LAUSR

We present a 59-year-old man with gastric signet-ring cell carcinoma, initially staged with contrast-enhanced CT (CECT), revealing gastric wall thickening, lymph nodes, and lung metastases. Subsequently, [99mTc]-FAPI-46 SPECT/CT demonstrated increased tracer uptake in the gastric lesion, pulmonary nodule, and lymph nodes, alongside new findings of skeletal metastasis, omental and peritoneal deposits, altering the staging and clinical management. Our findings highlight the superior utility of [99mTc]-FAPI-46 in accurately staging gastric cancer and detecting occult metastatic lesions, which is critical for effective treatment planning, despite some limitations compared which diagnostic laparoscopy.