Pimonidazole is primarily used as a hypoxia marker in biomedical research. It binds selectively to hypoxic cells, which are cells with low oxygen levels, making it valuable for studying tumor hypoxia in cancer research. By identifying hypoxic regions within tumors, it helps researchers understand tumor biology and evaluate the effectiveness of treatments like radiotherapy and chemotherapy, which often target oxygen-deficient areas. Additionally, it is used in preclinical studies to assess hypoxia-related conditions in various diseases, aiding in the development of targeted therapies. Its application extends to imaging techniques, where it assists in visualizing hypoxic tissues in experimental models.