Multimodality PET/MRI agents targeted to activated macrophages.

PubMed

Tu, Chuqiao; Ng, Thomas S C; Jacobs, Russell E; Louie, Angelique Y

2014-02-01

The recent emergence of multimodality imaging, particularly the combination of PET and MRI, has led to excitement over the prospect of improving detection of disease. Iron oxide nanoparticles have become a popular platform for the fabrication of PET/MRI probes owing to their advantages of high MRI detection sensitivity, biocompatibility, and biodegradability. In this article, we report the synthesis of dextran-coated iron oxide nanoparticles (DIO) labeled with the positron emitter (64)Cu to generate a PET/MRI probe, and modified with maleic anhydride to increase the negative surface charge. The modified nanoparticulate PET/MRI probe (MDIO-(64)Cu-DOTA) bears repetitive anionic charges on the surface that facilitate recognition by scavenger receptor type A (SR-A), a ligand receptor found on activated macrophages but not on normal vessel walls. MDIO-(64)Cu-DOTA has an average iron oxide core size of 7-8 nm, an average hydrodynamic diameter of 62.7 nm, an r1 relaxivity of 16.8 mM(-1) s(-1), and an r 2 relaxivity of 83.9 mM(-1) s(-1) (37 °C, 1.4 T). Cell studies confirmed that the probe was nontoxic and was specifically taken up by macrophages via SR-A. In comparison with the nonmodified analog, the accumulation of MDIO in macrophages was substantially improved. These characteristics demonstrate the promise of MDIO-(64)Cu-DOTA for identification of vulnerable atherosclerotic plaques via the targeting of macrophages.

Tumor Targeting via Sialic Acid: [68Ga]DOTA-en-pba as a New Tool for Molecular Imaging of Cancer with PET.

PubMed

Tsoukalas, Charalambos; Geninatti-Crich, Simonetta; Gaitanis, Anastasios; Tsotakos, Theodoros; Paravatou-Petsotas, Maria; Aime, Silvio; Jiménez-Juárez, Rogelio; Anagnostopoulos, Constantinos D; Djanashvili, Kristina; Bouziotis, Penelope

2018-02-20

The aim of this study was to demonstrate the potential of Ga-68-labeled macrocycle (DOTA-en-pba) conjugated with phenylboronic vector for tumor recognition by positron emission tomography (PET), based on targeting of the overexpressed sialic acid (Sia). The imaging reporter DOTA-en-pba was synthesized and labeled with Ga-68 at high efficiency. Cell binding assay on Mel-C and B16-F10 melanoma cells was used to evaluate melanin production and Sia overexpression to determine the best model for demonstrating the capability of [ 68 Ga]DOTA-en-pba to recognize tumors. The in vivo PET imaging was done with B16-F10 tumor-bearing SCID mice injected with [ 68 Ga]DOTA-en-pba intravenously. Tumor, blood, and urine metabolites were assessed to evaluate the presence of a targeting agent. The affinity of [ 68 Ga]DOTA-en-pba to Sia was demonstrated on B16-F10 melanoma cells, after the production of melanin as well as Sia overexpression was proved to be up to four times higher in this cell line compared to that in Mel-C cells. Biodistribution studies in B16-F10 tumor-bearing SCID mice showed blood clearance at the time points studied, while uptake in the tumor peaked at 60 min post-injection (6.36 ± 2.41 % ID/g). The acquired PET images were in accordance with the ex vivo biodistribution results. Metabolite assessment on tumor, blood, and urine samples showed that [ 68 Ga]DOTA-en-pba remains unmetabolized up to at least 60 min post-injection. Our work is the first attempt for in vivo imaging of cancer by targeting overexpression of sialic acid on cancer cells with a radiotracer in PET.

Influence of FDG-PET on primary nodal target volume definition for head and neck carcinomas.

PubMed

van Egmond, Sylvia L; Piscaer, Vera; Janssen, Luuk M; Stegeman, Inge; Hobbelink, Monique G; Grolman, Wilko; Terhaard, Chris H

The role of 2-[ 18 F]-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in routine diagnostic staging remains controversial. In case of discordance between FDG-PET and CT, a compromise has to be made between the risk of false positive FDG-PET and the risk of delaying appropriate salvage intervention. Second, with intensity modulated radiation therapy (IMRT), smaller radiation fields allow tissue sparing, but could also lead to more marginal failures. We retrospectively studied 283 patients with head and neck carcinoma scheduled for radiotherapy between 2002 and 2010. We analyzed the influence of FDG-PET/CT versus CT alone on defining nodal target volume definition and evaluated its long-term clinical results. Second, the location of nodal recurrences was related to the radiation regional dose distribution. In 92 patients, CT and FDG-PET, performed in mold, showed discordant results. In 33%, nodal staging was altered by FDG-PET. In 24%, FDG-PET also led to an alteration in nodal treatment, including a nodal upstage of 18% and downstage of 6%. In eight of these 92 patients, a regional recurrence occurred. Only two patients had a recurrence in the discordant node on FDG-PET and CT and both received a boost (high dose radiation). These results support the complementary value of FDG-PET/CT compared to CT alone in defining nodal target volume definition for radiotherapy of head and neck cancer.

Drug Target Interference in Immunogenicity Assays: Recommendations and Mitigation Strategies.

PubMed

Zhong, Zhandong Don; Clements-Egan, Adrienne; Gorovits, Boris; Maia, Mauricio; Sumner, Giane; Theobald, Valerie; Wu, Yuling; Rajadhyaksha, Manoj

2017-11-01

Sensitive and specific methodology is required for the detection and characterization of anti-drug antibodies (ADAs). High-quality ADA data enables the evaluation of potential impact of ADAs on the drug pharmacokinetic profile, patient safety, and efficacious response to the drug. Immunogenicity assessments are typically initiated at early stages in preclinical studies and continue throughout the drug development program. One of the potential bioanalytical challenges encountered with ADA testing is the need to identify and mitigate the interference mediated by the presence of soluble drug target. A drug target, when present at sufficiently high circulating concentrations, can potentially interfere with the performance of ADA and neutralizing antibody (NAb) assays, leading to either false-positive or, in some cases, false-negative ADA and NAb assay results. This publication describes various mechanisms of assay interference by soluble drug target, as well as strategies to recognize and mitigate such target interference. Pertinent examples are presented to illustrate the impact of target interference on ADA and NAb assays as well as several mitigation strategies, including the use of anti-target antibodies, soluble versions of the receptors, target-binding proteins, lectins, and solid-phase removal of targets. Furthermore, recommendations for detection and mitigation of such interference in different formats of ADA and NAb assays are provided.

Multi-targeted priming for genome-wide gene expression assays.

PubMed

Adomas, Aleksandra B; Lopez-Giraldez, Francesc; Clark, Travis A; Wang, Zheng; Townsend, Jeffrey P

2010-08-17

Complementary approaches to assaying global gene expression are needed to assess gene expression in regions that are poorly assayed by current methodologies. A key component of nearly all gene expression assays is the reverse transcription of transcribed sequences that has traditionally been performed by priming the poly-A tails on many of the transcribed genes in eukaryotes with oligo-dT, or by priming RNA indiscriminately with random hexamers. We designed an algorithm to find common sequence motifs that were present within most protein-coding genes of Saccharomyces cerevisiae and of Neurospora crassa, but that were not present within their ribosomal RNA or transfer RNA genes. We then experimentally tested whether degenerately priming these motifs with multi-targeted primers improved the accuracy and completeness of transcriptomic assays. We discovered two multi-targeted primers that would prime a preponderance of genes in the genomes of Saccharomyces cerevisiae and Neurospora crassa while avoiding priming ribosomal RNA or transfer RNA. Examining the response of Saccharomyces cerevisiae to nitrogen deficiency and profiling Neurospora crassa early sexual development, we demonstrated that using multi-targeted primers in reverse transcription led to superior performance of microarray profiling and next-generation RNA tag sequencing. Priming with multi-targeted primers in addition to oligo-dT resulted in higher sensitivity, a larger number of well-measured genes and greater power to detect differences in gene expression. Our results provide the most complete and detailed expression profiles of the yeast nitrogen starvation response and N. crassa early sexual development to date. Furthermore, our multi-targeting priming methodology for genome-wide gene expression assays provides selective targeting of multiple sequences and counter-selection against undesirable sequences, facilitating a more complete and precise assay of the transcribed sequences within the genome.

PET imaging of T cells: Target identification and feasibility assessment.

PubMed

Auberson, Yves P; Briard, Emmanuelle; Rudolph, Bettina; Kaupmann, Klemen; Smith, Paul; Oberhauser, Berndt

2018-06-01

Imaging T cells using positron emission tomography (PET) would be highly useful for diagnosis and monitoring in immunology and oncology patients. There are however no obvious targets that can be used to develop imaging agents for this purpose. We evaluated several potential target proteins with selective expression in T cells, and for which lead molecules were available: PKC , Lck, ZAP70 and Itk. Ultimately, we focused on Itk (interleukin-2-inducible T cell kinase) and identified a tool molecule with properties suitable for in vivo imaging of T cells, (5aR)-5,5-difluoro-5a-methyl-N-(1-((S)-3-(methylsulfonyl)-phenyl)(tetrahydro-2H-pyran-4-yl)methyl)-1H-pyrazol-4-yl)-1,4,4a,5,5a,6-hexahydro-cyclopropa[f]-indazole-3-carboxamide (23). While not having the optimal profile for clinical use, this molecule indicates that it might be possible to develop Itk-selective PET ligands for imaging the distribution of T cells in patients. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Convergent effects of mouse Pet-1 deletion and human PET-1 variation on amygdala fear and threat processing.

PubMed

Wellman, Cara L; Camp, Marguerite; Jones, V Morgan; MacPherson, Kathryn P; Ihne, Jessica; Fitzgerald, Paul; Maroun, Mouna; Drabant, Emily; Bogdan, Ryan; Hariri, Ahmad R; Holmes, Andrew

2013-12-01

Serotonin is critical for shaping the development of neural circuits regulating emotion. Pet-1 (FEV-1) is an ETS-domain transcription factor essential for differentiation and forebrain targeting of serotonin neurons. Constitutive Pet-1 knockout (KO) causes major loss of serotonin neurons and forebrain serotonin availability, and behavioral abnormalities. We phenotyped Pet-1 KO mice for fear conditioning and extinction, and on a battery of assays for anxiety- and depression-related behaviors. Morphology of Golgi-stained neurons in basolateral amygdala (BLA) and prelimbic cortex was examined. Using human imaging genetics, a common variant (rs860573) in the PET-1 (FEV) gene was tested for effects on threat-related amygdala reactivity and psychopathology in 88 Asian-ancestry subjects. Pet-1 KO mice exhibited increased acquisition and expression of fear, and elevated fear recovery following extinction, relative to wild-type (WT). BLA dendrites of Pet-1 KO mice were significantly longer than in WT. Human PET-1 variation associated with differences in amygdala threat processing and psychopathology. This novel evidence for the role of Pet-1 in fear processing and dendritic organization of amygdala neurons and in human amygdala threat processing extends a growing literature demonstrating the influence of genetic variation in the serotonin system on emotional regulation via effects on structure and function of underlying corticolimbic circuitry. © 2013.

Molecular Targets for PET Imaging of Activated Microglia: The Current Situation and Future Expectations.

PubMed

Tronel, Claire; Largeau, Bérenger; Santiago Ribeiro, Maria Joao; Guilloteau, Denis; Dupont, Anne-Claire; Arlicot, Nicolas

2017-04-11

Microglia, as cellular mediators of neuroinflammation, are implicated in the pathogenesis of a wide range of neurodegenerative diseases. Positron emission tomography (PET) imaging of microglia has matured over the last 20 years, through the development of radiopharmaceuticals targeting several molecular biomarkers of microglial activation and, among these, mainly the translocator protein-18 kDa (TSPO). Nevertheless, current limitations of TSPO as a PET microglial biomarker exist, such as low brain density, even in a neurodegenerative setting, expression by other cells than the microglia (astrocytes, peripheral macrophages in the case of blood brain barrier breakdown), genetic polymorphism, inducing a variation for most of TSPO PET radiopharmaceuticals' binding affinity, or similar expression in activated microglia regardless of its polarization (pro- or anti-inflammatory state), and these limitations narrow its potential interest. We overview alternative molecular targets, for which dedicated radiopharmaceuticals have been proposed, including receptors (purinergic receptors P2X7, cannabinoid receptors, α7 and α4β2 nicotinic acetylcholine receptors, adenosine 2A receptor, folate receptor β) and enzymes (cyclooxygenase, nitric oxide synthase, matrix metalloproteinase, β-glucuronidase, and enzymes of the kynurenine pathway), with a particular focus on their respective contribution for the understanding of microglial involvement in neurodegenerative diseases. We discuss opportunities for these potential molecular targets for PET imaging regarding their selectivity for microglia expression and polarization, in relation to the mechanisms by which microglia actively participate in both toxic and neuroprotective actions in brain diseases, and then take into account current clinicians' expectations.

Alpha-v Integrin Targeted PET Imaging of Breast Cancer Angiogenesis and Low-Dose Metronomic Anti-Angiogenic Chemotherapy Efficacy

DTIC Science & Technology

2008-08-01

AD_________________ Award Number: W81XWH-04-1-0697 TITLE: Alpha -v Integrin Targeted PET Imaging of...SUBTITLE 5a. CONTRACT NUMBER Alpha -v Integrin Targeted PET Imaging of Breast Cancer Angiogenesis and Low- Dose Metronomic Anti-Angiogenic...Evaluation of biodistribution and anti-tumor effect of a dimeric RGD peptide-paclitaxel conjugate in mice with breast cancer” was published in Eur J Nucl

Pet Food Palatability Evaluation: A Review of Standard Assay Techniques and Interpretation of Results with a Primary Focus on Limitations

PubMed Central

Aldrich, Gregory C.; Koppel, Kadri

2015-01-01

Simple Summary Palatability of pet foods is typically measured using a single-bowl or a two-bowl test. While these tests give a general understanding of the liking or preference of one food over another, opportunities exist for further method development. Abstract The pet food industry continues to grow steadily as a result of new innovative products. Quality control and product development tests for pet foods are typically conducted through palatability testing with dogs and cats. Palatability is the measure of intake of a food that indicates acceptance or the measure of preference of one food over another. Pet food palatability is most commonly measured using a single-bowl or a two-bowl assay. While these tests answer some questions about the animals’ perception of the food, there are many limitations as well. This review addresses some of these limitations and indicates opportunities for future research. PMID:26479136

SU-C-BRA-02: Gradient Based Method of Target Delineation On PET/MR Image of Head and Neck Cancer Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dance, M; Chera, B; Falchook, A

2015-06-15

Purpose: Validate the consistency of a gradient-based segmentation tool to facilitate accurate delineation of PET/CT-based GTVs in head and neck cancers by comparing against hybrid PET/MR-derived GTV contours. Materials and Methods: A total of 18 head and neck target volumes (10 primary and 8 nodal) were retrospectively contoured using a gradient-based segmentation tool by two observers. Each observer independently contoured each target five times. Inter-observer variability was evaluated via absolute percent differences. Intra-observer variability was examined by percentage uncertainty. All target volumes were also contoured using the SUV percent threshold method. The thresholds were explored case by case so itsmore » derived volume matched with the gradient-based volume. Dice similarity coefficients (DSC) were calculated to determine overlap of PET/CT GTVs and PET/MR GTVs. Results: The Levene’s test showed there was no statistically significant difference of the variances between the observer’s gradient-derived contours. However, the absolute difference between the observer’s volumes was 10.83%, with a range from 0.39% up to 42.89%. PET-avid regions with qualitatively non-uniform shapes and intensity levels had a higher absolute percent difference near 25%, while regions with uniform shapes and intensity levels had an absolute percent difference of 2% between observers. The average percentage uncertainty between observers was 4.83% and 7%. As the volume of the gradient-derived contours increased, the SUV threshold percent needed to match the volume decreased. Dice coefficients showed good agreement of the PET/CT and PET/MR GTVs with an average DSC value across all volumes at 0.69. Conclusion: Gradient-based segmentation of PET volume showed good consistency in general but can vary considerably for non-uniform target shapes and intensity levels. PET/CT-derived GTV contours stemming from the gradient-based tool show good agreement with the anatomically and

Analysis of FET-PET imaging for target volume definition in patients with gliomas treated with conformal radiotherapy.

PubMed

Rieken, Stefan; Habermehl, Daniel; Giesel, Frederik L; Hoffmann, Christoph; Burger, Ute; Rief, Harald; Welzel, Thomas; Haberkorn, Uwe; Debus, Jürgen; Combs, Stephanie E

2013-12-01

Modern radiotherapy (RT) techniques such as stereotactic RT, intensity-modulated RT, or particle irradiation allow local dose escalation with simultaneous sparing of critical organs. Several trials are currently investigating their benefit in glioma reirradiation and boost irradiation. Target volume definition is of critical importance especially when steep dose gradient techniques are employed. In this manuscript we investigate the impact of O-(2-(F-18)fluoroethyl)-l-tyrosine-positron emission tomography/computer tomography (FET-PET/CT) on target volume definition in low and high grade glioma patients undergoing either first or re-irradiation with particles. We investigated volumetric size and uniformity of magnetic resonance imaging (MRI)- vs. FET-PET/CT-derived gross tumor volumes (GTVs) and planning target volumes (PTVs) of 41 glioma patients. Clinical cases are presented to demonstrate potential benefits of integrating FET-PET/CT-planning into daily routine. Integrating FET-uptake into the delineation of GTVs yields larger volumes. Combined modality-derived PTVs are significantly enlarged in high grade glioma patients and in case of primary RT. The congruence of MRI and FET signals for the identification of glioma GTVs is poor with mean uniformity indices of 0.39. MRI-based PTVs miss 17% of FET-PET/CT-based GTVs. Non significant alterations were detected in low grade glioma patients and in those undergoing reirradiation. Target volume definition for malignant gliomas during initial RT may yield significantly differing results depending upon the imaging modality, which the contouring process is based upon. The integration of both MRI and FET-PET/CT may help to improve GTV coverage by avoiding larger incongruences between physical and biological imaging techniques. In low grade gliomas and in cases of reirradiation, more studies are needed in order to investigate a potential benefit of FET-PET/CT for planning of RT. Copyright © 2013 Elsevier Ireland Ltd. All

Fully Bayesian Analysis of High-throughput Targeted Metabolomics Assays

EPA Science Inventory

High-throughput metabolomic assays that allow simultaneous targeted screening of hundreds of metabolites have recently become available in kit form. Such assays provide a window into understanding changes to biochemical pathways due to chemical exposure or disease, and are usefu...

Consequences of additional use of PET information for target volume delineation and radiotherapy dose distribution for esophageal cancer.

PubMed

Muijs, Christina T; Schreurs, Liesbeth M; Busz, Dianne M; Beukema, Jannet C; van der Borden, Arnout J; Pruim, Jan; Van der Jagt, Eric J; Plukker, John Th; Langendijk, Johannes A

2009-12-01

To determine the consequences of target volume (TV) modifications, based on the additional use of PET information, on radiation planning, assuming PET/CT-imaging represents the true extent of the tumour. For 21 patients with esophageal cancer, two separate TV's were retrospectively defined based on CT (CT-TV) and co-registered PET/CT images (PET/CT-TV). Two 3D-CRT plans (prescribed dose 50.4 Gy) were constructed to cover the corresponding TV's. Subsequently, these plans were compared for target coverage, normal tissue dose-volume histograms and the corresponding normal tissue complication probability (NTCP) values. The addition of PET led to the modification of CT-TV with at least 10% in 12 of 21 patients (57%) (reduction in 9, enlargement in 3). PET/CT-TV was inadequately covered by the CT-based treatment plan in 8 patients (36%). Treatment plan modifications resulted in significant changes (p<0.05) in dose distributions to heart and lungs. Corresponding changes in NTCP values ranged from -3% to +2% for radiation pneumonitis and from -0.2% to +1.2% for cardiac mortality. This study demonstrated that TV's based on CT might exclude PET-avid disease. Consequences are under dosing and thereby possibly ineffective treatment. Moreover, the addition of PET in radiation planning might result in clinical important changes in NTCP.

