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[177Lu]Lu-Ibu-DAB-PSMA was previously characterized with moderate albumin-binding properties enabling high tumor accumulation but reasonably low retention in the blood. The aim of this study was to investigate [177Lu]Lu-Ibu-DAB-PSMA in preclinical in vivo experiments and compare its therapeutic efficacy and potential undesired side effects with those of [177Lu]Lu-PSMA-617 and the previously developed [177Lu]Lu-PSMA-ALB-56. BALB/c nude mice without tumors were investigated on Day 10 and 28 after injection of 10 MBq radioligand. It was revealed that most plasma parameters were in the same range for all groups of mice and histopathological examinations of healthy tissue did not show any alternations in treated mice as compared to untreated controls. Based on these results, a therapy study over twelve weeks was conducted with PC-3 PIP tumor-bearing mice for comparison of the radioligands’s therapeutic efficacy up to an activity of 10 MBq (1 nmol) per mouse. In agreement with the increased mean absorbed tumor dose, [177Lu]Lu-Ibu-DAB-PSMA (~ 6.6 Gy/MBq) was more effective to inhibit tumor growth than [177Lu]Lu-PSMA-617 (~ 4.5 Gy/MBq) and only moderately less potent than [177Lu]Lu-PSMA-ALB-56 (~ 8.1 Gy/MBq). As a result, the survival of mice treated with 2 MBq of an albumin-binding radioligand was significantly increased (p, European Journal of Nuclear Medicine and Molecular Imaging, 49 (11), ISSN:1619-7070, ISSN:1619-7089

Purpose Various preclinical study designs are described in the literature for the evaluation of PSMA radioligands. In this study, [177Lu]Lu-Ibu-DAB-PSMA, an albumin-binding radioligand, and [177Lu]Lu-PSMA-617 were investigated and compared under variable experimental conditions. Methods In vitro cell uptake studies were performed with PC-3 PIP and LNCaP tumor cells using a range of molar concentrations (0.75–500 nM) of both radioligands. Biodistribution and SPECT/CT imaging studies were carried out with the respective tumor mouse models using 0.05 nmol and 1.0 nmol injected ligand per mouse. Results In both tumor cell lines, the uptake of the radioligands was increased when using low molar concentrations of the respective ligand. The observed saturation effect at high ligand concentrations was more pronounced for LNCaP cells that express PSMA at lower levels than for PC-3 PIP cells. At all investigated timepoints, the in vivo uptake of both radioligands was higher in PC-3 PIP tumors than in LNCaP tumors. A low molar amount of injected ligand increased the PC-3 PIP tumor uptake mainly for [177Lu]Lu-Ibu-DAB-PSMA; however, the molar amount of ligand was relevant for both radioligands when using LNCaP tumors. Renal retention of both radioligands was, however, up to fourfold higher during the first hours after application of a low ligand amount compared to the high ligand amount. Conclusion The results of this preclinical study underline the relevance of the tumor model and applied ligand amount for the characterization of PSMA radioligands. The application of equal preclinical study designs is crucial to allow the comparison of novel radioligands with existing ones and, thus, predict potential advantages of new radioligands in view of a clinical application. ISSN:1619-7070 ISSN:1619-7089

Purpose The prostate-specific membrane antigen (PSMA) has emerged as an interesting target for radionuclide therapy of metastasized castration-resistant prostate cancer (mCRPC). The aim of this study was to investigate 161Tb (T1/2 = 6.89 days; Eβ-uperscript>av = 154 keV) in combination with PSMA-617 as a potentially more effective therapeutic alternative to 177Lu-PSMA-617, due to the abundant co-emission of conversion and Auger electrons, resulting in an improved absorbed dose profile. Methods 161Tb was used for the radiolabeling of PSMA-617 at high specific activities up to 100 MBq/nmol. 161Tb-PSMA-617 was tested in vitro and in tumor-bearing mice to confirm equal properties, as previously determined for 177Lu-PSMA-617. The effects of 161Tb-PSMA-617 and 177Lu-PSMA-617 on cell viability (MTT assay) and survival (clonogenic assay) were compared in vitro using PSMA-positive PC-3 PIP tumor cells. 161Tb-PSMA-617 was further investigated in therapy studies using PC-3 PIP tumor-bearing mice. Results 161Tb-PSMA-617 and 177Lu-PSMA-617 displayed equal in-vitro properties and tissue distribution profiles in tumor-bearing mice. The viability and survival of PC-3 PIP tumor cells were more reduced when exposed to 161Tb-PSMA-617 as compared to the effect obtained with the same activities of 177Lu-PSMA-617 over the whole investigated concentration range. Treatment of mice with 161Tb-PSMA-617 (5.0 MBq/mouse and 10 MBq/mouse, respectively) resulted in an activity-dependent increase of the median survival (36 vs 65 days) compared to untreated control animals (19 days). Therapy studies to compare the effects of 161Tb-PSMA-617 and 177Lu-PSMA-617 indicated the anticipated superiority of 161Tb over 177Lu. Conclusion 161Tb-PSMA-617 showed superior in-vitro and in-vivo results as compared to 177Lu-PSMA-617, confirming theoretical dose calculations that indicate an additive therapeutic effect of conversion and Auger electrons in the case of 161Tb. These data warrant more preclinical research for in-depth investigations of the proposed concept, and present a basis for future clinical translation of 161Tb-PSMA-617 for the treatment of mCRPC. Electronic supplementary material The online version of this article (10.1007/s00259-019-04345-0) contains supplementary material, which is available to authorized users.

The β−-particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating 169Er from 168Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure 169Er. The quality of the 169Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a 169Er-PSMA-617, to show the potential of 169Er to reduce tumor cell viability., Frontiers in Medicine, 8, ISSN:2296-858X

Additional file 3: S3. Participants and injections data.

Additional file 5: S5. Supplementary Material

Additional file 4: Figure S4. Patient MIP images at 60 min using the same SUV scale for all images (0–5 g/mL).

