Radiology 6 Flashcards

Low Energy
Terms Definitions
without, not
blood condition
backward, behind
Ultrasound, Ultrasonography
under, below
Cystic Fibrosis
air, lung
Heart Failure
across, through
formation, production
Most common: spontaneous/idiopathicOther common: alcoholism, corticosteroid
separation, destruction, loosening
Right Upper Quadrant
alk phos
alkaline phosphatase
instrument for measuring
Digital Subtraction Angiography
Acute Myelogenous Leukemia
Internal Oblique/Mylohyoid Ridge
AVN4 stages
Avascular (most severe)RevascularizationRepairDeformity
bone marrow, spinal cord
forming an opening (mouth)
Uses non-ionizing RadiationPatient placed in a large magnet (Large external magnetic field)Hydrogen atoms in the patient align themselves with the magnetic fieldApplication of RF signalRemoval of RF signalHydrogen atoms come back to their original position after releasing energy Energy (signal) is detected and used to construct image
Barlow's diseaseLong term deficiency of Vit CCapillary fragilityMistaken for child abuseosteopenic bones
_______respiration during exposure of AP axial inlet pelvis.
specialist in the study of
increase horizontal angulation, image shifts to _____.
parental exposure
puncture through the skin
Absorbed Dose
SI: Gray (Gy)
Traditional: Rad
Severs Disease
Not a necrosis!Sclerosis and fragmentation of the calcaneal apophysis represents normal anatomy
maxillary tuberosity
- posterior aspect of maxilla
Mounted radiographs may be adequately viewed by holding the film mount up to the room light.
parallel technique
an intraoral radiographic technique used to expose periapical films: film is placed parallel to long axis of tooth; central ray is directed perpendicular to film and long axis of tooth; and film holder must be used.
Which have greater kinetic energy: outer or inner shell e-?
Anode (+)
○ Positive electrode
○ Purpose: converts electrons into x-rays
○ Tungsten target: has a focal spot that converts electrons to x-rays
○ Copper stem: dissipates heat from the target
Legg-Calve-Perthes diseasePrognosis
Depends on:early diagnosis (poorer in advanced disease)Age (younger better)Sex (poorer in females)
Proximal ____ of femur should be visualized on AP unilateral hip
Clay-Shoveler's Fracture
Flexion injury that results in avulsion of the spinous process (posterior)
Dental Follicle Sac
- connective tissue sorrounding developing tooth- produces cementum, PDL, and part of alveolar bone
What are phleboliths?
small, rounded calcifications that represent calcified venous thrombi, usually found in pelvic veins of women and are not pathological
____ reduced by - parallel alignment of teeth and film- perpendicular alignment of central ray- NOT related to PID or object-film distance
subject contrast
- results from differential absorption of x-rays through different tissues of patient's body
located in nucleus of atom, has neutral charge
Coherent Scattering
Scattered - no absorption 
Low energy photon passes near an outer electronCauses electron to vibrateIncident photon ceases to existThe vibration of the electron causes it to radiate energy in the form of another x-ray photonOnly 8% of total interactions
What are some properties of film?
Total dose:
total amount of radiation energy absorbed
Spine infectionEarly radiographic features
rapid disc space lossEndplate destruction
What anatomical structures are cones and cylinders often used for?
Head and spine
Mandibular anterior occlusal
- Indicates presence of developing permanent teeth in children and visualizing large pathologic lesions in anterior mandible
Nutrient Canals
- carry neurovascular tissue to bone and teeth- thick, uniform vertical radiolucent lines
Alveolar Crest
- pointed structure in anterior teeth and flat in posterior areas
The filament and the anode target are both made of ?
Film viewing refers to the placing of films in a supporting structure.