Evaluation of (68)Ga- and (177)Lu-DOTA-PEG4-LLP2A for VLA-4-Targeted PET Imaging and Treatment of Metastatic Melanoma.

PubMed

Beaino, Wissam; Nedrow, Jessie R; Anderson, Carolyn J

2015-06-01

Malignant melanoma is a highly aggressive cancer, and the incidence of this disease is increasing worldwide at an alarming rate. Despite advances in the treatment of melanoma, patients with metastatic disease still have a poor prognosis and low survival rate. New strategies, including targeted radiotherapy, would provide options for patients who become resistant to therapies such as BRAF inhibitors. Very late antigen-4 (VLA-4) is expressed on melanoma tumor cells in higher levels in more aggressive and metastatic disease and may provide an ideal target for drug delivery and targeted radiotherapy. In this study, we evaluated (177)Lu- and (68)Ga-labeled DOTA-PEG4-LLP2A as a VLA-4-targeted radiotherapeutic with a companion PET agent for diagnosis and monitoring metastatic melanoma treatment. DOTA-PEG4-LLP2A was synthesized by solid-phase synthesis. The affinity of (177)Lu- and (68)Ga-labeled DOTA-PEG4-LLP2A to VLA-4 was determined in B16F10 melanoma cells by saturation binding and competitive binding assays, respectively. Biodistribution of the LLP2A conjugates was determined in C57BL/6 mice bearing B16F10 subcutaneous tumors, while PET/CT imaging was performed in subcutaneous and metastatic models. (177)Lu-DOTA-PEG4-LLP2A showed high affinity to VLA-4 with a Kd of 4.1 ± 1.5 nM and demonstrated significant accumulation in the B16F10 melanoma tumor after 4 h (31.5 ± 7.8%ID/g). The tumor/blood ratio of (177)Lu-DOTA-PEG4-LLP2A was highest at 24 h (185 ± 26). PET imaging of metastatic melanoma with (68)Ga-DOTA-PEG4-LLP2A showed high uptake in sites of metastases and correlated with bioluminescence imaging of the tumors. These data demonstrate that (177)Lu-DOTA-PEG4-LLP2A has potential as a targeted therapeutic for treating melanoma as well as other VLA-4-expressing tumors. In addition, (68)Ga-DOTA-PEG4-LLP2A is a readily translatable companion PET tracer for imaging of metastatic melanoma.

Performance of highly sensitive cardiac troponin T assay to detect ischaemia at PET-CT in low-risk patients with acute coronary syndrome: a prospective observational study.

PubMed

Morawiec, Beata; Fournier, Stephane; Tapponnier, Maxime; Prior, John O; Monney, Pierre; Dunet, Vincent; Lauriers, Nathalie; Recordon, Frederique; Trana, Catalina; Iglesias, Juan-Fernando; Kawecki, Damian; Boulat, Olivier; Bardy, Daniel; Lamsidri, Sabine; Eeckhout, Eric; Hugli, Olivier; Muller, Olivier

2017-07-10

Highly sensitive troponin T (hs-TnT) assay has improved clinical decision-making for patients admitted with chest pain. However, this assay's performance in detecting myocardial ischaemia in a lowrisk population has been poorly documented. To assess hs-TnT assay's performance to detect myocardial ischaemia at positron emission tomography/CT (PET-CT) in low-risk patients admitted with chest pain. Patients admitted for chest pain with a nonconclusive ECG and negative standard cardiac troponin T results at admission and after 6 hours were prospectively enrolled. Their hs-TnT samples were at T0, T2 and T6. Physicians were blinded to hs-TnT results. All patients underwent a PET-CT at rest and during adenosine-induced stress. All patients with a positive PET-CT result underwent a coronary angiography. Forty-eight patients were included. Six had ischaemia at PET-CT. All of them had ≥1 significant stenosis at coronary angiography. Areas under the curve (95% CI) for predicting significant ischaemia at PET-CT using hs-TnT were 0.764 (0.515 to 1.000) at T0, 0.812(0.616 to 1.000) at T2 and 0.813(0.638 to 0.989) at T6. The receiver operating characteristicbased optimal cut-off value for hs-TnT at T0, T2 and T6 needed to exclude significant ischaemia at PET-CT was <4 ng/L. Using this value, sensitivity, specificity, positive and negative predictive values of hs-TnT to predict significant ischaemia were 83%/38%/16%/94% at T0, 100%/40%/19%/100% at T2 and 100%/43%/20%/100% at T6, respectively. Our findings suggest that in low-risk patients, using the hs-TnT assay with a cut-off value of 4 ng/L demonstrates excellent negative predictive value to exclude myocardial ischaemia detection at PET-CT, at the expense of weak specificity and positive predictive value. ClinicalTrials.gov Identifier: NCT01374607. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly

Radiotherapy planning: PET/CT scanner performances in the definition of gross tumour volume and clinical target volume.

PubMed

Brianzoni, Ernesto; Rossi, Gloria; Ancidei, Sergio; Berbellini, Alfonso; Capoccetti, Francesca; Cidda, Carla; D'Avenia, Paola; Fattori, Sara; Montini, Gian Carlo; Valentini, Gianluca; Proietti, Alfredo; Algranati, Carlo

2005-12-01

Positron emission tomography is the most advanced scintigraphic imaging technology and can be employed in the planning of radiation therapy (RT). The aim of this study was to evaluate the possible role of fused images (anatomical CT and functional FDG-PET), acquired with a dedicated PET/CT scanner, in delineating gross tumour volume (GTV) and clinical target volume (CTV) in selected patients and thus in facilitating RT planning. Twenty-eight patients were examined, 24 with lung cancer (17 non-small cell and seven small cell) and four with non-Hodgkin's lymphoma in the head and neck region. All patients underwent a whole-body PET scan after a CT scan. The CT images provided morphological volumetric information, and in a second step, the corresponding PET images were overlaid to define the effective target volume. The images were exported off-line via an internal network to an RT simulator. Three patient were excluded from the study owing to change in the disease stage subsequent to the PET/CT study. Among the remaining 25 patients, PET significantly altered the GTV or CTV in 11 (44%) . In five of these 11 cases there was a reduction in GTV or CTV, while in six there was an increase in GTV or CTV. FDG-PET is a highly sensitive imaging modality that offers better visualisation of local and locoregional tumour extension. This study confirmed that co-registration of CT data and FDG-PET images may lead to significant modifications of RT planning and patient management.

FDG-PET/CT at the end of immuno-chemotherapy in follicular lymphoma: the prognostic role of the ratio between target lesion and liver SUVmax (rPET).

PubMed

Annunziata, Salvatore; Cuccaro, Annarosa; Tisi, Maria Chiara; Hohaus, Stefan; Rufini, Vittoria

2018-06-01

To retrospectively investigate the prognostic role of the ratio between target lesion and liver SUV max (rPET) in patients with follicular lymphoma (FL) submitted to FDG-PET/CT at the end of immuno-chemotherapy (PI-PET), and to compare rPET with International Harmonization Project criteria (IHP), Deauville Score (5p-DS) and FL International Prognostic Index at diagnosis (FLIPI). Eighty-nine patients with FL undergoing PI-PET were evaluated. The receiver operating characteristic (ROC) approach was applied to identify the optimal cut-point of rPET with respect to 5-years progression free survival (PFS). The prognostic significance of rPET was compared with IHP, DS and FLIPI. Positive predictive value (PPV) and negative predictive value (NPV) were calculated using the presence of adverse events as gold standard. The ROC analysis for rPET as predictor of progression showed an optimal rPET cut-point of 0.98. Patients with positive values of IHP, DS and rPET had a PFS of 50, 30 and 31%. PPV were of 56, 80 and 80%, NPV of 83, 86 and 88%, respectively. DS and rPET differed only in two patients. FLIPI was not predictive of progression and relapse. rPET is a prognostic factor in patients with FL submitted to PI-PET. Although it has a similar prognostic power as DS, it can have methodological advantages over visual analysis. PI-PET with different evaluation systems has a stronger prognostic power than FLIPI at diagnosis, so it could be useful to identify patients with FL at risk for early relapse after immuno-chemotherapy.

Use of enzyme-linked immunosorbent assay to screen for aflatoxins, ochratoxin A, and deoxynivalenol in dry pet foods.

PubMed

Okuma, Tara A; Huynh, Thu P; Hellberg, Rosalee S

2018-03-01

The objective of this study was to perform a market survey on dry pet foods using enzyme-linked immunosorbent assay (ELISA) to detect total aflatoxins (AFs), ochratoxin A (OTA), and deoxynivalenol (DON). Pet food products (n = 58) marketed for dogs, cats, birds, and rabbits were tested in duplicate with ELISA, and results above the limit of quantitation were confirmed using liquid chromatography tandem mass spectrometry (LC-MS/MS). OTA was detected in one product (rabbit food) and AFs were detected in two products (one dog treat and one bird treat). In contrast, DON was detected in the majority (74%) of products tested. Bird and rabbit products were the most affected by DON, with levels above 0.5 μg/g in 50 and 80% of samples, respectively. One rabbit sample tested positive for both OTA and DON. Overall, the findings of this study revealed a low incidence of AFs and OTA in commercial pet food. Although DON was detected in numerous products, the levels were well below those associated with acute toxic effects.

A high-affinity [ 18F]-labeled phosphoramidate peptidomimetic PSMA-targeted inhibitor for PET imaging of prostate cancer

DOE PAGES

Ganguly, Tanushree; Dannoon, Shorouk; Hopkins, Mark R.; ...

2015-06-09

Here in this study, a structurally modified phosphoramidate scaffold, with improved prostate-specific membrane antigen (PSMA) avidity, stability and in vivo characteristics, as a PET imaging agent for prostate cancer (PCa), was prepared and evaluated. p-Fluorobenzoyl-aminohexanoate and 2-(3-hydroxypropyl)glycine were introduced into the PSMA-targeting scaffold yielding phosphoramidate 5. X-ray crystallography was performed on the PSMA/5 complex. [ 18F]5 was synthesized, and cell uptake and internalization studies were conducted in PSMA(+) LNCaP and CWR22Rv1 cells and PSMA(-) PC-3 cells. In vivo PET imaging and biodistribution studies were performed at 1 and 4 h post injection in mice bearing CWR22Rv1 tumor, with or withoutmore » blocking agent. The crystallographic data showed interaction of the p-fluorobenzoyl group with an arene-binding cleft on the PSMA surface. In vitro studies revealed elevated uptake of [ 18F]5 in PSMA(+) cells (2.2% in CWR22Rv1 and 12.1% in LNCaP) compared to PSMA(-) cells (0.08%) at 4 h. In vivo tumor uptake of 2.33% ID/g and tumor-to-blood ratio of 265:1 was observed at 4 h. In conclusion, we have successfully synthesized, radiolabeled and evaluated a new PSMA-targeted PET agent. The crystal structure of the PSMA/5 complex highlighted the interactions within the arene-binding cleft contributing to the overall complex stability. The high target uptake and rapid non-target clearance exhibited by [ 18F]5 in PSMA(+) xenografts substantiates its potential use for PET imaging of PCa.« less

Quantitative imaging of protein targets in the human brain with PET

NASA Astrophysics Data System (ADS)

Gunn, Roger N.; Slifstein, Mark; Searle, Graham E.; Price, Julie C.

2015-11-01

PET imaging of proteins in the human brain with high affinity radiolabelled molecules has a history stretching back over 30 years. During this period the portfolio of protein targets that can be imaged has increased significantly through successes in radioligand discovery and development. This portfolio now spans six major categories of proteins; G-protein coupled receptors, membrane transporters, ligand gated ion channels, enzymes, misfolded proteins and tryptophan-rich sensory proteins. In parallel to these achievements in radiochemical sciences there have also been significant advances in the quantitative analysis and interpretation of the imaging data including the development of methods for image registration, image segmentation, tracer compartmental modeling, reference tissue kinetic analysis and partial volume correction. In this review, we analyze the activity of the field around each of the protein targets in order to give a perspective on the historical focus and the possible future trajectory of the field. The important neurobiology and pharmacology is introduced for each of the six protein classes and we present established radioligands for each that have successfully transitioned to quantitative imaging in humans. We present a standard quantitative analysis workflow for these radioligands which takes the dynamic PET data, associated blood and anatomical MRI data as the inputs to a series of image processing and bio-mathematical modeling steps before outputting the outcome measure of interest on either a regional or parametric image basis. The quantitative outcome measures are then used in a range of different imaging studies including tracer discovery and development studies, cross sectional studies, classification studies, intervention studies and longitudinal studies. Finally we consider some of the confounds, challenges and subtleties that arise in practice when trying to quantify and interpret PET neuroimaging data including motion artifacts

Postoperative PET/CT and target delineation before adjuvant radiotherapy in patients with oral cavity squamous cell carcinoma.

PubMed

Dutta, Pinaki R; Riaz, Nadeem; McBride, Sean; Morris, Luc G; Patel, Snehal; Ganly, Ian; Wong, Richard J; Palmer, Frank; Schöder, Heiko; Lee, Nancy

2016-04-01

The purpose of this study was for us to present our evaluation of the effectiveness of positron emission tomography (PET)/CT imaging in postoperative patients with oral cavity squamous cell carcinoma (SCC) before initiating adjuvant radiation therapy. Treatment planning PET/CT scans were obtained in 44 patients with oral cavity SCC receiving adjuvant radiation. We identified target areas harboring macroscopic disease requiring higher radiation doses or additional surgery. Fourteen PET/CT scans were abnormal. Thirteen patients underwent surgery and/or biopsy, increased radiation dose, and/or addition of chemotherapy. Eleven patients received higher radiation doses. Patients undergoing imaging >8 weeks were more likely to have abnormal results (p = .01). One-year distant metastases-free survival was significantly worse in patients with positive PET/CT scans (61.5% vs 92.7%; p = .01). The estimated positive predictive value (PPV) was 38% for postoperative PET/CT scanning. We demonstrated that 32% of patients have abnormal PET/CT scans resulting in management changes. Patients may benefit from postoperative PET/CT imaging to optimize adjuvant radiation treatment planning. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1285-E1293, 2016. © 2015 Wiley Periodicals, Inc.

Modelling PET radionuclide production in tissue and external targets using Geant4

NASA Astrophysics Data System (ADS)

Amin, T.; Infantino, A.; Lindsay, C.; Barlow, R.; Hoehr, C.

2017-07-01

The Proton Therapy Facility in TRIUMF provides 74 MeV protons extracted from a 500 MeV H- cyclotron for ocular melanoma treatments. During treatment, positron emitting radionuclides such as 1C, 15O and 13N are produced in patient tissue. Using PET scanners, the isotopic activity distribution can be measured for in-vivo range verification. A second cyclotron, the TR13, provides 13 MeV protons onto liquid targets for the production of PET radionuclides such as 18F, 13N or 68Ga, for medical applications. The aim of this work was to validate Geant4 against FLUKA and experimental measurements for production of the above-mentioned isotopes using the two cyclotrons. The results show variable degrees of agreement. For proton therapy, the proton-range agreement was within 2 mm for 11C activity, whereas 13N disagreed. For liquid targets at the TR13 the average absolute deviation ratio between FLUKA and experiment was 1.9±2.7, whereas the average absolute deviation ratio between Geant4 and experiment was 0. 6±0.4. This is due to the uncertainties present in experimentally determined reaction cross sections.

Targeting Anti-Cancer Active Compounds: Affinity-Based Chromatographic Assays

PubMed Central

de Moraes, Marcela Cristina; Cardoso, Carmen Lucia; Seidl, Claudia; Moaddel, Ruin; Cass, Quezia Bezerra

2016-01-01

Affinity-based chromatography assays encompass the use of solid supports containing immobilized biological targets to monitor binding events in the isolation , identification and/or characterization of bioactive compounds. This powerful bioanalytical technique allows the screening of potential binders through fast analyses that can be directly performed using isolated substances or complex matrices. An overview of the recent researches in frontal and zonal affinity-based chromatography screening assays, which has been used as a tool in the identification and characterization of new anti-cancer agents, is discussed. In addition, a critical evaluation of the recently emerged ligands fishing assays in complex mixtures is also discussed. PMID:27306095

Flexible Al-doped ZnO films grown on PET substrates using linear facing target sputtering for flexible OLEDs

NASA Astrophysics Data System (ADS)

Jeong, Jin-A.; Shin, Hyun-Su; Choi, Kwang-Hyuk; Kim, Han-Ki

2010-11-01

We report the characteristics of flexible Al-doped zinc oxide (AZO) films prepared by a plasma damage-free linear facing target sputtering (LFTS) system on PET substrates for use as a flexible transparent conducting electrode in flexible organic light-emitting diodes (OLEDs). The electrical, optical and structural properties of LFTS-grown flexible AZO electrodes were investigated as a function of dc power. We obtained a flexible AZO film with a sheet resistance of 39 Ω/squ and an average transmittance of 84.86% in the visible range although it was sputtered at room temperature without activation of the Al dopant. Due to the effective confinement of the high-density plasma between the facing AZO targets, the AZO film was deposited on the PET substrate without plasma damage and substrate heating caused by bombardment of energy particles. Moreover, the flexible OLED fabricated on the AZO/PET substrate showed performance similar to the OLED fabricated on a ITO/PET substrate in spite of a lower work function. This indicates that LFTS is a promising plasma damage-free and low-temperature sputtering technique for deposition of flexible and indium-free AZO electrodes for use in cost-efficient flexible OLEDs.

Uterotrophic and Hershberger assays for endocrine disruption properties of plastic food contact materials polypropylene (PP) and polyethylene terephthalate (PET).

PubMed

Chung, Bu Young; Kyung, Minji; Lim, Seong Kwang; Choi, Seul Min; Lim, Duck Soo; Kwack, Seung Jun; Kim, Hyung Sik; Lee, Byung-Mu

2013-01-01

Plasticizers or plastic materials such as phthalates, bisphenol-A (BPA), and styrene are widely used in the plastic industry and are suspected endocrine-disrupting chemicals (EDC). Although plastic materials such as polypropylene (PP) and polyethylene terephthalate (PET) are not EDC and are considered to be safe, their potential properties as EDC have not been fully investigated. In this study, plastic samples eluted from plastic food containers (PP or PET) were investigated in Sprague-Dawley rats using Hershberger and uterotrophic assays. In the Hershberger assay, 6-wk-old castrated male rats were orally treated for 10 consecutive days with plastic effluent at 3 different doses (5 ml/kg) or vehicle control (corn oil, 1 ml/100 g) to determine the presence of both anti-androgenic and androgenic effects. Testosterone (0.4 mg/ml/kg) was subcutaneously administered for androgenic evaluation as a positive control, whereas testosterone (0.4 mg/ml/kg) and flutamide (3 mg/kg/day) were administered to a positive control group for anti-androgenic evaluation. The presence of any anti-androgenic or androgenic activities of plastic effluent was not detected. Sex accessory tissues such as ventral prostate or seminal vesicle showed no significant differences in weight between treated and control groups. For the uterotrophic assay, immature female rats were treated with plastic effluent at three different doses (5 ml/kg), with vehicle control (corn oil, 1 ml/100 g), or with ethinyl estradiol (3 μg/kg/d) for 3 d. There were no significant differences between test and control groups in vagina or uterine weight. Data suggest that effluents from plastic food containers do not appear to produce significant adverse effects according to Hershberger and uterotrophic assays.

