The MathWorks link lot of segmentation is there, first of all your create login id for MathWorks, and then refer it, your getting lot of image segmentation process
Refer this link getting some ideas for image segmentation
The Standardized Environment for Radiomics Analysis (SERA) Package is a Matlab®-based framework developed at Johns Hopkins University that calculates radiomic features based on guidelines from the Image Biomarker Standardization Initiative (IBSI). SERA is capable of processing images from various clinical imaging modalities such as CT, MRI, PET and SPECT. Radiomic features calculated with SERA are standardized and in compliance with IBSI, which ensures their reproducibility.