Open Standards for Real-Time 3D Communication

View hi-res graphic

Radiation therapy/surgery is a procedure that involves a robotic device for movement of a radiation emitter (Linear Accelerator - LINAC) able to deliver radiation doses to the internal tumor, hindering its’ reproduction mechanism.

With the advent of complex 3D treatment planning, there is an increasing use of oblique/nonaxial fields. In combination with machine head-mounted add-ons and patient immobilization devices and on-board image components, treatment planners are finding it increasingly difficult to generate combinations of beam parameters that would prevent potential collisions between different LINAC components and with the patient. This is especially prevalent in stereotactic radiosurgery treatments or hypofractionated extracranial treatments with complex beam arrangements.

Planners therefore, generally resort to “traditional” combinations of gantry-couch-collimator sets that are known to be “safe” from routine clinical experience. However, due to the lack of knowledge of the actual collision space, the planner will not be able to always generate the most “optimal” collision-free treatment plan.

Current treatment planning systems lack the ability to accurately model the geometry of the various LINAC components to present a realistic “room-eye-view” in combination with actual patient geometries on the treatment table. For example, laterally displaced lung tumors may require couch top shifts that would give rise to potential gantry-collimator collisions with the couch that would not occur if the treatment isocenter was closer to the patient medial plane. Hence, the need for an exact representation of patient-specific setups combined with machine geometry is an essential requirement for the planner to produce an “optimal” plan that is free of collision scenarios between the different LINAC components.

3DRTT is a real-time 3D graphical simulator for an advanced radiation therapy/surgery medical system (e.g. Varian LINAC) that significantly improves the radiation planning process. The simulator uses of 3D visualization technology, built using X3D. The distributed functionality of the 3D visual simulation system on the web is implemented using Java Server Pages and Java Servlet technology, offering easy system scalability and a friendly GUI. Being web-based, it can easily be shared between researchers and medical personnel in different facilities.

A 3D laser scanning system was used to obtain high accuracy 3D models for the LINAC’s hardware parts for integration into the simulation. Another important component of the system is the capability to embed real patient data in the simulation. The data is obtained through a software module that converts sets of CT scans into their associated X3D polygonal model.