To analyze datasets visually, systems with fast feedback loops on user interaction are beneficial. In this session rendering and preprocessing techniques for medical volume data will be presented using OpenGL and CUDA. In the context of the coronary artery disease the analysis of individual vessel branches is important. We show how local transfer function application and generation by means of histogramm analysis can help navigating and finding details in the datasets. Furthermore, domain-specific acceleration and illustration techniques for volume rendering are also applied to datasets from brain aneurysms.