Additional file 6: Figure S6. Time-activity curves (TAC), %IA/g and %IA/g corrected for 18F physical decay for all tumor analyzed (T#). In bracket, we indicated the patient identifier (P#).

Additional file 1: Figure S1. Segmented VOI obtained with PMOD software co-registered on the CT of the patient represented in Figure 1.

Background: Interstitial lung disease (ILD) is a common and severe complication in rheumatic diseases. Folate receptor-β is expressed on activated, but not resting macrophages which play a key role in dysregulated tissue repair including ILD. We therefore aimed to pre-clinically evaluate the potential of 18F-AzaFol-based PET/CT (positron emission computed tomography/computed tomography) for the specific detection of macrophage-driven pathophysiologic processes in experimental ILD. Methods: The pulmonary expression of folate receptor-β was analyzed in patients with different subtypes of ILD as well as in bleomycin (BLM)-treated mice and respective controls using immunohistochemistry. PET/CT was performed at days 3, 7, and 14 after BLM instillation using the 18F-based folate radiotracer 18F-AzaFol. The specific pulmonary accumulation of the radiotracer was assessed by ex vivo PET/CT scans and quantified by ex vivo biodistribution studies. Results: Folate receptor-β expression was 3- to 4-fold increased in patients with fibrotic ILD, including idiopathic pulmonary fibrosis and connective tissue disease-related ILD, and significantly correlated with the degree of lung remodeling. A similar increase in the expression of folate receptor-β was observed in experimental lung fibrosis, where it also correlated with disease extent. In the mouse model of BLM-induced ILD, pulmonary accumulation of 18F-AzaFol reflected macrophage-related disease development with good correlation of folate receptor-β positivity with radiotracer uptake. In the ex vivo imaging and biodistribution studies, the maximum lung accumulation was observed at day 7 with a mean accumulation of 1.01 ± 0.30% injected activity/lung in BLM-treated vs. control animals (0.31 ± 0.06% % injected activity/lung; p < 0.01). Conclusion: Our preclinical proof-of-concept study demonstrated the potential of 18F-AzaFol as a novel imaging tool for the visualization of macrophage-driven fibrotic lung diseases.

Background: Interstitial lung disease (ILD) is a common and severe complication in rheumatic diseases. Folate receptor-β is expressed on activated, but not resting macrophages which play a key role in dysregulated tissue repair including ILD. We therefore aimed to pre-clinically evaluate the potential of 18F-AzaFol-based PET/CT (positron emission computed tomography/computed tomography) for the specific detection of macrophage-driven pathophysiologic processes in experimental ILD. Methods: The pulmonary expression of folate receptor-β was analyzed in patients with different subtypes of ILD as well as in bleomycin (BLM)-treated mice and respective controls using immunohistochemistry. PET/CT was performed at days 3, 7, and 14 after BLM instillation using the 18F-based folate radiotracer 18F-AzaFol. The specific pulmonary accumulation of the radiotracer was assessed by ex vivo PET/CT scans and quantified by ex vivo biodistribution studies. Results: Folate receptor-β expression was 3- to 4-fold increased in patients with fibrotic ILD, including idiopathic pulmonary fibrosis and connective tissue disease-related ILD, and significantly correlated with the degree of lung remodeling. A similar increase in the expression of folate receptor-β was observed in experimental lung fibrosis, where it also correlated with disease extent. In the mouse model of BLM-induced ILD, pulmonary accumulation of 18F-AzaFol reflected macrophage-related disease development with good correlation of folate receptor-β positivity with radiotracer uptake. In the ex vivo imaging and biodistribution studies, the maximum lung accumulation was observed at day 7 with a mean accumulation of 1.01 ± 0.30% injected activity/lung in BLM-treated vs. control animals (0.31 ± 0.06% % injected activity/lung; p < 0.01). Conclusion: Our preclinical proof-of-concept study demonstrated the potential of 18F-AzaFol as a novel imaging tool for the visualization of macrophage-driven fibrotic lung diseases., Frontiers in Immunology, 10, ISSN:1664-3224

Table S1. Chemical admixtures of 160Gd2O3, provided by the supplier (Isoflex, USA). Table S2. Long-lived radioactive tracers used for bench experiments. Figure S1. Elution profile of Tb/Gd separation from the target material (10 mm x 170 mm Sykam resin column, 0.6 mL/min eluent flow rate). Experiment 1 (a) was run without addition of natGd2O3, while Experiment 2 (b) was performed with the addition of 140 mg natGd2O3. Figure S2. Elution profile of Tb separation from the target material (Gd) and the impurities of the target material (10 mm x 170 mm Sykam resin column, 0.6 mL/min eluent flow rate). Experiment 3 (a) 65Zn and 22Na were added to the system as impurities. Experiment 4 (b) 59Fe, 51Cr and 65Ni were added to the system as impurities. Figure S3. Elution profile of Tb separation from Cr as a possible radioactive impurity in the final 161Tb product (6 mm x 5mm LN3 resin column, 0.6 mL/min eluent flow rate). Figure S4. Gamma spectrum of the decayed product (161TbCl3) used for the determination of 160Tb radionuclidic impurity in the total 161Tb fraction. No other radionuclides, other than 160Tb were found. Figure S5. Radio TLC chromatogram of 161TbCl3 solution in 0.1 M sodium citrate (pH 5.5) for the determination of 161Tb radiochemical purity. (DOCX 911 kb)

