The National Cancer Institute (NCI) is collaborating with the National Library of Medicine (NLM) to create a database of digitized images of the uterine cervix for research, training, and education. The database of 100,000 images collected in NCI projects will be Web-accessible and will contain not only the digitized images, but also clinical, longitudinal data relevant to the detection of uterine cervix cancer. The database will also contain spatial data in the form of expert-marked boundary regions of anatomy and tissue regions of high interest. The collection of this spatial data is enabled by customized software, the Boundary Marking Tool (BMT). The BMT, its significance, and its use in preliminary research studies, are described in this paper.