Biodistribution and radiation dosimetry of the hypoxia marker 18F-HX4 in monkeys and humans determined by using whole-body PET/CT.
OBJECTIVE
F-HX4 is a novel positron emission tomography (PET) tracer for imaging hypoxia. The purpose of this study was to determine the biodistribution and estimate the radiation dose of F-HX4 using whole-body PET/computed tomography (CT) scans in monkeys and humans.


METHODS
Successive whole-body PET/CT scans were done after the injection of F-HX4 in four healthy humans (422±142 MBq) and in three rhesus monkeys (189±3 MBq). Biodistribution was determined from PET images and organ doses were estimated using OLINDA/EXM software.


RESULTS
The bladder, liver, and kidneys showed the highest percentage of the injected radioactivity for humans and monkeys. For humans, approximately 45% of the activity is eliminated by bladder voiding in 3.6 h, and for monkeys 60% is in the bladder content after 3 h. The critical organ is the urinary bladder wall with the highest absorbed radiation dose of 415±18 (monkeys) and 299±38 μGy/MBq (humans), in the 4.8-h bladder voiding interval model. The average value of effective dose for the adult male was estimated at 42±4.2 μSv/MBq from monkey data and 27±2 μSv/MBq from human data.


CONCLUSIONS
Bladder, kidneys, and liver have the highest uptake of injected F-HX4 activity for both monkeys and humans. The urinary bladder wall receives the highest dose of F-HX4 and is the critical organ. Thus, patients should be encouraged to maintain adequate hydration and void frequently. The effective dose of F-HX4 is comparable with that of other F-based imaging agents.
Diagnostic Imaging, Fox Chase Cancer Center, Philadelphia, PA 19111-2497, USA.
Mohan
M
Doss
James J
JJ
Zhang
Marie-José
MJ
Bélanger
James B
JB
Stubbs
Eric D
ED
Hostetler
Katherine
K
Alpaugh
Hartmuth C
HC
Kolb
Jian Q
JQ
Yu
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D000882:Haplorhini; D006801:Humans; D000860:Hypoxia; D008297:Male; D008875:Middle Aged; D009593:Nitroimidazoles / Q000493:pharmacokinetics*; D049268:Positron-Emission Tomography; D011874:Radiometry; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013045:Species Specificity; D014057:Tomography, X-Ray Computed; D014230:Triazoles / Q000493:pharmacokinetics*; D051598:Whole Body Imaging
C553729:3-fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3-triazol-1-yl)propan-1-ol; D015415:Biomarkers; D009593:Nitroimidazoles; D019275:Radiopharmaceuticals; D014230:Triazoles