Abstract
We studied the effects of data digitization on the detection accuracy of subtle microcalcifications on mammograms. Thereby, the required spatial resolution for providing enough detectability of mammographic microcalcifications was determined. Radiographs of a breast phantom, contained four sizes of simulated microcalcifications ranging from 120μm to 230μm, were digitized by five pixel sizes from 25μm to 500μm with 12-bit gray levels, by a drum scanner. Then the images were evaluated by physical image quality index, calculated from displayed amplitude model (peak detection strategy) in detection process, and were also assessed by the visual image quality rank in a human observer performance study. The results in the present work, for the first time of employing a spatial resolution smaller than 100μm pixel size, showed high or enough detectability of subtle microcalcifications on mammograms. In our experimental conditions, approximate 50μm pixel size digitization, with almost the same detectability as 25μm pixel size, provided required detectability of subtle microcalcifications ranging from 120μm to 230μm such that could be observed clearly by radiologists.
