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65 Cards in this Set

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Testing Grids: Grid Alignment
Equipment: regular cassette with regular film, grid alignment test tool, lead blockers, densitometer. The test is completed by exposing each dot on the test tool while blocking the others. A densitometer is then used to determine the optical density of the 5 dots after processing.
Grid Alignment Standards
The center dot should produce the highest density. Each subsequent dot should produce an equal increase in density the farther it is from the center dot.
Testing Grids: Grid Uniformity
Equipment: regular cassette with regular film, water phantom (10cm water in a plastic container), 8:1 snap on grid, densitometer. The test is completed by placing the water phantom on top of the cassette and grid. The film is then exposed and processed. Following processing, lines are drawn on the film to create four equivalent quandrants with a circle in the center. The densitometer is then used to read the optical densities in the quadrants and in the center of the circle.
Grid Uniformity Standards
All regions of the film should not vary +/-10% in optical density.
AEC testing: Density Control
Equipment: water phantom with 6in water, clear ruler, step wedge, 5 8x10 regular cassettes, densitometer. The test is completed by placing the step wedge in the container, lining the CR to step 6 and collimating down to the step wedge. The center cell should be activated. 5 images are taken changing only the density control levels. The densitometer is then used to determine the optical density at step 6 on each image.
AEC density control standards
Each step of density control away from neutral should produce a +/- 25% change in optical density.
AEC Reproducibility
Equipment: water phantom with 2in water, clear ruler, step wedge, 3 8x10 regular cassettes, densitometer. The test is completed by placing the step wedge in the water and centering the CR at step 6. The center cell should be activated with 80kVp and three identical exposures are taken. The densitometer is used to determine the optical density at step 6 on each of the films.
AEC reproducibility standards
Optical density should be consistent within +/- 5%.
AEC Uniformity of Fields
This is done to ensure that the AEC system produces consistent optical densities regardless of the cell selected.
AEC uniformity of fields equipment and method
Equipment: water phantom with 6in water, clear ruler, step wedge, 3 11x14 regular cassettes, densitometer. The test is completed by placing the step wedge in the water with the CR centered at step 6. Using 80 kVp, three images are taken each time with a different cell activated. The densitometer is then used to determine the optical density at step 6 for each image.
AEC Uniformity acceptance standards
Optical density on the films should be consistent within +/- 10%
AEC Response Capability
This test is done to ensure that the AEC system produces consistent densities across varying kVp ranges and water volumes.
AEC response capability equipment/methods
Equipment: water phantom, clear ruler, step wedge, 8 10x12 regular cassettes, densitometer. This test is completed by exposing the water phantom with the CR centered to step 6 on the step wedge. Begin with 2in of water and expose using 60, 80, 100 and 120 kVp. Repeat exposures using 3, 4, 5, and 6 inches of water. The densitometer is used to determine the optical density at step 6 on each image.
AEC response capability acceptance standards
Optical density should be consistent within +/- 0.2 OD.
AEC System Saturation
This is done to ensure that the AEC system produces consistent optical densities regardless of the mA selected with consistent back up time.
AEC system saturation equipment/methods
Equipment: water phantom with 6in water, clear ruler, step wedge, 5 8x10 regular cassettes, densitometer. This test is completed by placing the step wedge in the water with the CR centered at step 6. The center cell is activated using 80 kVp. 5 images are taken changing only the mA selection. The optical density is then measured at step 6 on each image.
AEC system saturation acceptance standards
Optical density should be consistent within +/- 10%.
Focal spot test: bar pattern test tool
This is done to ensure that the focal spot size has remained the same or is within acceptance limits indicated on the x-ray tube. This test should be performed upon installation, replacement of tube and annually.
Bar pattern test equipment/method
Equipment: bar pattern test tool, cardboard cassette, 2 regular films. At 24 SID, two images are taken with the film in the cardboard cassette; one using the small focal spot and the other using the large focal spot. Then determine the number of groups of bars that are clearly resolved on each image.
Bar pattern test acceptance standards
0.6 mm FSS: 10 groups of bars resolved
1.0 mm FSS: 8 groups of bars resolved
1.2 mm FSS: 7 groups of bars resolved
2 mm FSS: 4 groups of bars resolved
Focal Spot Testing: Star pattern test tool
This test is done to ensure that the focal spot size has remained the same or is within acceptance standards. This test should be conducted upon installation, replacement of tube and annually.
