Tumour hypoxia imaging with [18F]FAZA PET in head and neck cancer patients: a pilot study.
OBJECTIVE
Hypoxia is an important negative prognostic factor for radiation treatment of head and neck cancer. This study was performed to evaluate the feasibility of use of (18)F-labelled fluoroazomycin arabinoside ([(18)F]FAZA) for clinical PET imaging of tumour hypoxia.


METHODS
Eleven patients (age 59.6 +/- 9 years) with untreated advanced head and neck cancer were included. After injection of approximately 300 MBq of [(18)F]FAZA, a dynamic sequence up to 60 min was acquired on an ECAT HR+ PET scanner. In addition, approximately 2 and 4 h p.i., static whole-body PET (n = 5) or PET/CT (n = 6) imaging was performed. PET data were reconstructed iteratively (OSEM) and fused with CT images (either an external CT or the CT of integrated PET/CT). Standardised uptake values (SUVs) and tumour-to-muscle (T/M) ratios were calculated in tumour and normal tissues. Also, the tumour volume displaying a T/M ratio >1.5 was determined.


RESULTS
Within the first 60 min of the dynamic sequence, the T/M ratio generally decreased, while generally increasing at later time points. At 2 h p.i., the tumour SUV(max) and SUV(mean) were found to be 2.3 +/- 0.5 (range 1.5-3.4) and 1.4 +/- 0.3 (range 1.0-2.1), respectively. The mean T/M ratio at 2 h p.i. was 2.0 +/- 0.3 (range 1.6-2.4). The tumour volume displaying a T/M ratio above 1.5 was highly variable. At 2 h p.i., [(18)F]FAZA organ distribution was determined as follows: kidney > gallbladder > liver > tumour > muscle > bone > brain > lung.


CONCLUSIONS
[(18)F]FAZA PET imaging appears feasible in head and neck cancer patients, and the achieved image quality is adequate for clinical purposes. Based on our initial results, [(18)F]FAZA warrants further evaluation as a hypoxia PET tracer for imaging of cancer.
Souvatzoglou
M
M
Department of Nuclear Medicine, Technische Universität München, Ismaningerstr. 22, 81675 Munich, Germany.
Grosu
A L
AL
Röper
B
B
Krause
B J
BJ
Beck
R
R
Reischl
G
G
Picchio
M
M
Machulla
H-J
HJ
Wester
H-J
HJ
Piert
M
M
D000368:Aged; D015687:Cell Hypoxia; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009593:Nitroimidazoles / Q000493:pharmacokinetics*; D010100:Oxygen / Q000378:metabolism*; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D009593:Nitroimidazoles; D019275:Radiopharmaceuticals; C498052:fluoroazomycin arabinoside; D010100:Oxygen