Real-Time High-Resolution Radiation Fluence Profiling with the ONYX Detector

Objectives: : The objective of this study is to evaluate the ONYX detector system's potential to enhance quality assurance (QA) for Stereotactic Radiosurgery (SRS) by offering real-time, high-resolution beam diagnostics. Initially developed for proton therapy, ONYX aims to provide accurate measurements of beam parameters such as position, dose distribution, and pulse duration to meet the unique demands of SRS.

Methods: : The ONYX detector utilizes a large-area, innovative multi-directional ionization array capable of isotropic data capture with high spatial and temporal precision. Experiments conducted with proton beams at Mayo Clinic Arizona measured spatial resolution ( < 200μm) and temporal resolution (100μs). Future testing with a photon-specific prototype for SRS applications is scheduled for early 2025 to further validate these capabilities.

Results: : Preliminary proton beam tests demonstrate that ONYX can precisely capture sub-millimeter beam positioning and rapid temporal changes in real time. These results support ONYX’s capability for small field uniformity, edge sharpness, and alignment accuracy, essential for minimizing collateral exposure in SRS. Photon-based testing is expected to confirm similar performance.

Conclusion(s):: ONYX technology shows promise as a transformative QA tool in SRS, offering clinicians high confidence in beam targeting accuracy. With superior resolution, rapid frame rates, and real-time diagnostics, ONYX enables more effective and safe delivery of high-dose treatments. This system could set a new standard for QA in advanced radiotherapy modalities, including SRS and proton therapy.