Star pattern equipment/methods
Equipment: star pattern test tool, 2 cardboard cassettes with regular film, mm ruler. The test is completed by taping the star pattern test tool to the face of the collimater centered to the cross hairs. Using 24" SID, 2 images are taken using small and large focal spots. Using the ruler, the distance between points of blur is measured horizontally and vertically on each image. (D1 and D2)
Star pattern equations
Magnification: Image diameter/actual diameter
Focal spot size = (N/57.30) X (D/M-1)
N=the angle between bar pairs on the star test tool. This equation is used to determine the generated focal spot size.
Star pattern acceptance standards
</= 0.8 mm FSS ..... 50% acceptance in variation standards.
0.08 - 1.5 mm FSS ......40% acceptance in variation
>/= 1.6 mm FSS ...... 30% acceptance in variation
FujiFilm One Shot Phantom
This test is done to ensure monitor image quality
Equipment: one 14x17 CR cassette, FujiFilm One Shot Phantom
This test is completed by placing the cassette on a lead apron on the floor with the one shot phantom on top of the cassette. Using a 60" SID, an exposure is taken
One Shot Testing Frequency
Monthly: Relative sensitivity (S#) calibration test, shading test, contrast evaluation, sharpness test, laser jitter test, image noise/artifact test
Semi-annually: primary erasure of imaging plate test, accuracy of measurement tools/scale test, system linearity test
One Shot: S# Calibration
Measure the OD of the center "shading correction and sensitivity" circle.
Standard = +/- 0.15 OD
One Shot: Shading Correction
Measure OD of all three "shading correction and sensitivity" circles.
Standard = left and right circles should not vary greater than 10% of OD of center circle.
One Shot: Contrast Evaluation
Visually compare contrast patches to previously saved QA comparison image.
Standard: each patch should demonstrate two distinct densities and be visually comparable to saved QA image -- pass/fail test.
One Shot: Sharpness
Visually compare resolution capabilities with copper filter tool.
Standard = resolution should be compared with saved QA image and should not degrade.
One Shot: Laser Jitter
Inspect longitudinal and vertical edges of the "T"
Standard: look for jagged edges or loss of continuity
What is jitter?
Jitter is the deviation in or displacement of some aspect of the pulses in a high-frequency digital signal. Can be caused by electromagnetic interference or cross talk with other signals. "Shaky pulses."
One Shot: Image Noise/Artifact
Check the image for graininess or artifacts
Standard: there should be no graininess or artifacts
One Shot: Primary Erasure of Imaging Plate Test
After the original image is process, return the IP (process)
Standard: the second image should be blank
One Shot: Accuracy of Measurement Tools/Scale Test
Use measurement tool on monitor or printed image.
Standard: +/- 5% of 10cm (9.5 to 10.5 cm or 19 to 21 cm at 20cm)
One Shot: System Linearity
Take second image at 50% of the technique: Measure center circle -- Standard, S# should be double (+15%) that of the first image.
Take third image, expose twice at the original technique -- standard, S# should be half that of image 1.
Take fourth image, expose four times at the original technique -- standard, S# should be half that of image 3.
***Density for all images should remain the same within +/- 15%***
Image Quality: Screen Cleanliness Test
This test is done to ensure that the cassette screens are clean in an effort to reduce the number of dust artifacts found on a film.
Screen Cleanliness Test Equipment/Method
Equipment: cassettes, black light, anti-static screen cleaner, lint free cloth. This test is done by removing the film from the cassettes, using the black light to check the screens for light blue dust spots. The cassettes can then be cleaned and set on edge to dry. Once dry, they should be inspected again for dust particles using the black light.
Screen cleanliness standards
Screens should produce no artifacts on the film. If the artifacts are not removable with cleaning, the screens should be replaced. If the particles found on the cassette do not produce artifacts, they are considered acceptable.
Image Quality: Wire Mesh Test
This test is done to ensure proper film/screen contact.
Wire Mesh Equipment/Methods
Equipment: One 8x10, 10x12 and 11x14 cassettes, wire mesh test tool, light box. The test is completed by placing the wire mesh tool on top of the cassette with the CR centered and the collimation open to expose the entire cassette. Using 40" SID, expose the film and process. View the film in the light box at 72" evaluating for blurring of the wire mesh markings.
Wire Mesh Standards
In mammography, areas of blur larger than 1cm or more than 2 areas of blur less than 1cm on one film is not acceptable. Therefore the cassette should be repaired or discarded.
Compression Standards
All modern mammographic units must be equipped with a compression device. About 80% of x-rays transmit through this device at 30 kVp. The force of compression must be between 25 and 45 pounds. This pressure must be maintained for 15 seconds.
