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56 Cards in this Set
- Front
- Back
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Fixed photographic images (X-ray tube and film) |
Radiographic examination |
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Moving/dynamic images portrayed on tv monitor/fluoroscopic screen |
Fluoroscopic examinations |
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Metal filters "aluminum" Inserted in xray tube -Low energy xray emitted are absorbed before they can reach the patient |
Filtration |
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3 types of collimation |
-blade type diaphragm -adjustable light localizing collimator -cones |
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Restricts the useful xray beam to the part of the body that needs to be examined |
Collimation |
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Reduce the exposure of the patient By " 95% " |
Intensifying screens |
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Lead impregnated leather is used Vinyl-to make apron and gloves |
Protective apparel |
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Lead impregnated material for males |
Gonadal shielding |
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Where Radiographic control console is located behind ( Made of leaded glass window) |
Protective barriers |
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Film factors: |
-unexposed= lucent -exposed= opaque -heavily exposed= black |
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Refers to the fidelity with which the anatomic structure under examination is "imaged" on the radiograph |
Radiographic quality |
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"Density differences" contained in a high quality radiograph that are obvious and result in the image |
Radiographic contrast |
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Radiograph with sharp differences in density |
High contrast radiograph |
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Radiograph that has small and indistinct density differences |
Low contrast radiograph |
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Radiographic contrast is a product of 2 separate factors |
Film contrast Subject contrast |
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Inherent in the film and influenced by the film processing |
Film contrast |
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Determined by the size, shape and xray attenuated characteristics of the subject being examined |
Subject contrast |
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Xray is also used to follow a disease process and to monitor the effectiveness of therapy, ex: |
Orthopedic cases Cardiac cases Pulmonary cases Oncologic cases |
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Alterations of size, shape, contour, radioopacity |
Radiographic changes |
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Categorize into aggressive and non aggressive |
Differential diagnosis |
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T/F Bone lesions takes time to develop, w many disorders -the early radiograph lesions are specific |
False -may not be specific |
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T/F Pre-existing xray lesions may observe anormalities associated with 2nd disease process |
True |
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To make a Diagnosis |
Xray appearance Clinical signs History |
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T/F Xray abnormalities commonly lag behind clinical signs, lab results, and others |
True |
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Essential for "accurate" diagnosis |
Clinical parameters Radiographic findings Pathologic findings |
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T/F In some bone diseases, there may be poor correlation between clinical signs and radiographic signs |
True |
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10 basic radiation controls |
-understand and apply cardinal principles of radiation -dont allow familiarity to result intoo false security -never stand in primary beam (when not behind the protective barrier) -the person holding the patient must wear a lead apron and gloves -always wear protective apparel (when not behind the protective barrier)-the person holding the patient must wear a lead apron and gloves-wear a gonadal shieldings in child bearing age-no in pregnancy-collimate in smallest field size -wear a gonadal shieldings in child bearing age -no in pregnancy -collimate in smallest field size |
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3 cardinal principles of radiation |
Time Distancee Shielding |
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Imaging modality |
-cost-effective -readily available -easily performed -accurately interpreted in timely mannered |
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Clinical workup imaging |
-Lameness -GIT diseases -Genitourinary ds -Assessment of body trauma -Dental examinations -Metastatic survey before surgical removal or malignant tumor -multiple organ disease |
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Geometric factors |
Magnification Distortion Geometric unsharpness |
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Allows all images on the radiograph to be larger than the object they represent |
Magnification |
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Aka "Penumbra" Blurred region |
Geometric unsharpness |
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Factors affecting the subject contrast |
-patient thickness -tissue density -effectiveness anatomic number -object shape -Kilovoltage |
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Decrease Kvp= increase subject contrast |
Short scale contrast |
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Increase KVp = decrease subject contrast |
Long-scale contrast |
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Required for optimum film contrast primarily because the degree of development has a pronounces effect on the level of film fog and on the density resulting from a given exposure at a given film speed |
Proper film processing |
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Allows all images on the radiograph to be larger than the object they represent |
Magnification |
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Unequal magnification of different portions of the same object. It can hinder proper interpretation of the radiograph object |
Distortion |
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Also affects image distortion |
Object shape |
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____(thick/thin?) Body section will attenuate more xray |
Thick |
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T/F The degree of subject contrast is directly proportional to the relative number of xray exiting the adjoining sections of the body |
True |
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An important factor affecting subject contrast |
Tissue density |
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T/F Adjoining sections of the body may have equal thickness yet different densities |
True |
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Greatly influenced the subject contrast of tissue |
Effective atomic number |
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Influences the radiographic quality not only through its geometry but also through its contribution to subject contrast |
Object shape |
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This influence the film contrast but not to the extent that it controls subject contrast |
Kilovoltage |
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Radiographic images will appear either black or white with few shades of grey |
Short scale contrast |
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clinical considerations for improved radiographic quality |
patient positioning imaging devices selection of technique factors |
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the loss of radiographic quality due to movement of either the patient or xray tube during xray exposure that results in blurring of the radiographic image |
Motion unsharpness |
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Has higher film contrast than screen film when exposed without screens |
Direct exposure film |
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The primary control of radiographic contrast |
KVp |
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T/F Increase in KVp also increases the quality and quantity of xray |
True |
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T/F Increasing KVp loses the contrast Low conrast= latitude is high |
True |
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Xray machine consists of ? |
Xray tube High voltage generator Control panel |
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Within the xray tube, the "cathode" contains _____ that produces electron that is accelerated across a high voltage potential yo strike a tungsten target anode |
Heated filament |
