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, especially the development of linear accelerators, plays a key role in cancer management. The fast-rotating coplanar O-ring Halcyon Linac has demonstrated many advantages. The previous literature has mainly focused on the machine parameters and plan quality of Halcyon, with a lack of relevant research on its clinical application.
To evaluate the clinical performance of the O-ring Halcyon treatment system in a real-world application setting.
Data from sixty-one patients who were treated with the Halcyon system throughout the entire radiotherapy process in Peking Union Medical College Hospital between August 2019 and September 2020 were retrospectively reviewed. We evaluated the target tumour response to radiotherapy and irradiation toxicity from 1 to 3 mo after treatment. Dosimetric verification of Halcyon plans was performed using a quality assurance procedure, including portal dosimetry, ArcCHECK and point dose measurements for verification of the system delivery accuracy.
Of the 61 patients in the five groups, 16, 12, 7 and 26 patients had complete response, partial response, progressive disease and stable disease, respectively. No increase in the irradiated target tumour volume was observed when separately evaluating the local response. Regarding irradiation toxicity, no radiation-induced deaths were observed. 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. 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. All of the validated clinical plans were within 3% for point dose measurements, and Halcyon’s ArcCHECK demonstrated a high pass rate of 99.1% ± 1.1% for clinical gamma passing criteria of 3%/3 mm.
The O-ring Halcyon Linac could achieve a better therapeutic effect on the target volume by providing accurate treatment delivery plans with tolerable irradiation toxicity.
Core Tip: The fast-rotating coplanar O-ring Halcyon Linac has demonstrated many advantages in radiation therapy. Unlike previous studies, which focused more on the machine parameters and quality control aspects of the O-ring Halcyon Linac, our institution evaluated Halcyon more from the perspective of practical clinical applications concerning radiotherapy effects and irradiation toxicity. The O-ring Halcyon Linac can generate desired treatment plans that meet clinically accepted constraints, pass routine patient-specific quality assurance for delivery accuracy verification, and present acceptable radiation toxicity under prospective yield.