99mTc-FAPI SPECT/CT Provides Superior Diagnostic Performance to 18F-FDG in Poorly Differentiated Gastric...

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Gastric adenocarcinoma recurrence can be challenging to detect with standard imaging.
• Poorly differentiated tumors often exhibit limited uptake of fluorodeoxyglucose (FDG).
• Fibroblast Activation Protein (FAPI) is a target expressed in tumor stroma.

Purpose of the Study:

• To evaluate the utility of 99mTc-FAPI SPECT/CT in detecting recurrence of gastric adenocarcinoma.
• To compare FAPI imaging with conventional methods like CT and FDG PET/CT.

Main Methods:

• A 52-year-old woman with gastric adenocarcinoma underwent gastrectomy and chemotherapy.
• Diagnostic imaging included CT, FDG PET/CT, and 99mTc-FAPI SPECT/CT.
• FAPI targeted activated stromal tissue, particularly effective for poorly differentiated tumors.

Main Results:

• CT and FDG PET/CT did not clearly show recurrence.
• 99mTc-FAPI SPECT/CT successfully detected all peritoneal and omental metastatic deposits.
• FAPI imaging identified small peritoneal lesions missed by other modalities.

Conclusions:

• 99mTc-FAPI SPECT/CT demonstrated high sensitivity for detecting gastric cancer recurrence, especially in peritoneal and omental sites.
• FAPI imaging is a valuable tool for identifying metastatic disease in poorly differentiated tumors with low FDG uptake.
• This technique can significantly aid in the management and treatment guidance for recurrent gastric cancer.