Dosimetric Comparison of Noncoplanar VMAT Without Rotating the Patient Couch Versus Conventional Coplanar/Noncoplanar VMAT for Head and Neck Cancer: First Report of Dynamic Swing Arc

IF 2.2 Q3 ONCOLOGY

Advances in Radiation Oncology Pub Date : 2024-12-30 DOI:10.1016/j.adro.2024.101706

Kouta Hirotaki MS , Kento Tomizawa MD, PhD , Satoe Kitou BS , Shunta Jinno MS , Shunsuke Moriya PhD , Takeshi Fujisawa MD , Sadamoto Zenda MD, PhD , Takeji Sakae PhD , Masashi Ito BS

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引用次数: 0

Abstract

Purpose

This retrospective planning study aimed to verify the usefulness of a clinically available method, dynamic swing arc (DSA), a noncoplanar volumetric modulated arc therapy (VMAT) technique, of the new accelerator OXRAY for head and neck squamous cell carcinoma (HNSCC). We performed dosimetric comparisons between DSA and conventional coplanar/noncoplanar VMAT (C-VMAT/NC-VMAT) plans for HNSCC.

Methods and Materials

We selected 32 patients with oropharyngeal and hypopharyngeal cancer treated with C-VMAT at National Cancer Center Hospital East between September 2018 and July 2023. DSA and C/NC-VMAT plans were generated using OXRAY and TrueBeam, respectively. DSA employed noncoplanar 2-arc beams with an O-ring gantry swing, whereas C-VMAT and NC-VMAT used coplanar and noncoplanar 2-arc beams, respectively. Dosimetric parameters, normal tissue complication probability, and delivery times were compared pairwise using the Wilcoxon signed-rank test with Bonferroni correction.

Results

For high-risk planning target volume (PTV), D98 values in NC-VMAT plans were closest to the prescribed dose, significantly differing from C-VMAT and DSA plans. DSA plans showed significantly better median conformity and homogeneity indices (0.97 and 7.33, respectively) compared to C-VMAT (0.95 and 8.36) and NC-VMAT (0.96 and 7.96) plans. DSA plans significantly reduced the mean ipsilateral/contralateral parotid gland dose by 5.78/6.93 and 2.88/1.56 Gy (median) compared to C-VMAT and NC-VMAT. NC-VMAT and DSA plans significantly decreased the mean oral cavity dose by 2.16 and 3.22 Gy (median) compared to C-VMAT. DSA plans had the lowest median normal tissue complication for xerostomia with significant differences, followed by NC-VMAT and C-VMAT. The delivery time for DSA plans was longer than VMAT (151 seconds vs 124 seconds), but shorter than NC-VMAT.

Conclusions

DSA plans using OXRAY for HNSCC maintained PTV coverage while reducing parotid gland and oral cavity mean doses compared to coplanar VMAT plans, although delivery times increased. DSA plans reduced parotid gland doses and delivery times compared to noncoplanar VMAT plans.

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来源期刊

Advances in Radiation Oncology Medicine-Radiology, Nuclear Medicine and Imaging

CiteScore

4.60

自引率

4.30%

发文量

208

审稿时长

98 days

期刊介绍： The purpose of Advances is to provide information for clinicians who use radiation therapy by publishing: Clinical trial reports and reanalyses. Basic science original reports. Manuscripts examining health services research, comparative and cost effectiveness research, and systematic reviews. Case reports documenting unusual problems and solutions. High quality multi and single institutional series, as well as other novel retrospective hypothesis generating series. Timely critical reviews on important topics in radiation oncology, such as side effects. Articles reporting the natural history of disease and patterns of failure, particularly as they relate to treatment volume delineation. Articles on safety and quality in radiation therapy. Essays on clinical experience. Articles on practice transformation in radiation oncology, in particular: Aspects of health policy that may impact the future practice of radiation oncology. How information technology, such as data analytics and systems innovations, will change radiation oncology practice. Articles on imaging as they relate to radiation therapy treatment.