Basics of Radiology A pre-clinician needs an organized introduction to the fundamentals of radiology to appreciate the content & usefulness of radiological images. The focus of this material is the plain-film radiograph— the beginning of radiology. Remember, the instructor is not a radiologist; neither he nor the course material suggest that you need to be, or even should be, interpreting diagnostic images - - for that is the responsibility of the Radiologist.

Radiograph X-ray film with an image of an anatomy X-ray film with an image of an anatomy X-rays emanating from a localized source pass through a portion of the body onto a detector that records the density of x-rays as an image X-rays emanating from a localized source pass through a portion of the body onto a detector that records the density of x-rays as an image Plain Film/ Conventional Radiograph Made without contrast enhancement Made without contrast enhancement 80% of imaging examinations 80% of imaging examinations

Radiodensity Amount of x-irradiation absorbed by a substance Amount of x-irradiation absorbed by a substance Determined by composition (atomic weight) and thickness Determined by composition (atomic weight) and thickness Greater the atomic weight and thickness, the greater the radiodensity Greater the atomic weight and thickness, the greater the radiodensity Increased radiodensity, increased absorption of x-rays Increased radiodensity, increased absorption of x-rays As radiodensity increases, objective appears more white on image As radiodensity increases, objective appears more white on image

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Handling and viewing plain film radiographs

Image Distortion Magnification Magnification  The closer a structure is to the film, the less magnification there is and the detail & sharpness is better. Shortening & Lengthening Shortening & Lengthening  due to the angle of x-ray beam or angle of the structure.... relative to the film

Viewing Plain Radiographs Always need at least 2 views Always need at least 2 views Close to 90 degrees from each other Close to 90 degrees from each other “One View Is No View” “One View Is No View” Film Markers: Patient ID & anatomical side: Do not orient film to view a correctly positioned letter Film Markers: Patient ID & anatomical side: Do not orient film to view a correctly positioned letter

Radiographs: Common Views Anteroposterior (AP): beam passes anterior to posterior. Anteroposterior (AP): beam passes anterior to posterior. Posteroanterior (PA): beam passes posterior to anterior (common chest view) Posteroanterior (PA): beam passes posterior to anterior (common chest view) Lateral Lateral Oblique Oblique

Placing Radiographs on View Box For AP views (extremity, head/spine) and chest PA:   place in the viewing box with the patient facing you in anatomical position (except wrist-hand- fingers and feet-toes). The patient’s right is on your left. Hand-fingers (PA) or foot/toes (AP):   point the digits up; hands and feet are oriented right on right and left on left (rather than anatomical position). Spine AP views: orient in anatomical position with the “R” on the patient’s right side

Placing Radiographs on View Box In general for Lateral & Oblique views   typically face them to your LEFT,   or you can also attempt to orient in the same direction that the beam traveled (easy to say, hard to do).   If it is a multi-view film and there is an AP or PA view accompanying, then use the AP or PA view to correctly orient the entire film.

Orienting Films: Are the following oriented correctly?

AP of R. Humerus Which one is Oriented Correctly?

AP of L. Shoulder Is It Oriented Correctly?

AP of R. Elbow Is It Oriented Correctly?

AP of L knee ; Which one is Oriented Correctly??

PA of R. Wrist Is It Oriented Correctly?

AP– Left Foot L L Is It Oriented Correctly?

Lateral View – C-spine Is It Oriented Correctly?

AP Lower C-Spine R

AP View – Lumbar Spine R