RT Journal Article SR Electronic T1 Non-invasive evaluation of CXCR4 expression of MALT lymphoma using 68Ga-Pentixafor PET/MRI- a prospective study JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 563 OP 563 VO 58 IS supplement 1 A1 Leisser, Asha A1 Mayerhöfer, Marius A1 Raderer, Markus A1 Wadsak, Wolfgang A1 Mitterhauser, Markus A1 Pfaff, Sarah A1 Kropf, Saskia A1 Wester, Hans A1 Hacker, Marcus A1 Hartenbach, Markus A1 Haug, Alexander YR 2017 UL http://jnm.snmjournals.org/content/58/supplement_1/563.abstract AB 563Objectives: MALT lymphomas are a challenge for non-invasive diagnosis. So far, biopsy is still needed for staging and re-staging. MALT lymphoma express the chemokine receptor CXCR4 on a regular basis, and 68Ga-Pentixafor has shown to quantify CXCR4 expression non-invasively . Based on these findings, we evaluated for the first time 68Ga-Pentixafor PET/MRI for non-invasive diagnosis of MALT lymphoma.Methods: This study was approved by the local ethical committee. We prospectively included 14 patients with MALT lymphoma in this study (7 male, age 69). Localisations were stomach (n=4), lung (n=2), liver (n=1), kidney (n=2), skin (n=1), tonsils (n=1), bladder (n=1) and orbita (n=2). Precursor for 68Ga-Pentixafor synthesis was provided by Scintomics in GMP grade. 60 minutes after application of mean 172 MBq 68Ga-Pentixafor whole-body PET images were acquired with 5 minutes per bed position. Simultaneously the following MRI sequences were acquired: axial T1 vibe Dixon, coronal T2 haste, axial diffusion weighted images (ADC, b_50, b_800). We evaluated the uptake (SUVmax, SUVmean, SUVpeak) and volume in MALT lymphoma and the SUVmax of the liver as background. All MALT lymphomas were verified by biopsy.Results: In all patients the MALT lymphoma showed increased uptake of 68Ga-Pentixafor. Mean SUVmax was 10.8 (range 4.1-25.4), SUVmean 5.5 (range 2.9-10.2), and SUVpeak 10.3 (range 7.1-22.7; 2 patients with low tumor volume were not evaluable). The mean SUVmax of the liver was 1.8. The tumor-to-background ratio was excellent with mean 5.8 (range 2.4-14.9). The mean tumor volume was 94.3 ml (range 3.4-306).Conclusion: In this study all MALT lymphoma had high 68Ga-Pentixafor uptake with excellent tumor-to-background ratios, therefore, enabling non-invasive diagnosis. Research Support: Scintomics GmbH