Published online Aug 6, 2022. doi: 10.12998/wjcc.v10.i22.7728
Peer-review started: January 6, 2022
First decision: February 8, 2022
Revised: March 7, 2022
Accepted: June 13, 2022
Article in press: June 13, 2022
Published online: August 6, 2022
Processing time: 196 Days and 16.8 Hours
Radiation therapy is commonly used in cancer management. Halcyon, a novel 6MV-flattening-filter-free O-ring linear accelerator (6X-FFF ORL), was designed to deliver treatment with greater speed than a traditional C-arm Linac, demonstrating great advantages.
The development of linear accelerators has played a key role in cancer management. Halcyon, as a new accelerator with many breakthrough innovations, is worthy of further exploration for clinical application. Previous studies have mainly focused on the machine parameters and plan quality of Halcyon, while relevant research on its clinical application has been lacking.
To evaluate the clinical performance of the O-ring Halcyon treatment system in a real-world application setting and share our clinical experience with 6X-FFF ORL radiation therapy for cancer management.
Patients who were treated with the Halcyon system throughout the entire radiotherapy process were retrospectively reviewed. We evaluated the Halcyon from three aspects: effects of radiotherapy, irradiation toxicity and quality assurance. Dosimetric verification of Halcyon plans was performed using quality assurance procedures such as portal dosimetry, ArcCHECK and point dose measurements to verify the system delivery accuracy.
Of the 61 patients in the five groups, no increase in the irradiated target tumour volume was observed when separately evaluating local response. Regarding irradiation toxicity, thirty-eight percent (23/61 patients) had no radiation toxicity after radiotherapy, 56% (34/61 patients) experienced radiation toxicity that resolved after treatment, and 6% (4/61 patients) had irreversible adverse reactions. All of the validated clinical plans were within 3% for point dose measurements, and the average gamma passing rates with a 2% dose difference and 2-mm distance to agreement for IMRT/VMAT/SRT plans were ArcCHECK at 96.4% and portal dosimetry at 96.7%, respectively.
We showed that the Halcyon platform can generate treatment plans that meet clinically accepted constraints and pass routine patient-specific quality assurance for delivery accuracy verification. For clinics that choose Halcyon as the treatment delivery option, administering VMAT and IMRT is feasible and safe.
Further follow-up is needed to assess late toxicity and long-term outcomes.