AIM:TSH-receptor (TSHR)-autoantibody (TRAb) is the serological hallmark of Graves' disease (GD). Recently, 3rd-generation radioimmunoassays (RIA) employing monoclonal TRAb such as M22 or T7 instead of TSH for the inhibition of human TRAb binding with solid-phase TSHR (coated tubes) have been introduced into laboratory routine. METHODS:As current assays typically employ a consecutive incubation of patient serum and labelled monoclonal TRAb, automation of TRAb RIA is a challenge. Thus, the assay procedure using human TSHR-coated tubes and the mouse monoclonal TRAb T7 was modified by combining both steps. The novel one-step method was compared with its corresponding consecutive 3rd-generation RIA by investigating 304 individuals encompassing 102 patients with active GD (GDa), 43 patients with GD after successful therapy (GDt), 31 with Hashimoto's disease (HD), 28 with non-autoimmune thyroid diseases (NAITD) and 100 healthy subjects (HS). RESULTS:With the new method, the incubation time was shortened by approximately one hour. Both 3rd-generation RIAs did not reveal a significantly different assay performance by comparing areas under the curve (AUC) with receiver operating characteristics curve analysis (AUC one-step: 0.94, AUC two-step: 0.96, p > 0.05, respectively). The two-step TRAb RIA demonstrated sensitivity and specificity values of 87.5 % and 96.2 %, respectively, whereas the one-step revealed 84.6 % and 96.2 %, respectively. CONCLUSION:One-step 3rd-generation RIA may be used for the reliable detection of TRAb. The shorter and easier assay design may improve its use and enable automation in routine nuclear medicine laboratories.

Introduction: Radiation-induced DNA damage occurs from direct and indirect effects. The induction is influenced by the physical characteristics of the radionuclide, especially its linear energy transfer. Hypoxia reduces the effect of irradiation treatment in tumor cells and leads to poor patient outcomes. High linear energy transfer emitters can overcome this obstacle. Our aim is to demonstrate the influence of hypoxia on the interaction of different radiation qualities with isolated DNA. Methods: PuC19 Plasmid DNA was irradiated with Ra-223, Re-188, Tc-99m and Tc-99m-labeled pyrene with and without DMSO under hypoxia or normoxic conditions. DNA damages in form of single-(SSB) and double-strand breaks (DSB) were analyzed by gel electrophoresis. Results: Radiation doses up to 200 Gy of Ra-223, Re-188 and Tc-99m led to maximal yields of 80% SSB and 30%, 28% and 32% DSB, respectively. Hypoxia had minor effects on damages from Ra-223, but caused a small enhancement in DSB for Re-188 and Tc-99m. DMSO prevented DSB completely and reduced SSB from the "free" radionuclides to comparable levels. DNA-binding Tc-99m-labeled pyrene induced less SSB and DSB compared to [Tc-99m]TcO4-. However, the incubation with DMSO could prevent the SSB and DSB induction only to a minor extent. Conclusions: Hypoxia does not limit DNA damage induced by Ra-223, Re-188, Tc-99m and Tc-99m-labeled pyrene. Dose-dependent radiation effects were comparable for alpha-emitters and both high- and low-energy electron emitters. The radioprotection by DMSO was not influenced by hypoxia. The results indicate the contribution of mainly indirect radiation effects for Tc-99m, Re-188 and Ra-223. Tc-99m-labeled pyrene caused direct DNA damages and Auger-electrons from Tc-99m-labeled pyrene are more effective than high-energy electrons or alpha particles. Advances in knowledge: Without the consideration of DNA repair mechanisms, oxygen has no direct influence in radiation-induced DNA damages by different radiation qualities. Implications for patient care: The short-time stimulation with oxygen during patient radiation could have minor influence compared to constant oxygen flooding to overcome hypoxic barriers. (C) 2020 Elsevier Inc. All rights reserved.

