Biodistribution and radiation dosimetry of the hypoxia... : Nuclear Medicine Communications (original) (raw)

ORIGINAL ARTICLES

Biodistribution and radiation dosimetry of the hypoxia marker 18F–HX4 in monkeys and humans determined by using whole-body PET/CT

Doss, Mohana; Zhang, James J.d; Bélanger, Marie-Joséb; Stubbs, James B.e; Hostetler, Eric D.b; Alpaugh, Katherinec; Kolb, Hartmuth C.d; Yu, Jian Q.a

aDiagnostic Imaging, Fox Chase Cancer Center

bImaging, Merck and Co., West Point

cProtocol Lab, Fox Chase Cancer Center, Philadelphia, Pennsylvania

dBiomarker Research, Siemens Molecular Imaging Inc., Culver City

eRadiation Dosimetry Systems, Inc., Palo Alto, California, USA

Correspondence to Dr Jian Q. Yu, MD, Diagnostic Imaging, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111-2497, USA Tel: +1 215 728 3865; fax: +1 215 728 4755; e-mail: [email protected]

Received June 17, 2010

Accepted September 12, 2010

Abstract

Objectives

18F-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 18F-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 18F-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.

Conclusion

Bladder, kidneys, and liver have the highest uptake of injected 18F-HX4 activity for both monkeys and humans. The urinary bladder wall receives the highest dose of 18F-HX4 and is the critical organ. Thus, patients should be encouraged to maintain adequate hydration and void frequently. The effective dose of 18F-HX4 is comparable with that of other 18F-based imaging agents.