Page 26 - Veterinary diagnostic imaging birds exotic pets wildlife

22 SECTION I III The Birds

A

B

Figure 1-17 • Leading edge or hanging drop projection. Radiographer extends the leading (front) edge of the hawk’s wing over and just
above the surface of the cassette, with the bird’s head hanging over the edge of the table. Once the bird is positioned satisfactorily, an

assistant will cover the radiographer’s fingers and any exposed parts of the hands with the glove’s adjustable fl aps (A), closely collimate
the x-ray beam, and make the exposure (B).

distilled down to two essential actions: (1) where to If the diagnosis is not immediately obvious through
look and (2) what to look for. In other words, the indi- this process (simple recognition-recall) or if there are
vidual performing the analysis relies on background two or more closely contending alternative diagnoses,

knowledge, as well as film-reading experience, to make then clinical reasoning comes into play in which alter-
the diagnosis. This is the way experts make the major- natives are weighed in light of their relative merits or
ity of their diagnoses: read or hear the history, search probabilities. It may also be possible to sort the various
the area of the film most likely to contain abnormali- possibilities on the basis of other abnormalities that

ties, look for one or more characteristic lesions, search were identified, especially those typically found with
medical images stored in the brain, and fi nd a match. the principal lesion, a process called pattern recognition.

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