@article{WernerHaenscheidLealetal.2018,
  author    = {Werner, Rudolf and H{\"a}nscheid, Heribert and Leal, Jeffrey P. and Javadi, Mehrbod S. and Higuchi, Takahiro and Lodge, Martin A. and Buck, Andreas K. and Pomper, Martin G. and Lapa, Constantin and Rowe, Steven P.},
  title     = {Impact of Tumor Burden on Quantitative [\(^{68}\)Ga]DOTATOC Biodistribution},
  series = {Molecular Imaging and Biology},
  journal   = {Molecular Imaging and Biology},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170280},
  pages     = {1-9},
  year      = {2018},
  abstract  = {Purpose: As has been previously reported, the somatostatin receptor (SSTR) imaging agent [\(^{68}\)Ga]-labeled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-d-Phe(1)-Tyr(3)-octreotate ([\(^{68}\)Ga]DOTATATE) demonstrates lower uptake in normal organs in patients with a high neuroendocrine tumor (NET) burden. Given the higher SSTR affinity of [\(^{68}\)Ga]DOTATATE, we aimed to quantitatively investigate the biodistribution of [\(^{68}\)Ga]-labeled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-d-Phe(1)-Tyr(3)-octreotide ([68Ga]DOTATOC) to determine a potential correlation between uptake in normal organs and NET burden. Procedures: Of the 44 included patients, 36/44 (82\%) patients demonstrated suspicious radiotracer uptake on [\(^{68}\)Ga]DOTATOC positron emission tomography (PET)/x-ray computed tomography (CT). Volumes of Interest (VOIs) were defined for tumor lesions and normal organs (spleen, liver, kidneys, adrenals). Mean body weight corrected standardized uptake value (SUV\(_{mean}\)) for normal organs was assessed and was used to calculate the corresponding mean specific activity uptake (Upt: fraction of injected activity per kg of tissue). For the entire tumor burden, SUV\(_{mean}\), maximum standardized uptake value (SUV\(_{max}\)), and the total mass (TBM) was calculated and the decay corrected tumor fractional uptake (TBU) was assessed. A Spearman's rank correlation coefficient was used to determine the correlations between normal organ uptake and tumor burden. Results: The median SUV\(_{mean}\) was 18.7 for the spleen (kidneys, 9.2; adrenals, 6.8; liver, 5.6). For tumor burden, the median values were SUV\(_{mean}\) 6.9, SUV\(_{max}\) 35.5, TBM 42.6g, and TBU 1.2\%. With increasing volume of distribution, represented by lean body mass and body surface area (BSA), Upt decreased in kidneys, liver, and adrenal glands and SUV\(_{mean}\) increased in the spleen. Correlation improved only for both kidneys and adrenals when the influence of the tumor uptake on the activity available for organ uptake was taken into account by the factor 1/(1-TBU). TBU was neither predictive for SUV\(_{mean}\) nor for Upt in any of the organs. The distribution of organ Upt vs. BSA/(1-TBU) were not different for patients with minor TBU (<3\%) vs. higher TBU (>7\%), indicating that the correlations observed in the present study are explainable by the body size effect. High tumor mass and uptake mitigated against G1 NET. Conclusions: There is no significant impact on normal organ biodistribution with increasing tumor burden on [\(^{68}\)Ga]DOTATOC PET/CT. Potential implications include increased normal organ dose with [\(^{177}\)Lu-DOTA]\(^0\)-D-Phe\(^1\)-Tyr\(^3\)-Octreotide and decreased absolute lesion detection with [\(^{68}\)Ga]DOTATOC in high NET burden.},
  subject      = {Positronen-Emissions-Tomografie},
  language  = {en}
}
@article{WernerChenHiranoetal.2018,
  author    = {Werner, Rudolf A. and Chen, Xinyu and Hirano, Mitsuru and Rowe, Steven P. and Lapa, Constantin and Javadi, Mehrbod S. and Higuchi, Takahiro},
