Radiology Flashcards

x-ray beam
Terms Definitions
pertaining to
childbirth, labor
through, across
record, writing
stone, calculus
every morning
dialation expansion
narrowing stricture
unequal, dissimilar
varied, irregular
Periapical Radiograph
insturment for examining
Nothing by mouth
Forced Vital Capacity
Coronary Care Unit
Erythrocyte Sedimentation Rate
Maxillary Cross-Sectional Occlusal
Define hyperechoic
many echoes
fixation (of an organ)
Chronic Obstructive Pulmonary Disease
wave concept
characterizes electromagnetic radiation as waves and focuses on the properties of velocity, wavelength and frequency
Exposure (air)
SI: Coulombs/Kilogram (C/kg)
Traditional: Roentgen ( R)
Spine InfectionRadiographic Features
Endplate destructionDisc destructionPre-vertebral ST swellingSOL
abnormal condition (produced by something specific)
- articulates anteriorly with zygomatic process of maxilla- appears inferiorly and posteriorly to zygomatic process- uniformly radiopaque, rounded structure superimposed on maxillary sinus
- 60/sec- voltage continuously changing- anode not always positive w/respect to cathode- electrons move across tube in half cycles when anode is (+)
The pinna is the...
ear flap
OsteoporosisRadiographic features (spine)
Osteopenia and radiolucencCortical thinning "pencil thin"Wedge shaped vertebrae codfish deformitySchmorl's nodes
Upper Left: Anterior Nasal Spine
Upper Right: Soft tissue of nose
Lower Left: Lateral Fossa
Lower Center: Maxillary Sinus
Lower Right: Maxillary Sinus: Inverted Y
When was CT developed?
In the 1970s
16" rectangular
which of the following position-indicating devices (PID) results in the smallest radiation dose to patient?- 8" round- 16" round- 8" rectangular- 16" rectangular
Contrast is effected by:
Subject contrast (barium)
Film type
• General screening
• Growth and development
• Gross pathology
• Supernumerary teeth
• 3rd molars
• Fractures
Too nonspecific to make the diagnosis without clinical information.Soft tissue swellingregional osteoporosisJoints are OKOsteoporosis may be patchy
Most common locations for Infection
KneeHipAnkle (distal tibia)shoulderSpine
Wedge Fracture
Flexion injury that results in compression of the anterior part of the vertebral body (anterior)
The more scattered x-rays, the ____ contrast
Extension Arm
this is what suspends the
xray tubehead and houses
the electrical wires
and allows for positioning
Mounted films are quicker and easier to view and interpret.
- degree of unwanted darkness on radiograph- caused by scattered radiation, light leaks, overheated developer, expired/warm film
infectious waste
anything saturated with blood or saliva
general/braking/bremsstrahlung radiation
electrons hits nucleus of tungsten atom or passes very close. is attracted and slows down. produces low energy ray*majority of x-rays are from general radiation
What is aerial image?
pattern of xray energy
Williams Rollins
Boston dentist known as "the father of science of radiation protection"
Particulate Radiation
Particles have both mass and energy
Travels in straight lines at high speeds from their sources
Some particles have positive, negative, or neutral charges
Periapical Exam:
• Purpose: examine the entire tooth
• Film type: periapical film
○ Peri- around
○ Apex- terminal end of the tooth
• Techniques:
○ Paralleling
○ Bisecting
Spontaneous osteonecrosis
Diagnostic term applied to the aged kneeassociated with medial meniscal lesions. Black triangles
The AP bilateral "frog-leg" projection of pelvis is also called _________
Modified Cleaves Method
lingual foramen
- opening in lingual surface of mandible- terminal branches of incisive branch of mandibular canal exit through foramen- appears as small radiolucency surrounded by radiopaque cortical wall of canal- donut-like
radiographic density
the degree of darkenss on the processed radiographdark = high
light  = low
What is the imaging of choice for appendicitis?
x-ray production time
- not produced continuously- in discrete impulses - 60/second
exposure time
- time during which electrons cross tube from cathode to anode- time you expose the patient- measured in impulses (1/60 sec) or seconds- determines number of x-rays, but not energy level
secondary radiation
primary beam that has reacted with matter (eg hits pt face)this is the beam that develops film
When is anesthesia a must in radiographing a patient?
