| Summary: | Objective: In this study,
we aimed to establish a standard protocol of measurements by taking quality control
tests belonging to digital mammography devices widely used in our country.
Breast cancer occurs in glandular tissue. For this reason, it is necessary to measure
the mean glandular tissue value and follow the standard values. The accuracy of
the system has been tested by considering whether the values specified are
within the acceptable limit values specified by the EUREF standard. Performing quality
control tests periodically will increase the quality of the image and reduce patient
doses by minimizing repetitive work.
Methods: The measurements
were performed on a Fujifilm Amulet Innovality digital mammography system.
Contrast detail Pro-Mamphantomand Pro-Mam software to simulate different breast
tissues for measurements, Ray SafeXi detector for dosimetry, MTF test for image
qualities, Image J software was used to measure the average pixel and standard deviation
of the pattern the image. The PMMA phantoms of different thicknesses have the mean
glandular tissue change (AGD), contrast-to-noiseratio (CNR), figure of merit
(FOM) values and modular transfer function (MTF), detective quantum efficiency
(DQE) and noise power spectrum (NPS) graphics are compared. HVL and CNR values
of W/Rh filter and W/Al filter are compared.
Results:
The
mean glandular dose was measured as 0.92
mGy on a 45 mm PMMA plate in normal dose mode. When the W/Rh filter is used,
the Contrast Noise Ratio (CNR) is 5.1, while the W/Al filter is 4.5. The FOM
value with a 45 mm PMMA plate at 26 kVp was measured as 42.905 with the W/Rh filter.
When there is a W/Al filter, it is measured as 50.115.
Conclusion:
The
average glandular dose at 45 mm to the EUREF standard should be less than 2.5 mGy,
the measured values are within the limit values. Breast dose, air kerma and AGD
values increased while CNR and FOM values decreased with increasing breast
thickness. When W/Rh filter is used, HVL, FOM and CNR values are higher because
the X rays are more cured. Thus, it has been determined that it is possible to obtain
a better image quality at a lower dose in the W/Rh combination.
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