  Malignant and benign breast tumors present differently in their shape and
size on sonography. Morphological information provided by tumor contours are
important in clinical diagnosis. However, ultrasound images contain noises and
tissue texture; clinical diagnosis thus highly depends on the experience of
physicians. The manual way to sketch three-dimensional (3D) contours of breast
tumor is a time-consuming and complicate task. If automatic contouring could
provide a precise breast tumor contour that might assist physicians in making
an accurate diagnosis. This study presents an efficient method for
automatically contouring breast tumors in 3D sonography. The proposed method
utilizes an efficient segmentation procedure, i.e. level-set method (LSM), to
automatic detect contours of breast tumors. This study evaluates 20 cases
comprising ten benign and ten malignant tumors. The results of computer
simulation reveal that the proposed 3D segmentation method provides robust
contouring for breast tumor on ultrasound images. This approach consistently
obtains contours similar to those obtained by manual contouring of the breast
tumor and can save much of the time required to sketch precise contours.