  title     = {SPECT vs. PET in Cardiac Innervation Imaging: Clash of the Titans},
  series = {Clinical and Translational Imaging},
  journal   = {Clinical and Translational Imaging},
  issn      = {2281-5872},
  doi       = {10.1007/s40336-018-0289-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-163628},
  year      = {2018},
  abstract  = {Purpose: We aim to provide an overview of the conventional single photon emission computed tomography (SPECT) and emerging positron emission tomography (PET) catecholamine analogue tracers for assessing myocardial nerve integrity, in particular focusing on \(^{18}\)F-labeled tracers. Results: Increasingly, the cardiac sympathetic nervous system (SNS) is being studied by non-invasive molecular imaging approaches. Forming the backbone of myocardial SNS imaging, the norepinephrine (NE) transporter at the sympathetic nerve terminal plays a crucial role for visualizing denervated myocardium: in particular, the single-photon-emitting NE analogue \(^{123}\)I-meta-Iodobenzylguanidine (\(^{123}\)I-mIBG) has demonstrated favorable results in the identification of patients at a high risk for cardiac death. However, cardiac neuronal PET agents offer several advantages inlcuding improved spatio-temporal resolution and intrinsic quantifiability. Compared to their \(^{11}\)C-labeled counterparts with a short half-life (20.4 min), novel \(^{18}\)F-labeled PET imaging agents to assess myocardial nerve integrity have the potential to revolutionize the field of SNS molecular imaging: The longer half-life of \(^{18}\)F (109.8 min) allows for more flexibility in the study design and delivery from central cyclotron facilities to smaller hospitals may lead to further cost reduction. A great deal of progress has been made by the first in-human studies of such \(^{18}\)F-labeled SNS imaging agents. Moreover, dedicated animal platforms open avenues for further insights into the handling of radiolabeled catecholamine analogues at the sympathetic nerve terminal. Conclusions: \(^{18}\)F-labeled imaging agents demonstrate key properties for mapping cardiac sympathetic nerve integrity and might outperform current SPECT-based or \(^{11}\)C-labeled tracers in the long run.},
  subject      = {Positronen-Emissions-Tomografie},
  language  = {en}
}
@inproceedings{WernerHayakawaAriasLozaetal.2017,
  author    = {Werner, Rudolf and Hayakawa, Nobuyuki and Arias-Loza, Paula-Anah and Wakabayashi, Hiroshi and Shinaji, Tetsuya and Lapa, Constantin and Pelzer, Theo and Higuchi, Takahiro},
  title     = {Bildgebung der fr{\"u}hen linksventrikul{\"a}ren Dysfunktion mit ECG-gated F-18-FDG PET in einem Diabetes-Ratten-Modell},
  series = {Nuklearmedizin},
  volume    = {56},
  booktitle = {Nuklearmedizin},
  number    = {2},
  publisher = {Schattauer Verlag},
  issn      = {0029-5566},
  doi       = {10.3413/Nukmed-0880-17-02},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161396},
  pages     = {Abstract Nr.: V119},
  year      = {2017},
  abstract  = {Einleitung: Die linksventrikul{\"a}re diastolische Dysfunktion (LVDD) ist bei Diabetikern noch vor Entwicklung einer klinisch apparenten Herzinsuffizienz eines der ersten Anzeichen einer kardialen Beteiligung. Daher soll in dieser Studie untersucht werden, ob die LVDD mit ECG-gated F-18-FDG PET in einem Diabetes-Rattenmodell dargestellt werden kann. Methodik: Es wurden F-18-FDG PET Scans in einem Typ-2-Diabetes Rattenmodell (ZDF fa/fa, n=6) und in ZL Kontrollen (n=6) vorgenommen (Alter, jeweils 13 Wochen). Unter Hyperinsulinemic-Euglycemic Clamp-Technik wurden 37 MBq 18F-FDG {\"u}ber die Schwanzvene appliziert. 