Orientador: Maria Beatriz Duarte Gavião Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba Resumo: A dor crônica associada aos tecidos moles e a dor miofascial são responsáveis por grande impacto na função do organismo, gerando incapacidade, determinada pela presença de pontos-gatilho (PGs). A cefaleia do tipo tensão (CTT) é a dor de cabeça mais frequente em adultos, comumente relacionada à presença de PGs nos músculos da cabeça e pescoço. Novas tecnologias vêm sendo testadas para o diagnóstico complementar de PGs, tais como a ultrassonografia bidimensional em escala de cinza e a elastografia ultrassonográfica (ELASTO). Assim, o objetivo do presente estudo foi acessar os dados clínicos de adultos jovens com o olhar voltado para a frequência de PGs e a rigidez muscular relacionadas à dor de origem miofascial das regiões de cabeça, pescoço e ombros. Um estudo observacional transversal foi conduzido, sendo a amostra composta por 15 homens e 17 mulheres, com idades entre 19 e 35 anos (25,78±3,93), IMC de 18,07 a 29,98 kg/m2 (23,00±3,22). Os dados coletados foram: informações gerais, imagens pela ultrassonografia bidimensional em escala de cinza, índice de resistência (IR) através da ELASTO, limiar de dor à pressão (LDP) através da algometria digital, intensidade de dor através da Escala Visual Analógica (EVA), palpação manual de PGs e classificação da CTT. Nos resultados, as mulheres apresentaram maior frequência de dor em outras partes do corpo do que os homens e maior intensidade de dor pela EVA. O LDP foi significativamente menor no grupo com presença de PGs ativos do que no grupo com PGs latentes, para os músculos trapézios direito e esquerdo. O LDP no músculo trapézio esquerdo mostrou-se menor no grupo com PGs ativos, apresentando também maiores valores de IR, indicando aumento de rigidez nos músculos com maior sensibilidade à pressão. O presente estudo demonstrou que as mulheres com dor de origem miofascial sentem-na com maior intensidade e em maior número de outras partes do corpo em relação aos homens. A ELASTO e a algometria foram eficazes na identificação de maior rigidez muscular e menor LDP em músculos com presença de PGs ativos Abstract: Chronic soft tissue pain syndromes and myofascial pain are responsible for serious impact on function and disability, which are determined by the presence of myofascial trigger points (MTrP). Tension-type headache (TTH) is the most frequent headache in adults in often associated with MTrP of head and neck muscles. New features have been tested for MTrP complementary diagnosis, such as two-dimensional ultrasonography and ultrasound elastography (ELASTO). The aim of this study was to access clinical outcomes from young adults looking forward the frequency of MTrP and muscle tenderness related to pain complaints of myofascial origin on the head, neck and shoulders regions. An observational cross-section study was carried on, with the sample consisted of 15 men and 17 women, aged between 19 and 35 years (25.78±3.93), BMI of 18.07 to 29,98 Kg/m2 (23.00±3.22). Data were collected concerning general info, two-dimensional ultrasound, ELASTO strain ratio (SR), pain pressure threshold (PPT) trough digital algometer, pain intensity trough Visual Analogue Scale (VAS), manual palpation of MTrP and TTH classification. Women had statistically significant more pain in other parts of the body than men and higher pain intensity through VAS. PPT was significantly lower in active than latent MTrP group for both right and left trapezius. PPT in the left trapezius muscle were lower and concerning SR, statistically significant higher values were found in the active MTrP group, indicating that the most sensitive muscle presented the highest stiffness. Women with pain of myofascial origin felt it in greater intensity and associated with other parts of the body frequently than men. ELASTO and algometry were effective in greater muscle stiffness and lower PPT values identification in muscles with active MTrP Doutorado Anatomia Doutora em Biologia Buco-Dental CAPES

Supporting information. (DOCX 671 kb)

Objective to evaluate the quality of life of HIV positive (HIVþ) pregnant women using the HIV/AIDS Target Quality of Life (HAT-QoL) instrument. Methods cross-sectional study, conducted between May 2014 and November 2015 , with HIVþ pregnant women selected by convenience sampling. Sociodemographic and behavioral data were collected through interviews, and the HAT-QoL questionnaire was applied. Clinical and laboratorial data were collected from medical records. Results twenty-seven pregnant women participated in the study. Their mean age was 27 years (standard deviation - SD: 7.3). The majority (59%) had up to 8 years of education, 52% identified themselves as white, 56% were unemployed, and 59% had a household income higher than the minimum wage. The mean infection time by the virus was 68.4 months (5.7 years). The majority (74%) were contaminated with HIV through sexual intercourse, and 67% declared not having a HIVþrelative. Regarding the use of condoms, 41% reported using them sporadically, and the same number did not have proper knowledge about them. Only 23 patients (85%) reported having been prescribed antiretrovirals. Fourteen (64%) had a CD4 count higher than 500 cells/mm3, and 13 pregnant women (59%) had an undetectable viral load. The scores from the quality of life questionnaire dimensions that were more affected are: infection "disclosure concerns" (mean: 39.8; SD: 27.1), followed by "financial concerns" (mean: 49.1; SD: 36), and "HIV acceptance" (mean: 49.1; SD: 35.8). The dimension with the best score was "medication concerns" (mean: 80.8; SD: 26.5). Conclusion quality of life has been increasingly used as a clinical outcome evaluation parameter. The results of this study contribute to the establishment of interventions based on the needs of HIVþ pregnant women. Resumo Objetivo Avaliar a qualidade de vida de gestantes com sorologia positiva para o HIV através do instrumento Target Quality of Life ( HAT-QoL ). Métodos Estudo transversal, realizado de maio de 2014 a novembro de 2015, em gestantes HIV þ , sendo a amostra de conveniência. Através de entrevista foram coletados dados sociodemográficos, comportamentais e aplicado o questionário HATQoL. Dados clínicos e laboratoriais foram aferidos dos prontuários. Resultados Participaram 27 gestantes. A idade média foi de 27 anos (dp:7,3). A maioria (59%) tem até oito anos de estudo, 52% se declararam brancas, 56% não estavam trabalhando e 59% tinham renda familiar superior a um salário mínimo. O tempo médio de infecção pelo vírus foi de 68,4 meses (5,7 anos). A maioria (74%) foi contaminada pelo HIV através da relação sexual e (67%) refere não ter familiar HIV þ . Em relação ao uso do preservativo, 41% declararam usar às vezes e a mesma proporção não tinha conhecimento adequado sobre o mesmo. Apenas 23 pacientes (85%) relataram prescrição de antirretrovirais. Apresentaram CD4 superior a 500 células/ mm3 14 (64%) e carga viral indetectável 13 (59%) gestantes. Os escores dos domínios do questionário de qualidade de vida mais comprometidos foram "Preocupação com sigilo sobre a infecção" (média: 39,8; dp: 27,1) seguido de "Preocupações financeiras" (média: 49,1; dp: 36) e "Aceitação do HIV"(média: 49,1; dp: 35,8). O domínio com melhor escore foi "Preocupação com a medicação" (média: 80,8; dp: 26,5). Conclusão A qualidade de vida vem sendo utilizada cada vez mais como avaliação de desfecho clínico, os resultados deste estudo contribuem para estabelecimento de intervenções baseadas nas necessidades das gestantes que vivem com HIV.

