Page 10 - A Practical Guide to Equine Radiography

VetBooks.ir LIST OF FIGURES AND TABLES

Figure 1.1 This figure illustrates the effect of radiographs of a foot; the image on the left was
distance on X-ray intensity, ‘inverse square law’. acquired with 60 kVp and 10 mAs whereas the
The intensity of the X-ray beam is inversely image on the right was acquired with half the
proportional to the square of the distance from mAs. The image on the right shows more noise
the source. This is obviously important for that can be appreciated as a speckled pattern
radiation safety consideration and must be and obscures anatomical detail compared to the
taken into account when adjusting exposure image on the left where there is less noise and
settings. 2 more detail. 15
Figure 2.1 On the left there is a ceiling-mounted Figure 4.1 Preparation of the foot prior to
X-ray generator. On the right, a portable X-ray obtaining radiographs. 18
generator with a purpose-made stand can be Figure 4.2 Positioning to obtain a LM view
observed. 7 of the foot. 19
Figure 3.1 This figure illustrates the effect of Figure 4.3 LM projection of the foot. 20
object–plate distance on image sharpness and Figure 4.4 Radiographic anatomy of the LM
magnification. In the image on the top, the plate projection of the foot. 20
was close to the fetlock joint on this lateromedial Figure 4.5 3D representation of the LM
radiograph, compared to the bottom image where projection of the foot. 20
there was a distance between the two. The image Figure 4.6 LM projection of the navicular bone. 21
on the top has sharper edges and is smaller Figure 4.7 Radiographic anatomy of the LM
compared to the bottom image. 12 projection of the navicular bone. 21
Figure 3.2 This figure shows the same Figure 4.8 3D representation of the LM
radiograph in different window levels. The image projection of the navicular bone. 21
on the right is windowed to highlight the soft Figure 4.9 Positioning to obtain a DPa view of
tissue envelope, whereas the image on the left the foot. 22
shows more bone detail. The ability to change Figure 4.10 DPa projection of the foot. 23
brightness and contrast of a radiograph is a huge Figure 4.11 Radiographic anatomy of the DPa
benefit of digital images and enhances our ability projection of the foot. 23
to assess these. 13 Figure 4.12 3D representation of the DPa
Figure 3.3 These images illustrate the projection of the foot. 23
effect of too high exposures resulting in a Figure 4.13 Positioning to obtain a DPr-PaDiO
‘blackout artefact’. The image on the left is a view of the foot using a high coronary
dorsoproximal-palmarodistal radiograph of the technique. 24
navicular bone, where too high exposures have Figure 4.14 Positioning to obtain a DPr-PaDiO
led to a ‘blackout’ artefact obscuring the lateral view of the foot using an upright pedal
and medial edges of the navicular bone. The technique. Red box represents collimation for
radiograph on the right is a radiograph of the the distal phalanx and blue box represents
same foot with lower exposures that shows collimation for the navicular bone. 25
considerable enthesophyte formation at the Figure 4.15 DPr-PaDiO projection of the distal
attachment of the sesamoidean collateral phalanx. 26
ligaments (white arrows). 15 Figure 4.16 Radiographic anatomy of the
Figure 3.4 This figure illustrates the effect of DPr-PaDiO projection of the distal phalanx. 26
exposure on the signal-to-noise ratio in an image. Figure 4.17 3D representation of the
These are two dorsoproximal-palmarodistal DPr-PaDiO projection of the distal phalanx. 26

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