Spine- cervical
Pelvis- hip dysplasia
What is kVp?
Potential Difference b/t Cathode and Anode
The antebrachium is also...
the radius and ulna
aka forearm
Position-indication device (PID):
Open-ended lead lined cylinder that aims and shapes the x-ray beam
Metal housing:
lead lined metal casing to prevent excessive radiation exposure
Union of acetabulum is similar to joints between ____ and _____ of long bones in growing children.
epiphyses and diaphyses
What is a grid?
An extremely effective device for reducing level of scatter radiation reaching IR
submandibular gland fossa
- depression in lingual aspect of mandible below mylohyoid ridge in molar region- submandibular salivary gland in here- diffuse radiolucency with sparse trabecular pattern
focusing cup
which component of the xray unti is made of molybdenum
Name intermediate and severe adverse reactions with contrast agents
angioneurotic edema, urticaria, wheezingcardiovascular collapse, laryngeal edema, apnea
half-wave rectification
- only half the voltage cycle is useful- aka self-rectified- most dental x-ray machines use this
dense core of the atom* K shell is closest to the nucleus and has the highest energy
Characteristics of medium speed film:
"Par" film/"standard" film. Most common. Has medium size crystals. Medium amount of exposure needed. Get moderate detail.
What are some adverse rxns to negative contrast?
Air embolism
X-rays produce an ___________ image on photographic film that is made visible by ___________

processing the film
Exposure Sequence for Film Placements:
• Anterior Exposure Sequence
○ Recommended to always start with anterior film because-
§ Size 1 film smaller and more comfortable
§ Patient less likely to gag
○ Posterior Exposure Film-
§ Take premolar view before molar views
The area inferior to a plane through the pelvic brim is termed the ___ or ___ pelvis
lesser ; true
What generalization can be made by increasing kVp (as far as BF)
Increase kVp, increase BF
The quality of an x-ray beam is determined by:
its penetrating power.
In the PA view what do the clavicles look like?
S shape
less thickness of tissue
which of the following will increase the transmission of x-rays through tissue?- lower energy x-rays- higher atomic # elements in tissue- less thickness of tissue- greater density of atoms in tissue
Object to Film Distance
Short object to film distances produce less magnification Short object to film distances produce sharper images
What does alot of white on the film mean?
Low density.
How can you make the film have less contrast and increase the overall density?
increase kVp
A kVp selector is aka...
choke coil (major/minor)
-in the High Voltage Circuit
What are considered extremities in regards to positioning in radiography?
Bones and joints of limbs
Radiation Injury Sequence, Repair and Accumulation
Latent period
Period of injury
Period of repair
What is the pit near the center of the head of the femur called?
Fovea capitis
What is the formula used to determine grid ratio?
Grid ratio = H/D
What are cicatrization causes of atelectasis?
post pirmary TB or granulomatous disease and pulmonary infarct or trauma
shorter wavelength that visible light
Which of the following is true regarding x-rays?- (+) charge- shorter wavelength that visible light- mass = to e-- absorbed more in soft tissue than in bone- lower frequency than radio waves
Characteristics of a Hi-plus screen:
A medium screen speed. Medium size crystal. Crystal is calcium tungstate. Has average resolution. Used for general x-rays.
What is a high speed screen?
Large crystal=higher amounts of light emitted. Less radiation needed. Poor resolution. More grainess (picture not as clear).