Orientador: Maria Beatriz Duarte Gavião Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba Resumo: O presente estudo, de caráter experimental, teve como objetivo a avaliação de pontos-gatilho miofasciais (PG) do músculo trapézio descendente (TPz) por imagens de ultrassonografia bidimensional em escala de cinza (US 2D) e elastografia ultrassonográfica (ELASTO), bem como avaliar a eficácia das técnicas de acupuntura (AC) e eletroacupuntura (EA) na diminuição da dor em mulheres com síndrome da dor miofascial (SDM) associada a queixas de dor nas regiões de cabeça, pescoço e parte superior do tronco. Uma amostra de conveniência de 24 voluntárias, com idades entre 20 e 40 anos (27,33±5,05), IMC entre 18,03 e 27,09 Kg/m² (22,59±3,11), ciclo menstrual regular, presença de ao menos um PG ativo em ambos os TPz, queixa de dor local e/ ou referida há pelo menos seis meses foi selecionada para o estudo. Após a assinatura do Termo de Consentimento Livre e Esclarecido (TCLE), as voluntárias foram randomizadas em três grupos, sendo: dois grupos de tratamento (AC e EA) e um grupo controle (SHAM). Oito sessões de tratamento foram então realizadas, duas vezes por semana, durante aproximadamente um mês, levando em consideração o ciclo menstrual das voluntárias. Imagens do músculo trapézio foram adquiridas pelas técnicas de US 2D e ELASTO para avaliação e diagnóstico das propriedades mecânicas e viscoelásticas do tecido miofascial e a comparação dessas características pré e pós-tratamento. Nas imagens de US 2D, as áreas dos PG foram mensuradas. Nos elastogramas adquiridos pela ELASTO, o índice de resistência (IR) foi calculado. Tanto as voluntárias quanto o examinador eram cegos em relação aos grupos. A intensidade de dor geral e localizada nos TPz direito e esquerdo (TPzD e TPzE, respectivamente) pré e pós-tratamento foi mensurada com o auxílio da escala visual analógica (EVA). A ocorrência de fatores influenciadores e as fases do ciclo menstrual foram monitoradas. Os dados foram analisados quanto à normalidade e simetria. Na avaliação intragrupo todos os dados apresentaram distribuição normal, sendo analisados pelo teste t student para dados pareados. Observou-se diminuição da intensidade de dor geral para o grupo AC (P

Molecular Imaging and Biology, 15 (6), ISSN:1860-2002, ISSN:1536-1632

The folate receptor (FR) is expressed in many tumor types, among those ovarian and lung cancer. Due to the high FR affinity of folic acid, it has been used for targeting of FR-positive tumors, allowing specific delivery of attached probes to the malignant tissue. Therefore, nuclear imaging of FR-positive cancer is of clinical interest for selecting patients who could benefit from innovative therapy concepts based on FR-targeting. Positron emission computed tomography (PET) has become an established technique in clinical routine because it provides an increased spatial resolution and higher sensitivity compared to single photon emission computed tomography (SPECT). Therefore, it is of critical importance to develop folate radiotracers suitable for PET imaging. This review article updates on the design, preparation and pre-clinical investigation of folate derivatives for radiolabeling with radioisotopes for PET. Among those the most relevant radionuclides so far are fluorine-18 (t1/2: 110 min, Eavβ+: 250 keV) and gallium-68 (t1/2: 68 min, Eav β+: 830 keV). Recent results obtained with new PET isotopes such as terbium-152 (t1/2: 17.5 h, Eβ+: 470 keV) or scandium-44 (t1/2: 3.97 h, Eav β+: 632 keV) are also presented and discussed. Current endeavors for clinical implementation of PET agents open new perspectives for identification of FR-positive malignancies in patients., Molecules, 18 (5), ISSN:1420-3049

European Journal of Nuclear Medicine and Molecular Imaging, 33 (10), ISSN:1619-7070, ISSN:1619-7089

Figure S1. Representative chromatograms of (a) 152Tb-PSMA-617 and (b) 177Lu-PSMA-617 after successful radiolabeling. Table S1. Stability of 152Tb-PSMA-617. (DOCX 517 kb)

