RT Journal Article SR Electronic T1 Comparison Between 18F-FDG PET, In-Line PET/CT, and Software Fusion for Restaging of Recurrent Colorectal Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 587 OP 595 VO 46 IS 4 A1 Jong-Ho Kim A1 Johannes Czernin A1 Martin S. Allen-Auerbach A1 Benjamin S. Halpern A1 Barbara J. Fueger A1 Joel R. Hecht A1 Osman Ratib A1 Michael E. Phelps A1 Wolfgang A. Weber YR 2005 UL http://jnm.snmjournals.org/content/46/4/587.abstract AB The aim of this study was to compare PET with 18F-FDG PET, in-line PET/CT, and software fusion of independently acquired CT and PET scans for staging of recurrent colorectal cancer (CRC). Methods: Fifty-one patients with suspected recurrent CRC were studied with in-line PET/CT. Thirty-four of these patients underwent an additional CT scan of the chest or abdomen within 4 wk of PET/CT. Software fusion of PET and CT was performed using a fully automated, intensity-based algorithm. The accuracy of the coregistration of PET and CT scans was evaluated by measuring the distance between landmarks visible in the PET and CT images. Histologic evaluation and follow-up for 6 mo served as the gold standard for the presence or absence of recurrent CRC. Results: On a patient basis, the accuracy of staging was significantly higher for in-line PET/CT than for PET (88% vs. 71%, P = 0.01). Software fusion of the independently acquired PET and CT images was unsuccessful in 8 patients (24%). In the remaining patients, the mean distance between 62 landmarks visible in PET and CT was 12.9 ± 7.9 mm, whereas it was only 7.7 ± 4.7 mm for in-line PET/CT (P < 0.001). Conclusion: In patients with suspected recurrent CRC, in-line PET/CT significantly improves staging compared with PET alone. Due to its high failure rate, software fusion of independently acquired PET and CT studies cannot be considered to represent an alternative to in-line PET/CT.