Bill Applegate; Bill Van Bonn; Eric D. Jensen
The use of radiology as a diagnostic tool in marine mammals has been well documented. However, limitations of radiographic equipment and logistical difficulties surrounding animal handling and positioning have led clinicians to shy away from this technology. Radiographic procedures have often become longer in duration than animal care staff considers tolerable, especially in clinically ill patients, and unfortunately, the results of these endeavors has often been disappointing. The veterinary staff at NRaD Vetlab has been attempting to develop methods that make radiology a more "useable" diagnostic tool. Vetlab uses a "phase matched" machine manufactured by Acoma Medical Imaging Inc. which delivers ranges of 50-125 kVp and 0.4-320 mAs. We utilize Kodak Lanex Fast Screen cassettes, Kodak diagnostic film (T-Mat H/RA TMH/RA I), and incorporate a Spectroline Adaptagrid (8:1 ratio and 40 lines/cm) in all of our exposures except for extremities (ex. pectoral flippers, skull, and dental arcades). Focal distances vary between 27 and 40 inches (69 and 102 cm) depending on the anatomic region being evaluated. This poster will introduce the reader to the radiographic equipment and animal handling procedures that we have been using. We will share our complete technique chart and cover the steps we took in the development of a chart specific for our own equipment; a process that is time and labor intensive but essential to obtain films of diagnostic quality in a minimal amount of time. Finally, we would like to present results from specialized procedures such as contrast radiology and oblique views to specific anatomy. Listed in Table 1 is our current technique chart used for Atlantic bottlenose dolphins. Please keep in mind that other film, screen, and tube head combinations will require the development of a different technique chart. Abdominal techniques are not presented here and continue to be developed.
Table 1
Anatomic Site
|
Thickness
|
Size
|
View
|
kVp
|
mAs
|
Thorax
|
42 cm
|
large
|
lateral
|
115
|
10.0
|
Thorax
|
39 cm
|
medium
|
lateral
|
120
|
5.0
|
Thorax
|
33 cm
|
calf
|
lateral
|
100
|
5.0
|
|
Thorax
|
46 cm
|
large
|
DV
|
120
|
5.0
|
Thorax
|
43 cm
|
medium
|
DV
|
125
|
2.5
|
Thorax
|
37 cm
|
calf
|
DV
|
100
|
2.5
|
|
Skull
|
28 cm
|
large
|
lateral
|
86
|
2.5
|
Skull
|
26 cm
|
medium
|
lateral
|
80
|
2.5
|
Skull
|
24 cm
|
small
|
lateral
|
76
|
2.5
|
Skull
|
22 cm
|
calf
|
lateral
|
72
|
2.5
|
|
Skull
|
25 cm
|
large
|
DV
|
96
|
2.5
|
Skull
|
23 cm
|
medium
|
DV
|
90
|
2.5
|
Skull
|
22 cm
|
small
|
DV
|
87
|
2.5
|
Skull
|
20 cm
|
calf
|
DV
|
81
|
2.5
|
|
Postrum/Dental
|
11 cm
|
large
|
all
|
86
|
1.25 no grid
|
Postrum/Dental
|
9 cm
|
medium
|
all
|
80
|
0.64 no grid
|
Postrum/Dental
|
7 cm
|
small
|
all
|
76
|
0.64 no grid
|
Postrum/Dental
|
5 cm
|
calf
|
all
|
72
|
0.64 no grid
|
|
Pectoral flipper
|
6 cm
|
large
|
all
|
62
|
0.64 no grid
|
Pectoral flipper
|
3 cm
|
medium
|
all
|
56
|
0.64 no grid
|
Pectoral flipper
|
2 cm
|
small
|
all
|
54
|
0.64 no grid
|
Pectoral flipper
|
1 cm
|
calf
|
all
|
52
|
0.64 no grid
|
One piece of equipment that has aided us tremendously in the radiographic process is the construction of an "open-sided" support frame. This frame supports the animal in a sling while allowing complete access to the tube head and a diverse number of radiographic views. X-rays are then shot "through" the sling with minimal decrease in radiographic quality. A photograph of the frame and sling, along with dimensions and materials are shown in Figure 1.
Figure 1. |
|
|
| |
Frame Dimensions and Materials
Height - 3'9"
Width - 3'3"
Length - 10'11"
Constructed of Cast Aluminum - 2.5" 0. D. / 2.0" I. D
Stretcher Materials
Constructed of 13-14 ounce vinyl coated polyester screen fabric (Textilene, Phifertex, or equivalent).