Assessment of Pulmonary Nodules and Colorectal Cancer Recurrences by FDG Scan on an «Ordinary» Coincidence Gamma Camera (CDET)

A FDG-CDET examination on a Picker gamma-camera equiped with coincidence detection and thick cristals was performed in 80 patients during the 2nd half of 1997. Sensitivity and specificity were both 100% for the detection of malignancy in primary lung tumours. Accuracy was 91% for the detection of hilar or mediastinal lymph nodes involvement vs 59% for CT; lymphangitic carcinomatosis, metastases and concomittant tumours were also successfully detected and confirmed. FDG-CDET contributed to significant management changes in 30% of the patients referred for lung abnormalities. FDG-CDET was also usefull in “occult” recurrence of colorectal cancer with an accuracy of 78% vs 42% for CT in this difficult indication; a longer follow-up is needed to be able to evaluate all the 25 patients whose management have been adequately modified in 60% of the cases. We conclude that the diagnostic performances of FDG-CDET derived from our current series cannot be distinguished from the corresponding results published with FDG-PET.