1Suggests that cell damage results when ionizing radiation directly hits critical areas, or targets, within the cell
Direct theory
2Suggests that xray photons are absorbed within the cell and cause the formation of toxins, which in turn damage the cell
Indirect theory
3Associated with large amount of radiation absorbed in a short time (ARS is a short term effect; not usually applicable to dentistry)
Short term effects
4Associated with small amounts of radiation absorbed repeatedly over a long period (linked to induction of cancer, birth abnormalities, and genetic effects)
Long term effects
5Seen in a person who has been irradiated (induction of cataracts and cancer, including leukemia- not transmitted to future generations)
Somatic effects
6Not seen in the irradiated person but passed on to future generations (do not affect the health of the exposed individual)
Genetic effects
7Important steps to take BEFORE imaging to limit exposure
Limiting the amount of x-radiation received by pt, only prescribed by dentist, examinations should never include a predetermined number of images, proper equipment, filtration (inherent, added, and total filtration, PID
8Important steps to take DURING imaging to limit exposure
Thyroid collar, lead apron, image receptors, beam alignment devices, exposure factor selection, and proper technique
9Important steps to take AFTER imaging to limit exposure
Proper receptor handling and proper film processing/image retrieval
10Refers to the placement of aluminum disks in the path of the xray beam between the collimator and the tubehead seal in the dental xray machine
Added filtration
11Purpose of the aluminum disks in added filtration is to filter out the
Longer-wavelength, low energy x-rays from the xray beam
12Filtration of the xray beam results in a
Higher energy more penetrating useful beam
13Takes place when the primary beam passes through the glass window of the xray tube, the insulating oil, and the tubehead seal
Inherent filtration
14Inherent filtration (does/does not) meet the standards regulated by state and federal laws
Does not
15Name some ways to protect yourself and limit exposure to x-radiation as a clinician
- maintain adequate distance during exposure
- use protective barrier (if needed)
- never hold a receptor in place for a patient
- never hold or stabilize the xray tubehead
- equipment monitoring (leakage radiation)
- personnel monitoring (radiation monitoring badge)
16Defined by NCRP as the maximum dose equivalent that a body is permitted to receive within a specific period; maximum dose the body can endure with little or no injury
Maximum permissible doses (MPD)
17States that all exposure to radiation must be kept to a minimum
ALARA concept
18As Low As Reasonably Achievable
ALARA stands for
19Used to describe the mean energy or penetrating ability of the xray beam; kV
Quality
20Refers to the number of xrays produced in the dental xray unit; mA
Quantity
21Determines the energy and penetrating power of radiation
Wavelength
22_________ wavelengths have more penetrating power
Shorter
23__________ wavelengths have less penetrating power
Longer
24Refers to how sharply dark and light areas are differentiated or separated on an image
Contrast
25Many black areas, many white areas, few shades of gray
High contrast
26Many shades of gray instead of black and white
Low contrast
27Distance from the source of radiation to the pts skin
Target-surface distance
28Distance from the source of radiation to the tooth
Target-object distance
29Distance from the source of radiation to the receptor
Target-receptor distance
30"The intensity of radiation is inversely proportional to the square of the distance from the source of radiation"
Inverse square law
31Overall blackness or darkness of an image
Density
32What three exposure factors control density
kV, mA, and exposure time
33Dental image that exhibits many densities, or shades of gray (low contrast)
Long scale
34Dental image that shows only two densities (areas of black and white)
Short scale
35Fuzzy unclear area that surrounds a structure (tooth) on an image; unsharpness or blurring of edges
Penumbra
36The capability of the receptor to reproduce the distinct outlines of an object (influenced by focal spot size, film composition, and movement)
Sharpness
37Enlargement of a radiographic image (results from diverging xray beam)
Magnification
38Image of a tooth that appears shorter than the actual tooth; result of steep or excessive vertical angulation
Foreshortening
39Image of tooth appears longer than the actual tooth; result of flat or insufficient vertical angulation
Elongation
40Geometric characteristic that refers to a variation in the true size and shape of the object being imaged; influenced by object-receptor alignment and the vertical angulation of the xray beam
Distortion
41Method of obtaining a digital image, in which an intraoral sensor is exposed to x-radiation to capture a dental image that can be viewed on a computer monitor
Direct digital imaging
42Method of obtaining a digital image, in which a sensor is scanned after exposure to x-radiation and then converted into a digital form that can be viewed on a computer monitor
Indirect digital imaging
43Example: storage phosphor imaging
Indirect
44Who can take xrays?
Dental hygienist, dental assistant, and dentist
45Used to examine the entire tooth (crown and root) and supporting bone
Periapical
46used to examine the crowns of both maxillary and mandibular teeth on a single image
Interproximal
47Used to examine large areas of the maxilla or the mandible on one image
Occlusal
48Series of intraoral dental images that show all the tooth-bearing areas of both jaws
Complete mouth series/ FMS
49Device used to hold an intraoral receptor in the mouth
Receptor holder
50Used to position an intraoral receptor in the mouth and maintain the receptor in position during exposure
Beam alignment device
51To divide into two equal parts
Bisect
52With film image appears clear, with digital sensor image appears black or white with no anatomical structures
Unexposed
53Image is light or low in density
Underexposed
54Image is dark or high in density
Overexposed
55the process of chewing food
mastication
56the utterance of vocal sounds
phonation
57the end of the muscle that is attached to the least movable structure
origin
58the end of the muscle which is attached to the more movable structure
insertion