Intra-image referencing for simplified assessment of HER2-expression in breast cancer metastases using the Affibody molecule ABY-025 with PET and SPECT

• DOI: 10.1007/s00259-017-3650-3
• Publication Date: 2017-03-05T23:46:36Z
• Authors: Dan Sandberg; Vladimir Tolmachev; Irina Velikyan; Helena Olofsson; Anders Wennborg; Joachim Feldwisch; Jörgen Carlsson; Henrik Lindman; Jens Sörensen
• Keywords: Whole body imaging

In phase I/II-studies radiolabelled ABY-025 Affibody molecules identified human epidermal growth factor receptor 2 (HER2) expression in breast cancer metastases using PET and SPECT imaging. Here, we wanted to investigate the utility of a simple intra-image normalization tumour-to-reference tissue-ratio (T/R) as HER2 status discrimination strategy overcome potential issues related cross-calibration scanning devices.Twenty-three women with pre-diagnosed HER2-positive/negative metastasized were scanned [111In]-ABY-025 SPECT/CT (n = 7) or [68Ga]-ABY-025 PET/CT 16). Uptake was measured all normal spleen, lung, liver, muscle, blood pool. Normal tissue uptake variation T/R-ratios established for various time points two different doses injected peptide from total 94 whole-body image acquisitions. Immunohistochemistry (IHC) used verify 28 biopsied metastases. compared IHC findings establish best reference each modality imaging time-point. The impact shed serum investigated.Spleen across modalities, followed by pool lung. Spleen-T/R highly correlated SUV after h (r 0.96, P < 0.001) reached an accuracy 100% discriminating HER2-positive negative at 4 (PET) 24 (SPECT) injection. single case, resulted intense tracer retention blood. remaining patients elevated, but without significant on biodistribution.T/R-ratios spleen accurately quantify PET. Tracer binding might affect quantification extreme case.