Ziel/Aim Strahlung verursacht unterschiedliche komplexe DNA-Schäden durch direkte und indirekte Effekte, wobei physikalische Eigenschaften der Strahlung maßgeblich sind, insbesondere der Lineare Energietransfer (LET). Hypoxie in Tumoren stellt eine wesentliche Limitation der Strahlentherapie dar. Daher soll die Wechselwirkung von Hypoxie und unterschiedlichen Strahlenqualitäten an isolierter Plasmid-DNA in An- und Abwesenheit des Radikalfängers DMSO untersucht werden.

Zusammenfassung Ziel Vor dem Hintergrund der neuen Strahlenschutzverordnung (StrlSchV) ist es sinnvoll, sich erneut einen Überblick über die Strahlenexposition des Personals bei Radiopharmakaherstellungen im radiopharmazeutischen Labor zu verschaffen. Dabei soll die Strahlenexposition im Bereich der Herstellung und Anwendung von Radiopharmaka erfasst werden, um Tätigkeiten mit hoher Exposition zu identifizieren und Arbeitsabläufe zu optimieren. In der Klinik und Poliklinik für Nuklearmedizin am Universitätsklinikum an der TU Dresden wurden dazu Messungen mit optisch stimulierten Lumineszenzdosimetern (OSL) durchgeführt. Material und Methode Es wurden lichtgeschützte OSL-Dosimeter auf die Fingerkuppen von Daumen, Zeigefinger und Mittelfinger beider Hände und auf der Stirn platziert. Jedes OSL-Dosimeter war zuvor kalibriert worden. Untersucht wurde die Teilkörperexposition der Hände im Präparationslabor bei: 99mTc-Präparationen im Routinebetrieb, Aufziehen von Spritzen zur Radiosynoviorthese und von 90Y-Sirtex-Partikeln sowie Herstellung von 177Lu- und 68Ga-Präparaten. Ergebnisse Es zeigte sich, dass die 99mTc-Präparationen zu einer relativ hohen Exposition führen aufgrund der Zahl der Präparationen und der Zahl an aufgezogenen Spritzen. Das Aufziehen der RSO-Spritzen führt in Abhängigkeit von der Zahl der zu füllenden Spritzen ebenfalls zu nennenswerter Handbelastung. Im Gegensatz dazu ist das Aufziehen der Sirtex-Partikel wenig belastend. Die Strahlenexposition bei 177Lu- und 68Ga-Präparationen hängt insbesondere vom Handling bei der Herstellung, der Verwendung von Modulen und der Art der Qualitätskontrolle ab. Bei der Ermittlung der Augenlinsenexposition wurden mit einer Ausnahme unkritische 0,02 mGy oder weniger gemessen.

Ga-68-PSMA ist der Goldstandard in der metabolischen Bildgebung des Prostatakarzinoms. Nicht in jedem Fall können Rezidive, primäre Tumormanifestationen oder Metastasen damit detektiert werden, was auch therapeutische Konsequenzen nach sich zieht (Lu-177-PSMA). Aus diesem Grund untersuchten wir den Bombesin-Antagonisten Ga-68-RM2 auf einen diagnostischen Benefit.

Regardless of its high positron energy, 68 Ga-labeled PSMA ligands have become standard of care in metabolic prostate cancer imaging. 64 Cu, a radionuclide with a much longer half-life (12.7 h), is available for PSMA labeling allowing imaging much later than 68 Ga. In this study, the diagnostic performance of 64 Cu-labeled PSMA was compared between early and late scans. Sixteen men (median age: 70 y) with prostate cancer in different stages underwent 64 Cu-PSMA-617-PET/CT 2 and 22 hours post tracer injection. Pathologic and physiologic uptakes were analyzed for both points of time. Pathologic tracer accumulations occurred in 12 patients. Five patients presented with pathologic uptake in 17 different lymph nodes, two patients showed pathologic bone uptake in nine lesions, and seven patients had pathologic PSMA uptake in eight prostatic lesions. Physiologic uptake of the renal parenchyma, urine bladder, and salivary glands decreased over time, while the physiologic uptake of liver and bowel increased. In the present study, 64 Cu-PSMA-617-PET demonstrated to be feasible for imaging prostate cancer for both the primary tumor site and metastases. Later imaging showed no additional, clinically relevant benefit compared with the early scans. At least the investigated time points we chose did not vindicate the additional expenditure.

