%0 Journal Article
%T Planning Target Volume Margin in Linac-Based Stereotactic Radiosurgery for Brain Metastases
%A Hany S. Attallah
%A Radwa M. Hamed
%A Khaled M. EL-Shahat
%A Aliaa Mahmoud
%A Mahmoud Abdallah
%A Ibraheem Haggag
%A Emad Moustafa
%A Adel Yassin
%J Journal of Cancer Therapy
%P 265-272
%@ 2151-1942
%D 2024
%I Scientific Research Publishing
%R 10.4236/jct.2024.157025
%X <b>Background:</b> 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. <b>Material and Methods</b>: 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 &#8722; GTV, Peel2 = PTV2 &#8722; GTV. <b>Results:</b> 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). <b>Conclusion:</b> According to our dosimetric analysis, expanding the GTV into a PTV by 1 mm margin is more convenient than 2 mm.
%K SRS
%K Brain Metastases
%K PTV
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=134415