Related Experiment Video
Updated: Jan 10, 2026
Stereotactic Radiosurgery for Gynecologic Cancer
Published on: April 17, 2012
Stratified dosimetric comparison between high-definition multileaf collimator-based D2SRS and robotic radiosurgery in
Canyang Lin1,2, Wei Liu2, Nan Xiao1
1Department of Oncology, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian, China.
Purpose:
To compare dosimetric characteristics and treatment efficiency between the high-definition multileaf collimator (HD-MLC) system and robotic radiosurgery (RRS) for brain metastases, with stratified analysis by lesion count.
Methods:
Twenty-nine patients (12 single [SBM], 17 multiple [MBM] brain metastases) treated with RRS (CyberKnife) were re-planned using a linear accelerator (LINAC) with 2.5-mm micro-MLC (D2SRS system). Key indices included target parameters (RTOG conformity index [RTOG CI], Paddick conformity index [Paddick CI], homogeneity index [HI], gradient index [GI], dose at 2 cm outside the target [D2cm]) and normal brain doses (V12Gy, V20Gy, V30Gy). The Wilcoxon signed-rank test was used (p < 0.05).
Results:
In SBM, RTOG CI, Paddick CI, and GI showed no significant differences, but Paddick CI favored RRS for tumor volume (TV) < 80 cc and D2SRS for TV > 80 cc. D2SRS had better HI (0.08 ± 0.02 vs. 0.12 ± 0.03, p < 0.01); RRS had lower D2cm (18.2 ± 5.5 Gy vs. 23.8 ± 6.7 Gy, p = 0.008), V12Gy (5.3 ± 2.1 cc vs. 8.7 ± 3.5 cc, p < 0.01), and V20Gy (18.47 ± 21.17 cc vs. 35.30 ± 53.85 cc, p = 0.015), with similar V30Gy. D2SRS had shorter treatment time (TT) (8.2 ± 2.1 min vs. 26.8 ± 7.8 min, p < 0.01). In MBM, D2SRS outperformed RRS in RTOG CI (1.12 ± 0.21 vs. 1.45 ± 0.33, p = 0.007), Paddick CI (0.85 ± 0.11 vs. 0.68 ± 0.14, p = 0.007), and HI (0.07 ± 0.02 vs. 0.13 ± 0.03, p = 0.03). RRS had lower V12Gy (38.5 ± 12.6 cc vs. 48.1 ± 15.3 cc, p = 0.017), V20Gy (14.5 ± 4.2 cc vs. 21.3 ± 6.8 cc, p = 0.04), and V30Gy (14.99 ± 20.81 cc vs. 18.49 ± 23.19 cc, p = 0.026). D2SRS reduced TT by 77.3% (12.4 ± 3.5 min vs. 54.6 ± 15.2 min, p < 0.01). No significant differences in Dmax of the brainstem, optic nerves, or lenses were found.
Conclusion:
RRS provides better normal brain protection in both groups, while D2SRS shows superior conformity and efficiency in MBM. Clinical selection should depend on lesion burden.
