Study on the correlation between collimator angles and dosimetry in stereotactic radiotherapy planning for liver cancer

Abstract

Abstract: Objective: To study the dosimetric effect of different collimator angle on stereotactic radiotherapy (SRT) for liver cancer, providing a reference for collimator angle selection in clinical SRT plan design for liver cancer.
Methods: A retrospective analysis was conducted on 20 liver cancer patients treated with SRT from 2018 to 2024. Nine plans were generated with collimator angles ranging from 0°/0° to 80°/280° at 10° intervals, under identical planning parameters. The Friedman test was used to compare differences in conformity index (CI), gradient index (GI), normal liver V₁₀/V₂₀/V₃₀, mean liver dose, 0.03 cm³ spinal cord dose (D_{0.03 cm3} ), monitor units, and γ pass rate (3%/2mm standard).
Results: The results showed that changes in collimator angle significantly affected CI, GI, normal liver V₁₀ and V₃₀, spinal cord D_{0.03 cm3}, and monitor units, with statistically significant differences (all P< 0.05). However, no significant differences were observed in normal liver V20, mean liver dose, or γ pass rate (all P> 0.05).
Conclusion: Collimator angle selection can optimize target dose distribution and reduce normal tissue irradiation, offering valuable clinical guidance for SRT plan design in liver cancer.

Key words: Liver cancer, Stereotactic radiotherapy, Collimator angle, Dosimetry, γpassing rate

Dai Wanting, Dong Yu, Wang Qiushi, Fan Pengfei, Li Yuheng, Wu Dengbin. Study on the correlation between collimator angles and dosimetry in stereotactic radiotherapy planning for liver cancer[J]. Electronic Journal of Liver Tumor, 2025, 12(4): 37-42.

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