Binding energy
- holds electrons in orbit around nucleus- greatest for K shell closest to nucleus
PID lengths
- short: 8in- medium: 12in- long: 16in
Properties of X-rays
Weightless packages of pure energyNo electric chargeTravel in wavesTravel with a specific frequencyat the speed of light
range of wavelengths:    0.1A to 0.5 A (1 A = 1/10 nm)
To change penetration you need to...
change the kVp
Define film density
overall blackness of a finished radiograph
A picture produced by the passage of x-rays through and object or body
Revascularization Phase
1. New Vessels grow into the necrotic bone, resulting in deposition and resorption.2. New Bone is deposited directly on the dead bone, thickening the trabeculation and increasing bone density3. New bone easily modeled relative to epiphyseal stresses (softer than normal)4. Fracture under the articular cortex may occur (cresent sign)5. Resorption is secondary to phagocytosis, fibrosis, and infiltration and produces bony fragmentation
The _______ is key in determination of correct leg and foot position.
Lesser trochanter
What are the different grid problems?
Off-level Grid
Off Center
Off focus
Upside down
mandibular incisor horizontal angulation
- horizontal angle aligned with embrasure space btwn central incisors- 0 degrees
What do radiodense and radiolucent mean in an MRI?
nothing, they don't apply
Identification Dot
A raised bump.
Used to determine film orientation.
length of PID
- affect exposure time- intensity of radiation varies inversely with the aquare of the distance btwn source and absorbing material
Factors affecting Density
when these things are increased they have the following results 
Anatomy being imaged         (Thickness         Density (g/cm3)         Atomic Number)-all cause lighter film2. Beam Energy / Quality        (KVp         Filtration)-both cause darker film
 3. Beam Intensity / Quantity        (MA        Exposure time)-both cause darker film        (Filtration
        Collimation         Distance (inverse square law)) -cause lighter film
   4. Film Speed        Faster Film greater Density and vice versa 
5.  Processing         (Time         Temperature         Concentration)- cause darker film6. Artifacts (lead aprons, film reversal, earrings, thyroid collars)….. lighter areas in the film  
What are grids?
Alternating thin strips of lead w/ spacers between them. Absorb any x-rays that are not parallel to the primary beam. Absorbtion of non-parallel x-rays produce a better picture/better contrast. Grids have an optimal focal distance grid ratio vs. height.
How can a film be fogged?
Stray light
Excess temp
Chem vapors
Safe light
Dental Radiograph
A photographic image of teeth and the periodontium
During the birth process the baby must travel______
inlet ----> cavity----->outlet
T/F: No molars in upper and lower = no BWs
What pathology shows a white lung field?
consolidation (i.e. pneumonia), atelectasis (collapse), pleural fluid accumulation, masses
photostimulable phosphor plates (PSP)
- very similar to film- reusable- flexible- thin- no wires
a form of energy carried by waves or a stream of particles
what landmarks are seen from the mandibular bicuspid view?
1. mental foramen-bilateral, radiolucent
2. mandibular canal- bilateral, radiolucent line
What is a slow speed screen?
Smaller cyrstals=less light emitted. More radiation needed. Better resolution. Less grainess.
What are the chart factors for the spine when going off the base technique?
mAs= 4x
kVp= -20
○ Total of 250 rads in a 14 day period will cause erythemea on the skin
○ To produce this you would need 500 dental films to be exposed in a 14 day period
Soft tissue signs of hip joint disease
Capsular swellingSmall obturator (hip flexion)Increased tear drop distance
The union of acetabulum is a _________joint of the ________, which is immovable or ___________ in an adult.
cartilaginous ; synchondrosis subtype ; synarthrodial
maxillary canine PA
- size 1- canine and distal 1/2 of lateral incisor w/at least 2mm bone around lamina dura- contact points between canine and lateral incisor with no more than 1/2 enamel thickness overlapped- palatal cusp of 1st premolar overlaps distal surface of canine (OK)
How many times the CXR radiation does chest CT expose a patient to?
over 100x the radiation
what is the x-ray tube?
the heart of the x-ray generating system. is a lead lined, glass vacuum tube containing a negative cathode and a positive anode.
How does elongation affect radiographic distortion?
