Fluke Biomedical 18-222 - Manual (Page 9)

2-1
Section 2
Operation
2.1 How To Use the Mammographic Phantom
What To Do First
• Select the technique you would use on a normal 4.5 cm compressed breast of average glandular composition.
• Take one photo-timed image at the technique normally used for the average breast patient.
• With standard densitometer, read central background density in the center of the phantom image. This
background density should be 1.0 to 1.2 optical density.
• If first film does not give OD of 1.0, then adjust technique to obtain a background OD of 1.0.
• Record technique and retain image. This now becomes your image control film.
Quantitative Procedures (at least once a week)
• Count the number of microcalcification groups visible and record the number.
• Count the number of simulated tumors and record the number.
• With optical densitometer, read fat and gland steps of the step wedge. Record the values, and the difference
(i.e., contrast). The fat/gland (steps 1 vs. step 5) should be .28 or greater.
• With a magnification lens, identify the number of line pair/mm, which are discernible.
• Record values on the record sheet (Figure 2-3).
Long Term Comparisons
• Once a quarter, take one of the weekly test films and compare visually to the initial film. You should see
identical images. If not, then corrective actions should be initiated.
Records To Keep
• Daily record of processor function (temperature and OD of step 10 or 11). This requirement is well understood
and not discussed further herein.
• Weekly record of step wedge contrast and detail visibility.
• Retained films of weekly phantom checks.
• Keep the QA record sheets (see Figure 2-3) in a file. These records of system performance are valuable to you
as a management tool and as proof of good "QA" should your system performance ever be challenged.
Care And Handling
These phantoms are manufactured from high quality materials but, like anatomy they represent, they can be broken.
Please handle with care.
If you will treat these phantoms as you would any fragile piece of technical equipment, they will serve you well for
many years.
When not in use, the phantom should be stored in a safe location. Store at normal room temperature. If subjected to
temperatures above 110° for any extended period of time, return the phantom to Cardinal Health, Radiation
Management Service for re-certification.