Adjustments to mAs and kVp are made in what increments?
mAs: 30-50%
kVp: 10-15%
Half Value Layer (HVL):
• To reduced the intensity of an x-ray beam, aluminum filters are placed in the path of the beam inside the tubehead
• Remove longer, low energy wavelengths; less penetrating x-rays
• The thickness of aluminum (filters) placed in the path of the x-ray beam that decreases the intensity of the beam by 1/2 is the HVL
• HVL: if the thickens of a 4mm of a material is placed in the path of the beam, and the intensity is reduced by one-half, the HVL of the x-ray beam is 4mm
• Measures HVL; determines the penetrating quality of the beam
• Measured in mm
• The higher the HVL the more penetrating the beam
What pathology is demonstrated for an AP axial projection of SI joints?
Assessment of fracture and joint dislocation or subluxation of SI joints.
List any method you can think of that would give you control over body thickness
compression paddles
compression in IVP
doing PA vs. AP
Full mouth series, 8, 7
- contains 15 PA radiographs- ____ in maxilla- ____ in mandible
What risk is there to using contrast?
dehydrated patients or cardiac and fluid imbalance patients are at riskcan cause change in viscosity and tonicity of blood, changes in BP, changes in cardiac output, changes in pulse rate
exposure time and milliamperage (and kVp)
which components of the x-ray unit most directly control the number of electrons in the primary beam of x-rays?- kVp and added filtration- added filtration and exposure time- exposure time and milliamperage- Milliamperage and added filtration
What happens during the developing step of processing?
The process of reducing the exposed silver halide crystals to black metallic crystals.
What does the spine do naturally in lateral position?
Nose tips down
Cervical spine sags
Thoracic spine stays straight
Lumbar spine sags
Sacral spine stays straight
What structures are shown on post. oblique pelvis?
Downside - anterior rim of acetabulum and posterior ilioischial column, iliac wing
Upside - posterior rim and anterior ilioischial column, obturator foramen
False! Loss of trabeculae can indicate destructive disease.
T/F: Loss of trabeculae do not indicate destructive disease.
Describe what information is placed on a film mount.
 Use a silver pencil and properly label the film holder before actually mounting the films.
Write clearly and legibly: + Patients full name + Date of exposure. (Won't necessarily need to document this info. in a dental office, however at CCD it is a requirement to notate the name of the prescribing dentist + radiographer's name)
For Digital: The computer automatically labels the "mount" with the patients name, and date. The student radiographer needs to add the name of the prescribing dentist and their name in the clinical notes under "A" of Adpie. 
When do you replace the developer solution?
Completely replace when it's green or brown. Film will have less contrast & appear over-exposed if needing replenishing. Adding replenishing solution to developer to return to original strength.
What is the heel effect?
xray beam is denser on cathode side of tube
-place thickest area under this end
Where are the body and ala located in ilium?
Body- inferior portion (includes upper 2/5 of acetabulum)
Ala- thin and flared upper part of ilium
What material is used to encase grid and what does it provide?
Thin cover of aluminum, rigidity of grid, helps seal out moisture
Where is US use limited?
In chest and MS system due to bony and gas containing structures obscuring tissues lying deeper
What are the 5 general steps to film processing?
Develop, Rinse, Fix, Wash and Dry
What do the intenifying screens do in terms of photons?
intensifies one photon of xray energy to become hundreds of photons of light
Why can't we take all radiographs with low kVp??
kVp must be high enough to ensure adequate penetration of the portion of the body being radiographed
what is the purpose of the lead collimator within the tube head?
restricts the size of the x-ray beam to try and prevent divergence
What are landmarks in a radiograph?
Parts of the body that you CAN SEE or palpate to make sure that the primary beam includes proper limits for that body part.
False! PAs and BWs provide only 2 dimensional views
T/F: You can see depth in PA and BW radiographs.
