Normal brain sparing approach for static field intensity modulated radiosurgery of single brain metastasis using a distance driven dose gradient function
Year: 2025
Type: article
Abstract: PURPOSE: To determine the cause and effects of sparing normal brain using a distance driven normal tissue dose gradient function for static field intensity modulated stereotactic radiosurgery planning of single brain metastasis (SBM). MATERIALS AND METHODS: Twenty seven SBM cases were planned for a dose of 20 Gy using 6 MV beams, to examine the cause and effects of dose gradients due to six NTO combinations formed from fall-off = 0.2, 0.6, and 1.0 mm-1, final-dose + priority = 10% +100 and 30% + 200. For comparative analysis, NTO combination of fall-off = 1.0 mm-1, final-dose + priority = 10% +100 was chosen as the control. Each combination was assessed for changes in field size (FS), high-to-low brain dose volumes (V14, V12, and V8), gradient index (GI), conformity index (CI), prescription isodose level (PIDL), and MU/Gy. Correlational analysis was performed to find meaningful relationships between FS, V12 and GI for all NTO combinations. RESULTS: Groups with fall-off ≥0.6 mm-1 plus priority = 200 showed considerable reductions for FS, V14, V12, V8, GI and PIDL (P < 0.0001). Substantial high-to-low brain dose volume decrease was observed because of increasing fluence conformity and consequent FS regression. CI was constant (±0.01), while GI improved significantly and PIDL decreased with associated MU/Gy increase, (P < 0.0001). Strong positive correlation between FS and V12 (r > 0.9) was observed meaning GI correlated inversely (r < -0.7). CONCLUSION: NTO strictness causes fluence contraction that spares normal brain, yielding better dose metrics to attain balanced plan goals.
Authors: Shabbir Ahamed, R. Padma Suvarna, Navin Singh
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7117756490