High resolution BrainPET combined with simultaneous MRI

 

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Summary

After the successful clinical introduction of PET/CT, a novel hybrid imaging technology combining PET with the versatile attributes of MRI is emerging. At the Forschungszentrum Jülich, one of four prototypes available worldwide combining a commercial 3T MRI with a newly developed BrainPET insert has been installed, allowing simultaneous data acquisition with PET and MRI. The BrainPET is equipped with LSO crystals of 2.5 mm width and Avalanche photodiodes (APD) as readout electronics. Here we report on some performance characteristics obtained by phantom studies and also on the initial BrainPET studies on various patients as compared with a conventional HR+ PET-only scanner. Material, methods: The radiotracers [¹⁸F]-fluoroethyl- tyrosine (FET), [¹¹C]-flumazenil and [¹⁸F]-FP-CIT were applied. Results: Comparing komthe PET data obtained with the BrainPET to those of the HR+ scanner demonstrated the high image quality and the superior resolution capability of the BrainPET. Furthermore, it is shown that various MR images of excellent quality could be acquired simultaneously with BrainPET scans without any relevant artefacts. Discussion, conclusion: Initial experiences with the hybrid MRI/BrainPET indicate a promising basis for further developments of this unique technique allowing simultaneous PET imaging combined with both anatomical and functional MRI.

Zusammenfassung

Nach der erfolgreichen klinischen Einführung von PET/CT zeichnet sich eine neue bildgebende Hybridtechnologie ab, die PET mit den umfangreichen Möglichkeiten der MRT kombiniert. Im Forschungszentrum Jülich wurde einer von vier weltweit verfügbaren Prototypen aufgestellt, die ein kommerzielles 3T MRT mit einem neu entwickelten BrainPET-Einsatz vereinen, so dass simultane Messungen von PET und MRT möglich sind. Der BrainPET ist mit 2,5 mm breiten LSO-Kristallen ausgestattet, die von Avalanche Photodioden (APD) ausgelesen werden. In dieser Arbeit beschreiben wir erstens einige mithilfe von Phantomuntersuchungen gemessene Leistungsparameter und zweitens erste BrainPET-Aufnahmen bei verschiedenen Patienten in Vergleich zu Messungen mit einem konventionellen HR+ PET. Material, Methoden: Als Radiotracer wurden [¹⁸F]-Fluorethyl-Tyrosin (FET), [¹¹C]-Flumazenil und [¹⁸F]-FP-CIT eingesetzt. Ergebnisse: Der Vergleich der mit dem BrainPET gewonnenen Daten mit denen des HR+ PET macht die sehr gute Bildqualität und die verbesserte Auflösung des BrainPET deutlich. Weiterhin wird gezeigt, dass unterschiedliche MR-Sequenzen simultan mit den BrainPET-Aufnahmen durchgeführt werden können, wobei eine ausgezeichnete Qualität ohne relevante Beeinträchtigungen erzielt wird. Diskussion, Schlussfolgerungen: Die anfänglichen Erfahrungen mit dem hybriden MRT/BrainPET sind eine viel versprechende Basis für Weiterentwicklungen dieser einzigartigen Technik, die funktionelle PET-Bildgebung mit der anatomischen und funktionellen MRT kombiniert.

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