15-35 Minuten nach Tracergabe wurden mittels eines Kleintier-PET-Scanners sowie unter EKG-Ableitung PET Scans angefertigt (16 frames/cardiac cycle). Die linksventrikul{\"a}re Ejektionsfraktion (EF) und die Peak F{\"u}llrate (PFR) wurden mittels einer geeigneten Software (Heart Function View) gemessen, wobei die Software an die Gr{\"o}ße des Rattenherzes angepasst wurde. Ergebnisse: Im Alter von 13 Wochen entwickeln ZDF Diabetes-Ratten eine im Vergleich zu Kontrolltieren eine signifikante myokardiale Hypertrophie, best{\"a}tigt durch post-mortem Analyse des Herzgewichtes (994±78mg vs. 871±44mg in ZDF Diabetes-Ratten vs. ZL Kontrollen, p<0.01). ECG-gated PET zeigte eine signifikante Abnahme der LV diastolischen PFR (10.4±0.5 vs. 11.8±0.4 EDV/sec in ZDF Diabetes-Ratten vs. ZL Kontrollen, p<0.001), jedoch zeigte sich kein signifikanter Unterschied zwischen LVEF und der Herzfrequenz in den untersuchten ZDF Diabetes-Ratten und Kontrollen (LVEF: 60.0±4.5 vs. 63.7±4.1\%, n.s. und HR: 305±25 vs. 323±24 bpm, n.s.). Schlussfolgerung: Im Diabetes-Ratten-Modell kann unter Verwendung eines ECG-gated FDG-PET Protokolls die diastolische Dysfunktion als Parameter der fr{\"u}hen diabetischen Kardiomyopathie nachgewiesen werden.},
  subject      = {Positronen-Emissions-Tomografie},
  language  = {de}
}
@article{WernerWeichHiguchietal.2017,
  author    = {Werner, Rudolf A. and Weich, Alexander and Higuchi, Takahiro and Schmid, Jan S. and Schirbel, Andreas and Lassmann, Michael and Wild, Vanessa and Rudelius, Martina and Kudlich, Theodor and Herrmann, Ken and Scheurlen, Michael and Buck, Andreas K. and Kropf, Saskia and Wester, Hans-J{\"u}rgen and Lapa, Constantin},
  title     = {Imaging of Chemokine Receptor 4 Expression in Neuroendocrine Tumors - a Triple Tracer Comparative Approach},
  series = {Theranostics},
  volume    = {7},
  journal   = {Theranostics},
  number    = {6},
  doi       = {10.7150/thno.18754},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158008},
  pages     = {1489-1498},
  year      = {2017},
  abstract  = {C-X-C motif chemokine receptor 4 (CXCR4) and somatostatin receptors (SSTR) are overexpressed in gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In this study, we aimed to elucidate the feasibility of non-invasive CXCR4 positron emission tomography/computed tomography (PET/CT) imaging in GEP-NET patients using [\(^{68}\)Ga]Pentixafor in comparison to \(^{68}\)Ga-DOTA-D-Phe-Tyr3-octreotide ([\(^{68}\)Ga]DOTATOC) and \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG). Twelve patients with histologically proven GEP-NET (3xG1, 4xG2, 5xG3) underwent [\(^{68}\)Ga]DOTATOC, [\(^{18}\)F]FDG, and [\(^{68}\)Ga]Pentixafor PET/CT for staging and planning of the therapeutic management. Scans were analyzed on a patient as well as on a lesion basis and compared to immunohistochemical staining patterns of CXCR4 and somatostatin receptors SSTR2a and SSTR5. [\(^{68}\)Ga]Pentixafor visualized tumor lesions in 6/12 subjects, whereas [\(^{18}\)F]FDG revealed sites of disease in 10/12 and [\(^{68}\)Ga]DOTATOC in 11/12 patients, respectively. Regarding sensitivity, SSTR-directed PET was the superior imaging modality in all G1 and G2 NET. CXCR4-directed PET was negative in all G1 NET. In contrast, 50\% of G2 and 80\% of G3 patients exhibited [\(^{68}\)Ga]Pentixafor-positive tumor lesions. Whereas CXCR4 seems to play only a limited role in detecting well-differentiated NET, increasing receptor expression could be non-invasively observed with increasing tumor grade. Thus, [\(^{68}\)Ga]Pentixafor PET/CT might serve as non-invasive read-out for evaluating the possibility of CXCR4-directed endoradiotherapy in advanced dedifferentiated SSTR-negative tumors.},
