Planning Target Volume Margin in Linac-Based Stereotactic Radiosurgery for Brain Metastases
Planning Target Volume Margin in Linac-Based Stereotactic Radiosurgery for Brain Metastases作者机构：Department of Radiation Oncology International Medical Center (IMC) Cairo Egypt Department of Radiation Oncology Armed Forces Medical Collogue (AFCM) Cairo Egypt Department of Medical Physics Al Azhar University Cairo Egypt Department of Medical Physics International Medical Center (IMC) Cairo Egypt Department of Medical Physics Department of Clinical Oncology Faculty of Medicine Zagazig University Zagazig Egypt
出 版 物：《Journal of Cancer Therapy》 (癌症治疗（英文）)
年 卷 期：2024年第15卷第7期
页 面：265-272页
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
主 题：SRS Brain Metastases PTV
摘 要：Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is a current debate. Radiotherapy centers use variable GTV-PTV margins, ranging from one to 2 mm. Material and Methods: We performed a dosimetric comparison in plans of twenty patients using three margins: PTV zero, PTV1, and PTV2. We also developed imaginary Peel volumes. These volumes are described as follows: Peel1 = PTV1 − GTV, Peel2 = PTV2 − GTV. Results: Our results showed that the mean PTV volume differed significantly across the different margins (p = 0.000). The V12 of the brain significantly varied as a function of PTV margin (p = 0.000). The target coverage and plan quality indices were not significantly different. The Peel volume dosimetric analysis showed that the mean dose was significantly higher in the nearby normal brain tissue: Peel1 (p = 0.022) and Peel 2 (p = 0.013). Conclusion: According to our dosimetric analysis, expanding the GTV into a PTV by 1 mm margin is more convenient than 2 mm.
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