REPLY: We would like to thank Dr. Kotzerke and his colleagues for the important insights into the uptake of DOTA-EB-TATE, an albumin-binding octreotate developed by us ([1][1]–[4][2]). The results presented by Dr. Kotzerke are of high importance, suggesting that the radiometal chelated into the

Evans Blue (EB) konjugierte DOTA-EB-TATE-Moleküle binden an Albumin, zirkulieren länger im Blut und akkumulieren effektiver im Tumor als die unkonjugierten DOTA-TATE-Verbindungen. In vivo können die pharmakokinetischen Eigenschaften von radiomarkiertem DOTA-EB-TATE zur Reduzierung der Nierentoxizität bei Peptidradiorezeptortherapie (PRRT) im Vergleich zu Lu-177/Y-90-DOTA-TATE führen. Ziel ist die Untersuchung des Uptakes der DOTA-EB-TATE- und DOTA-TATE-Radiotracer in vitro an somatostatinrezeptor-positiven Zellen (HEK293-sstr2) in Abhängigkeit vom Radionuklid.

Purpose We investigated whether propidium iodide (PI) enhances DNA damaging effects of ionizing and non-ionizing radiation species (X-rays, alpha-, beta-, auger electron emission and light of various wavelengths, respectively). This biophysical experimental setting allowed us, furthermore, to investigate whether Cherenkov emission can be detected by photodynamic effects and increased DNA damage. Material and methods Conformation changes of plasmid DNA were detected and quantified by gelelectrophoresis and fluorescence imaging. Hydrogen peroxide, stannous dichloride, and dimethylsulfoxide were used as chemical modulators, Tc-99m, Re-188, Ra-223, and x-ray (32 kV and 200 kV) reflected radiotoxicity and light (lambda = 254 nm, 366 nm and 530-575 nm) induced phototoxicity. Results Radiotracers and x-rays induced dose dependent DNA damage. PI did not serve as radiosensitizer in radioisotopes, while a low effect was detected in X-rays. The phototoxicity was dependent on the wavelengths of light. Light with a wavelength range of 530-575 nm in combination with PI resulted in direct DNA damage. The yield of Cherenkov emission was far below the photon emission of light irradiation and not distinguishable from general radiotoxicity. Conclusions PI binds to plasmid DNA, is not chemotoxic, and increases radiotoxicity only to minor extent. Phototoxicity and its stimulation by PI is dependent on the wavelength of the light. No kind of energy deposition was capable of inducing an Auger electron cascade. Furthermore, no increase in DNA damage induced by photodynamic effects from Cherenkov emission was detectable.

Zusammenfassung Ziel Untersucht wurde, ob Propidiumiodid (PI) die DNA-schädigende Wirkung von ionisierender und nicht ionisierender Strahlung (Röntgenstrahlung, Alpha-, Beta-, Auger-Elektronen-Strahlung bzw. Licht diverser Wellenlängen) verstärken kann. Diese biophysikalische Versuchsanordnung ermöglicht es zu überprüfen, ob Cherenkov-Strahlung in relevantem Umfang via photodynamischer Effekte und erhöhter DNA-Schädigung nachweisbar ist. Material und Methoden Konformationsänderungen der Plasmid-DNA durch DNA-Schäden wurden mittels Gelelektrophorese und Fluoreszenzfärbung detektiert und quantifiziert. Wasserstoffperoxid, Zinndichlorid und Dimethylsulfoxid wurden als chemische Modulatoren, Tc-99m, Re-188, Ra-223 und Röntgenstrahlung (32 kV und 200 kV) zur Bestimmung der Radiotoxizität und Licht (λ = 254 nm, 366 nm und 530–575 nm) zur Bestimmung der Phototoxizität eingesetzt. Ergebnisse Die Radiotracer und die Röntgenstrahlung verursachten dosisabhängige DNA-Schäden. PI fungierte nicht als Radio-Sensitizer bei den Radionukliden und nur in geringem Maß bei Röntgenstrahlung. Die Phototoxizität war abhängig von der Wellenlänge. Licht im Wellenlängenbereich von 530–575 nm (VIS) resultierte in Kombination mit PI in direkten DNA-Schäden. Die Ausbeuten der Cherenkov-Strahlung lagen weit unter der Photonen-Emission der Lichtbestrahlung und konnten daher von der Radiotoxizität nicht unterschieden werden. Schlussfolgerung PI bindet an Plasmid-DNA, ist nicht chemotoxisch und steigert kaum die Radiotoxizität. Die Phototoxizität und die Wirkung von PI sind abhängig von der Wellenlänge. Keine Art der Energiezufuhr konnte via PI eine Auger-Elektronen-Kaskade induzieren. Auch eine erhöhte DNA-Schädigung durch photodynamische Effekte via Cherenkov-Strahlung war nicht nachweisbar.