Childhood osteomalacia
surgical puncture
air, lung
standing still
Frozen Section
Vital Capacity
surgical repair
Genial Tubercles
HPT radiography
OsteopeniaSuboperiosteal ResorptionBrown tumorsSoft tissue calcification
excessive, above normal
involuntary contraction, twitching
prolapse, downward displacement
Ventricular Septal Defect
bursting forth (of)
Periodontal Ligament Space
Legg-Calve-Perthes diseaseRevascularization
Flattened,small epiphysis, fragmentation, homogenous sclerosis (snow cap), increased cortical density, metaphyseal cysts, patchy schlerosis, crescent sign, wide short neck
forming an opening (mouth)
bone marrow, spinal cord
Does mAs affect contrast?
Regional osteoporosis
Immobility and disuseReflex sympathetic dystrophy syndrome
Lactate Dehydrogenase, Lactic Acid Dehydrogenase (cardiac enzyme)
Which imaging study distinguishes flowing blood from structures?
Apical Infections
Apical periodontitisApical rarefying osteitisPeriapical abscessPeriapical granulomaPeriapical cyst Apical sclerosing osteitisCondensing osteitis
Moderate density
produces shades of gray
Draining sinusMore common with chronic diseaseRare complication is to develop a squamous cell carcinoma within the channel of the cloaca; the ulcerative channel with malignant transformation has been called Marjolin's Ulcer
abnormal breath sound heard on auscultation
Alveolar Crest
- Continuation of Lamina Dura
- assigns number to each voltage
Factors affecting Radiographic Contrast
Subject Contrast Film Contrast Scatter Radiation
Describe Barium Salts
Ideal for GI tract
TBComparison to osteomyelitis
Similar, but add: Multiple levelsParaspinal cold abcesses with Ca+
Freiberg's Disease
Avascular necrosis (usually the MTP 2)More common in females (high heel shoes)
______ is useful for evaluation of newborns for hip dislocations and assessment of joint stability during movement of the lower limbs.
As kVp is increased________ aslo increased
Scattered radiation
Lamina Dura
- radiopaque line surrounding PDL space representing bone into which ligaments attach to alveolus- appearance can vary due to different horizontal angulations- loss of this is an important sign of inflammation in association with PDL thickening
T/FThe size of the pulmonary vessels is greater at the base of the lungs than at the apex.
contrast resolution
- ability to distinguish varying densities- depends on differential attenuation of radiation in tissues- depends on ability of imaging system to reproduce differences in attenuation
long rectangular
best shape and length for PID
# of electrons moving through a conductor
Biological Effect (BE)
BE= Dose x Volume     Time
Where measure for thoracic, abd, thoraco-lumbar spine xray?
thickest/densest area
X-ray Generating Apparatus:
- Electricity and electrical currents
- Circuits
- Transformers
A high energy radiation produced when electrons collide with a metal
The ______ is a large opening formed by the ramus and body of each ischium and by the pubis.
obturator foramen
As field size is____ scatter is _____
increased, increased
Image of lingual object moves ___ in the opposite direction than the image of buccal objects.
Which ribs are more apparent on a frontal view CXR?
Also referred to as an illuminator.
A light source used to view dental radiographs.
viewing conditions
- affects viewer's ability to detect contrast on film- ideal: dark, quiet room
too light
Your normal exposure settings are 75 kVp, 10 mA, and an exposure time of 22 impulses If you accidentally set the exposure time at 15 impulses, how will the radiograph appear?
Law of BergonieandTribondeau
Cells from different organs react differently 
Number of cells in active proliferationDegree of cellular differentiationNumber of future divisionsThe larger effect there will be
If you increase the kVp...
more scatter
less detail
more penetrating power
Non-screen films are most sensitive to...
xrays not light
Characteristic Radiation:
- Inner electron is dislodged (K shell)
- Rearrangement of electrons --> energy
- Occurs at 70 kVp (with high speed electrons)
Radiation Injury Factors:
○ Total dose
○ Type of radiation
○ Dose rate
○ Amount of tissue irradiated
○ Cell sensitivity
○ Age
Visualize right joint with ______ and left joint with ______
The ___ projection is considered to be the initial baseline evaluation projection for hip or pelvis.
