The Flow of the Image Analytical and Automated Segmentation Algorithm

This flow chart is the Image analytical and automated segmentation algorithm. We developed an automated (i.e., unsupervised) clustering algorithm using FCM that is capable of analyzing T2w images of the radiation exposure region of the brain that had been delineated in the GKRS plan. Step 1. Interpolation. The dose intensity distribution from the dose map is converted into corresponding spatial positions on the T2w images using linear interpolation, and the Dose Grid Scaling factor is extracted from the header information of the dose data. The dose intensity distribution at the various voxel positions in the T2w image are then multiplied by the Dose Grid Scaling factor to obtain the radiation dose intensity distribution in centigrays (cGys). Step 2 is the Selection of prescription isodose region.

After selecting a prescribed peripheral radiation dose intensity, the selected radiation exposure region included the entire area in the T2w images that received radiation dose intensity equal to or greater than the prescription dose intensity. Next, Step 3 is about Registration, the TOF. The TOF is registered to the corresponding T2w image via 3-D voxel registration using the normalized mutual information method to correct for differences resulting from head movement. Next step is how to extract brain mask. A brain mask is extracted from the registered TOF based on estimates of the inner and outer skull surfaces using BET (Brain Extraction Tool), a software package developed at the FMRIB Centre, University of Oxford, Oxford, United Kingdom. Next step is ROI definition.

The ROI is identified using a logical and operation applied to the selected radiation exposure region and brain mask. Step 6. Fuzzy c-means classification. The voxels in the ROI of a T2w image are classified as the nidus, brain tissue, or CSF, according to differences in voxel intensity between the various forms of tissue. Finale step is the volumes or percentages of the nidus, brain tissue, and CSF within the ROI are calculated.