Biological Target Volume and Tumor Spread Index: A Combined Approach for Advanced Radiotherapy Targeting in Glioblastoma

Motivation: GBM patients experience poor outcomes, as radiotherapy planning (GTV, CTV, PTV) fails to account for biological abnormalities near GTV and glioma cell spread along white matter tracts. Goal(s): Utilizing advanced MRI to tailor the GTV and CTV margin to each patient's unique tumour progression pathway. Approach: MRI data (DTI, DSC, T1-weighted) were analyzed to create Tumor Spread Index (TSI) and Biological Target Volume (BTV) maps, generating personalized target volumes. Results: Preliminary results showed traditional methods underestimated tumor extent. Personalized clinical target volumes showed modified CTV margins depending on the risk of tumour spread vs uniform margin for the standard CTV. Impact: Integration of TSI and BTV into GBM radiotherapy planning enhances tumor targeting by accounting for white matter infiltration and biological abnormalities. This personalized approach reduces unnecessary radiation to healthy tissue, improves treatment accuracy, and may lead to better patient outcomes.