The use of image morphing to improve the detection of tumors in emission imaging

Two of the limitations on the utility of SPECT and planar scintigraphy for the non-invasive detection of carcinoma are the small sizes of many tumors and the possible low contrast between tumor uptake and background. This is particularly true for breast imaging. Use of some form of image processing can improve the visibility of tumors which are at the limit of hardware res olution. Smoothing, by some form of image averaging, either during or post- reconstruction, is widely used to reduce noise and thereby improve the dete ctability of regions of elevated activity. However, smoothing degrades reso lution and, by averaging together closely spaced noise, may make noise look like a valid region of increased uptake. Image morphing by erosion and dilation does not average together image valu es; it instead selectively removes small features and irregularities from a n image without changing the larger features. Application of morphing to em ission images has shown that it does not, therefore, degrade resolution and does not always degrade contrast. For these reasons it may be a better met hod of image processing for noise removal in some images. In this paper we present a comparison of the effects of smoothing and morph ing using breast and liver studies.