Biodistribution and Radiation Dosimetry of the Anti-HER2 Affibody Molecule 68Ga-ABY-025 in Breast Cancer Patients
Mattias Sandström, Karolina Lindskog, Irina Velikyan, Anders Wennborg, Joachim Feldwisch, Dan Sandberg, Vladimir Tolmachev, Anna Orlova, Jens Sörensen, Jörgen Carlsson, Henrik Lindman, Mark Lubberink, Mattias Sandström, Karolina Lindskog, Irina Velikyan, Anders Wennborg, Joachim Feldwisch, Dan Sandberg, Vladimir Tolmachev, Anna Orlova, Jens Sörensen, Jörgen Carlsson, Henrik Lindman, Mark Lubberink
Abstract
(68)Ga-ABY-025 is a radiolabeled Affibody molecule for in vivo diagnosis of human epidermal growth factor receptor 2 (HER2)-positive breast cancer tumors with PET. The aim of the present work was to measure the biodistribution and estimate the radiation dosimetry of (68)Ga-ABY-025 for 2 different peptide mass doses in a single group of patients using dynamic and serial whole-body PET/CT.
Methods: Eight patients with metastatic breast cancer were included. Each patient underwent an abdominal 45-min dynamic and 3 whole-body PET/CT scans at 1, 2, and 4 h after injection of a low peptide dose (LD) and a high peptide dose (HD), with approximately the same amount of radioactivity, in separate investigations 1 wk apart. As input to the absorbed dose calculations, volumes of interest were drawn on all clearly identifiable source organs: liver, kidneys, spleen, descending aorta, and upper large intestine. Absorbed doses were calculated using OLINDA/EXM, version 1.1.
Results: Of the major organs, the highest radionuclide uptake at 1, 2, and 4 h after injection was observed in the kidneys and liver. The highest absorbed organ doses were seen in the kidneys, followed by the liver for both LD and HD (68)Ga-ABY-025. Absorbed doses to liver and kidneys were slightly but significantly higher for LD. Total effective dose was 0.030 ± 0.003 mSv/MBq for LD and 0.028 ± 0.002 mSv/MBq for HD.
Conclusion: The effective dose for a typical 200-MBq administration of (68)Ga-ABY-025 is 6.0 mSv for LD and 5.6 mSv for HD. Therefore, from a radiation dosimetry point of view, HD is preferred for PET/CT evaluation of HER2-expressing breast cancer tumors. These effective doses are somewhat higher than earlier published values for other (68)Ga-labeled tracers, such as 0.021 ± 0.003 mSv/MBq for (68)Ga-DOTATATE and (68)Ga-DOTATOC, mainly because of higher uptake in liver and kidney.
Keywords: 68Ga-gallium; Affibody; HER2-receptor; breast cancer metastases; dosimetry.
© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
Source: PubMed