Trial Information

Assessment of Head and Neck Tumor Hypoxia Using 18F-Fluoromisonidazole

Hypoxic (low oxygen) cells have long been known to exist in animal tumors. It is also known
that hypoxic cells are more difficult to eliminate with radiotherapy than tumor cells at
normal levels of oxygen (normoxic cells). However, the extent to which hypoxic cells limit
the curability of human tumors is uncertain. To determine if hypoxic cells exist in human
tumors and how hypoxic cells might influence the efficacy of radiotherapy, this study
involves direct measurements of oxygen levels in human tumors compared to the tumor uptake
of the experimental drug, 18F-fluoromisonidazole (18F-FMISO), visualized with PET scanning.
18F-fluoromisonidazole has been used with PET imaging to tell the difference between growing
tumors which have high and low oxygen content.

Before beginning radiotherapy, a PET scan (series of pictures, 20 min. scan) will be
performed at 2 hours after an intravenous injection of a small amount of radioactive traces
drug, 18F-fluoromisonidazole (18F-FMISO) to observe the active hypoxia tumors areas. Upon
completion of the 18F-FMISO PET scan, direct oxygen measurements will be obtained by placing
a small needle into the tumor under computer tomographic (CT) guidance. The PET scan and
needle measurements will be repeated every 4 weeks into the course of radiotherapy and again
after the completion of radiotherapy. The measurement obtained by 18F-FMISO PET scanning
(non-invasive technique) and by direct needle measurements (invasive technique) will be
correlated with the eventual treatment outcome for future use.