iaea human health series publications - SEDIM

dose received by inhomogeneous real breasts and the image quality may not be easily predicted from measurementsof such physical quantities as the SDNR and MGD obtained using uniform blocks of polymethyl methacrylate(PMMA).2.3.6. Standard image formatsTo facilitate intercompatibility of digital images, the DICOM Committee has created a standard for digitalmedical images. This standard has specific provisions, known as DICOM MG, for digital mammograms. DICOMconforming images contain a header that provides general information describing the characteristics of each image,followed by the image data. Some CR products use the CR DICOM header, which may or may not include all theinformation required for proper workflow on IHE compliant mammographic workstations.Two types of DICOM image format have been defined for mammography (Fig. 5). The DICOM ‘forprocessing’ image is the image initially provided by the detector. Some basic corrections for detectornon-uniformity and possibly detector blurring have been applied to these images. These images can then beprocessed to create DICOM ‘for presentation’ images, which are suitable for display on a monitor or for printing.2.3.7. Image processingImage processing is an important feature of all digital mammography systems, and processing operations maybe applied at several stages of image formation (see Fig. 5).Flat field correctionRemoval of ‘bad’ pixelsDeblurringUnsharp masking breastPeripheral enhancementLogarithmic scalingA B C DAcquisitionDetectorcorrectionsImage ‘forprocessing’ProcessingImage ‘forpresentation’DisplayDICOM imageUnprocessedimagestorageProcessedimagestorageFIG. 5. Concept of the DICOM ‘for processing’ and ‘for presentation’ formats.13