[Diagnosis of local recurrence of colorectal cancer, using PET and immunoscintigraphy by means of 131I or 111In anti-CEA monoclonal antibody].

The accurate and early diagnosis of the tumor in the point of the size, the location, the depth of invasion of other organs or the stages of the recurrent cancer became much more important than before, not only for the selection of the treatment method but also for the decision of the quality of the operation for preserving the function as much as possible for the quality of the life of the patient. The usefulness of positron emission tomography (PET) and immunoscintigraphy by means of 131I or 111In anti-CEA onoclonal antibody for the diagnosis of the recurrent colorectal cancer had been confirmed in clinical use of colorectal cancers. No adverse effect of this monoclonal anti-body of the mouse was seen in this studies. The differential absorption ratio (DAR) was useful indicator in PET-imaging to differentiate the true tumor tissue from the scar tissue or granulation-tissue around the tumor. Even though the imaging, structure of PET is inferior to those of CT or MRI, the imaging of PET reflects the biological character of tumor, itself and makes the more accurate diagnosis possibly by combined use with regular CT and MRI.