AP pelvis
As grid ratio _____ the amount of cleanup_____
increases, increases
zygomatic process of maxilla
- articulates with zygoma- thickened extension on buccal surface of maxilla- articulation of zygoma w/maxilla- buttress that prevents maxilla from separating from base of skull
What is the deep sulcus sign?
inferiorly displaced costophrenic angle on supine view - seen in pneumothorax
accurate image formation
- long PID length- short object-film distance- small focal spot- film and object parallel- x-ray beam at right angle to film
- lower frequency
Compared to gamma rays, x-ray photons have:- greater velocity- shorter wavelength- lower frequency- more energy
Bremsstrahlung:                 Electron to nucleus interaction
X rays are produced when high velocity electrons are suddenly decelerated when they pass close to the nuclei of high Z # absorbing material = tungsten 
How do you change the focal spot size?
anode angle
What drugs should not be given to a patient before a contrast study?
How are x-rays produced:
Through the unleaded glass window --> tubehead seal --> aluminum disks (filters out longer wavelengths) --> lead collimator (restrict size) --> PID --> through the patient --> radiographic film
Period of injury
injuries of the cell include
§ Cell death
§ Changes in cell function
§ Breaking or clumping of chromosomes
§ Cessation of mitotic activity
§ Abnormal mitotic activity
What pathology is demonstrated during an AP unilateral hip projection?
Postoperative exam to demonstrate acetabulum, femoral head, neck and greater trochanter, condition and placement of any existing orthopedic appliance.
How is aperture diaphragm designed?
Opening in diaphragm usually designed to cover just less than size of IR used
What imaging studies are used to evaluate the abdomen?
CT, US, MRI, endoscopy
Transmission is more likely
- high energy x-rays- low absorbing material- low density of atoms in material- low thickness of absorbing material
vacuum tube
a sealed glass tube from which most of the air has been evacuated
Advantages to automatic film processing.
Reduces developing & drying time. Reduces artifacts. It's more consistent processing. Less expertise required.
What is Alternating Current?
Magnet spins inside wire
1/2 spin= + current
next 1/2 spin= - current
Vertical Axis of Teeth:
• True vertical axis of teeth generally varies with the vertical axis of the crown by 5 to 20 degrees
What pathology is demonstrated by posterior oblique pelvis?
evalutates acetabular fracture or hip dislocation.  both right and left oblique taken for comparison
The absolute number of compton interactions ____ and what does this mean?  (As x-ray energy is increased)
Decreases; relative number of compton interactions increases
median palatal suture/intermaxillary suture
- union of palatal shelves- appears as thin, uniform radiolucent line vertically positioned between central incisors- may be widened at alveolar crest
What are some adverse reactions to contrast agents?
nausea, vomiting, sneezing, flushes, diaphoresis, feeling of warmth, headache
Real image formation
A real image is formed when the object is located between the rotation center and film
How does material unsharpness affect definition or image sharpness?
Fast intensifying screens cause loss of sharpness due to large phosphor crystals. Poor screen film contact causes loss of sharpness(ex. if it's loose).
What is the time-temperature method?
Films spend less time in warmer solutions and more time in cold = same results
How many shells are there surrounding an atom and what are they named?
There are 7 shells; K,L,M,N,O,P,Q
Where is CR for AP pelvis?
Perpendicular to IR ; midway between level of ASIS and symphysis pubis (2 inches inferior to ASIS)
How much improvement would be gained by a CIF by 1, 1.5 or 2.5?
1- no improvement, 1.5-2.5 = approximately doubled
What are 3 causes of r. ventricular enlargement?
pulmonary disease, pulmonary artery hypertension, tricuspid valve disease
true! it clears any extra electrons
T/F: before PSP exposure, white light is ok.
what land marks are seen from the maxillary molar view?