Background The targeting of the prostate-specific membrane antigen (PSMA) is of particular interest for radiotheragnostic purposes of prostate cancer. Radiolabeled PSMA-617, a 1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA)-functionalized PSMA ligand, revealed favorable kinetics with high tumor uptake, enabling its successful application for PET imaging (68Ga) and radionuclide therapy (177Lu) in the clinics. In this study, PSMA-617 was labeled with cyclotron-produced 44Sc (T 1/2 = 4.04 h) and investigated preclinically for its use as a diagnostic match to 177Lu-PSMA-617. Results 44Sc was produced at the research cyclotron at PSI by irradiation of enriched 44Ca targets, followed by chromatographic separation. 44Sc-PSMA-617 was prepared under standard labeling conditions at elevated temperature resulting in a radiochemical purity of >97% at a specific activity of up to 10 MBq/nmol. 44Sc-PSMA-617 was evaluated in vitro and compared to the 177Lu- and 68Ga-labeled match, as well as 68Ga-PSMA-11 using PSMA-positive PC-3 PIP and PSMA-negative PC-3 flu prostate cancer cells. In these experiments it revealed similar in vitro properties to that of 177Lu- and 68Ga-labeled PSMA-617. Moreover, 44Sc-PSMA-617 bound specifically to PSMA-expressing PC-3 PIP tumor cells, while unspecific binding to PC-3 flu cells was not observed. The radioligands were investigated with regard to their in vivo properties in PC-3 PIP/flu tumor-bearing mice. 44Sc-PSMA-617 showed high tumor uptake and a fast renal excretion. The overall tissue distribution of 44Sc-PSMA-617 resembled that of 177Lu-PSMA-617 most closely, while the 68Ga-labeled ligands, in particular 68Ga-PSMA-11, showed different distribution kinetics. 44Sc-PSMA-617 enabled distinct visualization of PC-3 PIP tumor xenografts shortly after injection, with increasing tumor-to-background contrast over time while unspecific uptake in the PC-3 flu tumors was not observed. Conclusions The in vitro characteristics and in vivo kinetics of 44Sc-PSMA-617 were more similar to 177Lu-PSMA-617 than to 68Ga-PSMA-617 and 68Ga-PSMA-11. Due to the almost four-fold longer half-life of 44Sc as compared to 68Ga, a centralized production of 44Sc-PSMA-617 and transport to satellite PET centers would be feasible. These features make 44Sc-PSMA-617 particularly appealing for clinical application., EJNMMI Research, 7 (1), ISSN:2191-219X

Background Radiolabelled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumours, in which BN2/gastrin-releasing peptide receptors are overexpressed. We describe the influence of the specific activity of a 177Lu-DOTA-PEG5k-Lys-B analogue on its therapeutic efficacy and compare it with its non-PEGylated counterpart. Methods Derivatisation of a stabilised DOTA-BN(7–14)[Cha13,Nle14] analogue with a linear PEG molecule of 5 kDa (PEG5k) was performed by PEGylation of the ϵ-amino group of a β3hLys-βAla-βAla spacer between the BN sequence and the DOTA chelator. The non-PEGylated and the PEGylated analogues were radiolabelled with 177Lu. In vitro evaluation was performed in human prostate carcinoma PC-3 cells, and in vivo studies were carried out in nude mice bearing PC-3 tumour xenografts. Different specific activities of the PEGylated BN analogue and various dose regimens were evaluated concerning their therapeutic efficacy. Results The specificity and the binding affinity of the BN analogue for BN2/GRP receptors were only slightly reduced by PEGylation. In vitro binding kinetics of the PEGylated analogue was slower since steady-state condition was reached after 4 h. PEGylation improved the stability of BN conjugate in vitro in human plasma by a factor of 5.6. The non-PEGylated BN analogue showed favourable pharmacokinetics already, i.e. fast blood clearance and renal excretion, but PEGylation improved the in vivo behaviour further. One hour after injection, the tumour uptake of the PEG5k-BN derivative was higher compared with that of the non-PEGylated analogue (3.43 ± 0.63% vs. 1.88 ± 0.4% ID/g). Moreover, the increased tumour retention resulted in a twofold higher tumour accumulation at 24 h p.i., and increased tumour-to-non-target ratios (tumour-to-kidney, 0.6 vs. 0.4; tumour-to-liver, 8.8 vs. 5.9, 24 h p.i.). In the therapy study, both 177Lu-labelled BN analogues significantly inhibited tumour growth. The therapeutic efficacy was highest for the PEGylated derivative of high specific activity administered in two fractions (2 × 20 MBq = 40 MBq) at day 0 and day 7 (73% tumour growth inhibition, 3 weeks after therapy). Conclusions PEGylation and increasing the specific activity enhance the pharmacokinetic properties of a 177Lu-labelled BN-based radiopharmaceutical and provide a protocol for targeted radionuclide therapy with a beneficial anti-tumour effectiveness and a favourable risk-profile at the same time., EJNMMI Research, 2 (1), ISSN:2191-219X

Formula for the calculation of the 47Sc activity in Bq (s−1), accessible under the applied irradiation conditions. σ = nuclear cross section of the 46Ca(n,γ)47Ca reaction in cm−2, NT = number of 46Ca atoms, Φth = thermal neutron flux in n * cm−2 * s−1, λSc and λCa = decay constants of 47Sc and 47Ca in s−1, tirr = irradiation time and twait = post irradiation waiting time in s. b Formula for the calculation of the optimal post irradiation waiting time (topt) in s, accessible at the applied irradiation time (tirr in s). The decay constants of 47Sc (λSc) and 47Ca (λCa) are given in s−1. c Formula for the calculation of the optimal relative 47Sc activity (a(47Sc)opt) (dimensionless), accessible under the applied irradiation conditions. σ = nuclear cross section of the 46Ca(n,γ)47Ca reaction in cm−2, NT = number of 46Ca atoms, Φth = thermal neutron flux in n * cm−2 * s−1, λSc and λCa = decay constants of 47Sc and 47Ca in s−1. d Formula for the maximal obtainable 47Sc activity (dimensionless). The irradiation time (tirr) is given in s and the decay constants of 47Sc (λSc) and 47Ca (λCa) in s−1. Figure S2. γ-Ray spectra of 47Sc and 47Ca from the neutron-irradiated 46Ca ampoule, obtained 71 h after the end of irradiation (measurement time: 10 s) (a) and of the pure 47Sc eluate after separation (Method B), obtained 1 h after the end of separation (measurement time: 250 s) (b). Figure S3. γ-Ray spectrum of the neutron-irradiated 47Ti ampoule at SINQ, obtained 21 d after the end of irradiation (measurement time: 9600 s). Figure S4. Measured cross section values (squares, retrieved from the EXFOR-database) (Zerkin 2016) as well as the theoretical calculations from the TENDL-2015 library (straight line) (Koning, Rochman et al. 2015) for the 47Ti(n,p)47Sc (blue) and the 47Ti(n,p + n)46Sc (black) nuclear reactions. Table S5. Trace metal analysis of the reduced 46Ti metal by ICP-OES. Only the elements determined at a concentration higher than the detection limit are listed below. (DOCX 415 kb)

