2253 - Real-Time Laser System for Collision Visualization to Enhance Patient Safety

02:30pm - 04:00pm PT

Hall F

Screen: 8

POSTER

Presenter(s)

Piotr Dubrowski, MS, MCCPM - Stanford University, San Jose, CA

A. Wang¹, P. Dubrowski², L. Skinner³, S. J. Yu⁴, and A. Burns¹; ¹Stanford University, palo alto, CA, ²Department of Radiation Oncology, Stanford University School of Medicine, Palo Alto, CA, ³Stanford University, Stanford, CA, ⁴Department of Radiation Oncology, Stanford University, Palo Alto, CA

Purpose/Objective(s):

Despite numerous prior efforts, the risk of collisions with C-arm linacs remains inadequately addressed. Existing solutions predominantly focus on simulation and planning methodologies; however, truncated CT scans and uncertainties in patient positioning cannot be accurately predicted. Manual clearance checks are time and labor-intensive and adversely impact patient comfort, overall experience, and efficiency of clinical workflows. To address this challenge, we propose the implementation of a ring of lasers mounted isocentrically on the gantry to delineate a visible boundary indicating potential collision zones. We posit that this system will enhance collision prediction through clear visualization of collisions to the treating team and ultimately contribute to safer treatment outcomes for patients

Materials/Methods:

The prototype of laser ring was constructed with 40 laser diodes uniformly distributed along a circular perimeter with a radius of 40 cm, corresponding to clearance of the linac gantry and imaging systems. These laser diodes are securely housed within 3D-printed holders featuring a three-point aligning system, designed to mitigate uncertainties with both the 3D printing process and the manufacturing of the laser diodes. A programmable microcontroller was used to independently control each segment of the laser ring (5 laser diodes distributed across 37.5 degrees). Following the development of the system, three mock treatment plans were evaluated, incorporating patient setup uncertainties using volunteer participants.

Results:

The system successfully visualized potential collisions. Prior to a volunteer being positioned on the treatment table, mock patient-specific collisions identified from the Treatment Planning System (TPS) were visualized to the therapy team by independently flashings corresponding laser ring segments. In instances of setup uncertainty, the laser beams were interrupted by the volunteer's anatomy or immobilization devices. This system serves as a visual indicator of potential collisions, effectively accounting for the full three-dimensional geometries of both the patient and the linac.

Conclusion:

The real-time information provided by this system increases awareness of potential collisions compared to existing approaches. It enhances visibility for therapists operating the system, both from within and outside the treatment room. The system issues warnings of potential impending collisions based on the interruption of the laser ring as well as draws attention to predicted collisions from the TPS, thereby facilitating proactive measures. In addition to minimizing collision occurrences, this system decreases the time required for dry runs, as the laser ring offers an immediate visual indication of whether the treatment space is unobstructed. Although collisions are infrequent, they represent a potentially serious or even fatal risk, making them one of the most concerning accidents in radiation therapy.