Comparative Study With New Accuracy Metrics for Target Volume Contouring in PET Image Guided Radiation Therapy

PubMed Central

Shepherd, T; Teras, M; Beichel, RR; Boellaard, R; Bruynooghe, M; Dicken, V; Gooding, MJ; Julyan, PJ; Lee, JA; Lefèvre, S; Mix, M; Naranjo, V; Wu, X; Zaidi, H; Zeng, Z; Minn, H

2017-01-01

The impact of positron emission tomography (PET) on radiation therapy is held back by poor methods of defining functional volumes of interest. Many new software tools are being proposed for contouring target volumes but the different approaches are not adequately compared and their accuracy is poorly evaluated due to the ill-definition of ground truth. This paper compares the largest cohort to date of established, emerging and proposed PET contouring methods, in terms of accuracy and variability. We emphasize spatial accuracy and present a new metric that addresses the lack of unique ground truth. Thirty methods are used at 13 different institutions to contour functional volumes of interest in clinical PET/CT and a custom-built PET phantom representing typical problems in image guided radiotherapy. Contouring methods are grouped according to algorithmic type, level of interactivity and how they exploit structural information in hybrid images. Experiments reveal benefits of high levels of user interaction, as well as simultaneous visualization of CT images and PET gradients to guide interactive procedures. Method-wise evaluation identifies the danger of over-automation and the value of prior knowledge built into an algorithm. PMID:22692898

SU-E-I-81: Targeting of HER2-Expressing Tumors with Dual PET-MR Imaging Probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, P; Peng, Y; Sun, M

2015-06-15

Purpose: The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Trastuzumab, effective in about 15 % of women with breast cancer, downregulates signalling through the Akt/PI3K and MAPK pathways.These pathways modulate metabolism which can be monitored by positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: The relationship between response of HER2 overexpressing tumours and changes in imaging PET or SPECT and MRI willmore » be examined by a integrated bimodal imaging probe.Small (7 kDa) high-affinity anti-HER2 Affibody molecules and KCCYSL targeting peptide may be suitable tracers for visualization of HER2-expressing tumors. Peptide-conjugated iron oxide nanoparticles (Fe3O4 NPs) as MRI imaging and CB-TE2A as PET imaging are integrated into a single synthetic molecule in the HER2 positive cancer. Results: One of targeted contrast bimodal imaging probe agents was synthesized and evaluated to target HER2-expressing tumors in a HER2 positive rat model. We will report the newest results regarding the development of bimodal imaging probes. Conclusion: The preliminary results of the bimodal imaging probe presents high correlation of MRI signal and PET imaging intensity in vivo. This unique feature can hardly be obtained by single model contrast agents. It is envisioned that this bimodal agents can hold great potential for accurate detection of HER2-expressing tumors which are critical for clinical management of the disease.« less

Target volume definition for 18F-FDG PET-positive lymph nodes in radiotherapy of patients with non-small cell lung cancer.

PubMed

Nestle, Ursula; Schaefer-Schuler, Andrea; Kremp, Stephanie; Groeschel, Andreas; Hellwig, Dirk; Rübe, Christian; Kirsch, Carl-Martin

2007-04-01

FDG PET is increasingly used in radiotherapy planning. Recently, we demonstrated substantial differences in target volumes when applying different methods of FDG-based contouring in primary lung tumours (Nestle et al., J Nucl Med 2005;46:1342-8). This paper focusses on FDG-positive mediastinal lymph nodes (LN(PET)). In our institution, 51 NSCLC patients who were candidates for radiotherapy prospectively underwent staging FDG PET followed by a thoracic PET scan in the treatment position and a planning CT. Eleven of them had 32 distinguishable non-confluent mediastinal or hilar nodal FDG accumulations (LN(PET)). For these, sets of gross tumour volumes (GTVs) were generated at both acquisition times by four different PET-based contouring methods (visual: GTV(vis); 40% SUVmax: GTV40; SUV=2.5: GTV2.5; target/background (T/B) algorithm: GTV(bg)). All differences concerning GTV sizes were within the range of the resolution of the PET system. The detectability and technical delineability of the GTVs were significantly better in the late scans (e.g. p = 0.02 for diagnostic application of SUVmax = 2.5; p = 0.0001 for technical delineability by GTV2.5; p = 0.003 by GTV40), favouring the GTV(bg) method owing to satisfactory overall applicability and independence of GTVs from acquisition time. Compared with CT, the majority of PET-based GTVs were larger, probably owing to resolution effects, with a possible influence of lesion movements. For nodal GTVs, different methods of contouring did not lead to clinically relevant differences in volumes. However, there were significant differences in technical delineability, especially after early acquisition. Overall, our data favour a late acquisition of FDG PET scans for radiotherapy planning, and the use of a T/B algorithm for GTV contouring.

Targeted proteomic assays for quantitation of proteins identified by proteogenomic analysis of ovarian cancer

DOE PAGES

Song, Ehwang; Gao, Yuqian; Wu, Chaochao; ...

2017-07-19

Here, mass spectrometry (MS) based targeted proteomic methods such as selected reaction monitoring (SRM) are becoming the method of choice for preclinical verification of candidate protein biomarkers. The Clinical Proteomic Tumor Analysis Consortium (CPTAC) of the National Cancer Institute has investigated the standardization and analytical validation of the SRM assays and demonstrated robust analytical performance on different instruments across different laboratories. An Assay Portal has also been established by CPTAC to provide the research community a resource consisting of large set of targeted MS-based assays, and a depository to share assays publicly, providing that assays meet the guidelines proposed bymore » CPTAC. Herein, we report 98 SRM assays covering 70 candidate protein biomarkers previously reported as associated with ovarian cancer that have been thoroughly characterized according to the CPTAC Assay Characterization Guidance Document. The experiments, methods and results for characterizing these SRM assays for their MS response, repeatability, selectivity, stability, and reproducible detection of endogenous analytes are described in detail.« less

Performance Assessment PCR-Based Assays Targeting Bacteroidales Genetic Markers of Bovine Fecal Pollution▿

PubMed Central

Shanks, Orin C.; White, Karen; Kelty, Catherine A.; Hayes, Sam; Sivaganesan, Mano; Jenkins, Michael; Varma, Manju; Haugland, Richard A.

2010-01-01

There are numerous PCR-based assays available to characterize bovine fecal pollution in ambient waters. The determination of which approaches are most suitable for field applications can be difficult because each assay targets a different gene, in many cases from different microorganisms, leading to variation in assay performance. We describe a performance evaluation of seven end-point PCR and real-time quantitative PCR (qPCR) assays reported to be associated with either ruminant or bovine feces. Each assay was tested against a reference collection of DNA extracts from 247 individual bovine fecal samples representing 11 different populations and 175 fecal DNA extracts from 24 different animal species. Bovine-associated genetic markers were broadly distributed among individual bovine samples ranging from 39 to 93%. Specificity levels of the assays spanned 47.4% to 100%. End-point PCR sensitivity also varied between assays and among different bovine populations. For qPCR assays, the abundance of each host-associated genetic marker was measured within each bovine population and compared to results of a qPCR assay targeting 16S rRNA gene sequences from Bacteroidales. Experiments indicate large discrepancies in the performance of bovine-associated assays across different bovine populations. Variability in assay performance between host populations suggests that the use of bovine microbial source-tracking applications will require a priori characterization at each watershed of interest. PMID:20061457

Presynaptic selectivity of a ligand for serotonin 1A receptors revealed by in vivo PET assays of rat brain.

PubMed

Saijo, Takeaki; Maeda, Jun; Okauchi, Takashi; Maeda, Jun-ichi; Morio, Yasunori; Kuwahara, Yasuhiro; Suzuki, Masayuki; Goto, Nobuharu; Fukumura, Toshimitsu; Suhara, Tetsuya; Higuchi, Makoto

2012-01-01

A novel investigational antidepressant with high affinity for the serotonin transporter and the serotonin 1A (5-HT(1A)) receptor, called Wf-516 (structural formula: (2S)-1-[4-(3,4-dichlorophenyl)piperidin-1-yl]-3-[2-(5-methyl-1,3,4-oxadiazol-2-yl)benzo[b]furan-4-yloxy]propan-2-ol monohydrochloride), has been found to exert a rapid therapeutic effect, although the mechanistic basis for this potential advantage remains undetermined. We comparatively investigated the pharmacokinetics and pharmacodynamics of Wf-516 and pindolol by positron emission tomographic (PET) and autoradiographic assays of rat brains in order to elucidate their molecular interactions with presynaptic and postsynaptic 5-HT(1A) receptors. In contrast to the full receptor occupancy by pindolol in PET measurements, the binding of Wf-516 to 5-HT(1A) receptors displayed limited capacity, with relatively high receptor occupancy being achieved in regions predominantly containing presynaptic receptors. This selectivity was further proven by PET scans of neurotoxicant-treated rats deficient in presynaptic 5-HT(1A) receptors. In addition, [(35)S]guanosine 5'-O-[γ-thio]triphosphate autoradiography indicated a partial agonistic ability of Wf-516 for 5-HT(1A) receptors. This finding has lent support to reports that diverse partial agonists for 5-HT(1A) receptors exert high sensitivity for presynaptic components. Thus, the present PET data suggest a relatively high capacity of presynaptic binding sites for partial agonists. Since our in vitro and ex vivo autoradiographies failed to illustrate these distinct features of Wf-516, in vivo PET imaging is considered to be, thus far, the sole method capable of pharmacokinetically demonstrating the unique actions of Wf-516 and similar new-generation antidepressants.

Presynaptic Selectivity of a Ligand for Serotonin 1A Receptors Revealed by In Vivo PET Assays of Rat Brain

PubMed Central

Okauchi, Takashi; Maeda, Jun-ichi; Morio, Yasunori; Kuwahara, Yasuhiro; Suzuki, Masayuki; Goto, Nobuharu; Fukumura, Toshimitsu; Suhara, Tetsuya; Higuchi, Makoto

2012-01-01

A novel investigational antidepressant with high affinity for the serotonin transporter and the serotonin 1A (5-HT1A) receptor, called Wf-516 (structural formula: (2S)-1-[4-(3,4-dichlorophenyl)piperidin-1-yl]-3-[2-(5-methyl-1,3,4-oxadiazol-2-yl)benzo[b]furan-4-yloxy]propan-2-ol monohydrochloride), has been found to exert a rapid therapeutic effect, although the mechanistic basis for this potential advantage remains undetermined. We comparatively investigated the pharmacokinetics and pharmacodynamics of Wf-516 and pindolol by positron emission tomographic (PET) and autoradiographic assays of rat brains in order to elucidate their molecular interactions with presynaptic and postsynaptic 5-HT1A receptors. In contrast to the full receptor occupancy by pindolol in PET measurements, the binding of Wf-516 to 5-HT1A receptors displayed limited capacity, with relatively high receptor occupancy being achieved in regions predominantly containing presynaptic receptors. This selectivity was further proven by PET scans of neurotoxicant-treated rats deficient in presynaptic 5-HT1A receptors. In addition, [35S]guanosine 5′-O-[γ-thio]triphosphate autoradiography indicated a partial agonistic ability of Wf-516 for 5-HT1A receptors. This finding has lent support to reports that diverse partial agonists for 5-HT1A receptors exert high sensitivity for presynaptic components. Thus, the present PET data suggest a relatively high capacity of presynaptic binding sites for partial agonists. Since our in vitro and ex vivo autoradiographies failed to illustrate these distinct features of Wf-516, in vivo PET imaging is considered to be, thus far, the sole method capable of pharmacokinetically demonstrating the unique actions of Wf-516 and similar new-generation antidepressants. PMID:22880045

Detection of early stage atherosclerotic plaques using PET and CT fusion imaging targeting P-selectin in low density lipoprotein receptor-deficient mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Ikuko, E-mail: nakamuri@riken.jp; Department of Cardiovascular Medicine, Saga University, Saga; Hasegawa, Koki

2013-03-29

Highlights: ► P-selectin regulates leukocyte recruitment as an early stage event of atherogenesis. ► We developed an antibody-based molecular imaging probe targeting P-selectin for PET. ► This is the first report on successful PET imaging for delineation of P-selectin. ► P-selectin is a candidate target for atherosclerotic plaque imaging by clinical PET. -- Abstract: Background: Sensitive detection and qualitative analysis of atherosclerotic plaques are in high demand in cardiovascular clinical settings. The leukocyte–endothelial interaction mediated by an adhesion molecule P-selectin participates in arterial wall inflammation and atherosclerosis. Methods and results: A {sup 64}Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid conjugated anti-P-selectin monoclonal antibody ({sup 64}Cu-DOTA-anti-P-selectinmore » mAb) probe was prepared by conjugating an anti-P-selectin monoclonal antibody with DOTA followed by {sup 64}Cu labeling. Thirty-six hours prior to PET and CT fusion imaging, 3 MBq of {sup 64}Cu-DOTA-anti-P-selectin mAb was intravenously injected into low density lipoprotein receptor-deficient Ldlr-/- mice. After a 180 min PET scan, autoradiography and biodistribution of {sup 64}Cu-DOTA-anti-P-selectin monoclonal antibody was examined using excised aortas. In Ldlr-/- mice fed with a high cholesterol diet for promotion of atherosclerotic plaque development, PET and CT fusion imaging revealed selective and prominent accumulation of the probe in the aortic root. Autoradiography of aortas that demonstrated probe uptake into atherosclerotic plaques was confirmed by Oil red O staining for lipid droplets. In Ldlr-/- mice fed with a chow diet to develop mild atherosclerotic plaques, probe accumulation was barely detectable in the aortic root on PET and CT fusion imaging. Probe biodistribution in aortas was 6.6-fold higher in Ldlr-/- mice fed with a high cholesterol diet than in those fed with a normal chow diet. {sup 64}Cu-DOTA-anti-P-selectin m

SU-E-CAMPUS-I-06: Y90 PET/CT for the Instantaneous Determination of Both Target and Non-Target Absorbed Doses Following Hepatic Radioembolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasciak, A; Kao, J

2014-06-15

Purpose The process of converting Yttrium-90 (Y90) PET/CT images into 3D absorbed dose maps will be explained. The simple methods presented will allow the medical physicst to analyze Y90 PET images following radioembolization and determine the absorbed dose to tumor, normal liver parenchyma and other areas of interest, without application of Monte-Carlo radiation transport or dose-point-kernel (DPK) convolution. Methods Absorbed dose can be computed from Y90 PET/CT images based on the premise that radioembolization is a permanent implant with a constant relative activity distribution after infusion. Many Y90 PET/CT publications have used DPK convolution to obtain 3D absorbed dose maps.more » However, this method requires specialized software limiting clinical utility. The Local Deposition method, an alternative to DPK convolution, can be used to obtain absorbed dose and requires no additional computer processing. Pixel values from regions of interest drawn on Y90 PET/CT images can be converted to absorbed dose (Gy) by multiplication with a scalar constant. Results There is evidence that suggests the Local Deposition method may actually be more accurate than DPK convolution and it has been successfully used in a recent Y90 PET/CT publication. We have analytically compared dose-volume-histograms (DVH) for phantom hot-spheres to determine the difference between the DPK and Local Deposition methods, as a function of PET scanner point-spread-function for Y90. We have found that for PET/CT systems with a FWHM greater than 3.0 mm when imaging Y90, the Local Deposition Method provides a more accurate representation of DVH, regardless of target size than DPK convolution. Conclusion Using the Local Deposition Method, post-radioembolization Y90 PET/CT images can be transformed into 3D absorbed dose maps of the liver. An interventional radiologist or a Medical Physicist can perform this transformation in a clinical setting, allowing for rapid prediction of treatment efficacy

Comparison of quantitative PCR assays for Escherichia coli targeting ribosomal RNA and single copy genes

EPA Science Inventory

Aims: Compare specificity and sensitivity of quantitative PCR (qPCR) assays targeting single and multi-copy gene regions of Escherichia coli. Methods and Results: A previously reported assay targeting the uidA gene (uidA405) was used as the basis for comparing the taxono...

The impact of 18 F-FET PET-CT on target definition in image-guided stereotactic radiotherapy in patients with skull base lesions.

PubMed

Badakhshi, Harun; Graf, Reinhold; Prasad, Vikas; Budach, Volker

2014-06-25

18 F-fluoro-ethyl-tyrosine PET is gaining more indications in the field of oncology. We investigated the potentials of usage of FET-PET/CT in addition to MRI for definition of gross tumor volume (GTV) in stereotactic radiotherapy of lesions of skull base. We included in a prospective setting 21 cases. An MRI was performed, completed by FET PET/CT. Different GTV's were defined based on respective imaging tools: 1. GTVMRI, 2. GTV MRI /CT, 3. GTV composit (1 + 2), and GTVPET = GTV Boost. Lesions could be visualised by MRI and FET-PET/CT in all patients. FET tracer enhancement was found in all cases. Skull base infiltration by these lesions was observed by MRI, CT (PET/CT) and FET-PET (PET/CT) in all patients. Totally, brain tissue infiltration was seen in 10 patients. While, in 7 (out 10) cases, MRI and CT (from PET/CT) were indicating brain infiltration, FET-PET could add additional information regarding infiltrative behaviour: in 3 (out 10) patients, infiltration of the brain was displayed merely in FET-PET. An enlargement of GTVMRI/CT due to the FET-PET driven information, which revealed GTVcomposite , was necessary in 7 cases,. This enlargement was significant by definition (> 10% of GTVMRI/CT). The mean PET-effect on GTV counted for 1 ± 4 cm3. The restricted boost fields were based mainly on the GTVPET volume. In mean, about 8.5 cm3 of GTVMRI/CT, which showed no FET uptake, were excluded from target volume. GTV boost driven by only-PET-activity, was in mean by 33% smaller than the initial large treatment field, GTV composite, for those cases received boost treatment. FET-PET lead to significant (>10%) changes in the initial treatment fields in 11/21 patients and showed additional tumour volume relevant for radiation planning in 6/21 cases, and led to a subsequent decrease of more than 10% of the initial volumes for the boost fields. The implementation of FET PET into the planning procedures showed a benefit in terms of accurate definition of skull base lesions

Discovery of Phosphodiesterase 10A (PDE10A) PET Tracer AMG 580 to Support Clinical Studies.

PubMed

Hu, Essa; Chen, Ning; Kunz, Roxanne K; Hwang, Dah-Ren; Michelsen, Klaus; Davis, Carl; Ma, Ji; Shi, Jianxia; Lester-Zeiner, Dianna; Hungate, Randall; Treanor, James; Chen, Hang; Allen, Jennifer R

2016-07-14

We report the discovery of PDE10A PET tracer AMG 580 developed to support proof of concept studies with PDE10A inhibitors in the clinic. To find a tracer with higher binding potential (BPND) in NHP than our previously reported tracer 1, we implemented a surface plasmon resonance assay to measure the binding off-rate to identify candidates with slower washout rate in vivo. Five candidates (2-6) from two structurally distinct scaffolds were identified that possessed both the in vitro characteristics that would favor central penetration and the structural features necessary for PET isotope radiolabeling. Two cinnolines (2, 3) and one keto-benzimidazole (5) exhibited PDE10A target specificity and brain uptake comparable to or better than 1 in the in vivo LC-MS/MS kinetics distribution study in SD rats. In NHP PET imaging study, [(18)F]-5 produced a significantly improved BPND of 3.1 and was nominated as PDE10A PET tracer clinical candidate for further studies.

Quantitative PET Imaging with Novel HER3 Targeted Peptides Selected by Phage Display to Predict Androgen Independent Prostate Cancer Progression

DTIC Science & Technology

2017-08-01

9 4 1. Introduction The subject of this research is the design and testing of a PET imaging agent for the detection and...AWARD NUMBER: W81XWH-16-1-0447 TITLE: Quantitative PET Imaging with Novel HER3-Targeted Peptides Selected by Phage Display to Predict Androgen...MA 02114 REPORT DATE: August 2017 TYPE OF REPORT: Annual PREPARED FOR: U.S. Army Medical Research and Materiel Command Fort Detrick, Maryland

Molecular prevalence of Cryptosporidium species among household cats and pet shop kittens in Japan.

PubMed

Ito, Yoichi; Itoh, Naoyuki; Iijima, Yuko; Kimura, Yuya

2017-01-01

To address the lack of up-to-date published data, the present study evaluates the PCR-based prevalence of Cryptosporidium species infection and molecular characteristics of isolates among household cats and pet shop kittens in Japan. A total of 357 and 329 fresh faecal samples were collected from household cats and pet shop kittens, respectively, with or without clinical signs of infection. A nested PCR assay targeting the 18S rRNA gene was employed for the detection of Cryptosporidium species. After specific DNA fragments (approximately 826 base pairs) were confirmed, the amplicons were sequenced to determine species. Seven (2.0%) household cats and one (0.3%) pet shop kitten tested positive for the presence of Cryptosporidium species. In household cats, there was a significant difference in prevalence between cats aged <1 year (4.6%) and those aged ⩾1 year (0.4%). No significantly different prevalence was observed with regard to faecal condition in either household cats or pet shop kittens. A total of eight Cryptosporidium species isolates, seven from household cats and one from a pet shop kitten, were identified as Cryptosporidium felis . The present study demonstrates the risk of zoonotic transmission of Cryptosporidium species from household cats and pet shop kittens to humans is low in Japan.