Purpose Various preclinical study designs are described in the literature for the evaluation of PSMA radioligands. In this study, [177Lu]Lu-Ibu-DAB-PSMA, an albumin-binding radioligand, and [177Lu]Lu-PSMA-617 were investigated and compared under variable experimental conditions. Methods In vitro cell uptake studies were performed with PC-3 PIP and LNCaP tumor cells using a range of molar concentrations (0.75–500 nM) of both radioligands. Biodistribution and SPECT/CT imaging studies were carried out with the respective tumor mouse models using 0.05 nmol and 1.0 nmol injected ligand per mouse. Results In both tumor cell lines, the uptake of the radioligands was increased when using low molar concentrations of the respective ligand. The observed saturation effect at high ligand concentrations was more pronounced for LNCaP cells that express PSMA at lower levels than for PC-3 PIP cells. At all investigated timepoints, the in vivo uptake of both radioligands was higher in PC-3 PIP tumors than in LNCaP tumors. A low molar amount of injected ligand increased the PC-3 PIP tumor uptake mainly for [177Lu]Lu-Ibu-DAB-PSMA; however, the molar amount of ligand was relevant for both radioligands when using LNCaP tumors. Renal retention of both radioligands was, however, up to fourfold higher during the first hours after application of a low ligand amount compared to the high ligand amount. Conclusion The results of this preclinical study underline the relevance of the tumor model and applied ligand amount for the characterization of PSMA radioligands. The application of equal preclinical study designs is crucial to allow the comparison of novel radioligands with existing ones and, thus, predict potential advantages of new radioligands in view of a clinical application., European Journal of Nuclear Medicine and Molecular Imaging, 49 (2), ISSN:1619-7070, ISSN:1619-7089

Targeted radionuclide therapy with 177Lu- and 90Y-labeled radioconjugates is a clinically-established treatment modality for metastasized cancer. 47Sc is a therapeutic radionuclide that decays with a half-life of 3.35 days and emits medium-energy β−-particles. In this study, 47Sc was investigated, in combination with a DOTA-folate conjugate, and compared to the therapeutic properties of 177Lu-folate and 90Y-folate, respectively. In vitro, 47Sc-folate demonstrated effective reduction of folate receptor-positive ovarian tumor cell viability similar to 177Lu-folate, but 90Y-folate was more potent at equal activities due to the higher energy of emitted β−-particles. Comparable tumor growth inhibition was observed in mice that obtained the same estimated absorbed tumor dose (~21 Gy) when treated with 47Sc-folate (12.5 MBq), 177Lu-folate (10 MBq), and 90Y-folate (5 MBq), respectively. The treatment resulted in increased median survival of 39, 43, and 41 days, respectively, as compared to 26 days in untreated controls. There were no statistically significant differences among the therapeutic effects observed in treated groups. Histological assessment revealed no severe side effects two weeks after application of the radiofolates, even at double the activity used for therapy. Based on the decay properties and our results, 47Sc is likely to be comparable to 177Lu when employed for targeted radionuclide therapy. It may, therefore, have potential for clinical translation and be of particular interest in tandem with 44Sc or 43Sc as a diagnostic match, enabling the realization of radiotheragnostics in future., Pharmaceutics, 11 (8)

Figure S1. Representative chromatograms of (a) 152Tb-PSMA-617 and (b) 177Lu-PSMA-617 after successful radiolabeling. Table S1. Stability of 152Tb-PSMA-617. (DOCX 517 kb)

Folate receptor (FR)-targeted radionuclide therapy using folate radioconjugates is of interest due to the expression of the FR in a variety of tumor types. The high renal accumulation of radiofolates presents, however, a risk of radionephropathy. A potential option to address this challenge would be to use radioprotectants, such as amifostine. Methods for early detection of kidney damage that—in this case—cannot be predicted based on dose estimations, would facilitate the development of novel therapies. The aim of this study was, therefore, to assess potentially changing levels of plasma and urine biomarkers and to determine DNA damage at an early stage after radiofolate application. The identification of an early indicator for renal damage in mice would be useful since histological changes become apparent only several months after treatment. Mice were injected with different quantities of 177Lu-folate (10 MBq, 20 MBq and 30 MBq), resulting in mean absorbed kidney doses of ~23 Gy, ~46 Gy and ~69 Gy, respectively, followed by euthanasia two weeks (>85% of the mean renal radiation dose absorbed) or three months later. Whereas all investigated biomarkers remained unchanged, the number of γ-H2AX-positive nuclei in the renal cortex showed an evident dose-dependent increase as compared to control values two weeks after treatment. Comparison with the extent of kidney injury determined by histological changes five to eight months after administration of the same 177Lu-folate activities suggested that the quantitative assessment of double-strand breaks can be used as a biological indicator for long-term radiation effects in the kidneys. This method may, thus, enable faster assessment of radiopharmaceuticals and protective measures by preventing logistically challenging long-term investigations to detect kidney damage., Pharmaceuticals, 10 (2), ISSN:1424-8247

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two 55Co-labeled albumin-binding folate derivatives-[55Co]Co-cm10 and [55Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both 55Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [64Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors., Pharmaceuticals, 12 (4), ISSN:1424-8247

