An OctreoScan can very occasionally show a carcinoid before CT scan or chemistries indicate its presence, but this situation is very infrequent. Visually it is used to help locate a tumor when chemistries show it is present and CT scan doesn’t image it. Also when CT scan is positive the OctreoScan may show additional sites of the tumor not seen on CT.
Finally even when tumor is seen on a CT scan and chemistries are positive, the OctreoScan is useful because a positive result indicates the presence of SST2 receptors in the tumor and that means the patient will most likely respond well to treatment with Sandostatin and also has a better prognosis than does the patient with carcinoid tumor but a negative OctreoScan.
