The peritoneum consists of 2 layers the parietal layer covering the inner surface of abdomen and visceral layer which reflects over and surround the abdominal organs. Peritoneal carcinomatosis is one of the frequent sites of metastasis in many gastrointestinal and gynecological tumors mostly colorectal and ovarian cancer.
Various forms of peritoneal carcinomatosis could be noted in the form of ascites, micronodular, nodular, plaque like, mass like, omental cake, teca aspect and ileal freezing.
Positron emission tomography (PET) is being increasingly used for diagnosis, staging, and follow-up of various malignancies. In peritoneal carcinomatosis, FDG-PET/CT has been shown to have higher sensitivity and positive predictive value (up to 92%) compared to FDG-PET and CT alone. It also has higher specificity (up to 97%) compared to FDG-PET alone, with similar specificity compared to CT alone. It is more useful than just PET the addition of CT allows better anatomic visualization and can detect the presence of cancer lesions based on the glucose uptake of the cells. It identifies the exact localization and area of the peritoneal metastasis, PET-CT provides better accuracy. It adds good value to the conventional imaging mainly for monitoring response to the therapy, especially on long-term follow-up.
PET/CT has multiple clinical applications in peritoneal oncology detecting the primary tumor in unknown primary, tumor staging and restaging; treatment planning, post therapy response, differentiating recurrence from post therapy changes; distinguishing malignant from benign peritoneal disease; can be used as a biomarker as well as alternative tracers for cancer evaluation.