State-of-the-art cancer treatment implies careful planning with use of innovative radiotherapy systems to specify the exact shape and location of the radiation dose in relation to the tumour in order to optimize the clinical effectiveness. Nucletron is a worldwide specialist in treatment planning products with headquarters in The Netherlands and developer of the revolutionary PLATO system. Recently, a new Virtual Simulation System (VSS) module was introduced to the PLATO unit, which also includes the CT Assisted Simulation (CTA Sim) option. CTA Sim allows the full integration of conventional and virtual simulation in order to enhance the accuracy of the treatment planning process.
The Computed Tomography (CT) Assisted Simulation tool enables the radiation oncologist to apply conventional simulation as a resource for monitoring the outcome of the virtual planning process. As such, the whole treatment planning team obtains a higher degree of control over the impact of patient positioning and beam placement. In this way, verification of the targeted radiation doses can be optimized via intensive data interchange between the CTA Sim extension and Simulix, the simulator device designed by Nucletron, of which there are two types, the Simulix-HP or MC.
First, the physician has to define the exact anatomical volumes and areas of treatment by means of the Virtual Simulation System. Next, the CTA Sim transmits the acquired field parameter data to the Simulix for automated set-up and verification of the treatment plan. The simulator thus helps the radiation therapist to save precious time since the manual transcription of critical data can be avoided. Subsequently, the live fluoroscopy image can be compared in detail with the Digitally Reconstructed Radiographs (DRR) of the calculated plan while the relevant patient is lying on the table. In this stage, eventual parameter changes made by the Simulix are automatically adapted by the Virtual Simulation System for recalculation of the doses and for transfer to the treatment Record and Verify system.
In fact, the CTA Sim tool smoothly organizes the workflow of the complete treatment planning chain as the central unit of information gathering. The data from various devices is assembled in one focal point in order to optimize the seamless transition from intended plan to actual treatment set-up, as Edwin Vandermeulen, Managing Director of Nucletron B.V., explains. For the first time ever, one single comprehensive radiation treatment planning environment is generated with the PLATO system which integrates patient information proceeding from both virtual and conventional simulation.
The Virtual Simulation System allows the physician to create a 3D patient model, based on CT images, which can be displayed in single or multiple windows to help the radiation oncologist decide on the final treatment plan. The patient no longer has to be bothered since the physician can view the acquired images on a dedicated workstation during this preliminary phase. As such, volume definition can be determined by means of simple contouring on user-selected slices. The physician is equally able to quickly indicate all volumes of interest, using tools to add margins and interpolation. Once again, no waste of time anymore in this formerly traditional bottleneck in treatment planning based on CT images.
The images are displayed in a fourfold window to provide all the necessary information for beam placement, including 3D surface rendering, a Beam's Eye View (BEV) with Multi-Leaf Collimator display, transverse as well as reformatted image options, and Digitally Reconstructed Radiographs (DRR) to the BEV. In addition, the volumes and beams which are defined by the Virtual Simulation System can be applied for dose planning in the PLATO RTS system. In December 1998, the Virtual Simulation System becomes commercially available and can be purchased in a stand-alone 3D treatment planning environment or with integration of the CTA Sim tool. The latter offers interface options with the two types of simulator systems, Simulix-MC and HP for continuous data exchange.