  subject      = {Positronen-Emissions-Tomografie},
  language  = {en}
}
@article{WernerSheikhbahaeiJonesetal.2017,
  author    = {Werner, Rudolf A. and Sheikhbahaei, Sara and Jones, Krystyna M. and Javadi, Mehrbod S. and Solnes, Lilja B. and Ross, Ashley E. and Allaf, Mohamad E. and Pienta, Kenneth J. and Lapa, Constantin and Buck, Andreas K. and Higuchi, Takahiro and Pomper, Martin G. and Gorin, Micheal A. and Rowe, Steven P.},
  title     = {Patterns of uptake of prostate-specific membrane antigen (PSMA)-targeted \(^{18}\)F-DCFPyL in peripheral ganglia},
  series = {Annals of Nuclear Medicine},
  volume    = {31},
  journal   = {Annals of Nuclear Medicine},
  number    = {9},
  issn      = {0914-7187},
  doi       = {10.1007/s12149-017-1201-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166971},
  pages     = {696-702},
  year      = {2017},
  abstract  = {Objective: Radiotracers targeting prostate-specific membrane antigen (PSMA) have increasingly been recognized as showing uptake in a number of normal structures, anatomic variants, and non-prostate-cancer pathologies. We aimed to explore the frequency and degree of uptake in peripheral ganglia in patients undergoing PET with the PSMA-targeted agent \(^{18}\)F-DCFPyL. Methods: A total of 98 patients who underwent \(^{18}\)F-DCFPyL PET/CT imaging were retrospectively analyzed. This included 76 men with prostate cancer (PCa) and 22 patients with renal cell carcinoma (RCC; 13 men, 9 women). Scans were evaluated for uptake in the cervical, stellate, celiac, lumbar and sacral ganglia. Maximum standardized uptake value corrected to body weight (SUV\(_{max}\)), and maximum standardized uptake value corrected to lean body mass (SUL\(_{max}\)) were recorded for all ganglia with visible uptake above background. Ganglia-to-background ratios were calculated by dividing the SUV\(_{max}\) and SUL\(_{max}\) values by the mean uptake in the ascending aorta (Aortamean) and the right gluteus muscle (Gluteusmean). Results: Overall, 95 of 98 (96.9\%) patients demonstrated uptake in at least one of the evaluated peripheral ganglia. With regard to the PCa cohort, the most frequent sites of radiotracer accumulation were lumbar ganglia (55/76, 72.4\%), followed by the cervical ganglia (51/76, 67.1\%). Bilateral uptake was found in the majority of cases [lumbar 44/55 (80\%) and cervical 30/51 (58.8\%)]. Additionally, discernible radiotracer uptake was recorded in 50/76 (65.8\%) of the analyzed stellate ganglia and in 45/76 (59.2\%) of the celiac ganglia, whereas only 5/76 (6.6\%) of the sacral ganglia demonstrated \(^{18}\)F-DCFPyL accumulation. Similar findings were observed for patients with RCC, with the most frequent locations of radiotracer uptake in both the lumbar (20/22, 90.9\%) and cervical ganglia (19/ 22, 86.4\%). No laterality preference was found in mean PSMA-ligand uptake for either the PCa or RCC cohorts. Conclusion: As PSMA-targeted agents become more widely disseminated, the patterns of uptake in structures that are not directly relevant to patients' cancers must be understood. This is the first systematic evaluation of the uptake of \(^{18}\)F-DCFPyL in ganglia demonstrating a general trend with a descending frequency of radiotracer accumulation in lumbar, cervical, stellate, celiac, and sacral ganglia. The underlying biology that leads to variability of PSMA-targeted radiotracers in peripheral ganglia is not currently understood, but may provide opportunities for future research.},
  subject      = {Positronen-Emissions-Tomografie},
  language  = {en}
}