Radiology Exam 2 Flashcards

x-ray beam
Terms Definitions
study of
discharge, flow
same, alike
hernia, swelling
at bedtime
Respiratory Distress
in, within
Cardiopulmonary Resuscitation
study of
Maxillary Tuberosity
Unilateral sacroilitis?
Think Infection
belly, belly side
Magnetic Resonance Imagiing
Irritable Bowel Syndrome
Shortness of Breath
Bundle Branch Block
Idiopathic Thrombocytopenic Purpura
Mandibular/Inferior Alveolar Canal
Epiphyseal InfarctionSclerosis
Occurs with revascularization
Impression (synonymous with diagnosis)
Posteroanterior, Pernicious Anemia, Pulmonary Artery
Inflammation of bone marrowPredisposing conditions :MalnutritionDiabetesLeukemiaAnemiaAlcoholism 
Sclerosing bone disease (more white)Decreased osteoclast activity
back (of body), behind, posterior
abnormal condition, increase (used primarily with blood cells)
T/FCT is recommended for ulcers.
Compton Scattering
Partial absorption 
Photon interacts with an outer orbital electronA scattered photon of lower energy is produced And a recoil electron is ejected from the target atom62% of all interactionsScattered photon travels in all directions30% of the scattered photons exit the patient’s head
To curve across or through
Kienbock's Disease
Avascular necrosis of lunateAssociated with manual labor20-40 year olds75% have short ulna (ulna minus)pain and swelling of wristLunate increases density-fragments and collapsessclerosis, radiolucent, flatteningPrecipitates DJD
meninges (membrane covering brain and spinal cord)
- normally cannot be distinguished from dentin- can be distinct in hypercementosis
contrast resolution
DDR: 8 bit gray scale
Soft tissue surrounding the crownThird molarsPainful and swollenRadiographic features :Underlying osteitisLoss of cortical outline
Does OFD effect contrast or density?
Secondary Radiation
Primary beam interacts with matter
Less penetrating than primary
Osteomalacia2 main causes
Vitamin D deficiencyRenal tubular phosphate loss (Fanconi's syndrome)
Patients who have had hip replacement surgery should NOT be placed in the _______ position for any postsurgical procedures.
symbol for degree of acidity of alkylinity
Maxillary Sinus
- air-filled cavity lined by mucoperiosteum in maxilla- usually extends from canine to molars, may be smaller- appears as a round or oval radiolucency- surrounded by thin uniform radiopaque wall- may extend btwn roots of teeth and may have septa within cavity
What is pneumobilia?
air in the biliary system
fluorohalide in PSP
- similar to silver halide
- reduces radiation dose- best length for PID- more absorption of x-rays by PID
any object that can puncture the skin
Light radiographs
insufficient exposure time, mA or kVincreased source to film distancemomentary drop in incoming voltagefilm exposed backwardsinsufficient development, cold developerold, poorly mixed or contaminated developerlow replenishment
Large phosphor crystals...
require less exposure
produce more light
less detail (Quantum mottle)
What are Dental X-rays?
- Electromagnetic radiation.
- Weightless packages of energy (photon/quantum) that have no charges that travel in waves.
- Wavelength and frequency will determine the amount of energy it has, thus it's penetrating ability
The art and science of making radiographs by the exposure of film to x-rays
Hormones and nutrients that stimulate bone production
Growth hormoneThyroid hormoneCalcitoninVitamin DVitamin C
Cones and cylinders are considered to be modifications of____
Aperture diaphragm
genial tubercles
- bony extensions on lingual surface of anterior mandible- attachments for genioglossus and geniohyoid muscles- usually seen only on occlusal cross-sectional radiographs- appears as linear, uniformly radiopaque structures at midline
nasolacrimal canal
- extends from medial aspect of inferior orbit to nasal cavity below inferior turbinate- can appear on maxillary occlusal radiographs as round/oval radiolucency in molar area
What is the most useful imaging for evaluation of pericardial effusion?
To place in an appropriate setting, as for display or study.
significant underexposure
- image too light- little density difference btwn different tissues
- 85-90%
Which of the following is true regarding brehmsstrahlung radiation?- makes up 85-90% of x-rays produced in x-ray tube- consists of x-rays with a single energy level- results from interaction with K shell electrons in tungsten
ADA case type I periodontitis
Gingivitis, no bone loss
What is the SID usually kept constant at?
Internal and External are refering to what type of structures?
hollow organs
Radiographic Diagnisis
is the responsibility of the dentist to provide a diagnosis based on a radiograph.

