@article{WeichWernerBucketal.2021,
  author    = {Weich, Alexander and Werner, Rudolf A. and Buck, Andreas K. and Hartrampf, Philipp E. and Serfling, Sebastian E. and Scheurlen, Michael and Wester, Hans-J{\"u}rgen and Meining, Alexander and Kircher, Stefan and Higuchi, Takahiro and Pomper, Martin G. and Rowe, Steven P. and Lapa, Constantin and Kircher, Malte},
  title     = {CXCR4-Directed PET/CT in Patients with Newly Diagnosed Neuroendocrine Carcinomas},
  series = {Diagnostics},
  volume    = {11},
  journal   = {Diagnostics},
  number    = {4},
  issn      = {2075-4418},
  doi       = {10.3390/diagnostics11040605},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234231},
  year      = {2021},
  abstract  = {We aimed to elucidate the diagnostic potential of the C-X-C motif chemokine receptor 4 (CXCR4)-directed positron emission tomography (PET) tracer \(^{68}\)Ga-Pentixafor in patients with poorly differentiated neuroendocrine carcinomas (NEC), relative to the established reference standard \(^{18}\)F-FDG PET/computed tomography (CT). In our database, we retrospectively identified 11 treatment-na{\"i}ve patients with histologically proven NEC, who underwent \(^{18}\)F-FDG and CXCR4-directed PET/CT for staging and therapy planning. The images were analyzed on a per-patient and per-lesion basis and compared to immunohistochemical staining (IHC) of CXCR4 from PET-guided biopsies. \(^{68}\)Ga-Pentixafor visualized tumor lesions in 10/11 subjects, while \(^{18}\)F-FDG revealed sites of disease in all 11 patients. Although weak to moderate CXCR4 expression could be corroborated by IHC in 10/11 cases, \(^{18}\)F-FDG PET/CT detected significantly more tumor lesions (102 vs. 42; total lesions, n = 107; p < 0.001). Semi-quantitative analysis revealed markedly higher 18F-FDG uptake as compared to \(^{68}\)Ga-Pentixafor (maximum and mean standardized uptake values (SUV) and tumor-to-background ratios (TBR) of cancerous lesions, SUVmax: 12.8 ± 9.8 vs. 5.2 ± 3.7; SUVmean: 7.4 ± 5.4 vs. 3.1 ± 3.2, p < 0.001; and, TBR 7.2 ± 7.9 vs. 3.4 ± 3.0, p < 0.001). Non-invasive imaging of CXCR4 expression in NEC is inferior to the reference standard \(^{18}\)F-FDG PET/CT.},
  language  = {en}
}
@article{LinzBrandsKertelsetal.2021,
  author    = {Linz, Christian and Brands, Roman C. and Kertels, Olivia and Dierks, Alexander and Brumberg, Joachim and Gerhard-Hartmann, Elena and Hartmann, Stefan and Schirbel, Andreas and Serfling, Sebastian and Zhi, Yingjun and Buck, Andreas K. and K{\"u}bler, Alexander and Hohm, Julian and Lapa, Constantin and Kircher, Malte},
  title     = {Targeting fibroblast activation protein in newly diagnosed squamous cell carcinoma of the oral cavity - initial experience and comparison to [\(^{18}\)F]FDG PET/CT and MRI},
  series = {European Journal of Nuclear Medicine and Molecular Imaging},
  volume    = {48},
  journal   = {European Journal of Nuclear Medicine and Molecular Imaging},
  number    = {12},
  issn      = {1619-7070},
  doi       = {10.1007/s00259-021-05422-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-307246},
  pages     = {3951-3960},
  year      = {2021},
  abstract  = {Purpose While [\(^{18}\)F]-fluorodeoxyglucose ([\(^{18}\)F]FDG) is the standard for positron emission tomography/computed tomography (PET/CT) imaging of oral squamous cell carcinoma (OSCC), diagnostic specificity is hampered by uptake in inflammatory cells such as neutrophils or macrophages. Recently, molecular imaging probes targeting fibroblast activation protein α (FAP), which is overexpressed in a variety of cancer-associated fibroblasts, have become available and might constitute a feasible alternative to FDG PET/CT. Methods Ten consecutive, treatment-na{\"i}ve patients (8 males, 2 females; mean age, 62 ± 9 years) with biopsy-proven OSCC underwent both whole-body [\(^{18}\)F]FDG and [\(^{68}\)Ga]FAPI-04 (FAP-directed) PET/CT for primary staging prior to tumor resection and cervical lymph node dissection. Detection of the primary tumor, as well as the presence and number of lymph node and distant metastases was analysed. Intensity of tracer accumulation was assessed by means of maximum (SUV\(_{max}\)) and peak (SUV\(_{peak}\) standardized uptake values. Histological work-up including immunohistochemical staining for FAP served as standard of reference. Results [\(^{18}\)F]FDG and FAP-directed PET/CT detected all primary