High performance ZnO:Al films deposited on PET substrates using facing target sputtering

NASA Astrophysics Data System (ADS)

Guo, Tingting; Dong, Guobo; Gao, Fangyuan; Xiao, Yu; Chen, Qiang; Diao, Xungang

2013-10-01

ZnO:Al (ZAO) thin films have been deposited on flexible PET substrates using a plasma damage-free facing target sputtering system at room temperature. The structure, surface morphology, electrical and optical properties were investigated as a function of working power. All the samples have a highly preferred orientation of the c-axis perpendicular to the PET substrate and have a high quality surface. With increased working power, the carrier concentration changes slightly, the mobility increases at the beginning and decreases after it reaches a maximum value, in line with electrical conductivity. The figure of merit has been significantly improved with increasing of the working power. Under the optimized condition, the lowest resistivity of 1.3 × 10-3 Ω cm with a sheet resistance of 29 Ω/□ and the relative visible transmittance above 93% in the visible region were obtained.

A cell death assay for assessing the mitochondrial targeting of proteins.

PubMed

Camara Teixeira, Daniel; Cordonier, Elizabeth L; Wijeratne, Subhashinee S K; Huebbe, Patricia; Jamin, Augusta; Jarecke, Sarah; Wiebe, Matthew; Zempleni, Janos

2018-06-01

The mitochondrial proteome comprises 1000 to 1500 proteins, in addition to proteins for which the mitochondrial localization is uncertain. About 800 diseases have been linked with mutations in mitochondrial proteins. We devised a cell survival assay for assessing the mitochondrial localization in a high-throughput format. This protocol allows us to assess the mitochondrial localization of proteins and their mutants, and to identify drugs and nutrients that modulate the mitochondrial targeting of proteins. The assay works equally well for proteins directed to the outer mitochondrial membrane, inner mitochondrial membrane mitochondrial and mitochondrial matrix, as demonstrated by assessing the mitochondrial targeting of the following proteins: carnitine palmitoyl transferase 1 (consensus sequence and R123C mutant), acetyl-CoA carboxylase 2, uncoupling protein 1 and holocarboxylase synthetase. Our screen may be useful for linking the mitochondrial proteome with rare diseases and for devising drug- and nutrition-based strategies for altering the mitochondrial targeting of proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

Targeted Molecular Imaging in Adrenal Disease—An Emerging Role for Metomidate PET-CT

PubMed Central

Mendichovszky, Iosif A.; Powlson, Andrew S.; Manavaki, Roido; Aigbirhio, Franklin I.; Cheow, Heok; Buscombe, John R.; Gurnell, Mark; Gilbert, Fiona J.

2016-01-01

Adrenal lesions present a significant diagnostic burden for both radiologists and endocrinologists, especially with the increasing number of adrenal ‘incidentalomas’ detected on modern computed tomography (CT) or magnetic resonance imaging (MRI). A key objective is the reliable distinction of benign disease from either primary adrenal malignancy (e.g., adrenocortical carcinoma or malignant forms of pheochromocytoma/paraganglioma (PPGL)) or metastases (e.g., bronchial, renal). Benign lesions may still be associated with adverse sequelae through autonomous hormone hypersecretion (e.g., primary aldosteronism, Cushing’s syndrome, phaeochromocytoma). Here, identifying a causative lesion, or lateralising the disease to a single adrenal gland, is key to effective management, as unilateral adrenalectomy may offer the potential for curing conditions that are typically associated with significant excess morbidity and mortality. This review considers the evolving role of positron emission tomography (PET) imaging in addressing the limitations of traditional cross-sectional imaging and adjunctive techniques, such as venous sampling, in the management of adrenal disorders. We review the development of targeted molecular imaging to the adrenocortical enzymes CYP11B1 and CYP11B2 with different radiolabeled metomidate compounds. Particular consideration is given to iodo-metomidate PET tracers for the diagnosis and management of adrenocortical carcinoma, and the increasingly recognized utility of 11C-metomidate PET-CT in primary aldosteronism. PMID:27869719

Expediting SRM assay development for large-scale targeted proteomics experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Chaochao; Shi, Tujin; Brown, Joseph N.

2014-08-22

Due to their high sensitivity and specificity, targeted proteomics measurements, e.g. selected reaction monitoring (SRM), are becoming increasingly popular for biological and translational applications. Selection of optimal transitions and optimization of collision energy (CE) are important assay development steps for achieving sensitive detection and accurate quantification; however, these steps can be labor-intensive, especially for large-scale applications. Herein, we explored several options for accelerating SRM assay development evaluated in the context of a relatively large set of 215 synthetic peptide targets. We first showed that HCD fragmentation is very similar to CID in triple quadrupole (QQQ) instrumentation, and by selection ofmore » top six y fragment ions from HCD spectra, >86% of top transitions optimized from direct infusion on QQQ instrument are covered. We also demonstrated that the CE calculated by existing prediction tools was less accurate for +3 precursors, and a significant increase in intensity for transitions could be obtained using a new CE prediction equation constructed from the present experimental data. Overall, our study illustrates the feasibility of expediting the development of larger numbers of high-sensitivity SRM assays through automation of transitions selection and accurate prediction of optimal CE to improve both SRM throughput and measurement quality.« less

Highly sensitive detection of target molecules using a new fluorescence-based bead assay

NASA Astrophysics Data System (ADS)

Scheffler, Silvia; Strauß, Denis; Sauer, Markus

2007-07-01

Development of immunoassays with improved sensitivity, specificity and reliability are of major interest in modern bioanalytical research. We describe the development of a new immunomagnetic fluorescence detection (IM-FD) assay based on specific antigen/antibody interactions and on accumulation of the fluorescence signal on superparamagnetic PE beads in combination with the use of extrinsic fluorescent labels. IM-FD can be easily modified by varying the order of coatings and assay conditions. Depending on the target molecule, antibodies (ABs), entire proteins, or small protein epitopes can be used as capture molecules. The presence of target molecules is detected by fluorescence microscopy using fluorescently labeled secondary or detection antibodies. Here, we demonstrate the potential of the new assay detecting the two tumor markers IGF-I and p53 antibodies in the clinically relevant concentration range. Our data show that the fluorescence-based bead assay exhibits a large dynamic range and a high sensitivity down to the subpicomolar level.

Impact of 4D-(18)FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study.

PubMed

Chirindel, Alin; Adebahr, Sonja; Schuster, Daniel; Schimek-Jasch, Tanja; Schanne, Daniel H; Nemer, Ursula; Mix, Michael; Meyer, Philipp; Grosu, Anca-Ligia; Brunner, Thomas; Nestle, Ursula

2015-06-01

Evaluation of the effect of co-registered 4D-(18)FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors. Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement. 11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm(3) and PET/CT-ITV 8.6 cm(3), resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p=0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm(3), PET/CT-ITVs 44.2 cm(3), without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p<0.05). 2/10 PET/CT-ITVs exceeded the PTVs derived from CT-ITVs by >1 ml in average for all observers. The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

FDG PET Imaging in Pneumocystis Pneumonia.

PubMed

Kono, Masanori; Yamashita, Hiroyuki; Kubota, Kazuo; Kano, Toshikazu; Mimori, Akio

2015-08-01

A 69-year-old woman with rheumatoid arthritis and pleuritis presented with dyspnea. On admission, she was afebrile and had an oxygen saturation of 97% on ambient air. Chest radiography and CT revealed only subtle ground-glass opacities. However, FDG PET revealed pathological uptake in both lungs. A diagnosis of Pneumocystis pneumonia was made based on a positive β-D-glucan assay and polymerase chain reaction amplification of Pneumocystis jirovecii from the sputum. Posttreatment FDG PET revealed resolution of the previously noted uptake. This case illustrates that FDG PET can be used to diagnose Pneumocystis pneumonia when the CT findings are equivocal.

Type I collagen-targeted PET probe for pulmonary fibrosis detection and staging in preclinical models

PubMed Central

Désogère, Pauline; Tapias, Luis F.; Hariri, Lida P.; Rotile, Nicholas J.; Rietz, Tyson A.; Probst, Clemens K.; Blasi, Francesco; Day, Helen; Mino-Kenudson, Mari; Weinreb, Paul; Violette, Shelia M.; Fuchs, Bryan C.; Tager, Andrew M.; Lanuti, Michael; Caravan, Peter

2017-01-01

Pulmonary fibrosis is a scarring of the lungs that can arise from radiation injury, drug toxicity, environmental or genetic causes, and for unknown reasons [idiopathic pulmonary fibrosis (IPF)]. Overexpression of collagen is a hallmark of organ fibrosis. Here, we describe a peptide-based PET probe (68Ga-CBP8) that targets collagen type I. We evaluated 68Ga-CBP8 in vivo in the bleomycin-induced mouse model of pulmonary fibrosis. 68Ga-CBP8 showed high specificity for pulmonary fibrosis and high target:background ratios in diseased animals. The lung PET signal and lung 68Ga-CBP8 uptake (quantified ex vivo) correlated linearly (r2=0.80) with the amount of lung collagen in mice with fibrosis. We further demonstrated that the 68Ga-CBP8 probe could be used to monitor response to treatment in a second mouse model of pulmonary fibrosis associated with vascular leak. Ex vivo analysis of lung tissue from patients with IPF supported the animal findings. These studies indicate that 68Ga-CBP8 is a promising candidate for non-invasive imaging of human pulmonary fibrosis. PMID:28381537

A Multi-Receptor and Multi-Species Assay for Potential Endocrine Disruptor Targets (SLAS meeting)

EPA Science Inventory

Screening methods for detecting potential endocrine disrupting chemicals rely chiefly on transactivation assays targeting nuclear receptors such as the estrogen (ER) and androgen receptors (AR). These assays are predominately human-based; yet environmental exposure can affect div...

Optimal de novo design of MRM experiments for rapid assay development in targeted proteomics.

PubMed

Bertsch, Andreas; Jung, Stephan; Zerck, Alexandra; Pfeifer, Nico; Nahnsen, Sven; Henneges, Carsten; Nordheim, Alfred; Kohlbacher, Oliver

2010-05-07

Targeted proteomic approaches such as multiple reaction monitoring (MRM) overcome problems associated with classical shotgun mass spectrometry experiments. Developing MRM quantitation assays can be time consuming, because relevant peptide representatives of the proteins must be found and their retention time and the product ions must be determined. Given the transitions, hundreds to thousands of them can be scheduled into one experiment run. However, it is difficult to select which of the transitions should be included into a measurement. We present a novel algorithm that allows the construction of MRM assays from the sequence of the targeted proteins alone. This enables the rapid development of targeted MRM experiments without large libraries of transitions or peptide spectra. The approach relies on combinatorial optimization in combination with machine learning techniques to predict proteotypicity, retention time, and fragmentation of peptides. The resulting potential transitions are scheduled optimally by solving an integer linear program. We demonstrate that fully automated construction of MRM experiments from protein sequences alone is possible and over 80% coverage of the targeted proteins can be achieved without further optimization of the assay.

Molecular prevalence of Cryptosporidium species among household cats and pet shop kittens in Japan

PubMed Central

Ito, Yoichi; Itoh, Naoyuki; Iijima, Yuko; Kimura, Yuya

2017-01-01

Objectives To address the lack of up-to-date published data, the present study evaluates the PCR-based prevalence of Cryptosporidium species infection and molecular characteristics of isolates among household cats and pet shop kittens in Japan. Methods A total of 357 and 329 fresh faecal samples were collected from household cats and pet shop kittens, respectively, with or without clinical signs of infection. A nested PCR assay targeting the 18S rRNA gene was employed for the detection of Cryptosporidium species. After specific DNA fragments (approximately 826 base pairs) were confirmed, the amplicons were sequenced to determine species. Results Seven (2.0%) household cats and one (0.3%) pet shop kitten tested positive for the presence of Cryptosporidium species. In household cats, there was a significant difference in prevalence between cats aged <1 year (4.6%) and those aged ⩾1 year (0.4%). No significantly different prevalence was observed with regard to faecal condition in either household cats or pet shop kittens. A total of eight Cryptosporidium species isolates, seven from household cats and one from a pet shop kitten, were identified as Cryptosporidium felis. Conclusions and relevance The present study demonstrates the risk of zoonotic transmission of Cryptosporidium species from household cats and pet shop kittens to humans is low in Japan. PMID:28955478

Fluorescence self-quenching assay for the detection of target collagen sequences using a short probe peptide.

PubMed

Nian, Linge; Hu, Yue; Fu, Caihong; Song, Chen; Wang, Jie; Xiao, Jianxi

2018-01-01

The development of novel assays to detect collagen fragments is of utmost importance for diagnostic, prognostic and therapeutic decisions in various collagen-related diseases, and one essential question is to discover probe peptides that can specifically recognize target collagen sequences. Herein we have developed the fluorescence self-quenching assay as a convenient tool to screen the capability of a series of fluorescent probe peptides of variable lengths to bind with target collagen peptides. We have revealed that the targeting ability of probe peptides is length-dependent, and have discovered a relatively short probe peptide FAM-G(POG) 8 capable to identify the target peptide. We have further demonstrated that fluorescence self-quenching assay together with this short probe peptide can be applied to specifically detect the desired collagen fragment in complex biological media. Fluorescence self-quenching assay provides a powerful new tool to discover effective peptides for the recognition of collagen biomarkers, and it may have great potential to identify probe peptides for various protein biomarkers involved in pathological conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel photoinduced electron transfer (PET) primer technique for rapid real-time PCR detection of Cryptosporidium spp

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jothikumar, N., E-mail: jin2@cdc.gov; Hill, Vincent R.

Highlights: •Uses a single-labeled fluorescent primer for real-time PCR. •The detection sensitivity of PET PCR was comparable to TaqMan PCR. •Melt curve analysis can be performed to confirm target amplicon production. •Conventional PCR primers can be converted to PET PCR primers. -- Abstract: We report the development of a fluorescently labeled oligonucleotide primer that can be used to monitor real-time PCR. The primer has two parts, the 3′-end of the primer is complimentary to the target and a universal 17-mer stem loop at the 5′-end forms a hairpin structure. A fluorescent dye is attached to 5′-end of either the forwardmore » or reverse primer. The presence of guanosine residues at the first and second position of the 3′ dangling end effectively quenches the fluorescence due to the photo electron transfer (PET) mechanism. During the synthesis of nucleic acid, the hairpin structure is linearized and the fluorescence of the incorporated primer increases several-fold due to release of the fluorescently labeled tail and the absence of guanosine quenching. As amplicons are synthesized during nucleic acid amplification, the fluorescence increase in the reaction mixture can be measured with commercially available real-time PCR instruments. In addition, a melting procedure can be performed to denature the double-stranded amplicons, thereby generating fluorescence peaks that can differentiate primer dimers and other non-specific amplicons if formed during the reaction. We demonstrated the application of PET-PCR for the rapid detection and quantification of Cryptosporidium parvum DNA. Comparison with a previously published TaqMan® assay demonstrated that the two real-time PCR assays exhibited similar sensitivity for a dynamic range of detection of 6000–0.6 oocysts per reaction. PET PCR primers are simple to design and less-expensive than dual-labeled probe PCR methods, and should be of interest for use by laboratories operating in resource

The impact of PET/CT scanning on the size of target volumes, radiation exposure of organs at risk, TCP and NTCP, in the radiotherapy planning of non-small cell lung cancer.

PubMed

Vojtíšek, Radovan; Mužík, Jan; Slampa, Pavel; Budíková, Marie; Hejsek, Jaroslav; Smolák, Petr; Ferda, Jiří; Fínek, Jindřich

2014-05-01

To compare radiotherapy plans made according to CT and PET/CT and to investigate the impact of changes in target volumes on tumour control probability (TCP), normal tissue complication probability (NTCP) and the impact of PET/CT on the staging and treatment strategy. Contemporary studies have proven that PET/CT attains higher sensitivity and specificity in the diagnosis of lung cancer and also leads to higher accuracy than CT alone in the process of target volume delineation in NSCLC. Between October 2009 and March 2012, 31 patients with locally advanced NSCLC, who had been referred to radical radiotherapy were involved in our study. They all underwent planning PET/CT examination. Then we carried out two separate delineations of target volumes and two radiotherapy plans and we compared the following parameters of those plans: staging, treatment purpose, the size of GTV and PTV and the exposure of organs at risk (OAR). TCP and NTCP were also compared. PET/CT information led to a significant decrease in the sizes of target volumes, which had the impact on the radiation exposure of OARs. The reduction of target volume sizes was not reflected in the significant increase of the TCP value. We found that there is a very strong direct linear relationship between all evaluated dosimetric parameters and NTCP values of all evaluated OARs. Our study found that the use of planning PET/CT in the radiotherapy planning of NSCLC has a crucial impact on the precise determination of target volumes, more precise staging of the disease and thus also on possible changes of treatment strategy.

Microbubble Enzyme-Linked Immunosorbent Assay for the Detection of Targeted Microbubbles in in Vitro Static Binding Assays.

PubMed

Wischhusen, Jennifer; Padilla, Frederic

2017-07-01

Targeted microbubbles (MBs) are ultrasound contrast agents that are functionalized with a ligand for ultrasound molecular imaging of endothelial markers. Novel targeted MBs are characterized in vitro by incubation in protein-coated wells, followed by binding quantification by microscopy or ultrasound imaging. Both methods provide operator-dependent results: Between 3 and 20 fields of view from a heterogeneous sample are typically selected for analysis by microscopy, and in ultrasound imaging, different acoustic settings affect signal intensities. This study proposes a new method to reproducibly quantify MB binding based on enzyme-linked immunosorbent assay (ELISA), in which bound MBs are revealed with an enzyme-linked antibody. MB-ELISA was adapted to in vitro static binding assays, incubating the MBs in inverted position or by agitation, and compared with microscopy. The specificity and sensitivity of MB-ELISA enable the reliable quantification of MB binding in a rapid, high-throughput and whole-well analysis, facilitating the characterization of new targeted contrast agents. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Molecular Imaging of Human Embryonic Stem Cells Stably Expressing Human PET Reporter Genes After Zinc Finger Nuclease-Mediated Genome Editing.

PubMed

Wolfs, Esther; Holvoet, Bryan; Ordovas, Laura; Breuls, Natacha; Helsen, Nicky; Schönberger, Matthias; Raitano, Susanna; Struys, Tom; Vanbilloen, Bert; Casteels, Cindy; Sampaolesi, Maurilio; Van Laere, Koen; Lambrichts, Ivo; Verfaillie, Catherine M; Deroose, Christophe M

2017-10-01

Molecular imaging is indispensable for determining the fate and persistence of engrafted stem cells. Standard strategies for transgene induction involve the use of viral vectors prone to silencing and insertional mutagenesis or the use of nonhuman genes. Methods: We used zinc finger nucleases to induce stable expression of human imaging reporter genes into the safe-harbor locus adeno-associated virus integration site 1 in human embryonic stem cells. Plasmids were generated carrying reporter genes for fluorescence, bioluminescence imaging, and human PET reporter genes. Results: In vitro assays confirmed their functionality, and embryonic stem cells retained differentiation capacity. Teratoma formation assays were performed, and tumors were imaged over time with PET and bioluminescence imaging. Conclusion: This study demonstrates the application of genome editing for targeted integration of human imaging reporter genes in human embryonic stem cells for long-term molecular imaging. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Assessment of α-fetoprotein targeted HSV1-tk expression in hepatocellular carcinoma with in vivo imaging.

