Image segmentation in treatment planning for prostate cancer using the region growing technique

The purpose of this study was to evaluate the performance of a region growi ng technique for segmenting prostate, bladder and rectum in CT images of pr ostate cancer patients. Prostate, bladder and rectum were segmented in all CT images of 10 patients using the region growing technique and manual trac ing. Volumes of the above organs computed with the region growing technique were compared with those from manually traced images on a slice-by-slice b asis. Measurement reproducibility of both segmentation techniques was evalu ated using the data obtained from four independent observers. The region gr owing technique was 1.5 times faster than manual tracing. There was no stat istical difference between the slice volumes of prostate, bladder and rectu m obtained by the two segmentation techniques (p>0.05, paired Student's t-t est). Correlation between slice volumes of all organs of interest provided both by region growing and by manual tracing was very good (prostate r(2)=0 .84; bladder r(2)=0.93; rectum r(2)=0.85). An overall reasonable agreement was found between the two segmentation techniques. The intraobserver and in terobserver variations for prostate, bladder and rectum volume segmentation were found to be lower with the region growing technique than with manual tracing. The suggested semi-automatic technique allows the possibility of g enerating accurate and reproducible segmentation of prostate, bladder and r ectum From CT data with great saving in labour.