tumors with a SUVmax of 25.5 ± 13.2 (FDG) and 20.5 ± 6.4 (FAP-directed) and a SUVpeak of 16.1 ± 10.3 ([\(^{18}\)F]FDG) and 13.8 ± 3.9 (FAP-directed), respectively. Regarding cervical lymph node metastases, FAP-directed PET/CT demonstrated comparable sensitivity (81.3\% vs. 87.5\%; P = 0.32) and specificity (93.3\% vs. 81.3\%; P = 0.16) to [\(^{18}\)F]FDG PET/CT. FAP expression on the cell surface of cancer-associated fibroblasts in both primary lesions as well as lymph nodes metastases was confirmed in all samples. Conclusion FAP-directed PET/CT in OSCC seems feasible. Future research to investigate its potential to improve patient staging is highly warranted.},
  language  = {en}
}
@article{HaenscheidHartrampfSchirbeletal.2021,
  author    = {H{\"a}nscheid, Heribert and Hartrampf, Philipp E. and Schirbel, Andreas and Buck, Andreas K. and Lapa, Constantin},
  title     = {Intraindividual comparison of [\(^{177}\)Lu]Lu-DOTA-EB-TATE and [\(^{177}\)Lu]Lu-DOTA-TOC},
  series = {European Journal of Nuclear Medicine and Molecular Imaging},
  volume    = {48},
  journal   = {European Journal of Nuclear Medicine and Molecular Imaging},
  number    = {8},
  issn      = {1619-7089},
  doi       = {10.1007/s00259-020-05177-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265470},
  pages     = {2566-2572},
  year      = {2021},
  abstract  = {Purpose The radiolabelled somatostatin analogue [\(^{177}\)Lu]Lu-DOTA-EB-TATE binds to albumin via Evans blue, thereby increasing the residence time in the blood and potentially allowing more therapeutic agent to be absorbed into the target tissue during peptide receptor radionuclide therapy. It was tested in selected patients whether the substance is superior to [\(^{177}\)Lu]Lu-DOTA-TOC. Methods Activity kinetics in organs and tumours after [\(^{177}\)Lu]Lu-DOTA-EB-TATE and [\(^{177}\)Lu]Lu-DOTA-TOC were compared intraindividually in five patients with progressive somatostatin receptor-positive disease scheduled for radionuclide therapy. Resuluts In comparison to [\(^{177}\)Lu]Lu-DOTA-TOC, tumour doses per administered activity were higher for [\(^{177}\)Lu]Lu-DOTA-EB-TATE in 4 of 5 patients (median ratio: 1.7; range: 0.9 to 3.9), kidney doses (median ratio: 3.2; range: 1.6 to 9.8) as well as spleen doses (median ratio: 4.7; range 1.2 to 6.2) in all patients, and liver doses in 3 of 4 evaluable patients (median ratio: 4.0; range: 0.7 to 4.9). The tumour to critical organs absorbed dose ratios were higher after [\(^{177}\)Lu]Lu-DOTA-TOC in 4 of 5 patients. Conclusions Prior to a treatment with [\(^{177}\)Lu]Lu-DOTA-EB-TATE, it should be assessed individually whether the compound is superior to established substances.},
  language  = {en}
}
@article{HartrampfLapaSerflingetal.2021,
  author    = {Hartrampf, Philipp E. and Lapa, Constantin and Serfling, Sebastian E. and Buck, Andreas K. and Seitz, Anna Katharina and Meyer, Philipp T. and Ruf, Juri and Michalski, Kerstin},
  title     = {Development of Discordant Hypermetabolic Prostate Cancer Lesions in the Course of [\(^{177}\)Lu]PSMA Radioligand Therapy and Their Possible Influence on Patient Outcome},
  series = {Cancers},
  volume    = {13},
  journal   = {Cancers},
  number    = {17},
  issn      = {2072-6694},
  doi       = {10.3390/cancers13174270},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245168},
  year      = {2021},
  abstract  = {Simple Summary Discordant FDG-positive but PSMA-negative (FDG+/PSMA-) metastases constitute a negative prognostic marker of overall survival in patients undergoing PSMA radioligand therapy (RLT). The aim of this analysis was to investigate the prognostic implications of new FDG+/PSMA- lesions, which occur during or after PSMA RLT. In a retrospective bicentric analysis of 32 patients undergoing PSMA RLT and follow-up dual tracer staging with PSMA and FDG PET/CT, FDG+/PSMA- lesions occurred in a limited number of patients. However, the presence of FDG+/PSMA- lesions appears not to have a significant impact on the OS, but further studies are needed to establish the clinical relevance of such lesions. Abstract Introduction: Positron emission tomography/computer tomography (PET/CT) targeting the prostate-specific membrane antigen (PSMA) is crucial for the assessment of adequate PSMA expression in patients with metastatic castration-resistant prostate cancer (mCRPC) prior to PSMA radioligand