PubMed

Park, Ju Hui; Kim, Kwang Il; Lee, Kyo Chul; Lee, Yong Jin; Lee, Tae Sup; Chung, Wee Sup; Lim, Sang Moo; Kang, Joo Hyun

2015-02-01

Tumor-specific enhancer/promoter is applicable for targeting gene expression in tumors and helpful for tumor-targeting imaging and therapy. We aimed to acquire α-fetoprotein (AFP)-producing hepatocellular carcinoma (HCC) specific images using adenovirus containing HSV1-tk gene controlled by AFP enhancer/promoter and evaluate in vivo ganciclovir (GCV)-medicated therapeutic effects on AFP-targeted HSV1-tk expression with (18)F-FDG positron emission tomography (PET). Recombinant adenovirus expressing HSV1-tk under AFP enhancer/promoter was produced (AdAFP-TK) and the expression levels were evaluated by RT-PCR and (125)I-IVDU uptake. GCV-mediated HSV1-tk cytotoxicity was determined by MTT assay. After the mixture of AdAFP-fLuc and AdAFP-TK was administrated, bioluminescent images (BLIs) and (18)F-FHBG PET images were obtained in tumor-bearing mice. In vivo therapeutic effects of AdAFP-TK and GCV in the HuH-7 xenograft model were monitored by (18)F-FDG PET. When infected with AdAFP-TK, cell viability in HuH-7 was reduced, but those in HT-29 and SK-Hep-1 were not significantly decreased at any GCV concentration less than 100 μM. AFP-targeted fLuc and HSV1-tk expression were clearly visualized by BLI and (18)F-FHBG PET images in AFP-producing HCC, respectively. In vivo GCV-mediated tumor growth inhibition by AFP-targeted HSV1-tk expression was monitored by (18)F-FDG PET. Recombinant AdAFP-TK could be applied for AFP-targeted HCC gene therapy and imaging in AFP-producing HCC.

Comparison of Gull Feces-specific Assays Targeting the 16S rRNA Gene of Catellicoccus Marimammalium and Streptococcus spp.

EPA Science Inventory

Two novel gull-specific qPCR assays were developed using 16S rRNA gene sequences from gull fecal clone libraries: a SYBR-green-based assay targeting Streptococcus spp. (i.e., gull3) and a TaqMan qPCR assay targeting Catellicoccus marimammalium (i.e., gull4). The main objectives ...

AssayR: A Simple Mass Spectrometry Software Tool for Targeted Metabolic and Stable Isotope Tracer Analyses.

PubMed

Wills, Jimi; Edwards-Hicks, Joy; Finch, Andrew J

2017-09-19

Metabolic analyses generally fall into two classes: unbiased metabolomic analyses and analyses that are targeted toward specific metabolites. Both techniques have been revolutionized by the advent of mass spectrometers with detectors that afford high mass accuracy and resolution, such as time-of-flights (TOFs) and Orbitraps. One particular area where this technology is key is in the field of metabolic flux analysis because the resolution of these spectrometers allows for discrimination between 13 C-containing isotopologues and those containing 15 N or other isotopes. While XCMS-based software is freely available for untargeted analysis of mass spectrometric data sets, it does not always identify metabolites of interest in a targeted assay. Furthermore, there is a paucity of vendor-independent software that deals with targeted analyses of metabolites and of isotopologues in particular. Here, we present AssayR, an R package that takes high resolution wide-scan liquid chromatography-mass spectrometry (LC-MS) data sets and tailors peak detection for each metabolite through a simple, iterative user interface. It automatically integrates peak areas for all isotopologues and outputs extracted ion chromatograms (EICs), absolute and relative stacked bar charts for all isotopologues, and a .csv data file. We demonstrate several examples where AssayR provides more accurate and robust quantitation than XCMS, and we propose that tailored peak detection should be the preferred approach for targeted assays. In summary, AssayR provides easy and robust targeted metabolite and stable isotope analyses on wide-scan data sets from high resolution mass spectrometers.

AssayR: A Simple Mass Spectrometry Software Tool for Targeted Metabolic and Stable Isotope Tracer Analyses

PubMed Central

2017-01-01

Metabolic analyses generally fall into two classes: unbiased metabolomic analyses and analyses that are targeted toward specific metabolites. Both techniques have been revolutionized by the advent of mass spectrometers with detectors that afford high mass accuracy and resolution, such as time-of-flights (TOFs) and Orbitraps. One particular area where this technology is key is in the field of metabolic flux analysis because the resolution of these spectrometers allows for discrimination between 13C-containing isotopologues and those containing 15N or other isotopes. While XCMS-based software is freely available for untargeted analysis of mass spectrometric data sets, it does not always identify metabolites of interest in a targeted assay. Furthermore, there is a paucity of vendor-independent software that deals with targeted analyses of metabolites and of isotopologues in particular. Here, we present AssayR, an R package that takes high resolution wide-scan liquid chromatography–mass spectrometry (LC-MS) data sets and tailors peak detection for each metabolite through a simple, iterative user interface. It automatically integrates peak areas for all isotopologues and outputs extracted ion chromatograms (EICs), absolute and relative stacked bar charts for all isotopologues, and a .csv data file. We demonstrate several examples where AssayR provides more accurate and robust quantitation than XCMS, and we propose that tailored peak detection should be the preferred approach for targeted assays. In summary, AssayR provides easy and robust targeted metabolite and stable isotope analyses on wide-scan data sets from high resolution mass spectrometers. PMID:28850215

An Optimized Transient Dual Luciferase Assay for Quantifying MicroRNA Directed Repression of Targeted Sequences

PubMed Central

Moyle, Richard L.; Carvalhais, Lilia C.; Pretorius, Lara-Simone; Nowak, Ekaterina; Subramaniam, Gayathery; Dalton-Morgan, Jessica; Schenk, Peer M.

2017-01-01

Studies investigating the action of small RNAs on computationally predicted target genes require some form of experimental validation. Classical molecular methods of validating microRNA action on target genes are laborious, while approaches that tag predicted target sequences to qualitative reporter genes encounter technical limitations. The aim of this study was to address the challenge of experimentally validating large numbers of computationally predicted microRNA-target transcript interactions using an optimized, quantitative, cost-effective, and scalable approach. The presented method combines transient expression via agroinfiltration of Nicotiana benthamiana leaves with a quantitative dual luciferase reporter system, where firefly luciferase is used to report the microRNA-target sequence interaction and Renilla luciferase is used as an internal standard to normalize expression between replicates. We report the appropriate concentration of N. benthamiana leaf extracts and dilution factor to apply in order to avoid inhibition of firefly LUC activity. Furthermore, the optimal ratio of microRNA precursor expression construct to reporter construct and duration of the incubation period post-agroinfiltration were determined. The optimized dual luciferase assay provides an efficient, repeatable and scalable method to validate and quantify microRNA action on predicted target sequences. The optimized assay was used to validate five predicted targets of rice microRNA miR529b, with as few as six technical replicates. The assay can be extended to assess other small RNA-target sequence interactions, including assessing the functionality of an artificial miRNA or an RNAi construct on a targeted sequence. PMID:28979287

Targeting MT1-MMP as an ImmunoPET-Based Strategy for Imaging Gliomas

PubMed Central

Oteo, M.; Romero, E.; Cámara, J. A.; de Martino, A.; Arroyo, A. G.; Morcillo, M. Á.; Squatrito, M.; Martinez-Torrecuadrada, J. L.; Mulero, F.

2016-01-01

vivo validation showed high-specific-contrast imaging of MT1-MMP positive GBM tumors and provided strong evidence for utility of MT1-MMP-targeted immunoPET as an alternate to nonspecific imaging of GBM. PMID:27462980

Dose Optimization in TOF-PET/MR Compared to TOF-PET/CT

PubMed Central

Queiroz, Marcelo A.; Delso, Gaspar; Wollenweber, Scott; Deller, Timothy; Zeimpekis, Konstantinos; Huellner, Martin; de Galiza Barbosa, Felipe; von Schulthess, Gustav; Veit-Haibach, Patrick

2015-01-01

Purpose To evaluate the possible activity reduction in FDG-imaging in a Time-of-Flight (TOF) PET/MR, based on cross-evaluation of patient-based NECR (noise equivalent count rate) measurements in PET/CT, cross referencing with phantom-based NECR curves as well as initial evaluation of TOF-PET/MR with reduced activity. Materials and Methods A total of 75 consecutive patients were evaluated in this study. PET/CT imaging was performed on a PET/CT (time-of-flight (TOF) Discovery D 690 PET/CT). Initial PET/MR imaging was performed on a newly available simultaneous TOF-PET/MR (Signa PET/MR). An optimal NECR for diagnostic purposes was defined in clinical patients (NECRP) in PET/CT. Subsequent optimal activity concentration at the acquisition time ([A]0) and target NECR (NECRT) were obtained. These data were used to predict the theoretical FDG activity requirement of the new TOF-PET/MR system. Twenty-five initial patients were acquired with (retrospectively reconstructed) different imaging times equivalent for different activities on the simultaneous PET/MR for the evaluation of clinically realistic FDG-activities. Results The obtained values for NECRP, [A]0 and NECRT were 114.6 (± 14.2) kcps (Kilocounts per second), 4.0 (± 0.7) kBq/mL and 45 kcps, respectively. Evaluating the NECRT together with the phantom curve of the TOF-PET/MR device, the theoretical optimal activity concentration was found to be approximately 1.3 kBq/mL, which represents 35% of the activity concentration required by the TOF-PET/CT. Initial evaluation on patients in the simultaneous TOF-PET/MR shows clinically realistic activities of 1.8 kBq/mL, which represent 44% of the required activity. Conclusion The new TOF-PET/MR device requires significantly less activity to generate PET-images with good-to-excellent image quality, due to improvements in detector geometry and detector technologies. The theoretically achievable dose reduction accounts for up to 65% but cannot be fully translated into clinical

Targeting personalized medicine in a non-Hodgkin lymphoma patient with 18F-FDG and 18F-choline PET/CT.

PubMed

Ribeiro, Thalles H; S, Raul; Castro, Ana Carolina G; Paulino, Eduardo; Mamede, Marcelo

2017-02-01

Early diagnosis and staging of non-Hodgkin lymphoma (NHL) is essential for therapeutic strategy decision. Positron emission tomography/computed tomography (PET/CT) with fluordeoxyglucose (FDG), a glucose analogue, labeled with fluor-18 (18F-FDG) has been used to evaluate staging, therapy response and prognosis in NHL patients. However, in some cases, 18F-FDG has shown false-positive uptake due to inflammatory reaction after chemo and/or radiation therapy. In this case report, we present a NHL patient evaluated with 18F-FDG and 18F-choline PET/CT scan imaging pre- and post-therapy. 18F-FDG and 18F-choline PET/CT were performed for the purpose of tumor staging and have shown intense uptake in infiltrative tissue as well as in the lymph node, but with some mismatching in the tumor. Post-treatment 18F-FDG and 18F-choline PET/ CT scans revealed no signs of radiotracer uptake, suggesting complete remission of the tumor. 18F-choline may be a complimentary tool for staging and assessment of therapeutic response in non-Hodgkin lymphoma, while non-18F-FDG tracer can be used for targeted therapy and patient management.

In vivo PET imaging of neuroinflammation in Alzheimer's disease.

PubMed

Lagarde, Julien; Sarazin, Marie; Bottlaender, Michel

2018-05-01

Increasing evidence suggests that neuroinflammation contributes to the pathophysiology of many neurodegenerative diseases, especially Alzheimer's disease (AD). Molecular imaging by PET may be a useful tool to assess neuroinflammation in vivo, thus helping to decipher the complex role of inflammatory processes in the pathophysiology of neurodegenerative diseases and providing a potential means of monitoring the effect of new therapeutic approaches. For this objective, the main target of PET studies is the 18 kDa translocator protein (TSPO), as it is overexpressed by activated microglia. In the present review, we describe the most widely used PET tracers targeting the TSPO, the methodological issues in tracer quantification and summarize the results obtained by TSPO PET imaging in AD, as well as in neurodegenerative disorders associated with AD, in psychiatric disorders and ageing. We also briefly describe alternative PET targets and imaging modalities to study neuroinflammation. Lastly, we question the meaning of PET imaging data in the context of a highly complex and multifaceted role of neuroinflammation in neurodegenerative diseases. This overview leads to the conclusion that PET imaging of neuroinflammation is a promising way of deciphering the enigma of the pathophysiology of AD and of monitoring the effect of new therapies.

Conventional 3D staging PET/CT in CT simulation for lung cancer: impact of rigid and deformable target volume alignments for radiotherapy treatment planning.

PubMed

Hanna, G G; Van Sörnsen De Koste, J R; Carson, K J; O'Sullivan, J M; Hounsell, A R; Senan, S

2011-10-01

Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans. 10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTV(CT)) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice's similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan. When the GTV(CT) delineated on the staging scan after both rigid registration and deformation was compared with the GTV(CT)on the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p = 0.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration. No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.

PET Imaging in Huntington's Disease.

PubMed

Roussakis, Andreas-Antonios; Piccini, Paola

2015-01-01

To date, little is known about how neurodegeneration and neuroinflammation propagate in Huntington's disease (HD). Unfortunately, no treatment is available to cure or reverse the progressive decline of function caused by the disease, thus considering HD a fatal disease. Mutation gene carriers typically remain asymptomatic for many years although alterations in the basal ganglia and cortex occur early on in mutant HD gene-carriers. Positron Emission Tomography (PET) is a functional imaging technique of nuclear medicine which enables in vivo visualization of numerous biological molecules expressed in several human tissues. Brain PET is most powerful to study in vivo neuronal and glial cells function as well as cerebral blood flow in a plethora of neurodegenerative disorders including Parkinson's disease, Alzheimer's and HD. In absence of HD-specific biomarkers for monitoring disease progression, previous PET studies in HD were merely focused on the study of dopaminergic terminals, cerebral blood flow and glucose metabolism in manifest and premanifest HD-gene carriers. More recently, research interest has been exploring novel PET targets in HD including the state of phosphodiesterse expression and the role of activated microglia. Hence, a better understanding of the HD pathogenesis mechanisms may lead to the development of targeted therapies. PET imaging follow-up studies with novel selective PET radiotracers such as 11C-IMA-107 and 11C-PBR28 may provide insight on disease progression and identify prognostic biomarkers, elucidate the underlying HD pathology and assess novel pharmaceutical agents and over time.

Utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer and atelectasis.

PubMed

Yin, Li-Jie; Yu, Xiao-Bin; Ren, Yan-Gang; Gu, Guang-Hai; Ding, Tian-Gui; Lu, Zhi

2013-03-18

To investigate the utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer (NSCLC) and atelectasis. Thirty NSCLC patients who underwent radical radiotherapy from August 2010 to March 2012 were included in this study. All patients were pathologically confirmed to have atelectasis by imaging examination. PET-CT scanning was performed in these patients. According to the PET-CT scan results, the gross tumor volume (GTV) and organs at risk (OARs, including the lungs, heart, esophagus and spinal cord) were delineated separately both on CT and PET-CT images. The clinical target volume (CTV) was defined as the GTV plus a margin of 6-8 mm, and the planning target volume (PTV) as the GTV plus a margin of 10-15mm. An experienced physician was responsible for designing treatment plans PlanCT and PlanPET-CT on CT image sets. 95% of the PTV was encompassed by the 90% isodose curve, and the two treatment plans kept the same beam direction, beam number, gantry angle, and position of the multi-leaf collimator as much as possible. The GTV was compared using a target delineation system, and doses distributions to OARs were compared on the basis of dose-volume histogram (DVH) parameters. The GTVCT and GTVPET-CT had varying degrees of change in all 30 patients, and the changes in the GTVCT and GTVPET-CT exceeded 25% in 12 (40%) patients. The GTVPET-CT decreased in varying degrees compared to the GTVCT in 22 patients. Their median GTVPET-CT and median GTVPET-CT were 111.4 cm3 (range, 37.8 cm3-188.7 cm3) and 155.1 cm3 (range, 76.2 cm3-301.0 cm3), respectively, and the former was 43.7 cm3 (28.2%) less than the latter. The GTVPET-CT increased in varying degrees compared to the GTVCT in 8 patients. Their median GTVPET-CT and median GTVPET-CT were 144.7 cm3 (range, 125.4 cm3-178.7 cm3) and 125.8 cm3 (range, 105.6 cm3-153.5 cm3), respectively, and the former was 18.9 cm3 (15.0%) greater than the latter

One-week 96-well soft agar growth assay for cancer target validation.

PubMed

Ke, Ning; Albers, Aaron; Claassen, Gisela; Yu, De-hua; Chatterton, Jon E; Hu, Xiuyuan; Meyhack, Bernd; Wong-Staal, Flossie; Li, Qi-Xiang

2004-05-01

Soft agar growth, used to measure cell anchorage-independent proliferation potential, is one of the most important and most commonly used assays to detect cell transformation. However, the traditional soft agar assay is time-consuming, labor-intensive, and plagued with inconsistencies due to individual subjectivity. It does not, therefore, meet the increasing demands of today's oncology drug target screening or validation processes. This report describes an alternative 96-well soft agar growth assay that can function as a replacement for the traditional method and overcomes the aforementioned limitations. It offers the following advantages: a shortened assay duration (1 week instead of 4 weeks) that makes transient transfection or treatment possible; plate reader quantification of soft agar growth (measuring cloning efficiency and colony size); and a significant reduction in required labor. Higher throughput also makes it possible to process large numbers of samples and treatments simultaneously and in a much more efficient manner, while saving precious workspace and overall cost.

Bacteriophages safely reduce Salmonella contamination in pet food and raw pet food ingredients.

PubMed

Soffer, Nitzan; Abuladze, Tamar; Woolston, Joelle; Li, Manrong; Hanna, Leigh Farris; Heyse, Serena; Charbonneau, Duane; Sulakvelidze, Alexander

2016-01-01

Contamination of pet food with Salmonella is a serious public health concern, and several disease outbreaks have recently occurred due to human exposure to Salmonella tainted pet food. The problem is especially challenging for raw pet foods (which include raw meats, seafood, fruits, and vegetables). These foods are becoming increasingly popular because of their nutritional qualities, but they are also more difficult to maintain Salmonella -free because they lack heat-treatment. Among various methods examined to improve the safety of pet foods (including raw pet food), one intriguing approach is to use bacteriophages to specifically kill Salmonella serotypes. At least 2 phage preparations (SalmoFresh® and Salmonelex™) targeting Salmonella are already FDA cleared for commercial applications to improve the safety of human foods. However, similar preparations are not yet available for pet food applications. Here, we report the results of evaluating one such preparation (SalmoLyse®) in reducing Salmonella levels in various raw pet food ingredients (chicken, tuna, turkey, cantaloupe, and lettuce). Application of SalmoLyse® in low (ca. 2-4×10 6 PFU/g) and standard (ca. 9×10 6 PFU/g) concentrations significantly ( P < 0.01) reduced (by 60-92%) Salmonella contamination in all raw foods examined compared to control treatments. When SalmoLyse®-treated (ca. 2×10 7 PFU/g) dry pet food was fed to cats and dogs, it did not trigger any deleterious side effects in the pets. Our data suggest that the bacteriophage cocktail lytic for Salmonella can significantly and safely reduce Salmonella contamination in various raw pet food ingredients.

PET-based compartmental modeling of (124)I-A33 antibody: quantitative characterization of patient-specific tumor targeting in colorectal cancer.

PubMed

Zanzonico, Pat; Carrasquillo, Jorge A; Pandit-Taskar, Neeta; O'Donoghue, Joseph A; Humm, John L; Smith-Jones, Peter; Ruan, Shutian; Divgi, Chaitanya; Scott, Andrew M; Kemeny, Nancy E; Fong, Yuman; Wong, Douglas; Scheinberg, David; Ritter, Gerd; Jungbluth, Achem; Old, Lloyd J; Larson, Steven M

2015-10-01

The molecular specificity of monoclonal antibodies (mAbs) directed against tumor antigens has proven effective for targeted therapy of human cancers, as shown by a growing list of successful antibody-based drug products. We describe a novel, nonlinear compartmental model using PET-derived data to determine the "best-fit" parameters and model-derived quantities for optimizing biodistribution of intravenously injected (124)I-labeled antitumor antibodies. As an example of this paradigm, quantitative image and kinetic analyses of anti-A33 humanized mAb (also known as "A33") were performed in 11 colorectal cancer patients. Serial whole-body PET scans of (124)I-labeled A33 and blood samples were acquired and the resulting tissue time-activity data for each patient were fit to a nonlinear compartmental model using the SAAM II computer code. Excellent agreement was observed between fitted and measured parameters of tumor uptake, "off-target" uptake in bowel mucosa, blood clearance, tumor antigen levels, and percent antigen occupancy. This approach should be generally applicable to antibody-antigen systems in human tumors for which the masses of antigen-expressing tumor and of normal tissues can be estimated and for which antibody kinetics can be measured with PET. Ultimately, based on each patient's resulting "best-fit" nonlinear model, a patient-specific optimum mAb dose (in micromoles, for example) may be derived.

