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71 Cards in this Set
- Front
- Back
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Sensitometry
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Measures the relationship between the intensity of radiation absorbed by the film and the optical density that is produced.
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Development of sensitometric film
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An 8x10 sheet of unexposed film is placed in the sensitometer in the darkroom and exposed. The exposed film is then processed. Then, optical density readings of each step and the clear part of the film are obtained. Indicators of processor perfomance can then be obtained from this data.
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Densitometer
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Also known as a transmission densitometer, measures the optical density of a portion of an image with a 0-4 scale. It is a photographic light meter that measures the amount of light transmitted through a portion of film and compares it with the original amount of light incident on the film.
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Calibration
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Sensitometers and densitometers should be calibrated annually to ensure accurate testing results.
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Tank Temperatures
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It is of vital importance to ensure that the temp of the developer is not too hot or too cool. Should be maintained between 68-72 degrees F (20-22.2 C). If it is above this range, then the density will increase; below, the density will decrease.
The fixer tank should be maintained at a temp +/- 5 degrees of the developer temp. to stop developing rxns on the film. The wash tank should be at a temp of 5 degrees F below the developer temp and the dryer should be at 100 degrees F. |
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Transport Timing
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Developer: 22 sec to achieve proper density
Fixer: 22 sec to stop oxidation/reduction reactions on the film Washer: should be 50-100% of the development time. |
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pH levels
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Developer: should be maintained at a pH of 10-11.5 and should not vary more than +/- 0.1 from manufacturer's specs.
Fixer: should be between 4-4.5 and should not vary more than +/- 0.1 from manufacturer's specs. Washer: should be 6.5-8.5 |
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Specific gravity
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This is a measurement of the solution concentration (the percentage of water vs other chemicals)
Developer: 1.07-1.1 and should not vary more than +/-0.004 from manufacturer's specs. Fixer: 1.077-1.11 and should not vary more than +/-0.004 from manufacturer's specs. |
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Illuminance
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The amount of light that falls on a given surface. Measured in foot-candles.
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Illuminator bulb brightness
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All beam-limiting devices must be equipped with a positioning light and mirror. The light bulb to center of the mirror distance must be equal to the distance from the x-ray focal spot to the center of the mirror.
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Testing Illuminance
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Using a photometer, light readings are taken at each quadrant of the light field and recorded. The illumination of the light source must be at least 15 foot-candles when measured at 100cm (40in) SID. If the light source is inadequate, replace the bulb.
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Light field-radiation field congruence
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This value measures how well the collimator regulates the field size and if the area illuminated by the positioning light and the area exposed are the same.
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The 9 Cent Test Tool
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This test is used to ensure that the x-ray field and the light field are congruent. Pennies are placed at the margins of the light field--just inside and just outside. The light field and radiation field must be congruent to within +/- 2% of the SID. At 40in SID, this is 2cm or one penny. This test should be conducted every 6 months.
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Wisconsin Test Plate
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This can be used to evaluate the light field and radiation field congruency. An image is taken of the test tool, processed and visually inspected to determine if the x-ray field and radiation field are congruent.
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Beam Alignment
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The x-ray beam must be mounted properly in its housing and aligned to the Bucky tray. This alignment should be tested annually.
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Perpendicularity
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The x-ray tube must be mounted in its housing so that the central ray of the x-ray beam is within 1 degree of perpendicular. This is determined by measuring the deviation between the upper (magnified bead) and the lower bead on the beam alignment test tool. Using the template and cylinder, an image is taken and processed. For true perpendicularity, the lead bead should be within 5mm of the exact center. The exposed rectangle on the film should also be within +/- 2cm on all four sides.
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Beam and Bucky Tray Alignment
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The center of the Bucky tray and the center of the x-ray beam must be aligned to avoid clipping important anatomy and to avoid grid cutoff. The same tool is used as for perpendicularity. The magnified bead should be within +/- 1cm of the exact center of the film. Beam alignment tests should be performed annually.
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Darkroom Fog--Safelight Test
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This test is performed to ensure that the darkroom is safe from all unwanted sources of light or radiation that may fog the radiograph. Also to ensure that all safelights are within proper working order.
