Fig. 5: FAPI-PET detects peritoneal metastases.

a Immunohistochemistry for FAP on peritoneal metastases tissue that was resected one year prior to FAPI-PET imaging. b Immunohistochemistry of EpCAM-positive tumour cells in the peritoneum show a strong ZEB1 and HTR2B staining. c FAPI-PET image shows tracer accumulation in pelvic peritoneal depositions and along the abdominal peritoneal lining (white arrows). See also Supplementary Fig. S6. d FAPI-PET image (same coronal section, same scaling)) after 2 months of chemotherapy shows a reduction of FAPI tracer uptake in the pelvic lesion and the serosal lesion and a complete loss of diffuse FAPI tracer uptake along the peritoneum.