Dental Hygienists can provide a preliminary Radiographic Diagnosis
Scatter Radiation
Form of secondary radiation that is deflected from it's path by the interaction with matter
Deflected in all directions: detrimental to the patient and radiographer
May cause film fog
Less abduction of femurs during AP bilateral frog-leg pelvis such as 20 to 30 degrees from vertical provides the least foreshortening of femoral necks, but this placement foreshortens the _________, which may not be desirable.
entire proximal femora
What is grid cut off?
Undesirable absorption of primary x-rays by grid
Nasal fossae
- paired air cavities superior to oral cavity- appear as radiolucencies overlying anterior teeth
T/F The left atrium is not seen under normal circumstances.
photostimulable phosphor plates
- europium ions added as imperfections on purpose- plate of barium fluorohalide in crystal lattice- x-rays excite Eu electrons to metastable state beyond valence band
An exposure time of 0.2 sec is equal to how many impulses?- 0.003- 0.2- 12- 20- 120
Buccal Object Rule (BOR)
“When two different radiographs are made of a pair of objects, the image of the buccal object moves, relative to the image of the lingual object, in the same direction that the x-ray beam is directed”
What is image contrast?
range of greys on the film
x-ray tube:
Vacuum that houses the cathode (-) and anode (+)
Rules of Paralleling Technique:
• Film placement: specific film placement to cover a prescribed area
• Film position: film must be parallel to the long axis of the tooth
• Vertical angulation: central ray must be perpendicular to the film and the long axis of the tooth
• Horizontal angulation: central ray must be directed through the contact areas between the teeth

Film exposure: x-ray beam must be centered on the film to ensure all areas of the film are exposed
What size cassette is used for AP axial SI?
10 X 12
_______ and ______ are used to reduce the level of scatter radiation
Collimators and grids
cone cut
- beam not aligned, part of sensor not exposed
What is ultrasound?
an image produced by direcing a beam of high frequency sound waves into the body and recording the waves reflected back
- number of waves hat pass a point in a unit of time
What can radiographs help to confirm?
confirm or classify suspected disease
What 4 things will a "diagnostic radiograph" have on it?
Sufficient densitiy, definition, contrast and penetration.
What is Mass number?
Number of PROTONS and NEUTRONS in nucleus.
aka atomic mass
When looking at positioning on a film what order do we go in?
Name tag
Film size
Critical organs:
§ A critical organ is an organ that, if damaged, diminishes the quality of a person's life
§ In dentistry the critical organs are (these are the organs that are exposed when taking dental radiographs):
□ Skin
□ Thyroid gland
□ Lens of the eye
□ Bone marrow
Correct positioning of modified axiolateral hip is evident by_______
Femoral head and neck seen in profile. 
Lesser trochanter seen projecting post. to femoral shaft.
The three types of beam restrictors are?
Aperture diaphragm, cones or cylinders, variable aperture collimator
maxillary central/lateral incisor PA
- central and lateral incisor on side being radiographed w/at least 2mm of bone around lamina dura- contact points between central and lateral incisors and between 2 central incisors w/no more than 1/2 enamel thickness overlapped
What are some causes of widened mediastinum?
aortic aneurysm, thyroid enlargement, mediastinal lymph node enlargement, aortic dilation, esophageal dilation, thymic tumors, trauma
Ghost Shadows are formed when.
Arise from structures located on the opposite side of the center of rotation away from the image layerProduced when the object is located between the x-ray source and the rotational center.
CharacteristicsSame general shapeAppears on the opposite sidePositioned higher than real structureMore blurred than the real structureVertical component is more blurryVertical component is highly magnified
What happens during latent image production?
X-rays hit screen phosphor crystals. The screen phosphor crystals emit visible light. The light causes a change in the silver halided on the film producing an invisible latent image. The latent image is made visible through processing.
What are the 2 reasons for a film being too light?
Insufficient mAs
Under processing
Decreasing the kVp by 10-15% wil...
decrease the number and penetrating power of the beam and HALVE the density of the finished radiograph
Production of Dental X-rays STEP 2 &3:
○ Step-up transformer is activated when the exposure button is pushed (controlled by the kVp)
○ This propels the electrons from the cathode to the anode
○ The focusing cup directs the electrons to the tungsten target (anode)
Where are the ischium and pubis located?
Ischium- inferior and posterior to acetabulum
Pubis- Inferior and anterior to acetabulum
What is the difference between parallel grids and crossed grids?
Parallel grids only clean up scatter along axis
What are some signs of tension pneumothorax?
shift of mobile structures (away), inversion of the diaphragm, and flatteing of the heart contour on side under tension
Discuss the importance of masking extraneous viewbox light seen around a film mount.
To reduce glare and intensify the detail and contrast in radiographic images.
what land marks are seen from a maxillary bicuspid view?
1. maxillary sinus- radiolucent
2. septum of the maxillary sinus-radiopaque
3. floor of the maxillary sinus -radiopaque
all bilateral
What do you do to increase the contrast of the subject on the film?
Decrease KVP and increase MAS.
What are the 2 types of positive contrast?
Barium Salts (Barium Sulphate suspension or paste)
Iodine Compounds
What are the subatomic particles that make up the atom (and their charges)?
Nucleus: Proton (+) Neutron (no charge)

