Idexx EquiView, Руководство оператора

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IDEXX EquiView
®
Digital Radiography System Operator’s Guide 9
becomes limiting and does not improve image quality after a certain level.
TIP: Moving the X-ray source closer to the body part, which increases the effective kVp, may
have a better impact on the image than simply continuing to increase mAs.
• Equine foot: The equine foot is another body part that produces a great deal of scatter. To
produce good images of the navicular bone, similar techniques to the above may be helpful.
A grid is always helpful for images where a grid can be easily used, in respect of maintaining
the geometric requirements. In addition, lead shielding of unwanted parts of the image can
be helpful.
To expose the plate:
1. Place the digital X-ray plate into your X-ray equipment’s holder for film cassettes or in another
suitable position. The plate’s active imaging surface must face the radiation source.
2. Select suitable settings on your X-ray equipment for exposure time and accelerating voltage.
WARNING: National regulations for dealing with X-ray radiation and the operation of X-ray
devices applies. Do not exceed the applicable national standards for the radiation doses.
Pay particular attention to the safety of the personnel in the vicinity of the X-ray equipment.
TIP: Use high kV and low exposure time. Dose increases proportionally with the kV, but to
second order with time.
TIP: Using old generators that do not have full-wave rectification and have exposure times
over 0.2 seconds is not ideal. If you have been using a good quality X-ray generator in the
past, setting kVp at 80 and mAs at 1.8 is ideal for most exams.
TIP: Most X-ray generators have a milliamperage of 15 mA, so the time factor would be set to
0.12 seconds: 15 mA x 0.12 s = 1.8 mAs. For large structures, 80 kVp and an mAs-product
of 15 mA x 0.25 s = .75 mAs can be used.
. Ensure that the desired structures are located between the X-ray source and the digital X-ray
plate. The plate must be aligned vertically to the direction of incidence of the X-ray beams.
The film-focal distance (FFD) should be in the range of 55–60 cm (21.6"–2.6").
TIP:
The X-ray generator should be placed closely to the region of interest.
TIP: Movement artifact is usually a combination of movement of the X-ray source, the horse
and the plate itself.
4. Press and hold the exposure switch halfway down until you hear the beep indicating that the
plate is ready for an exposure. This prepares the generator and plate, and can take up to 4
seconds. In addition to the beep, the light on the plate turns from green to red, and a blue
progress bar appears at the bottom of the computer screen and moves halfway across.
Take Images screen (X-ray mode)
Image area Borderline