Fluke Biomedical 07-647 - Manual (Page 7)

Operation
Procedure 2
2-1
Section 2
Operation
2.1 Procedure
As previously stated, it is preferred that system evaluation be performed daily. System evaluation should
occur prior to any patient exams, so that any difficulties detected can be rectified. For mobile c-arms,
evaluation should be performed whenever the system is set up for use. During the setup and evaluation
of the imaging system, you should also ensure that the system is operating correctly, e.g., that the image
intensifier tower moves smoothly and that the locks are working correctly. Any operational deficiencies
should be reported to the appropriate personnel.
Radiographic Systems
1. Setup for the exposure
• Select the Automatic Exposure Control mode using techniques typical for a small abdomen
(e.g., 70 kVp, neutral density, center cell).
• Record these settings.
• Position the Phantom on the table over the AEC detectors.
• Place a loaded cassette in the bucky tray and make the exposure.
• Record the resultant mAs.
2. Process the film as usual
• On the processed film, measure and record the optical density of the background, just outside
the "density difference" patch.
• Measure the optical density of the "density difference" patch.
• Subtract this value from the background OD and record the result.
3. Evaluate the image
• Hang the film on a viewbox.
• Determine the smallest mesh pattern that can be clearly resolved.
• Larger numbers correspond to smaller mesh patterns.
• Record this value.
• Determine and record the smallest low-contrast mass that can be detected.
Fluoroscopic Systems
1. Setup for the evaluation
• Place the Phantom on the table.
• Position the image intensifier tower approximately 12" above the table. Standardizing this
height is important for ensuring reproducibility of the high-contrast mesh patterns.
• Under fluoroscopy, center the Phantom under the image intensifier. Record the kVp and mA
yielded by the system. For the monitor adjustment squares to function properly, the tube
potential should be at least 70 kVp.