Magnetic resonance imaging (MRI) reveals fine brain details, but spotting a tumor still needs expert eyes. Deep neural networks have changed the game, yet they demand huge labeled datasets, which are costly and delicate to produce. That’s why researchers are turning to semi‑supervised learning, a strategy that mixes a few certified examples with many unlabeled images.
A popular trick is pseudo‑labeling: after an initial training, the network assigns provisional labels to unlabeled scans, then uses them to fine‑tune itself. Consistency regularization pushes the model to give similar outputs even when the image is slightly altered (noise, rotations). GANs (Generative Adversarial Networks) generate synthetic tumor images, enriching the training pool. Contrastive learning teaches the model to tell apart similar and different regions, sharpening its edge detection. Holistic approaches blend several of these ideas into one framework.
Recent studies show that with only 10‑20 % of labeled data, these methods match or surpass fully supervised networks. The outcome is faster diagnosis, less reliance on specialists, and a path toward more accessible clinical decision‑support tools.
