HyperArc VMAT planning for single and multiple brain metastases stereotactic radiosurgery: a new treatment planning approach

Radiation Oncology

Masahiko Koizumi¹  Akira Masaoka²  Takero Hirata²  Yoshihiro Ueda²  Teruki Teshima²  Shingo Ohira²  Masayoshi Miyazaki²  Misaki Hashimoto³  Yuichi Akino⁴ 

[1] Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine;Department of Radiation Oncology, Osaka International Cancer Institute;Department of Radiation Oncology, Yao Municipal Hospital;Division of Medical Physics, Oncology Center, Osaka University Hospital;

关键词: Brain metastases;    Stereotactic radiosurgery;    VMAT;    HyperArc;    Dosimetric parameter;   

DOI  :  10.1186/s13014-017-0948-z

来源: DOAJ

【 摘 要 】

Abstract Purpose The HyperArc VMAT (HA-VMAT) planning approach was newly developed to fulfill the demands of dose delivery for brain metastases stereotactic radiosurgery. We compared the dosimetric parameters of the HA-VMAT plan with those of the conventional VMAT (C-VMAT). Material and methods For 23 patients (1–4 brain metastases), C-VMAT and HA-VMAT plans with a prescription dose of 20–24 Gy were retrospectively generated, and dosimetric parameters for PTV (homogeneity index, HI; conformity index, CI; gradient index, GI) and brain tissue (V2Gy-V16Gy) were evaluated. Subsequently, the physical characteristics (modulation complexity score for VMAT, MCSV; Monitor unit, MU) of both treatment approaches were compared. Results HA-VMAT provided higher HI (1.41 ± 0.07 vs. 1.24 ± 0.07, p < 0.01), CI (0.93 ± 0.02 vs. 0.90 ± 0.05, p = 0.01) and lower GI (3.06 ± 0.42 vs. 3.91 ± 0.55, p < 0.01) values. Moderate-to-low dose spreads (V4Gy-V16Gy) were significantly reduced (p < 0.01) in the HA-VMAT plan over that of C-VMAT. HA-VMAT plans resulted in more complex MLC patterns (lower MCSV, p < 0.01) and higher MU (p < 0.01). Conclusions HA-VMAT plans provided significantly higher conformity and rapid dose falloff with respect to the C-VMAT plans.

【 授权许可】

Unknown