m-Iodobenzylguanidine hemisulfate salt is primarily used in nuclear medicine for diagnostic imaging. It is particularly valuable in the detection and localization of neuroendocrine tumors, such as pheochromocytoma, neuroblastoma, and paraganglioma. The compound acts as a radiopharmaceutical agent, where it is labeled with radioactive iodine (I-123 or I-131) to enable imaging through techniques like single-photon emission computed tomography (SPECT). Its ability to accumulate in adrenergic tissue makes it highly effective for identifying these types of tumors. Additionally, it is utilized in cardiac imaging to assess sympathetic innervation in conditions such as heart failure and cardiomyopathy. It is also employed in therapeutic applications for certain neuroendocrine cancers, where the radioactive component helps target and destroy malignant cells. Its specificity and efficacy have made it a critical tool in oncology, diagnostic radiology, and cardiology. Furthermore, it serves as a research tool in pharmacology and biology to study cellular and neural mechanisms.