4-7 Flashcards
Radiolucent
Refers to that portion of the image that is darker or black
Radiopaque
Refers the portion of the image that is the light or white
Density
Is the degree of darkness or image blackening radiographic image that appears late is said to have little density radiographic image that appears dark is said to be more dense
Contrast
Refers to the many shades of gray that separate the dark and light areas
Three basic requirements of an acceptable diagnostic radiograph
- All parts of the structured reporting must be images closes their natural shapes and sizes as the patient’s oral and then we will permit (must look like what is in their mouth)
- Area examined must be imaged completely, and with enough surrounding tissue to distinguish between the structures
- The radiograph should be free of errors ensure proper density contrast and definition
An image with high contrast as usual for the detection and progression of dental caries
T
Image with high contrast is useful for detection of periodontal or periapical disease
F low contrast
Short scale contrast
Called high contrast, very shades of gray and more black against white 60-70kvp. Great for diagnosing caries (tooth decay) less gray
Long scale contrast
Called Low contrast, many shades of gray 8200 KV P. Great for diagnosing periodontal disease long low
Direct theory
That cell damage results when ionizing radiation directly hits critical areas within the cell
Indirect theory
States the cell damage results indirectly when x-Rays causes the formation of toxins in the cell such as hydrogen peroxide. Toxins in turn cause the cell damage X-ray photons absorbed by the body and form toxins
Somatic cell
Any body cells except the reproductive cells
Genetic cells
The cells contained within the testes and ovaries consisting the genes
Alara concept
As las as reasonably achievable. Adopted as a culture and attitude by professionals who work with ionizing radiation to minimize radiation exposure and risks.
Half value
Thickness of a specified material that, when introduced into the path of given beam of radiation, reduces the exposure rate by half
Filtration
The use of absorbers for selectively absorbing or screening out low energy X-rays from the primary beam
Added filtration
Added to the inherent filtration built into the x-Ray machine. In the form of thin disks of pure aluminum, which can be inserted between the x-Ray tube and the lead collimator when the inherent filtration is not sufficient to meet modern radiation safety requirements
Total filtration
The combination of inherent and added filtration in an x-Ray machine. Many states require total filtration of 2.5 of aluminum equivalent for x-Ray machines operating at or above 70 kvp
Variation in kilovoltage
Kilovoltage peak controls the quality of the X-ray beam and measure the peak voltage of the current
When voltage peak increase by 15 expose time should decrease by half
When kv decreased, exposure time should be doubled
Radio sensitive cells
Cells that are easily harmed by the radiation rapid immature
Radioresiatant
Mature cells that don’t divide much
Put in order high sensitivity to low
A) Red blood cells, b)bone c) never d) muscles e) white f) brain cells g) epithelial h) immature I)connective j)endothelial
White Red Immature Epithelial Endothelial Connective Bone Never Brain Muscle
Latent period
Time between exposure to radiation and the first clinically observable symptoms ( hidden)
Period of injury
Fallowing Karen period certain effects can be observed
Recovery period
Following radiation exposure, some recovery can take place
Erythema
Redness of the skin caused by hypermedia of the capillaries in the lower layers of the skin. It occurs with any skin j jury, infection, or inflammation
Film speed
The amount of radiation and exposure time needs to rod ice a diagnostic radio graph
Maximum permissible dose
Does equivalent of ionizing radiation that is not expected to cause detectable body damage to average persons at any time during their lifetime
Maximum accurate dose
Occupationally exposed workers must not exceed an accumulated lifetime radiation dose
Base
Transparent base holds the emulsion and give its stiffness
Emulsion
Silver halide crystals suspend in a gelatin matrix
Gelatin
Keeps crystals spread out
Protective layer
Thin transparent coating placed over the emulsion to protect the emulsion surface
