I am new to AI & ML and trying to develop a model to classify a set of MRI scan images of brain tumors. It has two classes(‘Healthy’ and ‘Tumor’). My data set has 4600 images (2087 for Healthy,2513 for Tumor). I use 15 epochs, The accuracy is increasing gradually. But the validation loss and validation accuracy is going up and down. I feel it is because the model is overfitting. How can I improve my model to perform well? Thank you.