Positron emission tomography (PET) is a nuclear imaging technology (also referred to as molecular imaging) that enables visualization of metabolic processes in the body. The basics of PET imaging is that the technique detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (also called radiopharmaceuticals, radionuclides or radiotracer). The tracer is injected into a vein on a biologically active molecule, usually a sugar that is used for cellular energy. PET systems have sensitive detector panels to capture gamma ray emissions from inside the body and use software to plot to triangulate the source of the emissions, creating 3-D computed tomography images of the tracer concentrations within the body.
PET images (MIP 0-60 min) of three Cynomolgus monkeys. Strong signals are detected at the sites where inserted catheters had roughened surfaces. Almost no other background signal is visible. Only accumulation in the gallbladder becomes visible at the bottom of the image. Credit: Piramal Imaging GmbH, Berlin Germany.
IMAGE OF THE YEAR: Dual-labeled PSMA-inhibitors for the diagnosis and therapy of prostate cancer. Technology of dual-labeled PSMA-inhibitors for PET/CT imaging and fluorescence-guided intraoperative identification of metastases. This work might help to establish a new treatment regimen for more precise and sensitive pre-, intra- and post-therapeutic detection of prostate cancer.
Credit: Courtesy of A. Baranski, M. Schäfer, U. Bauder-Wüst, M. Roscher, J. Schmidt, E. Stenau, L. Maier-Hein, M. Eder, K. Kopka, German Cancer Research Center, Heidelberg, Germany; T. Simpfendörfer, B. Hadaschik, U. Haberkorn, Heidelberg University Hospital, Heidelberg, Germany; PET-image: Afshar-Oromieh et al., EJNMMI 2013; 40(4); STED-image: J. Matthias, German Cancer Research Center.
This study was supported by the VIP+ fund, Federal Ministry of Education & Research (BMBF), Germany.
Scientific Paper 531: “Preclinical evaluation of dual-labeled PSMA-inhibitors for the diagnosis and therapy of prostate cancer.” A. Baranski, M. Schäfer, U. Bauder-Wüst, M. Roscher, J. Schmidt, E. Stenau, L. Maier-Hein, M. Eder, K. Kopka, German Cancer Research Center (DKFZ), Heidelberg, Germany; T. Simpfendörfer, B. Hadaschik, U. Haberkorn, University Hospital, Heidelberg, Germany. Presented at SNMMI’s 64th Annual Meeting, June 10-14, 2017, Denver, Colo.
Axial fused 89Zr-5B1 antibody PET/CT image demonstrates focus of uptake in the liver (arrow). Focus of uptake correlates with increased liver metastasis seen on diagnostic CT (red arrow) performed 2 weeks prior. Image courtesy of Christian Lohrmann, Jason Lewis, Wolfgang Weber, Memorial Sloan Kettering Cancer Center; MabVax Therapeutics
FIGURE: MRI AND PET-MRI FUSION IMAGES OF PATIENTS WITH DIPG. Top row: Zr-89-bevacizumab PET (144 hrs p.i.) fused with T1-Gd weighted MRI per patient; middle row: T1-Gd weighted MRI; lower row: T2-weighted/FLAIR MR-images. Five tumors show variable uptake of Zr-89-bevacizumab (white arrows), with both PET negative and positive areas within each tumor. Two primary tumors are completely PET negative (Fig. 1C and 1E), while the T2 weighted images show tumor infiltration in the whole pons of both patients. In the middle row, the red arrows represent the areas of contrast enhancement within the tumor. In four out of five primary tumors, the PET-positive area corresponds with the contrast-enhancing area on MRI of the tumors (Fig. 1A, 1B, 1F and 1G). In Fig. 1C, the tumor shows an MRI contrast-enhancing area, while there is no Zr-89-bevacizumab uptake. Fig. 1D shows a PET positive tumor, while no Gd-enhancement is observed on MRI. Credit: Sophie Veldhuijzen van Zanten and Marc Jansen, VU University Medical Center, Amsterdam, The Netherlands.