Technical Note: an algorithm and software for conversion of radiotherapy contour-sequence data to ready-to-print 3D structures

PurposeThree-dimensional (3D) printing is one of the most promising technologies that can significantly improve the efficiency of various radiotherapy (RT) procedures. In order to 3D print any structure from a DICOM file, it first has to be converted to one of the typical formats recognized by printing software, such as STL files. Due to the specificity of the data from RT planning systems and a lack of standardized methods, the geometry processing might be tricky and complex. However, all the articles presented in the literature so far either describe this step very briefly, or do not mention it at all. MethodsWe present a detailed description of an algorithm and a piece of open-source software, that allow conversion of contour-sequence data included within DICOM files into ready-to-print 3D structures saved as STL files. The algorithm allows automatic handling of the data from RT planning systems and takes into account and corrects for all the typical issues, such as different orientation of curves or artifacts. The implementing software, included as a supplementary material, is distributed as open source under GNU GPL license, which means that it can be freely used, modified, and redistributed by anyone. ResultsThe algorithm and implementing software were used to convert numerous structures contained within DICOM files created with RT planning systems into ready-to-print 3D structures. The structures were converted with absolute fidelity, without any errors. ConclusionsThe presented tools can be used for research and development of patient-specific accessories for RT. The described algorithm and software can make 3D printing in RT more accessible to medical professionals, contributing to its further development.