Implementation and preliminary evaluation of a practical digital workflow for routine laser-radiation field coincidence quality assurance on the CyberKnife M6.

Authors

Linzheng Hu, Yongkang Zhao, Chunling Zheng, Jiajun Cai, Yajun Jia, Yi Tao, Yikun Liu, Yin Zhang, Zhitao Dai

Published in

Precision radiation oncology. Oct 24, 2026. Epub Oct 24, 2026.

Abstract

To implement and preliminarily evaluate a practical digital acquisition-and-analysis workflow for routine laser-radiation field coincidence quality assurance (QA) on the CyberKnife M6 by integrating multileaf collimator (MLC) QA tool-based laser reference definition, QA StereoChecker (QASC)-based external digital image acquisition, and automated analysis with CKQA, an in-house CyberKnife QA software, and to compare this workflow with clinically realistic film-based alternatives.
Methods a and b were film-based measurements performed at the perch position. Method a used manual laser marking on film, whereas method b used the central metal marker of the MLC QA tool to define the laser reference. Method c used QASC as an external digital image-acquisition platform in combination with the MLC QA tool, and method d used film on the same QASC-based setup as a control. All methods were tested with 10 fixed collimators (5-40 mm). Images were analyzed using ImageJ and CKQA. Mean deviation, standard deviation, root mean square error (RMSE), and pairwise two-sided exact Wilcoxon signed-rank tests were used for exploratory comparisons.
All evaluated workflows achieved submillimeter mean deviations. Across both analysis approaches, the mean deviation ranked consistently in descending order: method a > method b > method d > method c. Under the present experimental conditions, method c yielded the lowest mean deviation and RMSE (0.116 mm and 0.155 mm with CKQA), whereas method a showed the largest deviations. Dataset-level exact Wilcoxon signed-rank tests showed that several comparisons involving method a were statistically significant, but statistically significant differences were not uniform across both ImageJ- and CKQA-based comparisons. For comparisons between analysis methods within each workflow, CKQA and ImageJ were not significantly different for methods a and b, whereas CKQA yielded significantly lower deviations than ImageJ for methods c and d (p < 0.05).
Laser-radiation field coincidence testing is an established CyberKnife QA procedure. The present study implemented and preliminarily evaluated a practical digital acquisition-and-analysis workflow for this routine task. The workflow combining MLC QA tool-based laser reference definition, QASC-based external digital image acquisition, and automated CKQA analysis provided a standardized and less operator-dependent procedure under the present experimental conditions. Its main value lies in reducing manual marking, film handling, scanning, and subjective image-analysis steps rather than in introducing a new physical measurement principle. In centers where QASC is not available, the film-based workflow using the MLC QA tool (method b) may serve as a practical alternative.

PMID:
42927071
Bibliographic data and abstract were imported from PubMed on 25 Oct 2026.

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