Development of a Targeted Urine Proteome Assay for kidney diseases.

PubMed

Cantley, Lloyd G; Colangelo, Christopher M; Stone, Kathryn L; Chung, Lisa; Belcher, Justin; Abbott, Thomas; Cantley, Jennifer L; Williams, Kenneth R; Parikh, Chirag R

2016-01-01

Since human urine is the most readily available biofluid whose proteome changes in response to disease, it is a logical sample for identifying protein biomarkers for kidney diseases. Potential biomarkers were identified by using a multiproteomics workflow to compare urine proteomes of kidney transplant patients with immediate and delayed graft function. Differentially expressed proteins were identified, and corresponding stable isotope labeled internal peptide standards were synthesized for scheduled MRM. The Targeted Urine Proteome Assay (TUPA) was then developed by identifying those peptides for which there were at least two transitions for which interference in a urine matrix across 156 MRM runs was <30%. This resulted in an assay that monitors 224 peptides from 167 quantifiable proteins. TUPA opens the way for using a robust mass spectrometric technology, MRM, for quantifying and validating biomarkers from among 167 urinary proteins. This approach, while developed using differentially expressed urinary proteins from patients with delayed versus immediate graft function after kidney transplant, can be expanded to include differentially expressed urinary proteins in multiple kidney diseases. Thus, TUPA could provide a single assay to help diagnose, prognose, and manage many kidney diseases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A high-throughput assay for enzymatic polyester hydrolysis activity by fluorimetric detection.

PubMed

Wei, Ren; Oeser, Thorsten; Billig, Susan; Zimmermann, Wolfgang

2012-12-01

A fluorimetric assay for the fast determination of the activity of polyester-hydrolyzing enzymes in a large number of samples has been developed. Terephthalic acid (TPA) is a main product of the enzymatic hydrolysis of polyethylene terephthalate (PET), a synthetic polyester. Terephthalate has been quantified following its conversion to the fluorescent 2-hydroxyterephthalate by an iron autoxidation-mediated generation of free hydroxyl radicals. The assay proved to be robust at different buffer concentrations, reaction times, pH values, and in the presence of proteins. A validation of the assay was performed by analyzing TPA formation from PET films and nanoparticles catalyzed by a polyester hydrolase from Thermobifida fusca KW3 in a 96-well microplate format. The results showed a close correlation (R(2) = 0.99) with those obtained by a considerably more tedious and time-consuming HPLC method, suggesting the aptness of the fluorimetric assay for a high-throughput screening for polyester hydrolases. The method described in this paper will facilitate the detection and development of biocatalysts for the modification and degradation of synthetic polymers. The fluorimetric assay can be used to quantify the amount of TPA obtained as the final degradation product of the enzymatic hydrolysis of PET. In a microplate format, this assay can be applied for the high-throughput screening of polyester hydrolases. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

VPAC1-targeted PET/CT scan: improved molecular imaging for the diagnosis of prostate cancer using a novel cell surface antigen.

PubMed

Truong, Hong; Gomella, Leonard G; Thakur, Mathew L; Trabulsi, Edouard J

2018-05-01

Current approaches to prostate cancer screening and diagnosis are plagued with limitations in diagnostic accuracy. There is a compelling need for biomolecular imaging that will not only detect prostate cancer early but also distinguish prostate cancer from benign lesions accurately. In this topic paper, we review evidence that supports further investigation of VPAC1-targeted PET/CT imaging in the primary diagnosis of prostate cancer. A non-systematic review of Medline/PubMed was performed. English language guidelines on prostate cancer diagnosis and management, original articles, and review articles were selected based on their clinical relevance. VPAC1 receptors were overexpressed 1000 times more in prostate cancer than benign prostatic stromal tissue. In vitro and in vivo studies showed that Copper-64 labeled analogs of VPAC1 ligands can be synthesized with high radiochemical efficiency and purity. The radioactive probes had excellent VPAC1 receptor binding specificity and affinity. They had good biochemical stability in vitro and in mouse and human serum. They had minimal urinary excretion, which made them favorable for prostate cancer imaging. Initial feasibility study in men with prostate cancer showed that the probes were safe with no reported adverse reaction. 64 Cu-TP3805 PET/CT detected 98% of prostate cancer lesions and nodal metastasis as confirmed with whole mount histopathological evaluation. VPAC1 receptors are promising targets for biomolecular imaging of primary prostate cancer that can distinguish malignant from benign lesions non-invasively. Further investigations are warranted to validate initial findings and define the clinical utilities of VPAC1-targeted PET imaging for prostate cancer diagnosis and management.

Bacteriophages safely reduce Salmonella contamination in pet food and raw pet food ingredients

PubMed Central

Soffer, Nitzan; Abuladze, Tamar; Woolston, Joelle; Li, Manrong; Hanna, Leigh Farris; Heyse, Serena; Charbonneau, Duane; Sulakvelidze, Alexander

2016-01-01

ABSTRACT Contamination of pet food with Salmonella is a serious public health concern, and several disease outbreaks have recently occurred due to human exposure to Salmonella tainted pet food. The problem is especially challenging for raw pet foods (which include raw meats, seafood, fruits, and vegetables). These foods are becoming increasingly popular because of their nutritional qualities, but they are also more difficult to maintain Salmonella-free because they lack heat-treatment. Among various methods examined to improve the safety of pet foods (including raw pet food), one intriguing approach is to use bacteriophages to specifically kill Salmonella serotypes. At least 2 phage preparations (SalmoFresh® and Salmonelex™) targeting Salmonella are already FDA cleared for commercial applications to improve the safety of human foods. However, similar preparations are not yet available for pet food applications. Here, we report the results of evaluating one such preparation (SalmoLyse®) in reducing Salmonella levels in various raw pet food ingredients (chicken, tuna, turkey, cantaloupe, and lettuce). Application of SalmoLyse® in low (ca. 2–4×106 PFU/g) and standard (ca. 9×106 PFU/g) concentrations significantly (P < 0.01) reduced (by 60–92%) Salmonella contamination in all raw foods examined compared to control treatments. When SalmoLyse®-treated (ca. 2×107 PFU/g) dry pet food was fed to cats and dogs, it did not trigger any deleterious side effects in the pets. Our data suggest that the bacteriophage cocktail lytic for Salmonella can significantly and safely reduce Salmonella contamination in various raw pet food ingredients. PMID:27738557

Meat Species Identification using Loop-mediated Isothermal Amplification Assay Targeting Species-specific Mitochondrial DNA.

PubMed

Cho, Ae-Ri; Dong, Hee-Jin; Cho, Seongbeom

2014-01-01

Meat source fraud and adulteration scandals have led to consumer demands for accurate meat identification methods. Nucleotide amplification assays have been proposed as an alternative method to protein-based assays for meat identification. In this study, we designed Loop-mediated isothermal amplification (LAMP) assays targeting species-specific mitochondrial DNA to identify and discriminate eight meat species; cattle, pig, horse, goat, sheep, chicken, duck, and turkey. The LAMP primer sets were designed and the target genes were discriminated according to their unique annealing temperature generated by annealing curve analysis. Their unique annealing temperatures were found to be 85.56±0.07℃ for cattle, 84.96±0.08℃ for pig, and 85.99±0.05℃ for horse in the BSE-LAMP set (Bos taurus, Sus scrofa domesticus and Equus caballus); 84.91±0.11℃ for goat and 83.90±0.11℃ for sheep in the CO-LAMP set (Capra hircus and Ovis aries); and 86.31±0.23℃ for chicken, 88.66±0.12℃ for duck, and 84.49±0.08℃ for turkey in the GAM-LAMP set (Gallus gallus, Anas platyrhynchos and Meleagris gallopavo). No cross-reactivity was observed in each set. The limits of detection (LODs) of the LAMP assays in raw and cooked meat were determined from 10 pg/μL to 100 fg/μL levels, and LODs in raw and cooked meat admixtures were determined from 0.01% to 0.0001% levels. The assays were performed within 30 min and showed greater sensitivity than that of the PCR assays. These novel LAMP assays provide a simple, rapid, accurate, and sensitive technology for discrimination of eight meat species.

UK pet owners' use of the internet for online pet health information.

PubMed

Kogan, Lori; Oxley, James A; Hellyer, Peter; Schoenfeld, Regina; Rishniw, Mark

2018-05-26

The internet has been found to be a popular source for human health information. However, there is a lack of information on pet owners' use of the internet to source pet health information and implications for the owner-veterinarian relationship. Therefore, the aim of this study was to address this gap in knowledge by focusing on UK pet owners' general use of the internet to find online pet health information and the impact of this behaviour on the owner-veterinarian relationship. An online survey targeting UK pet owners resulted in 571 respondents. Respondents reported the most frequently used source for pet health information was the internet (78.6 per cent), followed by their veterinarian (72 per cent). Veterinarians and other pet owners, however, were rated as the most trustworthy sources. The topics searched for most often online were specific medical problems (61.3 per cent) and diet/nutrition (58.5 per cent). Regarding the owner-veterinarian relationship, 42.1 per cent of participants reported discussing information they found online 'sometimes' with their veterinarian. When asked if their veterinarian recommended specific websites, nearly half (49.6 per cent) stated that their veterinarian 'never' made such recommendations, yet over 90 per cent said they would visit veterinarian-recommended websites. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

PSMA PET in prostate cancer – a step towards personalized medicine

PubMed Central

Bouchelouche, Kirsten; Choyke, Peter L.

2017-01-01

Purpose of review Increasing attention is being given to personalized medicine in oncology, where therapies are tailored to the particular characteristics of the individual cancer patient. In recent years, there has been greater focus on PSMA in prostate cancer (PCa) as a target for imaging and therapy with radionuclides. This review highlights the recent advancements in PSMA PET in PCa during the past year. Recent findings Several reports on PSMA PET/CT in PCa patients are demonstrating promising results, especially for detection of biochemical recurrence. 18F-PSMA PET/CT may be superior to 68Ga-PSMA PET/CT. The detection rate of PSMA PET is influenced by PSA level. PSMA PET/CT may have a higher detection rate than choline PET/CT. Only a few reports have been published on PSMA PET/MRI, and this modality remains to be elucidated further. Conclusion Molecular imaging with PSMA PET is paving the way for personalized medicine in PCa. However, large prospective clinical studies are needed to further evaluate the role of PSMA PET/CT and PET/MRI in the clinical workflow of PCa. PSMA is an excellent target for imaging and therapy with radionuclides, and the “image and treat” strategy has the potential to become a milestone in the management of PCa patients. PMID:26967720

SU-F-I-57: Evaluate and Optimize PET Acquisition Overlap in 18F-FDG Oncology Wholebody PET/CT: Can We Scan PET Faster?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J; Natwa, M; Hall, NC

Purpose: The longer patient has to remain on the table during PET imaging, the higher the likelihood of motion artifacts due to patient discomfort. This study was to investigate and optimize PET acquisition overlap in 18F-FDG oncology wholebody PET/CT to speed up PET acquisition and improve patient comfort. Methods: Wholebody 18F-FDG PET/CT of phantoms, 8 pre-clinical patients (beagles) and 5 clinical oncology patients were performed in 90s/bed on a time-of-flight Gemini TF 64 system. Imaging of phantoms and beagles was acquired with reduced PET overlaps (40%, 33%, 27%, 20%, 13% and no overlap) in addition to the system default (53%).more » In human studies, 1 or 2 reduced overlaps from the listed options were used to acquire PET/CT sweeps right after the default standard of care imaging. Image quality was blindly reviewed using visual scoring criteria and quantitative SUV assessment. NEMA PET sensitivity was performed under different overlaps. Results: All PET exams demonstrated no significant impact on the visual grades for overlaps >20%. Blinded reviews assigned the best visual scores to PET using overlaps 53%–27%. Reducing overlap to 27% for oncology patients (12-bed) saved an average of ∼40% acquisition time (11min) compared to using the default overlap (18min). No significant SUV variances were found when reducing overlap to half of default for cerebellum, lung, heart, aorta, liver, fat, muscle, bone marrow, thighs and target lesions (p>0.05), except expected variability in urinary system. Conclusion: This study demonstrated by combined phantom, pre-clinical and clinical PET/CT scans that PET acquisition overlap in axial of today’s systems can be reduced and optimized. It showed that a reduction of PET acquisition overlap to 27% (half of system default) can be implemented to reduce table time by ∼40% to improve patient comfort and minimize potential motion artifacts, without prominently degrading image quality or compromising PET quantification.« less

PET imaging in adaptive radiotherapy of gastrointestinal tumours.

PubMed

Bulens, Philippe; Thomas, Melissa; Deroose, Christophe M; Haustermans, Karin

2018-06-04

Radiotherapy is the standard of care in the multimodality treatment of a variety of gastrointestinal (GI) tumours, such as oesophageal cancer, gastric cancer, rectal cancer and anal cancer. Additionally, radiotherapy has served as an alternative for surgery in patients with liver cancer, cancer of the biliary tract and pancreatic cancer. Positron-emission tomography (PET), generally in combination with computed tomography (CT), has an established role in the diagnosis, response assessment and (re-)staging of several GI tumours. However, the additional value of PET in adaptive radiotherapy, i.e. during the radiation treatment course and in the delineation process, is still unclear. When performed during radiotherapy, PET aims at assessing treatment-induced variations in functional tumour volumes to reduce the radiation target volume. Moreover, in the radiation treatment planning, tumour delineation could be more accurate by incorporating PET to identify the metabolic tumour volume. This review focuses on the additional value of PET for adaptive radiotherapy protocols as well as for the target volume adaptation for individualised treatment strategies in oesophageal, gastric, pancreatic, liver, biliary tract, rectal and anal neoplasms.

F-18-FDG-PET Confined Radiotherapy of Locally Advanced NSCLC With Concomitant Chemotherapy: Results of the PET-PLAN Pilot Trial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleckenstein, Jochen; Hellwig, Dirk; Kremp, Stephanie

2011-11-15

Purpose: The integration of fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) in the process of radiotherapy (RT) planning of locally advanced non-small-cell lung cancer (NSCLC) may improve diagnostic accuracy and minimize interobserver variability compared with target volume definition solely based on computed tomography. Furthermore, irradiating only FDG-PET-positive findings and omitting elective nodal regions may allow dose escalation by treating smaller volumes. The aim of this prospective pilot trial was to evaluate the therapeutic safety of FDG-PET-based RT treatment planning with an autocontour-derived delineation of the primary tumor. Methods and Materials: Eligible patients had Stages II-III inoperable NSCLC, and simultaneous, platinum-based radiochemotherapy wasmore » indicated. FDG-PET and computed tomography acquisitions in RT treatment planning position were coregistered. The clinical target volume (CTV) included the FDG-PET-defined primary tumor, which was autodelineated with a source-to-background algorithm, plus FDG-PET-positive lymph node stations. Limited by dose restrictions for normal tissues, prescribed total doses were in the range of 66.6 to 73.8 Gy. The primary endpoint was the rate of out-of-field isolated nodal recurrences (INR). Results: As per intent to treat, 32 patients received radiochemotherapy. In 15 of these patients, dose escalation above 66.6 Gy was achieved. No Grade 4 toxicities occurred. After a median follow-up time of 27.2 months, the estimated median survival time was 19.3 months. During the observation period, one INR was observed in 23 evaluable patients. Conclusions: FDG-PET-confined target volume definition in radiochemotherapy of NSCLC, based on a contrast-oriented source-to-background algorithm, was associated with a low risk of INR. It might provide improved tumor control because of dose escalation.« less

64Cu-p-NH2-Bn-DOTA-hu14.18K322A, a PET radiotracer targeting neuroblastoma and melanoma.

PubMed

Vavere, Amy L; Butch, Elizabeth R; Dearling, Jason L J; Packard, Alan B; Navid, Fariba; Shulkin, Barry L; Barfield, Raymond C; Snyder, Scott E

2012-11-01

The hu14.18K322A variant of the GD2-targeting antibody hu14.18 has been shown to elicit a level of antibody-dependent cell-mediated cytotoxicity toward human neuroblastoma cells similar to that of the parent antibody. However, hu14.18K322A exhibited a decreased complement activation and associated pain, the dose-limiting toxicity in neuroblastoma immunotherapy. PET with a radiolabeled analog of the same antibody used in treatment will provide insight into the ability of hu14.18K322A to reach its target, as well as nontarget uptake that may cause side effects. Such antibody radiotracers might also provide a method for measuring GD2 expression in tumors, thus enabling the prediction of response to anti-GD2 therapy for individual patients. The conjugation of hu14.18K322A with p-NH(2)-Bn-DOTA was accomplished using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide with subsequent (64)Cu radiolabeling at 37°C for 30 min. Immunoreactivity of the conjugate was assessed by a dose-escalation blocking experiment measuring binding to purified GD2 versus GD1b as a negative control. Cell uptake and biodistribution studies in M21 (GD2-positive) and PC-3 (GD2-negative) tumor models were performed, as was small-animal PET/CT of M21 and PC-3 tumor-bearing mice. The labeling of (64)Cu-p-NH(2)-Bn-DOTA-hu14.18K322A was achieved at more than 95% radiochemical purity and a specific activity of 127-370 MBq/mg (3.4-10 mCi/mg) after chromatographic purification. Preliminary in vitro data demonstrated a greater than 6-fold selectivity of binding to GD2 versus GD1b and dose-dependent inhibition of binding by unmodified hu14.8K322A. In vivo data, including small-animal PET/CT, showed significant GD2-positive tumor-targeting ability, with a persistent 2-fold-higher uptake of radiotracer than in GD2-negative tumors. (64)Cu-p-NH(2)-Bn-DOTA-hu14.18K322A represents a novel PET radiotracer to facilitate clinical investigations of anti-GD2 immunotherapies and to complement other imaging modalities in

[Primary study on fluro [ 19F] berberine derivative for human hepatocellular carcinoma targetting in vitro].

PubMed

Zhang, Tong; Wu, Xiaoai; Cai, Huawei; Liang, Meng; Fan, Chengzhong

2017-04-01

[ 18 F]HX-01, a Fluorine-18 labeled berberine derivative, is a potential positron emission tomography (PET) tumor imaging agent, while [ 19 F]HX-01 is a nonradioactive reference substance with different energy state and has the same physical and chemical properties. In order to collect data for further study of [ 18 F]HX-01 PET imaging of hepatocellular carcinoma in vivo , this study compared the uptake of [ 19 F]HX-01 by human hepatocellular carcinoma and normal hepatocytes in vitro . The target compound, [ 19 F]HX-01, was synthesized in one step using berberrubine and 3-fluoropropyl 4-methylbenzenesulfonate. Cellular uptake and localization of [ 19 F]HX-01 were performed by a fluorescence microscope in human hepatocellular carcinoma HepG2, SMMC-7721 and human normal hepatocyte HL-7702. Cellular proliferation inhibition and cell cytotoxicity assay of the [ 19 F]HX-01 were conducted using cell counting kit-8 (CCK-8) on HepG2, SMMC-7721 and HL-7702 cells. Fluorescent microscopy showed that the combining ability of [ 19 F]HX-01 to the carcinoma SMMC-7721 and HepG2 was higher than that to the normal HL-7702. Cellular proliferation inhibition assay demonstrated that [ 19 F]HX-01 leaded to a dose-dependent inhibition on SMMC-7721, HepG2, and HL-7702 proliferation. Cell cytotoxicity assay presented that the cytotoxicity of [ 19 F]HX-01 to SMMC-7721 and HepG2 was obviously higher than that to HL-7702. This in vitro study showed that [ 19 F]HX-01 had a higher selectivity on human hepatocellular carcinoma cells (SMMC-7721, HepG2) but has less toxicity to normal hepatocytes (HL-7702). This could set up the idea that the radioactive reference substance [ 18 F]HX-01 may be worthy of further development as a potential molecular probe targeting human hepatocellular carcinoma using PET.

