Abstract
This study was undertaken to: (i) demonstrate the feasibility of whole-body 62Cu-ETS PET/CT tumor perfusion imaging in patients with metastatic renal carcinoma; and (ii) validate 62Cu-ETS as a quantitative marker of tumor perfusion by direct comparison with 15O-water perfusion imaging. Methods: PET/CT imaging of 10 subjects with stage IV renal cell cancer was performed after i.v. administration of 15O-water (10-minute dynamic list mode study) with the heart and at least one tumor in the PET field-of-view, followed 10-minutes later by i.v. 62Cu-ETS (6-minute list mode study). Whole body 62Cu imaging was then carried out from 6-20 minutes at 2-3 minutes/bed. Blood flow (K1) was quantified with both agents for normal and malignant tissues in the 21.7 cm dynamic field-of-view. The required arterial input functions were derived from the left atrium, and in the case of 62Cu-ETS, corrected for partial decomposition of the agent by blood using data from an in vitro analysis using a sample of each patient's blood. This imaging protocol was repeated at an interval of 3-4 weeks following initiation of a standard clinical treatment course of the anti-angiogenic agent sunitinib. Results: All subjects received the scheduled 62Cu-ETS doses for the dynamic and subsequent whole-body PET/CT scans, but technical issues resulted in no baseline 15O-water data for two subjects. Direct comparisons of the perfusion estimates for normal tissues and tumor metastases were made in 18 paired baseline and treatment studies (10 subjects; 8 baseline studies, 10 repeat studies during treatment). There was an excellent correlation between the blood flow estimates made with 62Cu-ETSand 15O-water for normal tissues (muscle, thyroid, myocardium) and malignant lesions (pulmonary nodules, bone lesions); the regression line was y = 0.85x + 0.15, R2 = 0.83, for the 88 regions analyzed. Conclusion: 62Cu-ETS provided high quality whole-body PET/CT images, and 62Cu-ETS measures of blood flow were highly and linearly correlated with 15O-water derived K1 values (mL-1 ·min-1 ·g). This tracer is suitable for use as a PET tracer of tumor perfusion in patients with metastatic renal cell carcinoma.
- Molecular Imaging
- Oncology: GU
- PET/CT
- Radiochemistry
- Radiopharmaceuticals
- Radiotracer Tissue Kinetics
- Renal
- Copper-62 PET
- Renal cell carcinoma
- Tumor perfusion
- [15O]water
- [62Cu]Cu-ETS
- Copyright © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.