DSIT UNet a dual stream iterative transformer based UNet architecture for segmenting brain tumors from FLAIR MRI images.

Brain tumor segmentation remains challenging in medical imaging with conventional therapies and rehabilitation owing to the complex morphology and heterogeneous nature of tumors. Although convolutional neural networks (CNNs) have advanced medical image segmentation, they struggle with long-range dependencies because of their limited receptive fields. We propose Dual-Stream Iterative Transformer UNet (DSIT-UNet), a novel framework that combines Iterative Transformer (IT) modules with a dual-stream encoder-decoder architecture. Our model incorporates a transformed spatial-hybrid attention optimization (TSHAO) module to enhance multiscale feature interactions and balance local details with the global context. We evaluated DSIT-UNet using three benchmark datasets: The Cancer Imaging Archive (TCIA) from The Cancer Genome Atlas (TCGA), BraTS2020, and BraTS2021. On TCIA, our model achieved a Mean Intersection over Union of 95.21%, mean Dice Coefficient of 96.23%, precision of 95.91%, and recall of 96.55%. BraTS2020 attained a Mean IoU of 95.88%, mDice of 96.32%, precision of 96.21%, and recall of 96.44%, surpassing the performance of the existing methods. The superior results of DSIT-UNet demonstrate its effectiveness in capturing tumor boundaries and improving segmentation robustness through hierarchical attention mechanisms and multiscale feature extraction. This architecture advances automated brain tumor segmentation, with potential applications in clinical neuroimaging and future extensions to 3D volumetric segmentation.