RT Journal Article SR Electronic T1 Preclinical Safety Evaluation of 18F-FHBG: A PET Reporter Probe for Imaging Herpes Simplex Virus Type 1 Thymidine Kinase (HSV1-tk) or Mutant HSV1-sr39tk's Expression JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 706 OP 715 VO 47 IS 4 A1 Shahriar S. Yaghoubi A1 Marcelo A. Couto A1 Chang-Cheng Chen A1 Lathasree Polavaram A1 Guanggen Cui A1 Luyi Sen A1 Sanjiv S. Gambhir YR 2006 UL http://jnm.snmjournals.org/content/47/4/706.abstract AB 9-(4-18F-Fluoro-3-[hydroxymethyl]butyl)guanine (18F-FHBG) is a sensitive and specific PET reporter probe for imaging the PET reporter genes, herpes himplex 1 thymidine kinase (HSV1-tk) and its mutant HSV1-sr39tk. 18F-FHBG has suitable pharmacokinetics and dosimetry for clinical applications and imaging of HSV1-TK has been demonstrated in the livers of hepatocellular cancer patients. Methods: Male and female Sprague–Dawley rats and New Zealand White rabbits were divided into equal groups receiving either 14 μg/kg cold FHBG or carrier solution, for a 14-d acute toxicity assessment. We monitored body weight, food and water consumption, body temperature, cardiovascular electrical and functional indices, respiratory performance and oxygen saturation, comprehensive blood chemistry, complete blood count (CBC), and urinalysis. We conducted daily cage-side examinations for the detection of any clinical abnormalities. Tissues of the animals that were euthanized and necropsied on day 14 were prepared for histopathologic examination. Results: No significant differences in cardiovascular and respiratory parameters, food consumption, body weight, urine components, or clinical signs attributable to test article toxicity were observed between the treatment and control groups. Any differences noted in the blood chemistry and CBC parameters were deemed to be incidental findings unrelated to the administration of the FHBG. Conclusion: Acute toxicity evaluation of FHBG at 100 times the expected human dose does not indicate harm to organ function or tissues. The Food and Drug Administration has approved FHBG as an Investigational New Drug.