Future directions in 3-dimensional radiation treatment planning.

In recent years, computed tomography data have been used to build three-dimensional (3D) patient models for radiation treatment planning. The strength of 3D treatment planning systems lies in their ability to substantially improve the precision of radiation therapy and provide some of the tools needed to improve dose conformation. This article describes the V2 virtual simulation system used at the University of North Carolina at Chapel Hill. The virtual simulator allows the patient model to be rotated to determine the best beam angles and calculates the positions of the table, gantry, and collimator necessary to achieve desired beam orientations. Considerable disagreement remains as to how to produce an optimal radiation treatment plan using 3D systems. The University of North Carolina's VISTAnet project provides real-time 3D radiation dose calculation and display, allowing the user to search for the optimal plan.