TerahertzTerahertz radiation is electromagnetic energy commonly associated with frequencies around 0.1 to 10 THz, between microwaves and infrared, where many materials reveal distinctive propagation, absorption, and imaging behavior. More and millimeter-wave technologies offer promising non-ionizing tools for biomedicalTerahertz and millimeter-wave technologies offer promising non-ionizing tools for biomedical tissue analysis, particularly for breast cancer research. Their sensitivity to water content, tissue structure, and dielectric contrast can help distinguish... More tissue analysis, particularly for breast cancer research. Their sensitivity to water content, tissue structure, and dielectric contrast can help distinguish cancerous from non-cancerous regions in excised breast tissue. A key application is surgical margin assessment after breast-conserving surgery, where faster, label-free imaging could complement histopathology and help identify residual tumor tissue near the resection boundary. Although laboratory studies show encouraging results, clinical use still requires larger validation cohorts, standardized protocols, faster acquisition, and integration into surgical workflows.