1. Introduction
With the rapid development of modern imaging technology and information processing technology, the research of content-based medical image retrieval (CBMIR) has got more and more attentions [1]–[3]. Because of medical image's inherent characteristic, the retrieval methods in content-based image retrieval (CBIR) can not be simply repotted in CBMIR. The key issue is how to retrieve the right ones that could be used in clinical diagnosis, curing and the aspect of studying in the database.