The decay of terbium-161 results in the emission of β¯-particles as well as conversion and Auger electrons, which makes terbium-161 interesting for therapeutic purposes. The aim of this study was to use dual-isotope SPECT imaging in order to demonstrate visually that terbium-161 and lutetium-177 are interchangeable without compromising the pharmacokinetic profile of the radiopharmaceutical. The 161Tb- and 177Lu-labeled somatostatin (SST) analogues DOTATOC (agonist) and DOTA-LM3 (antagonist) were tested in vitro to demonstrate equal properties regarding distribution coefficients and cell uptake into SST receptor-positive AR42J tumor cells. The radiopeptides were further investigated in AR42J tumor-bearing nude mice using the method of dual-isotope (terbium-161/lutetium-177) SPECT/CT imaging to enable the visualization of their distribution profiles in the same animal. Equal pharmacokinetic profiles were demonstrated for either of the two peptides, irrespective of whether it was labeled with terbium-161 or lutetium-177. Moreover, the visualization of the sub-organ distribution confirmed similar behavior of 161Tb- and 177Lu-labeled SST analogues. The data were verified in quantitative biodistribution studies using either type of peptide labeled with terbium-161 or lutetium-177. While the radionuclide did not have an impact on the organ distribution, this study confirmed previous data of a considerably higher tumor uptake of radiolabeled DOTA-LM3 as compared to the radiolabeled DOTATOC., Pharmaceutics, 13 (4)

Background 161Tb is an interesting radionuclide for cancer treatment, showing similar decay characteristics and chemical behavior to clinically-employed 177Lu. The therapeutic effect of 161Tb, however, may be enhanced due to the co-emission of a larger number of conversion and Auger electrons as compared to 177Lu. The aim of this study was to produce 161Tb from enriched 160Gd targets in quantity and quality sufficient for first application in patients. Methods No-carrier-added 161Tb was produced by neutron irradiation of enriched 160Gd targets at nuclear research reactors. The 161Tb purification method was developed with the use of cation exchange (Sykam resin) and extraction chromatography (LN3 resin), respectively. The resultant product (161TbCl3) was characterized and the 161Tb purity compared with commercial 177LuCl3. The purity of the final product (161TbCl3) was analyzed by means of γ-ray spectrometry (radionuclidic purity) and radio TLC (radiochemical purity). The radiolabeling yield of 161Tb-DOTA was assessed over a two-week period post processing in order to observe the quality change of the obtained 161Tb towards future clinical application. To understand how the possible drug products (peptides radiolabeled with 161Tb) vary with time, stability of the clinically-applied somatostatin analogue DOTATOC, radiolabeled with 161Tb, was investigated over a 24-h period. The radiolytic stability experiments were compared to those performed with 177Lu-DOTATOC in order to investigate the possible influence of conversion and Auger electrons of 161Tb on peptide disintegration. Results Irradiations of enriched 160Gd targets yielded 6–20 GBq 161Tb. The final product was obtained at an activity concentration of 11–21 MBq/μL with ≥99% radionuclidic and radiochemical purity. The DOTA chelator was radiolabeled with 161Tb or 177Lu at the molar activity deemed useful for clinical application, even at the two-week time point after end of chemical separation. DOTATOC, radiolabeled with either 161Tb or 177Lu, was stable over 24 h in the presence of a stabilizer. Conclusions In this study, it was shown that 161Tb can be produced in high activities using different irradiation facilities. The developed method for 161Tb separation from the target material yielded 161TbCl3 in quality suitable for high-specific radiolabeling, relevant for future clinical application., EJNMMI Radiopharmacy and Chemistry, 4 (1)

Background For almost a decade, terbium radioisotopes have been explored for their potential theragnostic application in nuclear medicine: 152Tb and 155Tb are the radioisotopes identified for PET or SPECT imaging, while 149Tb and 161Tb have suitable decay characteristics for α- and combined β−/Auger-e−-therapy, respectively. In the present study, the application of 152Tb, in combination with PSMA-617 for imaging of prostate-specific membrane antigen (PSMA)-positive prostate cancer, was demonstrated in a preclinical setting and in a patient with metastatic castration-resistant prostate cancer (mCRPC). Results 152Tb was produced at the ISOLDE facility at CERN/Geneva, Switzerland, by spallation, followed by on-line mass separation. The chemical separation was performed at Paul Scherrer Institute using chromatographic methods, as previously reported. 152Tb was employed for labeling PSMA-617, and the radioligand was extensively investigated in vitro to demonstrate similar characteristics to its 177Lu-labeled counterpart. Preclinical PET/CT imaging studies performed with mice enabled visualization of PSMA-positive PC-3 PIP tumors, while uptake in PSMA-negative PC-3 flu tumors were absent. Based on these promising preclinical results, 152Tb was shipped to Zentralklinik Bad Berka, Germany, where it was used for labeling of PSMA-617, enabling PET imaging of a patient with mCRPC. PET/CT scans were performed over a period of 25 h post injection (p.i.) of the radioligand (140 MBq). The images were of diagnostic quality, particularly those acquired at later time points, and enabled the detection of the same metastatic lesions and of local recurrent tumor as previously detected by 68Ga-PSMA-11 PET/CT acquired 45 min p.i. Conclusions The results of this study demonstrate the successful preparation and preclinical testing of 152Tb-PSMA-617 and its first application in a patient with mCRPC. This work could pave the way towards clinical application of other Tb radionuclides in the near future, most importantly 161Tb, which has promising decay characteristics for an effective treatment of mCRPC patients., EJNMMI Research, 9 (1), ISSN:2191-219X

Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters revealed no signs of acute toxicity to the kidneys or liver in treated mice over the time of investigation. These results demonstrated the potential of folate-based α-radionuclide therapy in tumor-bearing mice.