Orbits: Electron (-)
Where is CR for modified axiolateral hip?
Angle CR mediolaterally as needed to be perp and centered to femoral neck.  Angled posteriorly 15 to 20 degrees from horizontal. 
What is technically being imaged using MRI?
hydrogen atoms in water and fat molecules
what is the purpose of the leaded glass housing?
to prevent x-rays from going everywhere
How does foreshortening affect radiographic distortion?
Object is not parallel to the film - causes the object to appear shorter than it is, with the elevated portion distorted.
Increasing the mA (amperage) in an electrical circuit allows...
more electrons to move through the wire: more xrays, darker film
The pelvic brim is defined by the ________
upper part of the symphysis pubis anteriorly and upper, prominent part of sacrum posteriorly.
Most grids have frequencies in the range of?
25-45 lines per cm (60-100 lines per inch)
What is the preferred imaging for liver, biliary tree, and gallbladder?
US or CTUS is less useful for distinguishing benign v. malignant cancer
What are two things that must happen during manual processing?
All solutions should be ideally at 68*. Always stir solutions before starting processing procedure.
Primary Radiation (Aka primary beam / useful beam
x-ray beam produced at the target of the anode and exits the tubehead
False! The alveolar crest is NO more than 2.0 mm apical to CEJ.
T/F: In health, the alveolar crest is more than 2.0 mm apical to CEJ.
What is the rinse bath stage of developing film?
It's usually water. Can also be acid "stop bath". Removes developer. Reduces carry-over of developer into fix.
increase kVp, mA, exposure time and make PID longer
How could you fix an image that is too light
If the PID is longer, the intensity of the radiation is weaker. Double the length, intensity decreases (1/2)2 or 1/4 of the original intensity. So you must increase exposure time by 4times to make up for this change.Tn/To = (Dn/Do)2Tn= new exposure timeTo
Your unit operates at 70 kVp, 7 mA and an exposure time of 0.12 second with a PID length of 8". The dentist decides to use a 16" PID instead. What exposure time should you use to produce radiographs with the same degree of darkness?
/ 125

Leave a Comment ({[ getComments().length ]})

Comments ({[ getComments().length ]})


{[ comment.comment ]}

View All {[ getComments().length ]} Comments
Ask a homework question - tutors are online