Abstract
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Objectives: The balance between tumor metabolism and vascularity provides important information about the tumor microenvironment. This study aims to assess the feasibility using perfusion CT-PET to simultaneously assess metabolism and vascularity of breast cancer.
Methods: Eight female patients (mean age 65.5years range 53-74years) with operable breast cancer (T-stages 1-2) underwent perfusion CT and FDG-PET using a 64-slice PET-CT system (GE Discovery-VCT). Tumor metabolism was expressed as the Standardized Uptake Value (SUV). Analysis of the temporal changes in tumor attenuation following intravenous contrast material (50mls of iodine concentration 50 mg/ml) yielded tumor perfusion, standardized perfusion value (SPV) and vascular permeability (Ktrans).
Results: Quantification of metabolism and vascularity was possible in 7 patients. One patient exhibited no increase in FDG uptake and no contrast enhancement. Mean (range) for SUV, perfusion, SPV and Ktrans were 8.4 (2.4-26.0), 39 (19-59) ml/min/100g, 3.8 (2.6-5.9) and 161 (86-296) µl/min/ml. Perfusion values were in accordance with previous studies using O-15 water PET and a significant correlation was observed between SPV and Ktrans (r=0.77, p<0.05). There were trends for tumor metabolism to correlate with SPV (r=0.64, p=0.11) and perfusion (r=0.54, p=0.22) but not Ktrans (r=0.08, p=0.85).
Conclusions: Combining perfusion CT with FDG-PET allows simultaneous measurement of tumor metabolism and multiple parameters of vascularity without the need for an on-site cyclotron.
Research Support: Funding was provided by the Breast Cancer Campaign.
- Society of Nuclear Medicine, Inc.