Fluke Biomedical 07-605-7777 - Manual (Page 6)

Nuclear Associates 07-605-7777
Operators Manual
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1.3 CR Images to be Viewed
If you are using CR images to be viewed on a soft-copy display, the image will be evaluated in a similar
manner:
1. Slight adjustment of the window/level may be necessary to visualize the step wedge and low
contrast objects on the monitor.
2. If the low contrast objects are not visualized, the mAs can be adjusted slightly to compensate.
Be sure to stay within the manufacturer’s recommended exposure range index.
3. The line-pair number should be recorded and compared to future exposure.
4. ROIs can be taken and recorded, and compared to future exposures.
5. An ROI reading should also be taken in a region of the phantom free area and compared to
future exposures.
6. You can now print a film of the phantom from the monitor. The printed image should be an
exact image of what you see on the monitor. The patches should be visualized and the line-pair
resolution should be the same, etc. If it is not, there is a problem somewhere.
Once the correct exposure factors and image processing are found to visualize the patches, and the
system is displaying and/or printing these patches properly, as well as visualizing the other objects in the
phantom, this process can be repeated on a regular basis (daily, weekly, etc.). This process is an
effective way to monitor the output of CR readers, as well as evaluated network connectivity and filming
outputs from soft-copy displays.
This process may also aid in making sure that x-ray room performance is also consistent. By alternating
the acquisition of the CR image to a different room every day, you may find a problem in the room instead
of the CR system.
Example
If your image doesn’t look right, the first thing you should do is repeat it using the same room. If it still
doesn’t appear accurate, you may suspect the room or the CR system. You could isolate the problem by
moving to another room and using the correct mAs and kVp you recorded on the initial image evaluation
of that room. If the processed image turned out properly, one would suspect the first room is not working
right. On the other hand, if the image still doesn’t look correct, your CR system may not be functioning
properly.