title: In vivo PET/CT in a human glioblastoma chicken chorioallantoic membrane model: a new tool for oncology and radiotracer development.
abstract: For many years the laboratory mouse has been used as the standard model for in vivo oncology research, particularly in the development of novel PET tracers, but the growth of tumors on chicken chorioallantoic membrane (CAM) provides a more rapid, low cost, and ethically sustainable alternative. For the first time, to our knowledge, we demonstrate the feasibility of in vivo PET and CT imaging in a U87 glioblastoma tumor model on chicken CAM, with the aim of applying this model for screening of novel PET tracers.
  
  
  METHODS
  U87 glioblastoma cells were implanted on the CAM at day 11 after fertilization and imaged at day 18. A small-animal imaging cell was used to maintain incubation and allow anesthesia using isoflurane. Radiotracers were injected directly into the exposed CAM vasculature. Sodium (18)F-fluoride was used to validate the imaging protocol, demonstrating that image-degrading motion can be removed with anesthesia. Tumor glucose metabolism was imaged using (18)F-FDG, and tumor protein synthesis was imaged using 2-(18)F-fluoro-l-tyrosine. Anatomic images were obtained by contrast-enhanced CT, facilitating clear delineation of the tumor, delineation of tracer uptake in tumor versus embryo, and accurate volume measurements.
  
  
  RESULTS
  PET imaging of tumor glucose metabolism and protein synthesis was successfully demonstrated in the CAM U87 glioblastoma model. Catheterization of CAM blood vessels facilitated dynamic imaging of glucose metabolism with (18)F-FDG and demonstrated the ability to study PET tracer uptake over time in individual tumors, and CT imaging improved the accuracy of tumor volume measurements.
  
  
  CONCLUSIONS
  We describe the novel application of PET/CT in the CAM tumor model, with optimization of typical imaging protocols. PET imaging in this valuable tumor model could prove particularly useful for rapid, high-throughput screening of novel radiotracers.
authors: Cyclotron Research Center, University of Liège, Liège, Belgium; and.
authors: Geoff
authors: G
authors: Warnock
authors: Andrei
authors: A
authors: Turtoi
authors: Arnaud
authors: A
authors: Blomme
authors: Florian
authors: F
authors: Bretin
authors: Mohamed Ali
authors: MA
authors: Bahri
authors: Christian
authors: C
authors: Lemaire
authors: Lionel Cyrille
authors: LC
authors: Libert
authors: Alain E J J
authors: AE
authors: Seret
authors: André
authors: A
authors: Luxen
authors: Vincenzo
authors: V
authors: Castronovo
authors: Alain R E G
authors: AR
authors: Plenevaux
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002645:Chickens; D049033:Chorioallantoic Membrane / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D055808:Drug Discovery; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D005947:Glucose / Q000378:metabolism; D006801:Humans; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography; D011849:Radioactive Tracers; D012969:Sodium Fluoride; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D005462:Fluorine Radioisotopes; D011849:Radioactive Tracers; D019788:Fluorodeoxyglucose F18; D014443:Tyrosine; C060489:2-fluorotyrosine; D012969:Sodium Fluoride; D005947:Glucose
keywords: CAM model; glioblastoma; imaging