title: A brief evaluation of tumor imaging in mice with 99mTc-glucarate including a comparison with 18F-FDG.
abstract: OBJECTIVE
  Recently 99mTc-glucarate, a radiolabeled glucose analogue, has been considered as a SPECT alternative to 18F-FDG and PET for non-invasive detection of certain tumors. Thus far there have been few studies on (99m) Tcglucarate for tumor imaging and fewer, if any, studies comparing (99m)Tc-glucarate with 18F-FDG. As a preliminary indication of the properties of (99m)Tc-glucarate as a possible substitute for 18F-FDG in animal studies, we have imaged mice bearing xenografts of four tumor types with (99m)Tc-glucarate and have compared in two mice with one of these tumor types the 99mTc and 18F biodistributions.
  
  
  METHODS
  Two mice bearing SUM190 breast cancer xenografts received 1 mCi of (99m)Tc-glucarate and were imaged on a NanoSPECT/CT small animal camera. One day later, the same animals received 1 mCi of 18F-FDG and were imaged on a MosaicHP PET small animal camera. In addition, 0.5-1 mCi of (99m)Tc-glucarate only was administered to mice bearing xenografts induced by BxPC3 pancreatic cancer cells, HEK-293 renal cell carcinomas cells or HCT-116 colorectal tumor cells. NanoSPECT/CT acquisitions were performed in these mice to evaluate tumor accumulations.
  
  
  RESULTS
  In the SUM190 xenografted mice, the average tumor accumulation was 1.4 % (ID%/cm3) for (99m)Tc-glucarate and 2.1 % (ID%/cm3) for 18F-FDG. While slightly higher than (99m)Tc-glucarate, the tumor accumulation of 18F-FDG was accompanied by higher bone marrow and muscle accumulations at levels that could interfere with the tumor image depending upon location. The whole body clearance of (99m)Tc-glucarate was faster than that of 18F-FDG. Tumor accumulation of (99m)Tc-glucarate varied among tumor types but the tumors were readily visible in all images.
  
  
  CONCLUSIONS
  In a direct comparison in the same two SUM190 tumored animals, SPECT images obtained with (99m)Tcglucarate compared favorably with PET images obtained with 18F-FDG. Tumor images with 99mTc-glucarate were also positive in three additional tumor mouse models. While further comparison studies are necessary, we conclude that (99m)Tcglucarate may be a more convenient and less expensive alternative to 18F-FDG for tumored mouse studies.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Cheng
authors.forename: Mary
authors.initials: M
authors.lastname: Rusckowski
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Liu
authors.forename: Guozheng
authors.initials: G
authors.lastname: Liu
authors.forename: Xinrong
authors.initials: X
authors.lastname: Liu
authors.forename: Donald
authors.initials: D
authors.lastname: Hnatowich
mesh_terms: D000818:Animals; D005260:Female; D019788:Fluorodeoxyglucose F18; D005937:Glucaric Acid / Q000031:analogs & derivatives*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000000981:diagnostic imaging*; D015609:Organotechnetium Compounds; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C067171:technetium Tc 99m glucarate; D019788:Fluorodeoxyglucose F18; D005937:Glucaric Acid