Exam 2 Flashcards
What are the 3 types of x-ray film?
Intraoral
Extraoral
Duplicate film
What is a recording medium?
Film
What are the components of the intraoral film packaging?
- Outer package wrapping
- Paper film wrapper
- Lead foil sheet
- X-ray film
What are the two sides of the outer package wrapping of the intraoral film?
Tube side
Label side
What side of the intraoral film must face teeth?
Tube side (white side)
What side of the intraoral film must face the tongue?
Label side
What is a soft vinyl or paper wrapper that seals intraoral film packet?
Outer package wrapping
What is the protective sheet that covers film and shields light of intraoral film?
Paper film wrapper
Single sheet placed behind film wrapped in protective paper for the intraoral film
Lead foil sheet
What shields intraoral film from backscatter radiation?
Lead foil sheet
What are the components of the X-ray film?
Double-emulsion
One or two film packet
Identification dot
What are the components of film composition?
- Film base
- Adhesive order
- Film emulsion
- Protective layer
What consists of gelatin and silver halide crystals?
Film emulsion
What gives sensitivity to x-radiation?
Film emulsion
Flexible polyester plastic (0.2mm thick) with a slight blue tint
Film base
- Chemical sensitive to radiation and light
- Absorb radiation during exposure
Halide crystals
What are the two types of halide crystals?
Silver bromide
Silver Iodine
- Suspends and disperses microscopic silver halide crystals
- Absorbs solution and allows chemicals to react with silver halide crystals
Gelatin
Energy is stored in silver halide crystals when film exposed to radiation
Latent image
Almost no radiation received
Behind amalgam
Most radiation received
Behind airspace
How many watts does a safelight have to be in a darkroom?
15 watts or less
What are the steps of manual film processing?
- development
- rinsing
- fixing
- washing
- drying
What step is removed from automatic film processing?
First rinse step
What are the ingredients in developer solution?
- Developing agent
- Preservative
- Accelerator
- Restrainer
What are the two developing agents?
Hydroquinone
Elon
What is the preservative in developer solution? Function?
Sodium sulfite
- prevents oxidation
What is the accelerator in developer solution? Function?
Sodium carbonate
- Activates developing agent
What is the restrainer in developer solution? Function?
Potassium bromide
- Prevents development of unexposed halide crystals
What are the fixer solution ingredients?
- Fixing agent
- Preservative
- Hardening agent
- Acidifier
What is the fixing agent in fixing solution? Function?
Sodium thiosulfate OR Ammonium Thiosulfate
- Removes unexposed or undeveloped silver halide crystals from emulsion
What is the preservative in fixer solution? Function?
Sodium sulfite
- Prevents deterioration of fixing agent
What is the hardening agent of fixer solution? Function?
Potassium alum
- Shrinks and hardens emulsion
What is the acidifier in fixer solution? Function?
Acetic acid or sulfuric acid
- Neutralizes pH of alkaline developer
What are the only speeds used in intraoral radiography?
D and F
Shows bony and soft tissue areas of facial profile
Cephalometric film
What is the majority of extraoral films?
Screen film
What is not recommended for use in dental radiography?
Nonscreen film
What is the extraoral film equipment?
- Intensifying screens
- Cassette
What transfers x-ray energy into invisible light to expose screen film for extraoral film?
Intensifying screens
What is used for patient referrals, insurance claims, teaching aids, etc?
Duplicating film
How is film stored?
- Cool and dry
- Temps between 50 and 70 F
- Away from radiation
- First in, first out
Radiographic image produced by film
Analog image
Filmless imaging system
Digital imaging
Image composed of pixels and stored on computer
Digital image
Picture element, unit of measure for contained digital information, digital equivalent to silver halide crystal in film
Pixel
Receptor used to capture intraoral/extraoral image
Sensor
What protects the sensor?
Front casing
What converts x-ray beam to visible light in the sensor?
Scintillator screen
What transmits light to sensor?
Fiber optic face plate
What captures light and charges pixel?
CMOS imaging chip
What reads charged pixels and transmits to computer in the sensor?
Sensor electronics
What protects and prevents backscatter for the sensor?
Back casing
What are the 3 types of digital sensors?
- Charged-couple device
- Complementary metal oxide semiconductor
- complementary metal oxide semiconductor-active pixel sensor
What digital sensor has a silicon chip and electrical circuit?
Charged-couple device
What digital sensor has smaller pixel size and lower power requirements?
Complementary metal oxide semiconductor
What digital sensor improves signal output and has a computer connection via USB?
Complementary metal oxide semiconductor-active pixel sensor
What is the difference between CCD and CMOS?
The way pixels are read
How big is a pixel?