Chimeric antigen receptor (CAR) T cells have shown impressive therapeutic potential. Due to the lack of direct control mechanisms, therapy-related adverse reactions including cytokine release- and tumor lysis syndrome can even become life-threatening. In case of target antigen expression on non-malignant cells, CAR T cells can also attack healthy tissues. To overcome such side effects, we have established a modular CAR platform termed UniCAR: UniCAR T cells per se are inert as they recognize a peptide epitope (UniCAR epitope) that is not accessible on the surface of living cells. Bifunctional adapter molecules termed target modules (TM) can cross-link UniCAR T cells with target cells. In the absence of TMs, UniCAR T cells automatically turn off. Until now, all UniCAR TMs were constructed by fusion of the UniCAR epitope to an antibody domain. To open up the wide field of low-molecular-weight compounds for retargeting of UniCAR T cells to tumor cells, and to follow in parallel the progress of UniCAR T cell therapy by PET imaging we challenged the idea to convert a PET tracer into a UniCAR-TM. For proof of concept, we selected the clinically used PET tracer PSMA-11, which binds to the prostate-specific membrane antigen overexpressed in prostate carcinoma. Here we show that fusion of the UniCAR epitope to PSMA-11 results in a low-molecular-weight theranostic compound that can be used for both retargeting of UniCAR T cells to tumor cells, and for non-invasive PET imaging and thus represents a member of a novel class of theranostics.

& xfeff;Aim (68) Ga-PSMA-11 is the gold standard for molecular imaging of prostate cancer. However, recurrent tumor manifestations or metastases cannot be detected in every case. Therefore, we investigated if there is an additive value of the gastrin-releasing peptide receptor (GRP-R) ligand (68) Ga-RM2 compared to the well-established (68) Ga-PSMA-11 in patients with (Group 1) and without (Group 2) pathologic PSMA-expression in different tumor stages. Patients and Methods Sixteen men (median age: 74 years, range 50-80 years) with prostate cancer in different stages who had a recent negative (n = 8) or pathologic (n = 8) PSMA PET underwent a subsequent (68) Ga-RM2 PET. Both examinations were analyzed qualitatively and quantitatively and compared in terms of pathologic and physiologic tracer distribution. Results None of the PSMA-negative patients showed any pathological RM2-accumulation. Pathologic PSMA-uptake was observed in 8 patients of whom 5 had pathologic RM2-uptake. The number of patients with a local recurrence was equal in both scans (n = 3). Bone metastases and lymph node metastases were detected in less patients in RM2 PET compared to PSMA PET (n = 4 vs. 7 and n = 2 vs. 5, respectively). In one patient, PSMA-positive liver metastases were not detected in RM2. RM2 PET revealed two additional lesions indicative for bone metastases in two patients with multiple PSMA-positive bone metastases, which had no therapeutic consequence. Conclusion At least in our small and heterogeneous patient population, (68) Ga-RM2 showed no clinically relevant, additional benefit compared to (68) Ga-PSMA-11 PET.