Purpose The prostate-specific membrane antigen (PSMA) has emerged as an interesting target for radionuclide therapy of metastasized castration-resistant prostate cancer (mCRPC). The aim of this study was to investigate 161Tb (T1/2 = 6.89 days; Eβ͞av = 154 keV) in combination with PSMA-617 as a potentially more effective therapeutic alternative to 177Lu-PSMA-617, due to the abundant co-emission of conversion and Auger electrons, resulting in an improved absorbed dose profile. Methods 161Tb was used for the radiolabeling of PSMA-617 at high specific activities up to 100 MBq/nmol. 161Tb-PSMA-617 was tested in vitro and in tumor-bearing mice to confirm equal properties, as previously determined for 177Lu-PSMA-617. The effects of 161Tb-PSMA-617 and 177Lu-PSMA-617 on cell viability (MTT assay) and survival (clonogenic assay) were compared in vitro using PSMA-positive PC-3 PIP tumor cells. 161Tb-PSMA-617 was further investigated in therapy studies using PC-3 PIP tumor-bearing mice. Results 161Tb-PSMA-617 and 177Lu-PSMA-617 displayed equal in-vitro properties and tissue distribution profiles in tumor-bearing mice. The viability and survival of PC-3 PIP tumor cells were more reduced when exposed to 161Tb-PSMA-617 as compared to the effect obtained with the same activities of 177Lu-PSMA-617 over the whole investigated concentration range. Treatment of mice with 161Tb-PSMA-617 (5.0 MBq/mouse and 10 MBq/mouse, respectively) resulted in an activity-dependent increase of the median survival (36 vs 65 days) compared to untreated control animals (19 days). Therapy studies to compare the effects of 161Tb-PSMA-617 and 177Lu-PSMA-617 indicated the anticipated superiority of 161Tb over 177Lu. Conclusion 161Tb-PSMA-617 showed superior in-vitro and in-vivo results as compared to 177Lu-PSMA-617, confirming theoretical dose calculations that indicate an additive therapeutic effect of conversion and Auger electrons in the case of 161Tb. These data warrant more preclinical research for in-depth investigations of the proposed concept, and present a basis for future clinical translation of 161Tb-PSMA-617 for the treatment of mCRPC., European Journal of Nuclear Medicine and Molecular Imaging, 46 (9), ISSN:1619-7070, ISSN:1619-7089

Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters revealed no signs of acute toxicity to the kidneys or liver in treated mice over the time of investigation. These results demonstrated the potential of folate-based α-radionuclide therapy in tumor-bearing mice., Pharmaceuticals, 7 (3), ISSN:1424-8247

Folic-acid-based radioconjugates have been developed for nuclear imaging of folate receptor (FR)-positive tumors; however, high renal uptake was unfavorable in view of a therapeutic application. Previously, it was shown that pre-injection of pemetrexed (PMX) increased the tumor-to-kidney ratio of radiofolates several-fold. In this study, PMX was combined with the currently best performing radiofolate ([177Lu]cm13), which is outfitted with an albumin-binding entity. Biodistribution studies were carried out in mice bearing KB or IGROV-1 tumor xenografts, both FR-positive tumor types. SPECT/CT was performed with control mice injected with [177Lu]folate only and with mice that received PMX in addition. Control mice showed high uptake of radioactivity in KB and IGROV-1 tumor xenografts, but retention in the kidneys was also high, resulting in tumor-to-kidney ratios of ~0.85 (4 h p.i.) and ~0.60 (24 h p.i.) or ~1.17 (4 h p.i.) and ~1.11 (24 h p.i.) respectively. Pre-injection of PMX improved the tumor-to-kidney ratio to values of ~1.13 (4 h p.i.) and ~0.92 (24 h p.i.) or ~1.79 (4 h p.i.) and ~1.59 (24 h p.i.), respectively, due to reduced uptake in the kidneys. It was found that a second injection of PMX—3 h or 7 h after administration of the radiofolate—improved the tumor-to-kidney ratio further to ~1.03 and ~0.99 or ~1.78 and ~1.62 at 24 h p.i. in KB and IGROV-1 tumor-bearing mice, respectively. SPECT/CT scans readily visualized the tumor xenografts, whereas accumulation of radioactivity in the kidneys was reduced in mice that received PMX. In this study, it was shown that PMX had a positive impact in terms of reducing the kidney uptake of albumin-binding radiofolates; hence, the administration of PMX resulted in ~1.3–1.7-fold higher tumor-to-kidney ratios. This is, however, a rather moderate effect in comparison to the previously shown effect of PMX on conventional radiofolates (without albumin binder), which led to 5–6-fold increased tumor-to-kidney ratios. An explanation for this result may be the different pharmacokinetic profiles of PMX and long-circulating radiofolates, respectively. Despite the promising potential of this concept, it is believed that a clinical translation would be challenging, particularly when PMX had to be injected more than once., Molecules, 23 (6), ISSN:1420-3049

Single photon emission computed tomography (SPECT) is the state of the art imaging modality in nuclear medicine despite the fact that only a few new SPECT tracers have become available in the past 20 years. Critical for the future success of SPECT is the design of new and specific tracers for the detection localization and staging of a disease and for monitoring therapy. The utility of SPECT imaging to address oncologic questions is dependent on radiotracers that ideally exhibit excellent tissue penetration high affinity to the tumor associated target structure specific uptake and retention in the malignant lesions and rapid clearance from non targeted tissues and organs. In general a target specific SPECT radiopharmaceutical can be divided into two main parts: a targeting biomolecule (e.g. peptide antibody fragment) and a ? radiation emitting radionuclide (e.g. (99m)Tc (123)I). If radiometals are used as the radiation source a bifunctional chelator is needed to link the radioisotope to the targeting entity. In a rational SPECT tracer design these single components have to be critically evaluated in order to achieve a balance among the demands for adequate target binding and a rapid clearance of the radiotracer. The focus of this chapter is to depict recent developments of tumor targeted SPECT radiotracers for imaging of cancer diseases. Possibilities for optimization of tracer design and potential causes for design failure are discussed and highlighted with selected examples.