en 4-Biomedical Signal & Image Processing Biomedical Signal & Image Processing Research Paper Research Paper <span style="font-size:11.0pt"><span style="line-height:115%"><span style="font-family:&quot;Calibri&quot;,sans-serif">Diagnostic image fusion across multiple modalities integrates diverse images, making it a crucial tool for improved diagnosis. To achieve the best fusion outcomes between MRI and PET brain images, the study presents an enhanced image fusion strategy that combines Spiking&nbsp;Neural P Systems with Non-subsampled Shearlet Transform (NSST). The proposed system first decomposes images into low-frequency and high-frequency regions by applying NSST and employs dynamic threshold neural P (DTNP) systems for high-frequency fusion and Coupled Neural P (CNP)&nbsp;systems for low-frequency fusion. Through practical testing of 48 pairs of PET and MRI related to various disorders of the brain, it is demonstrated that the suggested strategy outperforms seven popular fusion techniques, such as neuro-fuzzy and&nbsp;CNN-based models. It provides an Improvement in Structural Similarity Index (SSIM) and entropy by 23.8%, 17.6% respectively, compared to existing methods. Our approach helps medical practitioners make better decisions by producing precise observations about brain tumors,&nbsp;neurodegenerative disorders, and&nbsp;Alzheimer&#39;s disease. This contemporary fusion technique enhances the clinical interpretation and noticeable quality of fused images, leading to improved medical imaging capabilities.</span></span></span> image fusion, Spiking Neural P System, Non-subsampled Shearlet Transform, Coupled Neural P, dynamic threshold neural P, brain tumors, neurodegenerative disorders, Alzheimer's disease 3980 3980 http://ijeee.iust.ac.ir/browse.php?a_code=A-10-5941-1&slc_lang=en&sid=1 Ch Suryababu chsuryababu@sriniet.edu.in 1800319475328460017679 1800319475328460017679 Yes JNTUK, KAKINADA B Vijaya 1800319475328460017680 1800319475328460017680 No Arempula Sreenivasa Rao 1800319475328460017681 1800319475328460017681 No G Sattibabu 1800319475328460017682 1800319475328460017682 No R Rambabu 1800319475328460017683 1800319475328460017683 No K Ravi Kumar 1800319475328460017684 1800319475328460017684 No