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Incorporating Arc-Based Collision Detection Into Eclipse TPS for Lung IMRT/SBRT Patients

Z Pearson1*, W Weaver2, (1) University of Kentucky, Lexington, KY, (2) Alyzen Medical Physics, Jonesboro, AR


PO-BPC-Virtual-37 (Saturday, 4/17/2021)   [Eastern Time (GMT-4)]

Purpose: Collision detection software has been developed and implemented by others, however they require the treatment planning system (TPS) to be running locally. This report incorporates a collision detection software directly into the TPS, making it accessible to on-site and remote users. This software also includes the ability to account for anatomy not included in the CT scan.

Methods: A contour of the patient’s skin and of the couch exterior are created by the planner. Those structures are then segmented within the software. Isocenter is found for the specific beam that is being tested. Using characteristics of the beam, an arc is created about isocenter with a radius equal to the distance from isocenter to gantry head. The software then searches the segmented structure on each slice for the closest point to the generated arc. The closest distance for the structure is reported back along with the angle of the gantry head at that point. This software was tested against a phantom for plans containing couch rotations and shifts.

Results: The software was tested against a Solid Water phantom with various shifts applied. When shifts resulting in collision were applied, the software was able to correctly predict the angle of collision. For plans without collisions, closest approach distances from phantom to gantry head were predicted within 4.5 cm.

Conclusion: The collision detection software was incorporated into the Eclipse TPS. This tool has the potential to eliminate replanning by reporting collisions during the planning process, thus improving the quality and timeliness of patient care. With the ability to be used by remote users as well as on-site users, this tool is both accessible and accurate.


Computer Software, Stereotactic Radiosurgery, Treatment Verification


TH- External Beam- Photons: Development (new technology and techniques)

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