The effect of magnification technique on the optical density and size of object on mammography

Abstract

To visualize the existence of micro-calcifications in mammography there are a number of ways carried out including by the magnification technique. This study evaluates the effect of magnification technique on optical density (OD) and size of the objects of the image produced on mammography. The objects used were three circular coins. Source to image distance (SID) was 65 cm, with a focal spot size of 0.1 cm, a combination of targets/filters was Mo/Mo with a filter’s thickness of 30 µm. The tube loading was 100 mAs, the tube voltage was 27 kVp, and the magnification was in the range of 1.00 - 2.00 times with an increase of 0.25. Measurement of OD and size of the objects was using an ImageJ software. The results of this study revealed that the OD value decreases proportional to the magnification. The OD values calculated on the 2x magnification were 13.74, 14.26, and 13.44% lower than 1.0 magnification (without magnification), while the resulting image will be oval in proportion to the position of the coin from the chest wall and the magnification. An implementation of the magnification method in the mammography must be carried out with caution. In addition to a benefit to larger appear of micro-calcification, it also causes a decrease in OD and distortion of objects in the image.