Understanding the context for pet cat and dog feeding and exercising behaviour among pet owners in Ireland: a qualitative study.

PubMed

Downes, Martin J; Devitt, Catherine; Downes, Marie T; More, Simon J

2017-01-01

Pet cat and dog obesity contributes to increased risk of several diseases, including cancer and diabetes mellitus as well as a worsening of orthopaedic problems, and a reduction in survival rate. This study aims to develop a better understanding of cat and dog owners' self-reported beliefs and factors that influence owner behaviour around feeding and exercising their pet cat or dog, as there is a lack of in-depth understanding in this area. Seven focus group discussions, with 43 pet owners in total, were conducted. Pet owners often reported a perceived a low level of control over feeding; often undermined by other people feeding of their pet, their pets begging for food, and their pets attitude towards food. Treats were used in the absence of owner control over pet begging and emotional attachment, and to influence pet behaviour. The majority of participants had positive attitudes to pet exercise, which could be related to pet specific requirements, especially differences in cats and dogs. There were some negative experiences of stress associated with dog walking and fears over aggressive confrontations with other dogs. Feeding one's pet is influenced by beliefs about pet specific needs, pet food and pet health, pet owners' perceived control over feeding, and the implications for the pet owner. Pet exercise is influenced by beliefs about pet specific exercise needs, and the implications of exercising one's pet for the pet owner. Understanding owner behaviours on feeding and exercise allows for a more targeted approach to preventing and treating pet obesity.

PET imaging of tumor angiogenesis in mice with VEGF-A targeted 86Y-CHX-A″-DTPA-bevacizumab

PubMed Central

Nayak, Tapan K.; Garmestani, Kayhan; Baidoo, Kwamena E.; Milenic, Diane E.; Brechbiel, Martin W.

2010-01-01

Bevacizumab is a humanized monoclonal antibody that binds to tumor-secreted VEGF-A and inhibits tumor angiogenesis. In 2004, the antibody was approved by the United States FDA for the treatment of metastatic colorectal carcinoma in combination with chemotherapy. This report describes the preclinical evaluation of a radioimmunoconjugate, 86Y-CHX-A″-DTPA-bevacizumab, for potential use in PET imaging of VEGF-A tumor angiogenesis and as a surrogate marker for 90Y based radioimmunotherapy. Bevacizumab was conjugated to CHX-A″-DTPA and radiolabeled with 86Y. In vivo biodistribution and PET imaging studies were performed on mice bearing VEGF-A secreting human colorectal (LS-174T), human ovarian (SKOV-3) and VEGF-A negative human mesothelioma (MSTO-211H) xenografts. Biodistribution and PET imaging studies demonstrated high specific tumor uptake of the radioimmunoconjugate. In mice bearing VEGF-A secreting LS-174T, SKOV-3 and VEGF-A negative MSTO-211H tumors, the tumor uptake at 3 d post-injection (p.i) was 13.6 ± 1.5, 17.4 ± 1.7 and 6.8 ± 0.7 % ID/g, respectively. The corresponding tumor uptake in mice co-injected with 0.05 mg cold bevacizumab were 5.8 ± 1.3, 8.9 ± 1.9 and 7.4 ± 1.0 % ID/g, respectively at the same time point, demonstrating specific blockage of the target in VEGF-A secreting tumors. The LS-174T and SKOV3 tumors were clearly visualized by PET imaging after injecting 1.8–2.0 MBq 86Y-CHX-A″-DTPA-bevacizumab. Organ uptake quantified by PET closely correlated (r2=0.87, p=0.64, n=18) to values determined by biodistribution studies. This preclinical study demonstrates the potential of the radioimmunoconjugate, 86Y-CHX-A″-DTPA-bevacizumab, for non-invasive assessment of the VEGF-A tumor angiogenesis status and as a surrogate marker for 90Y-CHX-A″-DTPA-bevacizumab radioimmunotherapy. PMID:20473899

CRISPR Is an Optimal Target for the Design of Specific PCR Assays for Salmonella enterica Serotypes Typhi and Paratyphi A

PubMed Central

Fabre, Laetitia; Le Hello, Simon; Roux, Chrystelle; Issenhuth-Jeanjean, Sylvie; Weill, François-Xavier

2014-01-01

Background Serotype-specific PCR assays targeting Salmonella enterica serotypes Typhi and Paratyphi A, the causal agents of typhoid and paratyphoid fevers, are required to accelerate formal diagnosis and to overcome the lack of typing sera and, in some situations, the need for culture. However, the sensitivity and specificity of such assays must be demonstrated on large collections of strains representative of the targeted serotypes and all other bacterial populations producing similar clinical symptoms. Methodology Using a new family of repeated DNA sequences, CRISPR (clustered regularly interspaced short palindromic repeats), as a serotype-specific target, we developed a conventional multiplex PCR assay for the detection and differentiation of serotypes Typhi and Paratyphi A from cultured isolates. We also developed EvaGreen-based real-time singleplex PCR assays with the same two sets of primers. Principal findings We achieved 100% sensitivity and specificity for each protocol after validation of the assays on 188 serotype Typhi and 74 serotype Paratyphi A strains from diverse genetic groups, geographic origins and time periods and on 70 strains of bacteria frequently encountered in bloodstream infections, including 29 other Salmonella serotypes and 42 strains from 38 other bacterial species. Conclusions The performance and convenience of our serotype-specific PCR assays should facilitate the rapid and accurate identification of these two major serotypes in a large range of clinical and public health laboratories with access to PCR technology. These assays were developed for use with DNA from cultured isolates, but with modifications to the assay, the CRISPR targets could be used in the development of assays for use with clinical and other samples. PMID:24498453

Hybrid PET/MR imaging: physics and technical considerations.

PubMed

Shah, Shetal N; Huang, Steve S

2015-08-01

In just over a decade, hybrid imaging with FDG PET/CT has become a standard bearer in the management of cancer patients. An exquisitely sensitive whole-body imaging modality, it combines the ability to detect subtle biologic changes with FDG PET and the anatomic information offered by CT scans. With advances in MR technology and advent of novel targeted PET radiotracers, hybrid PET/MRI is an evolutionary technique that is poised to revolutionize hybrid imaging. It offers unparalleled spatial resolution and functional multi-parametric data combined with biologic information in the non-invasive detection and characterization of diseases, without the deleterious effects of ionizing radiation. This article reviews the basic principles of FDG PET and MR imaging, discusses the salient technical developments of hybrid PET/MR systems, and provides an introduction to FDG PET/MR image acquisition.

Advanced Tracers in PET Imaging of Cardiovascular Disease

PubMed Central

Zhang, Wei; Wu, Hua; Liu, Gang

2014-01-01

Cardiovascular disease is the leading cause of death worldwide. Molecular imaging with targeted tracers by positron emission tomography (PET) allows for the noninvasive detection and characterization of biological changes at the molecular level, leading to earlier disease detection, objective monitoring of therapies, and better prognostication of cardiovascular diseases progression. Here we review, the current role of PET in cardiovascular disease, with emphasize on tracers developed for PET imaging of cardiovascular diseases. PMID:25389529

18F-DCFBC Prostate-Specific Membrane Antigen-Targeted PET/CT Imaging in Localized Prostate Cancer: Correlation With Multiparametric MRI and Histopathology.

PubMed

Turkbey, Baris; Mena, Esther; Lindenberg, Liza; Adler, Stephen; Bednarova, Sandra; Berman, Rose; Ton, Anita T; McKinney, Yolanda; Eclarinal, Philip; Hill, Craig; Afari, George; Bhattacharyya, Sibaprasad; Mease, Ronnie C; Merino, Maria J; Jacobs, Paula M; Wood, Bradford J; Pinto, Peter A; Pomper, Martin G; Choyke, Peter L

2017-10-01

To assess the ability of (N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-F-fluorobenzyl-L-cysteine) (F-DCFBC), a prostate-specific membrane antigen-targeted PET agent, to detect localized prostate cancer lesions in correlation with multiparametric MRI (mpMRI) and histopathology. This Health Insurance Portability and Accountability Act of 1996-compliant, prospective, institutional review board-approved study included 13 evaluable patients with localized prostate cancer (median age, 62.8 years [range, 51-74 years]; median prostate-specific antigen, 37.5 ng/dL [range, 3.26-216 ng/dL]). Patients underwent mpMRI and F-DCFBC PET/CT within a 3 months' window. Lesions seen on mpMRI were biopsied under transrectal ultrasound/MRI fusion-guided biopsy, or a radical prostatectomy was performed. F-DCFBC PET/CT and mpMRI were evaluated blinded and separately for tumor detection on a lesion basis. For PET image analysis, MRI and F-DCFBC PET images were fused by using software registration; imaging findings were correlated with histology, and uptake of F-DCFBC in tumors was compared with uptake in benign prostatic hyperplasia nodules and normal peripheral zone tissue using the 80% threshold SUVmax. A total of 25 tumor foci (mean size, 1.8 cm; median size, 1.5 cm; range, 0.6-4.7 cm) were histopathologically identified in 13 patients. Sensitivity rates of F-DCFBC PET/CT and mpMRI were 36% and 96%, respectively, for all tumors. For index lesions, the largest tumor with highest Gleason score, sensitivity rates of F-DCFBC PET/CT and mpMRI were 61.5% and 92%, respectively. The average SUVmax for primary prostate cancer was higher (5.8 ± 4.4) than that of benign prostatic hyperplasia nodules (2.1 ± 0.3) or that of normal prostate tissue (2.1 ± 0.4) at 1 hour postinjection (P = 0.0033). The majority of index prostate cancers are detected with F-DCFBC PET/CT, and this may be a prognostic indicator based on uptake and staging. However, for detecting prostate cancer with high sensitivity, it

Fluorine-18-FDG PET/CT in a patient with angiomyolipoma: Response to mammalian target of rapamycin inhibitor therapy.

PubMed

Anwar, Hoda; Sachpekidis, Christos; Schwarzbach, Matthias; Dimitrakopoulou-Strauss, Antonia

2017-01-01

We report on a 27 years old female patient who was referred to our department for whole-body as well as dynamic positron emission tomography/computed tomography (dPET/CT) scan of the upper and middle abdomen with fluorine-18-fluorodeoxy glucose ( 18 F-FDG), for further evaluation of a mass in the left adrenal gland region. Positron emission tomography showed a suspicious, enlarged, hypermetabolic mass with an average standardized uptake value (SUV) of 4.5 and a maximum SUV of 5.9. The patient was referred for biopsy, which revealed an angiomyolipoma, a perivascular epithelioid cell tumor (PEComa) of the adrenal gland. Perivascular epithelioid cell tumors are mesenchymal tumors consisting of blood vessels, smooth muscles and fat cells. The patient received anti-proliferative treatment with Afinitor, a mammalian target of rapamycin (mTOR) inhibitor, and was referred again one month after onset of therapy for early response assessment. The follow-up 18 F-FDG PET/CT scan showed a nearly complete resolution of the previously detected adrenal mass, with very low tracer uptake and a decrease in its functional volume. Fluorine- 18-FDG PET/CT can be used for treatment response evaluation of angiomyolipoma treated with mTOR-inhibitors.

PET imaging of a collagen matrix reveals its effective injection and targeted retention in a mouse model of myocardial infarction.

PubMed

Ahmadi, Ali; Thorn, Stephanie L; Alarcon, Emilio I; Kordos, Myra; Padavan, Donna T; Hadizad, Tayebeh; Cron, Greg O; Beanlands, Rob S; DaSilva, Jean N; Ruel, Marc; deKemp, Robert A; Suuronen, Erik J

2015-05-01

Injectable biomaterials have shown promise for cardiac regeneration therapy. However, little is known regarding their retention and distribution upon application in vivo. Matrix imaging would be useful for evaluating these important properties. Herein, hexadecyl-4-[(18)F]fluorobenzoate ((18)F-HFB) and Qdot labeling was used to evaluate collagen matrix delivery in a mouse model of myocardial infarction (MI). At 1 wk post-MI, mice received myocardial injections of (18)F-HFB- or Qdot-labeled matrix to assess its early retention and distribution (at 10 min and 2h) by positron emission tomography (PET), or fluorescence imaging, respectively. PET imaging showed that the bolus of matrix at 10 min redistributed evenly within the ischemic territory by 2h. Ex vivo biodistribution revealed myocardial matrix retention of ∼ 65%, which correlated with PET results, but may be an underestimate since (18)F-HFB matrix labeling efficiency was ∼ 82%. For covalently linked Qdots, labeling efficiency was ∼ 96%. Ex vivo Qdot quantification showed that ∼ 84% of the injected matrix was retained in the myocardium. Serial non-invasive PET imaging and validation by fluorescence imaging confirmed the effectiveness of the collagen matrix to be retained and redistributed within the infarcted myocardium. This study identifies matrix-targeted imaging as a promising modality for assessing the biodistribution of injectable biomaterials for application in the heart. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of 64Cu-DOTA-conatumumab: a PET tracer for in vivo imaging of death receptor 5.

PubMed

Rossin, Raffaella; Kohno, Tadahiko; Hagooly, Aviv; Sharp, Terry; Gliniak, Brian; Arroll, Thomas; Chen, Qing; Hewig, Art; Kaplan-Lefko, Paula; Friberg, Greg; Radinsky, Robert; Evelhoch, Jeffrey L; Welch, Michael J; Hwang, Dah-Ren

2011-06-01

Conatumumab is a fully human monoclonal antibody that binds to and activates human death receptor 5 (DR5; also known as TRAIL receptor 2). The purpose of this study was to characterize (64)Cu-labeled conatumumab as a PET tracer for imaging DR5 in tumors. DOTA-conatumumab was synthesized by incubating conatumumab with 2,2',2″-(10-(2-(2,5-dioxopyrrolidin-1-yloxy)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (DOTA-NHS). The absolute numbers of DOTA molecules per conatumumab molecules were determined by matrix-assisted laser desorption ionization mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. (64)Cu-DOTA-conatumumab was prepared by incubating (64)CuCl(2) (33-222 MBq) with DOTA-conatumumab at 37°C for 1 h. Binding of conatumumab and DOTA-conatumumab to Fc-coupled human DR5 (huTR2-Fc) was tested in a kinetic analysis assay, and the biologic activity of copper-DOTA-conatumumab was measured using a caspase-3/7 luminescent assay. In vivo evaluation of DOTA-conatumumab and copper-DOTA-conatumumab was done in severe combined immunodeficiency mice bearing Colo205 xenografts: tissue uptake was determined with biodistribution studies, and small-animal PET and autoradiography were used to determine the uptake of (64)Cu-DOTA conatumumab into tumors and other tissues. DOTA-conatumumab was prepared with an average of 5 DOTA molecules per conatumumab molecule. The in vitro median effective concentration required to induce a 50% effect of DOTA-conatumumab and conatumumab from the assay were 389 and 320 pM, respectively. The median effective dose (±SD) of DOTA-conatumumab and conatumumab via the caspase assay was 135 ± 31 and 128 ± 30 pM, respectively. In female CB17 severe combined immunodeficiency mice bearing Colo205 xenografts, DOTA-conatumumab and conatumumab inhibited tumor growth to the same extent. Small-animal PET studies showed tumor uptake at 24 h after injection of the tracer, with a mean

Generic detection of poleroviruses using an RT-PCR assay targeting the RdRp coding sequence.

PubMed

Lotos, Leonidas; Efthimiou, Konstantinos; Maliogka, Varvara I; Katis, Nikolaos I

2014-03-01

In this study a two-step RT-PCR assay was developed for the generic detection of poleroviruses. The RdRp coding region was selected as the primers' target, since it differs significantly from that of other members in the family Luteoviridae and its sequence can be more informative than other regions in the viral genome. Species specific RT-PCR assays targeting the same region were also developed for the detection of the six most widespread poleroviral species (Beet mild yellowing virus, Beet western yellows virus, Cucurbit aphid-borne virus, Carrot red leaf virus, Potato leafroll virus and Turnip yellows virus) in Greece and the collection of isolates. These isolates along with other characterized ones were used for the evaluation of the generic PCR's detection range. The developed assay efficiently amplified a 593bp RdRp fragment from 46 isolates of 10 different Polerovirus species. Phylogenetic analysis using the generic PCR's amplicon sequence showed that although it cannot accurately infer evolutionary relationships within the genus it can differentiate poleroviruses at the species level. Overall, the described generic assay could be applied for the reliable detection of Polerovirus infections and, in combination with the specific PCRs, for the identification of new and uncharacterized species in the genus. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of Multiple Immunoassay Technology Platforms to Select the Anti-Drug Antibody Assay Exhibiting the Most Appropriate Drug and Target Tolerance

PubMed Central

Collet-Brose, Justine

2016-01-01

The aim of this study was, at the assay development stage and thus with an appropriate degree of rigor, to select the most appropriate technology platform and sample pretreatment procedure for a clinical ADA assay. Thus, ELISA, MSD, Gyrolab, and AlphaLISA immunoassay platforms were evaluated in association with target depletion and acid dissociation sample pretreatment steps. An acid dissociation step successfully improved the drug tolerance for all 4 technology platforms and the required drug tolerance was achieved with the Gyrolab and MSD platforms. The target tolerance was shown to be better for the ELISA format, where an acid dissociation treatment step alone was sufficient to achieve the desired target tolerance. However, inclusion of a target depletion step in conjunction with the acid treatment raised the target tolerance to the desired level for all of the technologies. A higher sensitivity was observed for the MSD and Gyrolab assays and the ELISA, MSD, and Gyrolab all displayed acceptable interdonor variability. This study highlights the usefulness of evaluating the performance of different assay platforms at an early stage in the assay development process to aid in the selection of the best fit-for-purpose technology platform and sample pretreatment steps. PMID:27243038

Targeted peptide measurements in biology and medicine: best practices for mass spectrometry-based assay development using a fit-for-purpose approach.