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Safelights
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This is a light source that emits wavelengths to which particular types of film are not sensitive. These lights should be 15 watts or less and must have the appropriate filter (red) for the film's sensitivities. Exposed areas of film are more sensitive to safelights than unexposed areas. The safelight should only produce a density of 0.05 greater than x-ray exposed only film. The actual time for safe handling of film should be 40 seconds. The safelight should be 3 feet away from the area where film is handled.
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kVp--half value layer
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This is the intensity of the x-ray beam. Half-value layer is the amount of filtering material that reduces the intensity of the radiation to one-half of its previous value
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kVp Accuracy
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This test is done to ensure that the kVp setting selected on the console is the actual kVp produced by the generator. Using the Wisconsin test cassette to test this, kVp accuracy should be within +/- 5% of the set kVp.
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kVp Reproducibility
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This test is used to confirm that the generator is producing the kVp as indicated on the control panel. This should be checked annually using the digital kVp meter. The actual kilovoltage produced should be within +/- 5% of the kVp set on the console.
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mA Reproducibility
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An x-ray generator should produce the same intensity of radiation each time the same set of technical factors are used to make the exposure. A dosimeter is used to test this and the variance should be less than +/- 5%.
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Reproducibility Variance Equation
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(mR max - mR min)/(mR max + mR min)
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mA Reciprocity
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The generator should produce the same intensity of radiation no matter the variations in time and mA settings as long as the total mAs and kVp settings remain consistent. A dosimeter is used to test this. Reciprocity variance should be less than +/- 10%.
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Reciprocity Variance Equation
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(mR/mAs max - mR/mAs min)/(mR/mAs average) all divided by 2
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mA Linearity
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This test is done to show that sequential increases in mAs should produce the same sequential increases in the exposure measured. This test is done with a dosimeter and any variance should be within +/- 10%. Variance is determined using the previous equation.
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Exposure Timers
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Tests are done to ensure that the exposure time set on the console is the actual amount of time allotted for x-rays to be produced.
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Manual Spin Top Test Tool
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Used for single-phase generators.
Half-wave rectified: correct number of dots = exposure time (sec) X 60 Full-wave rectified: correct number of dots = exposure time (sec) X 120 |
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Timer Acceptance Limits
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Timer accuracy should be within +/- 5% for exposure times greater than 10ms and within +/- 20% for exposure times less than 10ms.
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Digital Timer Test
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This test is used for any other generator other than a single-phase unit. The arc size tells the actual time allotted for the production of x-rays. Actual exposure time = arc size/360
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Copper Step Wedge Timer Test Tool
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This tool can also be used to test the accuracy of the timer, where actual exposure time = arc size/360.
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H&D Curve
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A graphical representation of the relationship between the intensity of radiation absorbed by the film and the optical density that is produced.
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Base + Fog
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The clear area on the film or the 1st "step." Should not vary more than +/- 0.05 from day to day.
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Speed Index
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This is the midrange density--usually step 11. Speed index = 1 + B + F. Should not vary more than +/- 0.15 from day to day.
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High-Density Index
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This is Dmax, the value close to the upper value of the diagnostic density range. Dmax = B + F + 2 and should not vary more than +/- 0.15 from day to day.
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Low-Density Index
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This is Dmin which approximates the low end of the diagnostic range of optical densities. Dmin = B + F + 0.25 and should not vary more than +/- 0.05 from day to day.
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Contrast Index
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This is the relative density difference. Contrast Index = Dmax - Dmin and should not vary more than +/- 0.15 from day to day.
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Safe Medical Devices Act
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The SMDA of 1990 was enacted in order to increase the amount of info the FDA and device manufacturers receive regarding problems with medical devices. It requires that facilities report any medical devices that have cause the death or serious injury of a patient or employee to the FDA and the device manufacturer.
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OSHA
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In the mid-1980's, Occupational Safety and Health Administration amended federal regulations concerning infection control in the workplace, mandating a policy on blood-born pathogens. This policy included required immunizations, and employee protection and disposal procedures.
