Digitally Reconstructed Portal Radiographs for Use in Radiotherapy Treatment Verification

Introduction In radiation treatment planning using virtual simulation [Sherouse, 1991], it is common practice in our clinic to verify a treatment plan by comparing a diagnostic-energy x-ray film from physical simulation to a digitally reconstructed radiograph (DRR) derived from the patient's CT dataset and the prescribed beam orientation [Chaney, 1994]. Likewise, the simulator radiograph is compared to a portal image (either a portal film or an electronic portal image) to verify the proper patient/treatment machine setup during actual therapy. Unfortunately, due to very different attenuation processes occurring at the different imaging energies, comparison of a diagnostic-energy simulator film or standard DRR to a megavoltage-energy portal image is not optimal for verification purposes. In this work, we describe a new means for generating realistic, reconstructed portal radiographs from virtual simulation and discuss their potential uses in areas related to radiotherapy treat

A Volumetric Virtual Environment for Catheter Insertion Simulation

. We present an experimental catheter insertion simulation system that provides users co-registered haptic and head-tracked stereoscopic visual feedback. The system works on patient-specific volumetric data acquired using standard medical imaging modalities. The actual needle insertion operation is simulated for individual patients, rather than being an example of a model surgical procedure on standard anatomy. Patient specific features may thus be studied in detail by the trainees, overcoming one of the major limitations of current training techniques. 1 Introduction The insertion of a catheter into a vessel (artery or vein) is one of the most common procedures in clinical practice. This procedure has an especially important role during percutaneous cardiac catheterization and every time central venous access is required. Precise catheter insertion requires a perfect knowledge of the three-dimensional development of vessels and a high level of dexterity during vessel puncture..