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. CONCLUSION: 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.

For many cancer types, being undetectable from early symptoms or blood tests, or often detected at late stages, medical imaging emerges as the most efficient tool for cancer screening. MRI, ultrasound, X-rays (mammography), and X-ray CT (CT) are currently used in hospitals with variable costs. Diagnostic materials that can detect breast tumors through molecular recognition and amplify the signal at the targeting site in combination with state-of-the-art CT techniques, such as dual-energy CT, could lead to a more precise detection and assist significantly in image-guided intervention. Herein, we have developed a ligand-specific X-ray contrast agent that recognizes α5β1 integrins overexpressed in MDA-MB-231 breast cancer cells for detection of triple (-) cancer, which proliferates very aggressively. In vitro studies show binding and internalization of our nanoprobes within those cells, towards uncoated nanoparticles (NPs) and saline. In vivo studies show high retention of ~3 nm ligand-PEG-S-AuNPs in breast tumors in mice (up to 21 days) and pronounced CT detection, with statistical significance from saline and iohexol, though only 0.5 mg of metal were utilized. In addition, accumulation of ligand-specific NPs is shown in tumors with minimal presence in other organs, relative to controls. The prolonged, low-metal, NP-enhanced spectral-CT detection of triple (-) breast cancer could lead to breakthrough advances in X-ray cancer diagnostics, nanotechnology, and medicine.