Substitution of Oral ¹⁸F-FDG for Intravenous ¹⁸F-FDG in PET Scanning

¹ Radiation Medicine Centre, Tata Memorial Hospital Annexe, Parel, Mumbai, India

^* To whom correspondence should be addressed. E-mail: drarchi23{at}hotmail.com.

	Abstract

The aim of this study was to see whether oral administration of ¹⁸F-FDG could be substituted--without significant loss of information--for intravenous injection of ¹⁸F-FDG in patients with difficult intravenous access of any cause, such as that often seen in cancer patients after many cycles of chemotherapy. Methods: PET after both oral and intravenous administration of ¹⁸F-FDG was performed on 2 healthy volunteers and 7 patients. An interval of 48 h was maintained between the oral administration and the intravenous administration. All scans were visually analyzed. Semiquantitative analysis of specific areas was done by calculating standardized uptake values (SUVs). Scanning was performed 60 min after intravenous tracer administration and 90 min after oral tracer administration. Results: All lesions seen after intravenous administration were visualized on the oral study as well. SUVs were lower on the oral study than on the intravenous study. Conclusion: Oral ¹⁸F-FDG can successfully be substituted for intravenous ¹⁸F-FDG in patients with difficult intravenous access. However, because of the large amount of ¹⁸F-FDG retained in the gut, careful interpretation will be required when disease of the gastrointestinal tract is being evaluated.