Quantifying regional hypoxia in human tumors with positron emission tomography of [18F]fluoromisonidazole: a pretherapy study of 37 patients.
OBJECTIVE
To assess pretreatment hypoxia in a variety of tumors using positron emission tomography (PET) after injection of the hypoxia-binding radiopharmaceutical [18F]fluoromisonidazole ([18F]FMISO).


METHODS
Tumor fractional hypoxic volume (FHV) was determined in 21 nonsmall cell lung cancer patients, 7 head and neck cancer patients, 4 prostate cancer patients, and 5 patients with other malignancies by quantitative PET imaging after injection of [18F]FMISO (0.1 mCi/kg). The FHV was defined as the proportion of pixels in the imaged tumor volume with a tissue:blood [18F] activity ratio > or = 1.4 at 120-160 min postinjection. A FHV > 0 was taken as evidence for tumor hypoxia.


RESULTS
Hypoxia was observed in 36 of 37 tumors studied with FMISO PET imaging; FHVs ranged from 0 to 94.7%. In nonsmall cell lung cancers (n = 21), the median FHV was 47.6% and the range, 1.3 to 94.7%. There was no correlation between tumor size and FHV. In the seven head and neck carcinomas, the median FHV was 8.8%, with a range from 0.2 to 18.9%. In the group of four prostate cancers, the median and range were 18.2% and 0 to 93.9%, while in a group of five tumors of different types the median FHV was 55.2% (range: 21.4 to 85.8%).


CONCLUSIONS
Hypoxia was present in 97% of the tumors studied and the extent of hypoxia varied markedly between tumors in the same site or of the same histology. Hypoxia also was distributed heterogeneously between regions within a single tumor. These results are consistent with O2 electrode measures with other types of human tumors. The intra- and intertumor variability indicate the importance of making oxygenation measures in individual tumors and the necessity to sample as much of the tumor volume as possible.
Department of Radiation Oncology, University of Washington, Seattle, 98195-6069, USA.
J S
JS
Rasey
W J
WJ
Koh
M L
ML
Evans
L M
LM
Peterson
T K
TK
Lewellen
M M
MM
Graham
K A
KA
Krohn
D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D015687:Cell Hypoxia; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008920:Misonidazole / Q000493:pharmacokinetics; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D008920:Misonidazole