We have recently reported on our experience with C-X-C-motif chemokine receptor 4 (CXCR4)–directed radioligand therapy (RLT) in multiple myeloma and acute leukemia. Methods: Six patients with heavily pretreated relapsed diffuse large B-cell lymphoma (3 men, 3 women; aged, 54 ± 8 y) underwent CXCR4-directed RLT in combination with conditioning chemotherapy and allogeneic stem cell transplantation. In 2 patients, radioimmunotherapy targeting CD20 or CD66 was added to enhance antilymphoma activity. Endpoints were incidence and severity of adverse events, progression-free survival, and overall survival. Results: RLT and additional radioimmunotherapy were well tolerated, without any acute adverse events or changes in vital signs. Successful engraftment was recorded after a median of 11 d (range, 9–13 d). Of the 4 patients who were available for follow-up (one patient died of CNS aspergillosis 29 d after RLT and another of sepsis in aplasia 34 d after RLT), CXCR4-directed RLT resulted in a partial response in two (both treated with additional radioimmunotherapy) and a mixed response in the remaining two. The response duration was rather short-lived, with a median progression-free survival of 62 d (range, 29–110 d) and a median overall survival of 76 d (range, 29–334 d). Conclusion: CXCR4-directed RLT (in combination with additional radioimmunotherapy) is feasible as a conditioning regimen before allogeneic stem cell transplantation in diffuse large B-cell lymphoma.

TSH receptor (TSHR) autoantibody (TRAb) is the serological hallmark of Graves' disease (GD). Third-generation enzyme-linked immunosorbent assays (ELISAs) using monoclonal TRAbs instead of TSH have been found useful for TRAb analysis recently. For the first time, a mouse monoclonal antibody (mAb) against TSHR was analyzed for TRAb detection and compared with human mAb M22 and TSH by the same competitive binding assay technique. A mouse monoclonal antibody (T7) binding to the TSH receptor and inhibiting TSH binding was generated and used for TRAb analysis in a third-generation ELISA. Obtained TRAb levels were compared with a second-generation TRAb assay employing bovine TSH and a third-generation assay with human mAb M22 as TSHR-binding reagents by investigating 89 patients with GD, 56 with Hashimoto's thyroiditis (HT), 73 with non-autoimmune thyroid diseases, 17 with rheumatoid arthritis, and 100 healthy subjects. The T7-based TRAb ELISA did not reveal a significantly different assay performance (area under the curve [AUC]) in contrast to the TSH and M22-based TRAb ELISAs by receiver operating characteristic (ROC) curve analysis (AUC-T7 0.967, AUC-TSH 0.972, AUC-M22 0.958, p>0.05, respectively). After adjustment of cutoffs by ROC, all three TRAb ELISAs demonstrated sensitivities and specificities above 89.9% and 96.0%, respectively. Both third-generation TRAb ELISAs showed a tendency for a higher prevalence of TRAb positives in HT in contrast to the second-generation ELISA. Mouse mAbs against the TSHR may be used for the reliable detection of TRAb by third-generation TRAb ELISA. The earlier reported higher sensitivity of third-generation TRAb ELISA in GD needs to be considered in the context of a slightly lower specificity regarding HT.

Zusammenfassung Ziel: Eine kombinierte interne-externe Radiotherapie (CIERT) erfordert eine einheitliche Betrachtung der biologischen Strahlenwirkung. Dafür sollte der Formalismus der Biologisch Effektiven Dosis (BED) am Zellmodell überprüft werden. Methoden: NIS-positive Schilddrüsenzellen FRTL-5 wurden mit Röntgenstrahlung oder/und mit Tc-99m-Pertechnetat bestrahlt. Anoder Abwesenheit von Perchlorat konnte die aktive zelluläre Aufnahme des Radiotracers während 24 h Bestrahlungsdauer verhindern oder zulassen. Die Dosisbestimmung für die Radionuklidbestrahlung erfolgte auf Basis gemessener Uptakewerte mittels Monte-Carlo-Simulation. Aus Dosiswirkungskurven mit Koloniebildungs-Assay als biologischem Endpunkt wurden zellspezifische radiobiologische Parameter abgeleitet. Für Kombinationsbestrahlungen unter Variation von Reihenfolge und Zeitabstand wurde das Zellüberleben mit Vorhersagewerten des BED-Formalismus verglichen. Ergebnisse: Die für Röntgenbestrahlung ermittelten Parameter α = (0,22 ± 0,02) Gy-1, β = (0,021 ± 0,001) Gy-2 und Reparaturhalbwertszeit (1,51 ± 0,21) h erklären auch die Dosiswirkungskurven für Tc-99m-Pertechnetat mit exponentiell fallender Dosisleistung. Die CIERT-Experimente zeigten keine signifikanten Unterschiede bezüglich Reihenfolge und Bestrahlungspause, jedoch bei Radionuklidaufnahme in die Zellen ein geringeres Überleben als durch die BED vorhergesagt. Schlussfolgerung: Am Zellmodell konnte verifiziert werden, dass die BED grundsätzlich zur Beschreibung von biologischen Strahleneffekten bei unterschiedlichen Strahlenqualitäten und Dosisleistungen anwendbar ist. Ob bei intrazellulärer Radionuklidaufnahme in Kombination mit Röntgenbestrahlung supraadditive Effekte entstehen, die auf Auger- und Konversionselektronen des Tc-99m zurückzuführen sind, bedarf weiterer Experimente.