Mammography kVp ranges
The kilovolt peak range available on most units is between 20 and 35 kVp. Therefore, the kVp meters used for testing must be sensitive to lower kVp settings.
Mammographic phantom
Phantom images are taken to assess OD, contrast, uniformity and image quality. This phantom is approximately equivalent to a 4.2-cm thick compressed breast consisting of 50% glandular and 50% adipose tissue. It also contains fibers, specks and masses with varying diameters. This phantom must be inspected daily to ensure quality and maintenance of the machinery.
Resolution test tool
When using the small focal spot, 11 line pairs/mm must be identifiable on the image.
Wire Mesh test tool
Used to evaluate accurate film/screen contact. When used in mammography, this tool must contain 40 lines per inch (compared to 5-10 in diagnostic imaging).
Fluoroscopy testing: kVp accuracy
This test is designed to confirm that the C-Arm is producing the kVp as indicated on the control panel. This should be checked every 6 months or when there is an indication that the generator is not producing the kilovoltage selected.
Fluoroscopy kVp accuracy: equipment and methods
Equipment: digital kVp meter.
This test is done by placing the kVp meter on the tabletop so that the x-ray tube is aimed at the top of the meter. 3 exposures are taken for two seconds using 80, 90, 100, 110 and 120 kVp's. The kVp variance can then be calculated using the kVp variance equation.
Fluoro kVp accuracy standards
The NCRP recommends that the kVp be within +/-5% for this lab test.
Fluoroscopy testing: kVp reproducibility
This test is designed to confirm that the C-arm is reproducing the same kVp for each exposure. This should be tested every 6 months.
Fluoroscopy kVp reproducibility equipment and methods
Equipment: 4 inch water phantom, dosimeter. This test is completed by placing the dosimeter between the phantom and the II. Using the max mA and a specific kVp setting, an exposure is made for 10 sec and the reading is recorded. This is repeated twice more and completed for different kVp settings.
Fluoroscopy testing: kVp accuracy
This test is designed to confirm that the C-Arm is producing the kVp as indicated on the control panel. This should be checked every 6 months or when there is an indication that the generator is not producing the kilovoltage selected.
Fluoroscopy kVp accuracy: equipment and methods
Equipment: digital kVp meter.
This test is done by placing the kVp meter on the tabletop so that the x-ray tube is aimed at the top of the meter. 3 exposures are taken for two seconds using 80, 90, 100, 110 and 120 kVp's. The kVp variance can then be calculated using the kVp variance equation.
Fluoro kVp accuracy standards
The NCRP recommends that the kVp be within +/-5% for this lab test.
Fluoroscopy testing: kVp reproducibility
This test is designed to confirm that the C-arm is reproducing the same kVp for each exposure. This should be tested every 6 months.
Fluoroscopy kVp reproducibility equipment and methods
Equipment: 4 inch water phantom, dosimeter. This test is completed by placing the dosimeter between the phantom and the II. Using the max mA and a specific kVp setting, an exposure is made for 10 sec and the reading is recorded. This is repeated twice more and completed for different kVp settings. NCRP recommends that the kVp be within +/-5% for this test.
Fluoroscopy testing: mA linearity
This test is done to show that sequential increases in mA produce the same sequential increases in dose.
mA linearity equipment and methods
Equipment: 4 inch water phantom, dosimeter. This test is completed by placing the dosimeter between the phantom and the II. Exposures are taken at all available mA stations using 80 kVp and 10 seconds.
mA linearity variance equation
After each exposure, the mR/mAs should be recorded and the following equation can be used to determine the mA variance:
(mR/mAs max - mR/mAs min) / mR/mAs average all divided by 2. Linearity variance should be within +/- 10%.
Fluoroscopy: automatic brightness gain
This adjusts brightness on the screen according to the changes in tissue density (output). To measure the automatic brightness gain, the dosimeter should be placed after the phantom.
Fluoroscopy: automatic brightness stabalization
This adjusts exposure with changes in patient thickness (input). To test, the dosimeter should be placed between the source and the phantom.
Fluoroscopy: max exposure
This is done to test the maximum output of the system. Using a lead apron as the "phantom," an exposure is made to determine the max output.
Vascular imaging
Lag should not be more than a 10% difference from the manufacturer's guidelines. For less invasive procedures, lag can be +/-20% from manufacturer's guidelines.
Relative Conversion Factor
As you increase the exposure to the II, there should be a relative improvement in image brightness on the monitor. This should be proportional and is set by the manufacturer. The limit is a 10% reduction in brightness.