1. maxillary sinus- radiolucent
2. zygomatic process- radiopaque
3. maxillary tuberosity- radiopaque
4. hamular process- radiopaque
5. coronoid process- radiopaque
all bilateral
What is contained on the wet side of the darkroom?
Processing tanks.Film viewer.Drying area for film.
If you increase the mA (Quantity)....
inc. Thermionic emissions of e-
inc. # of e- across gap
inc. # of e- that hit target
inc. e-/target interactions
inc. xrays (quantity)
inc. darkness of film
Overcome the Anatomy of the Oral Cavity:
• Maintain parallelism between the film and the tooth:
○ Maxilla- place the film towards the midline of the oral cavity
What does PBL stand for and how do they work?
Positive Beam Limiting
Sensing devices in tray identify size and alignment of cassette. 
What problems does a CXR with poor inspiration have?
heart appears larger and poorly defined, pulmonary vessels are more prominent, and there is blunting of the lung bases
what is the purpose of the aluminum disks within the tube head?
to filter out low frequency wavelengths
How does subject composition affect x-ray pentration?
Bone and metal are very dense and hard to penetrate.
What does the alkaline reducing agent do in the developer?
Causes the changed crystals on the film to become metallic silver (black)
What is the traditional method used to locate the femoral head and neck (midpoint line)?
Line between the ASIS and symphysis pubis.
DEcrease the horizontal angle to project the canine onto sensor and will not cause too much overlapping.
What is the only option when it is difficult to place a sensor anteriorly enough to capture the distal half of the canine?
What do you look for with pulmonary embolism?
look for increased density or dilation of other arteries and the right ventricle and atrium (compensation)
What is the Principle of Mutual Inductance?
Current flowing thru a wire induces a magnetic field
Moving a magnet field near a wire causes current to flow in the wire
What is the angle of the pubic arch in females and males?
Female- obtuse or greater than 90
Male- acute or less than 90
Where should the horizontal fissure of the right lung lie?
center to right hilum to level of 6th rib at axillary line
If you forget a label you can do the following, but they're not legal:
Pencil to scratch information onto film before or after developing. Use a photographic white ink or permanent marker on clear areas of exposed film. Use a piece of white tape on a clear area.
What 4 CXR views are done in a cardiac series?
PA, left lateral, r. anterior oblique and l. anterior oblique
pertaining to
discharge, flow
many, much
good, normal
many, much
carrying, transmission
after, behind
incomplete, imperfect
Low-Density Lipoprotein
pertaining to
same, equal
Nasopalatine Canals
instrument for measuring
form, shape, structure
belly, belly side
every other day
Arterial Blood Gas(es)
Mitral Valve Prolapse
Position Indicating Device
AKA CushingsMC: Exogenous corticosteroid administration
Sudden Infant Death Syndrome
T/FConsolidation density is uniform.
the carpus is...
the knee
Healed AVN
May have:Articular deformityEarly DJDAcetabular displasiaHanging rope signTrochanteric overgrowth
Single Photon Emission Computed Tomography
abnormal condition, increase (used primarily with blood cells)
high energy
- high frequency/short wavelength
Define anechoic
without echoes
lacking density
Epiphyseal InfarctionGeneral Radiological Features
Collapse of articular cortexFragmentationMottled trabecular patternSclerosisSubchondral cystsCrescent sign
The higher the frequency, the thicker/thinner the strips
What has largely replaced cardiac fluoroscopy?
- energy carried by radiation- "light"
What does a foot consist of?