Aim: Combined internal-external radiotherapy (CIERT) requires a unified assessment of biologic radiation effects in addition to the total dose. The concept of biological effective dose (BED) was evaluated in a cell model. Methods: The thyroid NIS-positive cell line FRTL-5 was irradiated with X-ray and the radiotracer Tc-99m pertechnetate either alone or in combination. The cellular uptake of the radionuclide during the incubation time of 24 h was controlled by the presence or absence of perchlorate. Dose calculation was performed based on measured uptake values. Cell specific radiobiologic parameters were derived from dose effect curves using the colony forming assay as biological endpoint. For the combination of the radiation qualities the sequence and time difference were varied. Cell survival was compared with the prediction of the BED model. Results: The radiobiologic parameters from X-ray dose response were alpha = (0.22 +/- 0.02) Gy(-1) and beta = (0.021 +/- 0.001) Gy(-2). The half life for repair was (1.51 +/- 0.21) h. These values could also explain the dose response curves for Tc-99m- irradiation with exponential decreasing dose rate. CIERT experiments showed no significant differences in cell survival regarding sequence and irradiation break. When the radionuclide uptake was not prevented the cell survival for the combination of X-ray and Tc-99m was lower than the prediction by BED calculations. Conclusions: The validity of the BED formalism for different dose rates and radiation qualities was verified. Supraaddive effects measured in the combination of X-ray and intracellular Tc-99m might be caused by Auger and conversion electrons, however further experiments are necessary.

In the above-mentioned article, the Supportive Care paragraph in the Methods section was printed incorrectly. The correct text should read: Antifungal and antiviral prophylaxis was performed with 2 × 200 mg fluconazole/day and acyclovir 3 × 200 mg/day starting on day -7. Trimethoprim-sulfamethoxazole was administered twice each week before starting RIC and after hematologic engraftment. Cytomegalovirus (CMV) plasma DNA was monitored twice weekly and pre-emptive therapy with ganciclovir was started in case of positivity. In the Discussion section, the isotope discussed should read “213-Bi” (bismuth, rather than Be, which stands for beryllium). The correct statement should read: Anti-CD33 mAbs, which get internalized, linked with an a-emitter (213-Bi or 225Ac) should in theory act more efficiently [33,34]. Reduced-Intensity Conditioning Combined with 188Rhenium Radioimmunotherapy before Allogeneic Hematopoietic Stem Cell Transplantation in Elderly Patients with Acute Myeloid Leukemia: The Role of In Vivo T Cell DepletionBiology of Blood and Marrow TransplantationVol. 21Issue 10PreviewThe combination of reduced-intensity conditioning, 188rhenium anti-CD66 radioimmunotherapy, and in vivo T cell depletion was successfully applied in elderly patients with acute myeloid leukemia or myelodysplastic syndrome. Within a prospective phase II protocol, we investigated whether a dose reduction of alemtuzumab (from 75 mg to 50 mg MabCampath) would improve leukemia-free survival by reducing the incidence of relapse. Fifty-eight patients (median age, 67 years; range, 54 to 76) received radioimmunotherapy followed by fludarabine 150 mg/m2 and busulfan 8 mg/kg combined with either 75 mg (n = 26) or 50 mg (n = 32) alemtuzumab. Full-Text PDF Open Archive