In order to enhance the sharing of DICOM, we have proposed to introduce XML into the DICOM Data
Dictionary and file system (SPIE2005 5748-57)<sup>1</sup>, which can extend the readability and the expansibility of
DICOM files. In our research, we will improve the data structure of DICOM on the basis of the idea we proposed.
We change the one-dimension array into the multilayer tree structure. We also change the original DICOM
Dictionary, which consists of numerical code, into the structured Data Dictionary according to the technique of
XML. All of the elements are in the special modules. The idea of modulization promotes the searching efficiency
and reduces the data redundancy. Data conversion replaces DICOM numerical code with character string tags
containing explicit meaning. These information modules are also formed as a multilayer tree structure according to
their modules, and they are kept as this structure in storage, transmission and display. After being added and
translated, the private data (such as a Diagnostic Report) will be linked directly as a new child-node to the
root-node so that the information is available without any special Data Dictionary. In this way, we can extend the
capacity of data elements, integrate data from different sources, and enlarge the scope of data sharing in DICOM.