High Voltage:
Provides the energy (65,000-100,000 volts) to accelerate the electrons from the cathode to anode and is regulated by the kVp
T and L3 contiguous vertebra5 degree anterior body wedgingIncreased KyphosisSchmorl's nodes
Suppurative OsteomyelitisKey Points
Main Cause: Staph AureusRadiographic latency period of 10 daysLytic destruction of bone that crosses anatomical barriers (vs. tumor)Joint/extremity involvement classicDisc space loss with endplate destruction classic in the spineEffective treatment requires early diagnosis
Each _________ passes down and posterior from symphysis pubis to join ramus of respective ischium.
inferior ramus
Define selectivity
Ratio of transmitted primary radiation to transmitted scatter radiation
What is used to evaluate gallbladder disease?
x-ray darkness
- lighter w/less x-rays hitting target
shorter wavelength
Compared to visible light, x-ray photons have:- greater velocity- shorter wavelength- lower frequency- less energy
thermionic emission
release of electrons from tungsten filament when electrical current passes through and heats filament. The outer shell electrons quire enough energy to move away and form a cloud.
What is corpuscular radiation?
tiny "packets" of radiation
-smallest portion of electromagnetic radiation
Fixing time should be ________ the developing time
Mandibular Premolar:
Include distal half of the canine
Bone Scintigraphy
Can detect infection within hours of infection.Utilizes Technetium (non specific)Galium tags RBCIndium tags WBCVery sensitiveOften followed by MRI to evaluate soft tissue
What is another name for the axiolateral inferosuperior projection of hip and femur?
Danelius-Miller method
A grid with ____ frequency shows more grid line
Mandibular anterior occlusal
- Indicates presence of developing permanent teeth in children and visualizing large pathologic lesions in anterior mandible
What is the most common neoplasm of spleen?
- unequal enlargement of parts of the image
- x-rays hit atoms and bounce in different direction- results in film fog- occurs through compton reaction
copper stem
located in the anode, functions to dissipate the heat away from the tungsten target.
Tissue density
The greater the tissue density the lesser the film density.Least dense(black) Gas-fat-water-bone-metal - most dense(white).
What is ultrasound not used for?
bone detail
dense calcification
The developer in x-ray film processing is an __________________ chemical solution that converts the latent (hidden) image on a film to a __________

visible image
Paralleling Technique:
• Also known as:
○ Extension cone paralleling technique (XCP)
○ Right angle technique
○ Long-cone technique
Exposure Time:
interval of time during which x-rays are produced
• Measured in impulses
• x-rays are created in a series of bursts (not a continuous stream)
• One impulse occurs every 1/60th of a second
• 60 impulses in one second
• To compensate for the penetrating power of the x-ray beam an adjustment in exposure time requires and adjustment in kVp
• Increase exposure time: darker film

Decrease exposure time: lighter film
The ____ is the largest foramen in human skeletal system.
obturator foramen
What is the normal shape of cones and cylinders?
What are the main differences between the two types of moving grids?
Pattern of motion
Dental Follicle Sac
- usually appears as thin, uniform radiolucency around unerupted tooth
What is highly sensitive and specific for detection of coronary artery disease?
thallium stress imaging
radiographic density increased with
- increased exposure time, increase mA, increased kVp, and/or short cone- image looks darker- sensor exposed to greater numbers of x-rays
What can radiographs help to evaluate?
evaluate growth and development
Characteristics of fast speed film:
"Ultraspeed". Large silver halide crystals. Need less exposure. Get less detail - grainier.
What is the fixer composed of?
Acidic Ammonium Thiosulphate (Hypo)
Vertical Angulation:
movement of the tubehead (PID or BID) up and down
§ Is measured in degrees
□ Downward angulation- positive (+)
□ Upward angulation- negative (-)
Exposure Time: mA Example
• Inversely related:
• Increase mA --> decrease exposure time
• Decrease mA --> increase exposure time
______ bears most of the weight of the body when someone sits.
ischial tuberosities
What three factors must be considered when selecting a grid?
degree of cleanup
patient dose
24 impulses
An exposure of time of 0.4 seconds is equal to how many impulses?
When is lordic view used for CXR?
assessment of lung apices
mA-s (milliampere-second) Law
- to keep number of photons constant, if mA is increased, time must decrease.- if mA is decreased, time must increase.
a beam of energy that has the power to penetrate substances and record image shadows on photographic film
What is density on a radiograph?