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MQSA
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Mammographic Quality Standards Act; developed in 1992, this act required the establishment of QA programs for all facilities performing mammography and that these facilities must be approved and certified by the American College of Radiology (ACR). Also includes specific requirements for dedicated equipment, physicians, technologists and medical physicists.
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QM
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Total Quality Management was introduced to the American industry in the early 1980s. These principles were incorporated by JCAHO in the Agenda of Change in the late 80s with the intent of improving quality of patient care and outcomes.
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Group Techniques
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-Brainstorming
-Consensus -Multi-voting -Nominal Group Technique |
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Brainstorming
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A group process used to develop a large collection of ideas without regard to their merit or validity.
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Consensus
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Following a brainstorming session, the group members, through discussion and teamwork, come to an agreement on the most important idea to be addressed.
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Multi-Voting
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Used to dismiss nonessential or non-realistic ideas. All members are given a list of all the ideas that were formulated, then they are asked to vote on the one they consider most important. The ideas with the fewest votes are discarded and the process is repeated until just one idea remains.
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Nominal Group Technique
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Decision making method in which all group members input their ideas and rank the list in order of importance. The idea with the lowest total score is chosen as the final idea.
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QC
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Quality Control is the part of the QA program that deals with the insturmentation and equipment.
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QA
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Quality Assurance is an all encompassing management program in healthcare whose primary objective is the enhancement of patient care. This part of quality deals with the employees, including scheduling, departmental policies, in-service education, and image interpretation with timely reports.
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QI
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Quality Improvement: improving the quality of patient care, having to do with the customers themselves.
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Benchmarking
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Involves the comparison of one organization's performance with that of another. It focuses on the other organization's key processes that achieve performance.
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W. Edward Deming
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Developed the 14 points of management. This system is focused on continually improving quality by focusing on improving the system or process in which individual workers function rather than on the individuals themselves.
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J. W. Jurans
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Argued that QA as a management tool is based on quality planning, QC and QI.
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Counts
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Data analysis tool used to determine the frequency of a particular event.
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Percents
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Used to express how large/small one quantity is relative to another.
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Rates
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Magnitude or frequency relative to a time unit.
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Ratio
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Comparison of two things with respect to their quantity, magnitude or degree.
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Mean
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The average value of a group of numbers. Add all values together and divide by the number of units.
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Median
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When the samples in a data set are placed in order, the median is the sample that lies in the middle.
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Mode
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This is the sample that appears the most in a data set.
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Range
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Refers to the difference between the highest and lowest values and is a measure of the dispersion of the data distribution.
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Standard Deviation
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This is the range of variation or dispersion of a set of values surrounding the mean. One standard deviation accounts for 68& of the data. Two standard deviations accounts for 95% of the data.
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Flowchart
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This is a pictorial representation of the individual steps that can be contained in a process. Designed to represent the sequence of events from the beginning to the end.
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Cause-Effect Diagram
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AKA "fishbone" or "Ishikawa" this is used to demonstrate graphically the causes and effects of different variables or conditions on a key quality characteristic and potential areas for improvement.
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Scatterplot
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A traditional two-axis graph with several data points that have been plotted throughout. It is designed to determine whether a relationship exists between two variables in a process.
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Bar Chart: Histogram
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A data display tool in the form of a bar graph that often plots the most frequent occurance of quantity in the center. The area of the bars denotes the value. Good for use with the distribution of continuous data (ie repeat rate)
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Pareto Chart
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Variation of the histogram, this chart prioritizes the most frequent problems at the y-axis of the graph and the other problems in decreasing order to the right.
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Trend Chart
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AKA run chart, pictorially demonstrates whether key indicators are moving up or down over a given period of time. Refers to the evaluation of data collected over a period of time for the purpose of identifying patterns or changes.
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Control Chart
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Modification of the trend chart, in which statistically determined upper and lower control limits are placed with a central line that indicates an accepted norm. If the plotted data points fall above or below these control limits, then the process is considered unstable.
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Process evaluation Tools
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-storyboard
-project notebook -process accounting |
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Acceptable repeat rates
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Diagnostic Radiography: should not exceed 4-6% and should be considered a great concern if it is above 10%.
Mammography: should be less than 5%. |