therapy (PSMA RLT). Moreover, initial dual tracer staging using combined PSMA and [\(^{18}\)F]fluorodeoxyglucose (FDG) PET/CT provides relevant information, since discordant FDG-positive but PSMA-negative (FDG+/PSMA-) lesions constitute a negative prognostic marker of overall survival (OS) after PSMA RLT. However, little is known about the prognostic implications of dual tracer imaging for restaging at follow-up. The aim of this analysis was to investigate the prognostic implications of new FDG+/PSMA- lesions during or after PSMA RLT. Methods: This bicentric analysis included 32 patients with mCRPC who underwent both FDG and PSMA PET/CT imaging after two or four cycles of PSMA RLT. Patients with FDG+/PSMA- lesions prior to PSMA RLT were not considered. The presence of FDG+/PSMA- lesions was assessed with follow-up dual tracer imaging of patients after two or four cycles of PSMA RLT. Patients with at least one new FDG+/PSMA- lesion were compared to patients without any FDG+/PSMA- lesions at the respective time points. A log-rank analysis was used to assess the difference in OS between subgroups. Results: After two cycles of PSMA RLT, four of 32 patients (13\%) had FDG+/PSMA- metastases. No significant difference in OS was observed (p = 0.807), as compared to patients without FDG+/PSMA- lesions. Follow-up dual tracer imaging after the 4th cycle of PSMA RLT was available in 18 patients. Of these, four patients presented with FDG+/PSMA- findings (n = 2 already after two cycles). After the fourth cycle of PSMA RLT, no significant difference in OS was observed between patients with and without FDG+/PSMA- lesions (p = 0.442). Conclusion: This study shows that FDG+/PSMA- lesions develop in a limited number of patients undergoing PSMA RLT. Further studies are needed to establish the clinical relevance of such lesions.},
  language  = {en}
}
@article{EisslerWernerAriasLozaetal.2021,
  author    = {Eissler, Cristoph and Werner, Rudolf A. and Arias-Loza, Paula and Nose, Naoko and Chen, Xinyu and Pomper, Martin G. and Rowe, Steven P. and Lapa, Constantin and Buck, Andreas K. and Higuchi, Takahiro},
  title     = {The number of frames on ECG-gated \(^{18}\)F-FDG small animal PET has a significant impact on LV systolic and diastolic functional parameters},
  series = {Molecular Imaging},
  volume    = {2021},
  journal   = {Molecular Imaging},
  doi       = {10.1155/2021/4629459},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265778},
  year      = {2021},
  abstract  = {Objectives. This study is aimed at investigating the impact of frame numbers in preclinical electrocardiogram- (ECG-) gated \(^{18}\)F-fluorodeoxyglucose (\(^{18}\)F-FDG) positron emission tomography (PET) on systolic and diastolic left ventricular (LV) parameters in rats. Methods. \(^{18}\)F-FDG PET imaging using a dedicated small animal PET system with list mode data acquisition and continuous ECG recording was performed in diabetic and control rats. The list-mode data was sorted and reconstructed with different numbers of frames (4, 8, 12, and 16) per cardiac cycle into tomographic images. Using an automatic ventricular edge detection software, left ventricular (LV) functional parameters, including ejection fraction (EF), end-diastolic (EDV), and end-systolic volume (ESV), were calculated. Diastolic variables (time to peak filling (TPF), first third mean filling rate (1/3 FR), and peak filling rate (PFR)) were also assessed. Results. Significant differences in multiple parameters were observed among the reconstructions with different frames per cardiac cycle. EDV significantly increased by numbers of frames (353.8 \& PLUSMN; 57.7 mu l*, 380.8 \& PLUSMN; 57.2 mu l*, 398.0 \& PLUSMN; 63.1 mu l*, and 444.8 \& PLUSMN; 75.3 mu l at 4, 8, 12, and 16 frames, respectively; *P < 0.0001 vs. 16 frames), while systolic (EF) and diastolic (TPF, 1/3 FR and PFR) parameters were not significantly different between 12 and 16 frames. In addition, significant differences between diabetic and control animals in 1/3 FR and PFR in 16 frames per cardiac cycle were observed (P < 0.005), but not for 4, 8, and 12 frames. Conclusions. Using ECG-gated PET in rats, measurements of cardiac function are significantly affected by the frames per cardiac cycle. Therefore, if you are going to compare those functional parameters, a consistent number of frames should be used.},
  language  = {en}
}