Adquate blackness on radiograph. Reveals all structural details of the object. Too much density will hide detail.
What are some facts of Non-screens?
Requires high exposure (50-100x mAs)
best detail
exposed deirectly by xrays
Thick emulsion
What is ABC in ultrasound?
Attenuation (what appears after pass thru of target)
Borders (outline of target)
Content (whats inside target)
Photons are pure energy and are _________
carried by the wave.
Two Film Survey:
• 2 Premolar bitewings
• When all contacts can be viewed as open on one film
• 1st premolars extracted
• Include distal half of canine
What are the three divisions of the hip bone?
1. Ilium
2.  Ischium
3.  Pubis
What is upside down grid?
A radiograph with uspide down focused grid shows severe grid cutoff on either side of CR
Increased film speed have what effect on radiographs?
Grainy appearance and decreased detail.
direct digital radiography (DDR)
- use sensor instead of silver halide film- electronic production of radiographic image- composed of thousands of pixels, each represented by a number
what landmarks are seen from a mandibular molar view?
1. ascending ramus- radiopaque
2. mylohyoid ridge- radiopaque
3. internal oblique ridge- radiopaque
4. external oblique ridge- radiopaque
5. mandibular canal- radiolucent band
6. submandibular fossa- radiolucent
all bilateral
What is contrast on a radiograph?
It proved variation in tissue opacity.
What view is used to see the anconeal process?
Flexed lat view
X-rays should be hung in what position if it is a lateral view?
head to the left
Long axis of the tooth
An imaginary line that divides the tooth longitudinally into two equal halves
What can cause diaphragm cut off?
Long axis of diaphragm must be parallel to long axis of IR
False! You place the sensor horizontally past the anterior teeth.
T/F: You place the sensor vertically past anterior teeth for posterior PAs.
What does contrast in US help visualize?
blood vessels and vascular organs, stenotic vessels, areas of ischemia, and tumors
impulses = seconds x 60(always 1 or more)
conversion of seconds --> impulses
What is the screen speed determined by?
The size of the "phosphor" crystal.
If a film requires 2x the exposure, then...
it is half as fast
How should the position be demonstrated during axiolateral inferosuperior hip?
Only small part if any of lesser trochanter visualized.
Only most distal part of femoral neck should be superimposed by greater trochanter.
The grids used in mammography are?
80 lines per cm (200 lines per inch)
What imaging do you use to look for PE?
spiral CT, V/Q scan, MRI
ABSORBED DOSEConventional Unit : SI Unit :
Conventional Unit : RadSI Unit : Gray (Gy)
How do you prevent angulation in a lateral spine shot?
Wedge under nose
Block under cervical spine
Block under lumbar spine
The negatively charged electrons from the cathode move across the tube to the anode, a tungsten covered plate and this results in _________
99% of energy generated is turned into heat

1% is the x-ray energy
What does it mean that the aperture diaphragm is the simplest type of beam restrictor?
Lead or lead lined metal diaphragm attached to x-ray tube head...very simple design. 
What is the most common finding with pulmonary embolism?
normal CXR that is incompatible with patient's cardiopulmonary distress
What is the importance of radiographs?
they give us the ability to see and diagnose conditions of the teeth and bones that we may not other wise see.
What are the steps and times of manual processing?
1. Developer (5min)
2. Rinse/Stop Bath (6min)
3. Fixer (10min)
4. Wash (1min)
5. Dry
The size and shape of the true pelvis are of greatest imporance during birth process because_____
true pelvis forms the actual birth canal
long gray scale or long scale contrast
- high kVp rays produce many shades of gray btwn black and clear (low contrast)
When do the copper block and target become the anode?
when we turn on the High Voltage Circuit
What is kept on the dry side of the darkroom?
Counter - load & unload cassette.Film is stored.Film hanger storage (manual).
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