TY  - JOUR
A1  - Werner, Rudolf A.
A1  - Weich, Alexander
A1  - Higuchi, Takahiro
A1  - Schmid, Jan S.
A1  - Schirbel, Andreas
A1  - Lassmann, Michael
A1  - Wild, Vanessa
A1  - Rudelius, Martina
A1  - Kudlich, Theodor
A1  - Herrmann, Ken
A1  - Scheurlen, Michael
A1  - Buck, Andreas K.
A1  - Kropf, Saskia
A1  - Wester, Hans-Jürgen
A1  - Lapa, Constantin
T1  - Imaging of Chemokine Receptor 4 Expression in Neuroendocrine Tumors - a Triple Tracer Comparative Approach
JF  - Theranostics
N2  - 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.
KW  - SSTR
KW  - peptide receptor radionuclide therapy
KW  - neuroendocrine tumor
KW  - [\(^{68}\)Ga]Pentixafor
KW  - CXCR4
KW  - chemokine receptor
KW  - PET/CT
KW  - DOTATOC
KW  - PRRT
KW  - Positronen-Emissions-Tomografie
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158008
VL  - 7
IS  - 6
ER  - 
TY  - JOUR
A1  - Schumann, Sarah
A1  - Scherthan, Harry
A1  - Frank, Torsten
A1  - Lapa, Constantin
A1  - Müller, Jessica
A1  - Seifert, Simone
A1  - Lassmann, Michael
A1  - Eberlein, Uta
T1  - DNA Damage in Blood Leukocytes of Prostate Cancer Patients Undergoing PET/CT Examinations with [\(^{68}\)Ga]Ga-PSMA I&T
JF  - Cancers
N2  - The aim was to investigate the induction and repair of radiation-induced DNA double-strand breaks (DSBs) as a function of the absorbed dose to the blood of patients undergoing PET/CT examinations with [68Ga]Ga-PSMA. Blood samples were collected from 15 patients before and at four time points after [68Ga]Ga-PSMA administration, both before and after the PET/CT scan. Absorbed doses to the blood were calculated. In addition, blood samples with/without contrast agent from five volunteers were irradiated ex vivo by CT while measuring the absorbed dose. Leukocytes were isolated, fixed, and stained for co-localizing γ-H2AX+53BP1 DSB foci that were enumerated manually. In vivo, a significant increase in γ-H2AX+53BP1 foci compared to baseline was observed at all time points after administration, although the absorbed dose to the blood by 68Ga was below 4 mGy. Ex vivo, the increase in radiation-induced foci depended on the absorbed dose and the presence of contrast agent, which could have caused a dose enhancement. The CT-dose contribution for the patients was estimated at about 12 mGy using the ex vivo calibration. The additional number of DSB foci induced by CT, however, was comparable to the one induced by 68Ga. The significantly increased foci numbers after [68Ga]Ga-PSMA administration may suggest a possible low-dose hypersensitivity.
KW  - DNA double-strand breaks
KW  - γ-H2AX
KW  - 53BP1
KW  - nuclear medicine
KW  - dosimetry
KW  - Ga-68
KW  - PSMA
KW  - PET/CT
KW  - contrast agent
KW  - prostate cancer
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200585
SN  - 2072-6694
VL  - 12
IS  - 2
ER  -