2mm
Obtaining digital images by exposing an intraoral sensor to x-radiation
Direct imaging
Obtaining digital images by scanning a sensor after exposure to x-radiation and converting that data into digital form
Indirect imaging
What do you need for direct digital imaging?
-Intaoral x-ray unit
-Sensor
-Computer with imaging software
What do you need for indirect digital imaging?
- Intraoral x-ray unit
- PSP plate
- Scanner
- Computer with imaging software
Many images collected to give one view
Panoramic imaging
What can be seen on a panoramic image?
Maxilla
Mandible
Oral and facial structures
What are the uses for a panoramic image?
o Evaluate
dentition/impacted teeth
o Evaluating development
o Disease detection
o Evaluate trauma
Why would we NOT use a panoramic image?
Diagnosing the following:
- Decay/caries
- Periodontal disease
- Periapical lesions
Why would we use extraoral bitewing imaging?
Discomfort/difficulty with intraoral exposures
Children, patients with special needs
Gag reflex
Large tori
Small mouth
Allows us to photograph one section of the body while burying others
Tomography
Pivot point/axis around which a receptor and x-ray tube head rotate
Rotation center
3-D curved zone in which structures are clearly demonstrated
Focal trough
o Structures lie between the receptor and moving rotation center
o Appears in correct anatomic location with varying degrees of sharpness and distortion
Real image
o Anatomic structure is located behind moving rotation center
o Penetrated twice by x-ray bean
o Same proportions as real image
o Located in same location on opposite side of receptor – mirror image
Double image
What are structures at the midline?
Epiglottis
Hyoid bone
Cervical spine
o Anatomic structure located outside focal plane and close to x-ray source
o Resembles true image
o Found on opposite side of receptor
Ghost image
What structures are located laterally or centrally?
Ramus
Jewelry
Hard palate
What does PAN equipment consist of?
Tubehead
Head positioner
Exposure control
Collimator
What does film PAN equipment consist of?
- CCD, CMOS, PSP plate, or film
- Screen film
- Intensifying screens
- Cassette
What steps are taken to prep the patient for a PAN image?
o Remove all artifacts
o Lead apron
o Patient bites on groove, standing tall
o Midsagittal plane
o Frankfort plane
o Tongue to roof of mouth, lips together
o Stand still
bottom of eye, top of ear canal
Frankfort plane
What needs to be parallel to the floor for a PAN image?
Frankfort plane
How do you know if adequate contrast is seen on a PAN image?
DEJ seen
What are some common PAN imaging patient errors?
-Artifacts
-Thyroid collar
-Chin too high/low
-Twisted/turned neck
-Too far forward/back
-Slumping
-Tongue/lip placement
What are some PAN film errors?
-No bite block
-Damaged screen/patient tilted
-Light leak
-Fog
-Improper loading
-Static electricity
-Movement
What are the advantages of PAN imaging?
o Field size
o Simplicity
o Patient cooperation
o Minimal exposure
What are the disadvantages of PAN imaging?
o Image quality
o Focal trough limitations
o Distortion
o Equipment cost
What does extraoral imaging evaluate?
Larger areas on skull/jaw
Development
Impacted teeth
Disease
Trauma
TMJ
What is the receptor holder and head positioner for extraoral imaging?
Cephalostat (craniostat)
What does lateral jaw imaging examine?
posterior region of mandible
What can be seen in the body of the mandible for lateral jaw imaging?
Impacted teeth
Fractures
Lesions
What can be seen in the ramus of the mandible for lateral jaw imaging?
Third molars
Larger lesions
Fractures
What does lateral cephalometric projection evaluate?
- Facial growth and development
- Trauma, disease, abnormalities
What does Posteroanterior projection evaluate?
- Facial growth and development
- Trauma, disease, abnormalities
What does Submentovertex projection evaluate?
- Position of condyles
- Base of skull
- Zygomatic arch fractures
- Sphenoid
- Ethmoid
- Sinuses
- Lateral wall of maxillary sinus
What does waters projection evaluate?
Maxillary sinus
What does reverse town projection evaluate?
Fractures of condylar neck and ramus
What does Temporomandibular joint imaging evaluate?
- Temporal bone
- Mandible
- Glenoid fossa
- Articular eminence
- Condyle
- Articular disk
- 3D viewing of oral-maxillofacial structures
- Cone-shaped x-ray beam
- Field of view
Cone-beam computed tomography (CBCT)
What are 3C pixels?
Voxels
How long does it take for a CBCT machine to work?
7-30 seconds
What is the number 1 use of CBCT?
Implant placement
What are the advantages of CBCT?
o Lower radiation dose
o Brief scanning time
o Anatomically accurate images
o Save/transport images
What are the disadvantages of CBCT?
o Patient movement and artifacts
o Size of FOV
o Cost of equipment
o Training
o Lack of training in interpretation
What is expose control based on?
Type of x-ray
Patient size