AbstractID: 9507 Title: Open-source DICOM and GUI tools for treatment planning research Treatment planning research is hampered by the lack of convenient tools for researchers to share clinical treatment planning data and research results. We will report on our progress integrating the DICOM-RT toolbox [Spezi et al, Phys Med Biol 47:4223-4232, 2002] with a Matlab-based treatment planning research tool CERR [Deasy et al, Med Phys, in press]. Current versions of Matlab provide highly convenient tools for manipulating DICOM information. The Matlab ‘structure’ datatype is essentially an array with named fields which can contain arbitrarily heterogeneous data. This is ideal for implementing keyword-based descriptions of radiotherapy or image data, as used by the DICOM and the RTOG archive standards. The DICOM-RT toolbox, also based on Matlab, implements the DICOM-RT protocol for transferring common radiation therapy treatment planning objects, such as CT images, dose distributions and other plan parameters. CERR also provides axial, coronal, sagittal, and 3-D viewers as well as DVH dose analysis tools and RTOG import capability. We are in the process of adding dose calculation capabilities to CERR. CERR is based on the RTOG keyword format whereas DICOM-RT is based on the International Electrotechnical Commission Radiotherapy Equipment Standard 1217. Nevertheless, the necessary conversions are straightforward. We expect that a combined DICOM-RT/CERR system will provide many unique capabilities. In particular, it would allow for comparisons of treatment planning results from a wide-range of clinical systems which can either export plans in DICOM-RT or RTOG archive format. Supported by CMS, Inc., and NIH grant R29 CA85181