
Means radiation that during passage through matter, has been deviated in direction. It usually has also been modified by a decrease in energy.
Secondary or Stray Radiation
Mean radiation not serving any useful purpose. It includes leakage and scattered radiation.
Material which is interposed between a radiation source and an irradiated site for the purpose of minimizing the radiation hazard (used to prevent or reduce the passage of radiation).
Usually made of lead which is dense and absorbs radiation easily. Used to protect the reproductive organs, testes or ovaries, from the x-ray beam during an examination.
The SI unit of dose equivalent equal to the produce of a dose of one Gray, the quality factor, and any other applicable modifying factors. ( 1 ___ = 100 rem).
Source-to-Image Distance (SID)
The distance measured along the central ray from the center of the front surface of the source (x-ray focal spot to the surface of the irradiated object or patient.
With intensifying screens, the __________ is defined as the ratio of the radiation dose (exposure) without screens to the radiation dose (exposure) required with screens to get the same degree of blackening of x-ray films.
Responsibility for and control of quality, radiation safety, and technical aspects of all x-ray examinations and procedures.
Means an evaluation of the radiation hazards incident to the production, use, release, disposal, or presence of sources of radiation.
Material at which electrons from the cathode in an x-ray tube are aimed in order to produce x-rays.
The distance from the x-ray tube target (anode) to the film measured in inches or centimeters.
The distance from the x-ray target (anode) to the skin of the patient where x-ray beam enters the body.
Means that part of the radiation which passes through the window, aperture, cone, or other collimating device of the tube housing.
Penetrating electromagnetic radiation whose wavelengths are shorter than those of visible light.
For radiographic purposes, ______ are usually produced by bombarding a metallic target with fast electrons in a vacuum.
A device which supplies electrical power to the x-ray tube. It does not, as the name implies, actually generate x-rays.