The x-ray tube isn't perpendicular to object - causes the object to appear longer than it is.
If you want to change the contrast, but don't want to change the density, you...
Use the density rule
Modification in Technique:
Mandibular premolar region
○ On insertion: the film is tipped away from the tongue while the bite-block is placed firmly on the mandibular premolars (A view)

When the patient closes on the bite-block, the film moves into proper position (B view)
Where and at what age do the hip bones fuse together? 
Acetabulum ; Mid-teens
What generalization can be made by higher grid ratio compared to lower grid ratio?
Higher grid ratio, higher bucky factor
The quantity (or intensity) of an x-ray beam is defined as:
amount of energy flowing per second.
What structures is the CXR an assessment of?
heart, lungs, mediastinum, and chest wall
what protective clothing is needed when taking radiographs?
you must wear an appropriate covering such as a gown or lab coat as well as gloves, masks and eye protection.
Characteristics of a focused grid:
The lead strips are parallel with the natural divergence of the primary beam. Focal distance is very important!
The film blocker should be placed...
near the narrowest part of the animal
What is the definition of x-ray?
it is a form of electromagnetic radiation similar to visible light but of a much shorter wavelength which results in more penetration.
What is part position for axiolateral inferosuperior hip?
Flex and elevate unaffected leg, out of collimation field. 
Prevent foot from touching hot collimator.
 No rotation of pelvis.
Place cassette in crease above iliac crest, adjust to be parallel to femoral neck and perp to CR.
Internally rotate affected leg 15 to 20 degrees if possible.
What is pericardial effusion?
heart is enlarged due to fluid in the pericardial sac
absorb low energy x0rays from primary beam
The function of added filtration in the x-ray unit is to:- absorb low energy rays from the primary beam- absorb low energy electrons from the tube current- absorb scattered photons from patient's head- absorb photoelectrons produced in tungsten
Is there proper penetration in the x-ray(light or dark)?
Ona a film that is inadequately penetrated, the anatomical parts are indistinct or imperceptible. If over pentrated, it will be too dark. Distinguishing between overpenetration and excessive density depends on a consideration of contrast.
What is Full Wave Rectification of Three Phase 60 Cycle AC?
inverts negative pulses of 3 waves resulting in 6 positive waves
What are the four bones of the pelvis?
two hip bones (ossa coxae, AKA innominate bones), one sacrum, one coccyx
What can occur if moving grids aren't designed properly?
Can produce stroboscopic effect due to synchronization between x-ray pulsation and grid movement.  Pronounced grid lines appear
What are some signs of COPD in the CXR?
increased lung volume (more ribs), flattened or depressed diaphragm, dangling heart, presence of bullae, decreased vascularity
What do you adjust for proper film penetration?
The standard change in KVP to increase or decrease pentration is 10-15%. 10% KVP change is the least change the human eye can detect.
Clearing time refers to the _______________
minimum amount of time a film needs to be in the fixer in order to adequately remove the unexposed crystals and is usually 1 minute. After this minute the radiograph can be taking out for up to a minute for a quick peek but must go back in to finish the remainder of time.
List the three factors to be used when selecting a grid
1. Patient dose increase with grid ratio
2. High ratio grids used for high kvp
3. patient dose at high kvp is less than at low kvp
Which is less radiation FMX E speed or D speed?
E speed is faster thus less radiation
What does an unexposed border mean?  What is the Ca. rule on this? 
The IR receives an image that is 1 cm smaller on all sides.
2 sides of borders must be unexposed
95 kVp and 11 impulses(You would raise the kVp and lower the impulses)
your x-ray unit is set to 80 kVp, 10 mA and an exposure time of 22 impulses The dentist wants to decrease the contrast of the images. Which of the following modifications will result in a decrease in contrast with no change in the density of the image?- 65 kVp and 44 impulses- 65 kVp and 11 impulses- 95 kVp and 44 impulses- 95 kVp and 11 impulses
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