A 3D digitization system for conventional radiation therapy simulation

While the majority of patients receiving external beam radiation therapy treatment are planned by CT simulation, a significant number of them are still planned using conventional simulators for various reasons. The information-collection process in a conventional simulation is often fragmented and done with primitive tools. For example, in many institutions body contours are still acquired using solder wires and tracing paper, a time-consuming and error-prone procedure. We have developed a 3D digitization system to assist the information-acquisition process at conventional simulations. The system consists of an infrared camera assembly, a wireless digitizer probe, and Windows-based software. The system can provide 3D coordinates of any points in space accessible by the probe with submillimeter accuracy. It can be used to capture body contours, to record the coordinates of portal points, and to take various measurements for dose calculations as well as for patient setup. The software can display all the captured data together with the planned treatment fields, providing a comprehensive geometric verification of the treatment configuration. The system can also transfer all the information to dose planning programs in DICOM-RT format, providing an integrated information flow from simulation to dose planning.