title: First Evaluation of PET-Based Human Biodistribution and Dosimetry of18F-FAZA, a Tracer for Imaging Tumor Hypoxia.
abstract: 18F-labeled fluoroazomycinarabinoside (18F-FAZA) is a PET biomarker for noninvasive identification of regional tumor hypoxia. The aim of the present phase I study was to evaluate the biodistribution and dosimetry of18F-FAZA in non-small cell lung cancer patients.Methods:Five patients awaiting surgical resection of histologically proven or radiologically suspected non-small cell lung cancer were prospectively enrolled in the study. The patients underwent PET/CT after injection of 371 ± 32 MBq of18F-FAZA. The protocol consisted of a 10-min dynamic acquisition of the heart to calculate the activity in blood, followed by 4 whole-body PET/CT scans, from the vertex to the mid thigh, at 10, 60, 120, and 240 min after injection. Urine samples were collected after each imaging session and at 360 min after injection. Volumes of interest were drawn around visually identifiable source organs to generate time-activity curves. Residence times were determined from time-activity curves, and effective doses to individual organs and the whole body were calculated using OLINDA/EXM 1.2 for the standard male and female phantoms.Results:Blood clearance was characterized by a rapid distribution followed by first-order elimination. The highest uptake was in muscle and liver, with respective percentage injected activity (%IA) peaks of 42.7 ± 5.3 %IA and 5.5 ± 0.6 %IA. The total urinary excretion was 15 %IA. The critical organ, with the highest absorbed radiation doses, was the urinary bladder wall, at 0.047 ± 0.008 and 0.067 ± 0.007 mGy/MBq for the 2- and 4-h voiding intervals, respectively. The effective doses for the standard male and female phantoms were 0.013 ± 0.004 and 0.014 ± 0.004 mSv/MBq, respectively, depending on the voiding schedule.Conclusion:With respect to the available literature, the biodistribution of18F-FAZA in humans appeared to be slightly different from that in mice, with a low clearance in humans. Therefore, use of animal data may moderately underestimate radiation doses to organs in humans. Our dosimetry data showed that a 370-MBq injection of18F-FAZA is safe for clinical use, similar to other widely used PET ligands. In particular, the effective dose is not appreciably different from those obtained with other hypoxia tracers, such as18F-fluoromisonidazole.
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Annarita
authors.initials: A
authors.lastname: Savi
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Incerti
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Fallanca
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Valentino
authors.initials: V
authors.lastname: Bettinardi
authors.affiliation: Thoracic Surgery Department, IRCCS San Raffaele Scientific Institute, Milan, Italy; and.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossetti
authors.affiliation: University of Milano-Bicocca, Milan, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Monterisi
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: Compierchio
authors.affiliation: Thoracic Surgery Department, IRCCS San Raffaele Scientific Institute, Milan, Italy; and.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Negri
authors.affiliation: Thoracic Surgery Department, IRCCS San Raffaele Scientific Institute, Milan, Italy; and.
authors.forename: Piero
authors.initials: P
authors.lastname: Zannini
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Gianolli
authors.affiliation: Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy picchio.maria@hsr.it.
authors.forename: Maria
authors.initials: M
authors.lastname: Picchio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009593:Nitroimidazoles / Q000493:pharmacokinetics*; D049268:Positron-Emission Tomography / Q000379:methods*; D011829:Radiation Dosage; D011849:Radioactive Tracers; D011874:Radiometry; D014018:Tissue Distribution; D000072258:Tumor Hypoxia
chemical_list: D009593:Nitroimidazoles; D011849:Radioactive Tracers; C498052:fluoroazomycin arabinoside
keywords: 18F-FAZA PET; biodistribution; dosimetry; hypoxia; lung cancer