Long-term monitoring in postoperative assessment is essential for clinicians to assess the effectiveness of therapies and establish subsequent clinical pharmacotherapeutic plans. However, precise and real-time postoperative assessment is often overlooked, relying instead on various clinical histopathological and cytological assays or the experience of physicians. Therefore, it is urgent to develop a general strategy for long-term, real-time, and accurate postoperative assessment. Herein, we present a facile method utilizing radiolabeled probes for postradiotherapy assessment. The probe consists of a tumor-specific targeting group, an external radiotherapy-activated peptide sequence (DEVD), and a