PubMed

Carr, Steven A; Abbatiello, Susan E; Ackermann, Bradley L; Borchers, Christoph; Domon, Bruno; Deutsch, Eric W; Grant, Russell P; Hoofnagle, Andrew N; Hüttenhain, Ruth; Koomen, John M; Liebler, Daniel C; Liu, Tao; MacLean, Brendan; Mani, D R; Mansfield, Elizabeth; Neubert, Hendrik; Paulovich, Amanda G; Reiter, Lukas; Vitek, Olga; Aebersold, Ruedi; Anderson, Leigh; Bethem, Robert; Blonder, Josip; Boja, Emily; Botelho, Julianne; Boyne, Michael; Bradshaw, Ralph A; Burlingame, Alma L; Chan, Daniel; Keshishian, Hasmik; Kuhn, Eric; Kinsinger, Christopher; Lee, Jerry S H; Lee, Sang-Won; Moritz, Robert; Oses-Prieto, Juan; Rifai, Nader; Ritchie, James; Rodriguez, Henry; Srinivas, Pothur R; Townsend, R Reid; Van Eyk, Jennifer; Whiteley, Gordon; Wiita, Arun; Weintraub, Susan

2014-03-01

Adoption of targeted mass spectrometry (MS) approaches such as multiple reaction monitoring (MRM) to study biological and biomedical questions is well underway in the proteomics community. Successful application depends on the ability to generate reliable assays that uniquely and confidently identify target peptides in a sample. Unfortunately, there is a wide range of criteria being applied to say that an assay has been successfully developed. There is no consensus on what criteria are acceptable and little understanding of the impact of variable criteria on the quality of the results generated. Publications describing targeted MS assays for peptides frequently do not contain sufficient information for readers to establish confidence that the tests work as intended or to be able to apply the tests described in their own labs. Guidance must be developed so that targeted MS assays with established performance can be made widely distributed and applied by many labs worldwide. To begin to address the problems and their solutions, a workshop was held at the National Institutes of Health with representatives from the multiple communities developing and employing targeted MS assays. Participants discussed the analytical goals of their experiments and the experimental evidence needed to establish that the assays they develop work as intended and are achieving the required levels of performance. Using this "fit-for-purpose" approach, the group defined three tiers of assays distinguished by their performance and extent of analytical characterization. Computational and statistical tools useful for the analysis of targeted MS results were described. Participants also detailed the information that authors need to provide in their manuscripts to enable reviewers and readers to clearly understand what procedures were performed and to evaluate the reliability of the peptide or protein quantification measurements reported. This paper presents a summary of the meeting and

Targeted Peptide Measurements in Biology and Medicine: Best Practices for Mass Spectrometry-based Assay Development Using a Fit-for-Purpose Approach*

PubMed Central

Carr, Steven A.; Abbatiello, Susan E.; Ackermann, Bradley L.; Borchers, Christoph; Domon, Bruno; Deutsch, Eric W.; Grant, Russell P.; Hoofnagle, Andrew N.; Hüttenhain, Ruth; Koomen, John M.; Liebler, Daniel C.; Liu, Tao; MacLean, Brendan; Mani, DR; Mansfield, Elizabeth; Neubert, Hendrik; Paulovich, Amanda G.; Reiter, Lukas; Vitek, Olga; Aebersold, Ruedi; Anderson, Leigh; Bethem, Robert; Blonder, Josip; Boja, Emily; Botelho, Julianne; Boyne, Michael; Bradshaw, Ralph A.; Burlingame, Alma L.; Chan, Daniel; Keshishian, Hasmik; Kuhn, Eric; Kinsinger, Christopher; Lee, Jerry S.H.; Lee, Sang-Won; Moritz, Robert; Oses-Prieto, Juan; Rifai, Nader; Ritchie, James; Rodriguez, Henry; Srinivas, Pothur R.; Townsend, R. Reid; Van Eyk, Jennifer; Whiteley, Gordon; Wiita, Arun; Weintraub, Susan

2014-01-01

Adoption of targeted mass spectrometry (MS) approaches such as multiple reaction monitoring (MRM) to study biological and biomedical questions is well underway in the proteomics community. Successful application depends on the ability to generate reliable assays that uniquely and confidently identify target peptides in a sample. Unfortunately, there is a wide range of criteria being applied to say that an assay has been successfully developed. There is no consensus on what criteria are acceptable and little understanding of the impact of variable criteria on the quality of the results generated. Publications describing targeted MS assays for peptides frequently do not contain sufficient information for readers to establish confidence that the tests work as intended or to be able to apply the tests described in their own labs. Guidance must be developed so that targeted MS assays with established performance can be made widely distributed and applied by many labs worldwide. To begin to address the problems and their solutions, a workshop was held at the National Institutes of Health with representatives from the multiple communities developing and employing targeted MS assays. Participants discussed the analytical goals of their experiments and the experimental evidence needed to establish that the assays they develop work as intended and are achieving the required levels of performance. Using this “fit-for-purpose” approach, the group defined three tiers of assays distinguished by their performance and extent of analytical characterization. Computational and statistical tools useful for the analysis of targeted MS results were described. Participants also detailed the information that authors need to provide in their manuscripts to enable reviewers and readers to clearly understand what procedures were performed and to evaluate the reliability of the peptide or protein quantification measurements reported. This paper presents a summary of the meeting and

A high content, high throughput cellular thermal stability assay for measuring drug-target engagement in living cells.

PubMed

Massey, Andrew J

2018-01-01

Determining and understanding drug target engagement is critical for drug discovery. This can be challenging within living cells as selective readouts are often unavailable. Here we describe a novel method for measuring target engagement in living cells based on the principle of altered protein thermal stabilization / destabilization in response to ligand binding. This assay (HCIF-CETSA) utilizes high content, high throughput single cell immunofluorescent detection to determine target protein levels following heating of adherent cells in a 96 well plate format. We have used target engagement of Chk1 by potent small molecule inhibitors to validate the assay. Target engagement measured by this method was subsequently compared to target engagement measured by two alternative methods (autophosphorylation and CETSA). The HCIF-CETSA method appeared robust and a good correlation in target engagement measured by this method and CETSA for the selective Chk1 inhibitor V158411 was observed. However, these EC50 values were 23- and 12-fold greater than the autophosphorylation IC50. The described method is therefore a valuable advance in the CETSA method allowing the high throughput determination of target engagement in adherent cells.

Design, Synthesis, and Biological Evaluation of 68Ga-DOTA-PA1 for Lung Cancer: A Novel PET Tracer for Multiple Somatostatin Receptor Imaging.

PubMed

Liu, Fei; Liu, Teli; Xu, Xiaoxia; Guo, Xiaoyi; Li, Nan; Xiong, Chiyi; Li, Chun; Zhu, Hua; Yang, Zhi

2018-02-05

Most of the radiolabeled somatostatin analogues (SSAs) are specific for subtype somatostatin receptor 2 (SSTR 2 ). Lack of ligands targeting other subtypes of SSTRs, especially SSTR 1, SSTR 3 , and SSTR 5 , limited their applications in tumors of low SSTR 2 expression, including lung tumor. In this study, we aimed to design and synthesize a positron emission tomography (PET) radiotracer targeting multi-subtypes of SSTRs for PET imaging. PA1 peptide and its conjugate with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator or fluorescein isothiocyanate (FITC) at the N-terminal of the lysine position were synthesized. 68 Ga was chelated to DOTA-PA1 to obtain 68 Ga-DOTA-PA1 radiotracer. The stability, lipophilicity, binding affinity, and binding specificity of 68 Ga-DOTA-PA1 and FITC-PA1 were evaluated by various in vitro experiments. Micro-PET imaging of 68 Ga-DOTA-PA1 was performed in nude mice bearing A549 lung adenocarcinoma, as compared with 68 Ga-DOTA-(Tyr3)-octreotate ( 68 Ga-DOTA-TATE). Histological analysis of SSTR expression in A549 tumor tissues and human tumor tissues was conducted using immunofluorescence staining and immunohistochemical assay. 68 Ga-DOTA-PA1 had high radiochemical yield and radiochemical purity of over 95% and 99%, respectively. The radiotracer was stable in vitro in different buffers over a 2 h incubation period. Cell uptake of 68 Ga-DOTA-PA1 was 1.31-, 1.33-, and 1.90-fold that of 68 Ga-DOTA-TATE, which has high binding affinity only for SSTR 2 , after 2 h incubation in H520, PG, and A549 lung cancer cell lines, respectively. Micro-PET images of 68 Ga-DOTA-PA1 showed that the PET imaging signal correlated with the total expression of SSTRs, instead of SSTR 2 only, which was measured by Western blotting and immunofluorescence analysis in mice bearing A549 tumors. In summary, a novel PET radiotracer, 68 Ga-DOTA-PA1, targeting multi-subtypes of SSTRs, was successfully synthesized and was confirmed to be useful for PET

Local recurrence of prostate cancer after radical prostatectomy is at risk to be missed in 68Ga-PSMA-11-PET of PET/CT and PET/MRI: comparison with mpMRI integrated in simultaneous PET/MRI.

PubMed

Freitag, Martin T; Radtke, Jan P; Afshar-Oromieh, Ali; Roethke, Matthias C; Hadaschik, Boris A; Gleave, Martin; Bonekamp, David; Kopka, Klaus; Eder, Matthias; Heusser, Thorsten; Kachelriess, Marc; Wieczorek, Kathrin; Sachpekidis, Christos; Flechsig, Paul; Giesel, Frederik; Hohenfellner, Markus; Haberkorn, Uwe; Schlemmer, Heinz-Peter; Dimitrakopoulou-Strauss, A

2017-05-01

The positron emission tomography (PET) tracer 68 Ga-PSMA-11, targeting the prostate-specific membrane antigen (PSMA), is rapidly excreted into the urinary tract. This leads to significant radioactivity in the bladder, which may limit the PET-detection of local recurrence (LR) of prostate cancer (PC) after radical prostatectomy (RP), developing in close proximity to the bladder. Here, we analyze if there is additional value of multi-parametric magnetic resonance imaging (mpMRI) compared to the 68 Ga-PSMA-11-PET-component of PET/CT or PET/MRI to detect LR. One hundred and nineteen patients with biochemical recurrence after prior RP underwent both hybrid 68 Ga-PSMA-11-PET/CT low-dose (1 h p.i.) and -PET/MRI (2-3 h p.i.) including a mpMRI protocol of the prostatic bed. The comparison of both methods was restricted to the abdomen with focus on LR (McNemar). Bladder-LR distance and recurrence size were measured in axial T2w-TSE. A logistic regression was performed to determine the influence of these variables on detectability in 68 Ga-PSMA-11-PET. Standardized-uptake-value (SUV mean ) quantification of LR was performed. There were 93/119 patients that had at least one pathologic finding. In addition, 18/119 Patients (15.1%) were diagnosed with a LR in mpMRI of PET/MRI but only nine were PET-positive in PET/CT and PET/MRI. This mismatch was statistically significant (p = 0.004). Detection of LR using the PET-component was significantly influenced by proximity to the bladder (p = 0.028). The PET-pattern of LR-uptake was classified into three types (1): separated from bladder; (2): fuses with bladder, and (3): obliterated by bladder). The size of LRs did not affect PET-detectability (p = 0.84), mean size was 1.7 ± 0.69 cm long axis, 1.2 ± 0.46 cm short-axis. SUV mean in nine men was 8.7 ± 3.7 (PET/CT) and 7.0 ± 4.2 (PET/MRI) but could not be quantified in the remaining nine cases (obliterated by bladder). The present study demonstrates

PET guidance for liver radiofrequency ablation: an evaluation

NASA Astrophysics Data System (ADS)

Lei, Peng; Dandekar, Omkar; Mahmoud, Faaiza; Widlus, David; Malloy, Patrick; Shekhar, Raj

2007-03-01

Radiofrequency ablation (RFA) is emerging as the primary mode of treatment of unresectable malignant liver tumors. With current intraoperative imaging modalities, quick, precise, and complete localization of lesions remains a challenge for liver RFA. Fusion of intraoperative CT and preoperative PET images, which relies on PET and CT registration, can produce a new image with complementary metabolic and anatomic data and thus greatly improve the targeting accuracy. Unlike neurological images, alignment of abdominal images by combined PET/CT scanner is prone to errors as a result of large nonrigid misalignment in abdominal images. Our use of a normalized mutual information-based 3D nonrigid registration technique has proven powerful for whole-body PET and CT registration. We demonstrate here that this technique is capable of acceptable abdominal PET and CT registration as well. In five clinical cases, both qualitative and quantitative validation showed that the registration is robust and accurate. Quantitative accuracy was evaluated by comparison between the result from the algorithm and clinical experts. The accuracy of registration is much less than the allowable margin in liver RFA. Study findings show the technique's potential to enable the augmentation of intraoperative CT with preoperative PET to reduce procedure time, avoid repeating procedures, provide clinicians with complementary functional/anatomic maps, avoid omitting dispersed small lesions, and improve the accuracy of tumor targeting in liver RFA.

Mass Spectrometry Based Ultrasensitive DNA Methylation Profiling Using Target Fragmentation Assay.

PubMed

Lin, Xiang-Cheng; Zhang, Ting; Liu, Lan; Tang, Hao; Yu, Ru-Qin; Jiang, Jian-Hui

2016-01-19

Efficient tools for profiling DNA methylation in specific genes are essential for epigenetics and clinical diagnostics. Current DNA methylation profiling techniques have been limited by inconvenient implementation, requirements of specific reagents, and inferior accuracy in quantifying methylation degree. We develop a novel mass spectrometry method, target fragmentation assay (TFA), which enable to profile methylation in specific sequences. This method combines selective capture of DNA target from restricted cleavage of genomic DNA using magnetic separation with MS detection of the nonenzymatic hydrolysates of target DNA. This method is shown to be highly sensitive with a detection limit as low as 0.056 amol, allowing direct profiling of methylation using genome DNA without preamplification. Moreover, this method offers a unique advantage in accurately determining DNA methylation level. The clinical applicability was demonstrated by DNA methylation analysis using prostate tissue samples, implying the potential of this method as a useful tool for DNA methylation profiling in early detection of related diseases.

Loop-mediated isothermal amplification (LAMP) assay for speedy diagnosis of tubercular lymphadenitis: The multi-targeted 60-minute approach.

PubMed

Sharma, Megha; Sharma, Kusum; Sharma, Aman; Gupta, Nalini; Rajwanshi, Arvind

2016-09-01

Tuberculous lymphadenitis (TBLA), the most common presentation of tuberculosis, poses a significant diagnostic challenge in the developing countries. Timely, accurate and cost-effective diagnosis can decrease the high morbidity associated with TBLA especially in resource-poor high-endemic regions. The loop-mediated isothermal amplification assay (LAMP), using two targets, was evaluated for the diagnosis of TBLA. LAMP assay using 3 sets of primers (each for IS6110 and MPB64) was performed on 170 fine needle aspiration samples (85 confirmed, 35 suspected, 50 control cases of TBLA). Results were compared against IS6110 PCR, cytology, culture and smear. The overall sensitivity and specificity of LAMP assay, using multi-targeted approach, was 90% and 100% respectively in diagnosing TBLA. The sensitivity of multi-targeted LAMP, only MPB64 LAMP, only IS6110 LAMP and IS6110 PCR was 91.7%, 89.4%, 84.7% and 75.2%, respectively among confirmed cases and 85.7%, 77.1%, 68.5% and 60%, respectively among suspected cases of TBLA. Additional 12/120 (10%) cases were detected using multi-targeted method. The multi-targeted LAMP, with its speedy and reliable results, is a potential diagnostic test for TBLA in low-resource countries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Patient Set-up and Respiration motion on Defining Biological Targets for Image-Guided Targeted Radiotherapy

NASA Astrophysics Data System (ADS)

McCall, Keisha C.

Identification and monitoring of sub-tumor targets will be a critical step for optimal design and evaluation of cancer therapies in general and biologically targeted radiotherapy (dose-painting) in particular. Quantitative PET imaging may be an important tool for these applications. Currently radiotherapy planning accounts for tumor motion by applying geometric margins. These margins create a motion envelope to encompass the most probable positions of the tumor, while also maintaining the appropriate tumor control and normal tissue complication probabilities. This motion envelope is effective for uniform dose prescriptions where the therapeutic dose is conformed to the external margins of the tumor. However, much research is needed to establish the equivalent margins for non-uniform fields, where multiple biological targets are present and each target is prescribed its own dose level. Additionally, the size of the biological targets and close proximity make it impractical to apply planning margins on the sub-tumor level. Also, the extent of high dose regions must be limited to avoid excessive dose to the surrounding tissue. As such, this research project is an investigation of the uncertainty within quantitative PET images of moving and displaced dose-painting targets, and an investigation of the residual errors that remain after motion management. This included characterization of the changes in PET voxel-values as objects are moved relative to the discrete sampling interval of PET imaging systems (SPECIFIC AIM 1). Additionally, the repeatability of PET distributions and the delineating dose-painting targets were measured (SPECIFIC AIM 2). The effect of imaging uncertainty on the dose distributions designed using these images (SPECIFIC AIM 3) has also been investigated. This project also included analysis of methods to minimize motion during PET imaging and reduce the dosimetric impact of motion/position-induced imaging uncertainty (SPECIFIC AIM 4).

F-18 Labeled Diabody-Luciferase Fusion Proteins for Optical-ImmunoPET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Anna M.

2013-01-18

The goal of the proposed work is to develop novel dual-labeled molecular imaging probes for multimodality imaging. Based on small, engineered antibodies called diabodies, these probes will be radioactively tagged with Fluorine-18 for PET imaging, and fused to luciferases for optical (bioluminescence) detection. Performance will be evaluated and validated using a prototype integrated optical-PET imaging system, OPET. Multimodality probes for optical-PET imaging will be based on diabodies that are dually labeled with 18F for PET detection and fused to luciferases for optical imaging. 1) Two sets of fusion proteins will be built, targeting the cell surface markers CEA or HER2.more » Coelenterazine-based luciferases and variant forms will be evaluated in combination with native substrate and analogs, in order to obtain two distinct probes recognizing different targets with different spectral signatures. 2) Diabody-luciferase fusion proteins will be labeled with 18F using amine reactive [18F]-SFB produced using a novel microwave-assisted, one-pot method. 3) Sitespecific, chemoselective radiolabeling methods will be devised, to reduce the chance that radiolabeling will inactivate either the target-binding properties or the bioluminescence properties of the diabody-luciferase fusion proteins. 4) Combined optical and PET imaging of these dual modality probes will be evaluated and validated in vitro and in vivo using a prototype integrated optical-PET imaging system, OPET. Each imaging modality has its strengths and weaknesses. Development and use of dual modality probes allows optical imaging to benefit from the localization and quantitation offered by the PET mode, and enhances the PET imaging by enabling simultaneous detection of more than one probe.« less

A new methodological approach for PET implementation in radiotherapy treatment planning.

PubMed

Bellan, Elena; Ferretti, Alice; Capirci, Carlo; Grassetto, Gaia; Gava, Marcello; Chondrogiannis, Sotirios; Virdis, Graziella; Marzola, Maria Cristina; Massaro, Arianna; Rubello, Domenico; Nibale, Otello

2012-05-01

In this paper, a new methodological approach to using PET information in radiotherapy treatment planning has been discussed. Computed tomography (CT) represents the primary modality to plan personalized radiation treatment, because it provides the basic electron density map for correct dose calculation. If PET scanning is also performed it is typically coregistered with the CT study. This operation can be executed automatically by a hybrid PET/CT scanner or, if the PET and CT imaging sets have been acquired through different equipment, by a dedicated module of the radiotherapy treatment planning system. Both approaches have some disadvantages: in the first case, the bore of a PET/CT system generally used in clinical practice often does not allow the use of certain bulky devices for patient immobilization in radiotherapy, whereas in the second case the result could be affected by limitations in window/level visualization of two different image modalities, and the displayed PET volumes can appear not to be related to the actual uptake into the patient. To overcome these problems, at our centre a specific procedure has been studied and tested in 30 patients, allowing good results of precision in the target contouring to be obtained. The process consists of segmentation of the biological target volume by a dedicated PET/CT console and its export to a dedicated radiotherapy system, where an image registration between the CT images acquired by the PET/CT scanner and a large-bore CT is performed. The planning target volume is contoured only on the large-bore CT and is used for virtual simulation, to individuate permanent skin markers on the patient.

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests.

PubMed

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-02-01

The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated aspects were spatial resolution, sensitivity, scatter fraction, count rate performance, image quality, count loss and random events correction accuracy. The findings of this study demonstrated superior sensitivity (~ 4 folds) of PET scanner in PET/MR compared to PET/CT system. Image quality test exhibited higher contrast in PET/MR (~ 9%) compared with PET/CT. The scatter fraction of PET/MR was 43.4% at noise equivalent count rate (NECR) peak of 218 kcps and the corresponding activity concentration was 17.7 kBq/cc. Whereas the scatter fraction of PET/CT was found as 39.2% at NECR peak of 72 kcps and activity concentration of 24.3 kBq/cc. The percentage error of the random event correction accuracy was 3.4% and 3.1% in PET/MR and PET/CT, respectively. It was concluded that PET/MR system is about 4 times more sensitive than PET/CT, and the contrast of hot lesions in PET/MR was ~ 9% higher than PET/CT. These outcomes also emphasize the possibility to achieve excellent clinical PET images with low administered dose and/or a short acquisition time in PET/MR.

[64Cu]NOTA-pentixather enables high resolution PET imaging of CXCR4 expression in a preclinical lymphoma model.

PubMed

Poschenrieder, Andreas; Schottelius, Margret; Osl, Theresa; Schwaiger, Markus; Wester, Hans-Jürgen

2017-01-01

The chemokine receptor 4 (CXCR4) is an important molecular target for both visualization and therapy of tumors. The aim of the present study was the synthesis and preclinical evaluation of a 64 Cu-labeled, CXCR4-targeting peptide for positron emission tomography (PET) imaging of CXCR4 expression in vivo. For this purpose, 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), or 1,4,7-triazacyclononane-triacetic acid (NOTA) was conjugated to the highly affine CXCR4-targeting pentixather scaffold. Affinities were determined using Jurkat T-lymphocytes in competitive binding assays employing [ 125 I]FC131 as the radioligand. Internalization and efflux studies of [ 64 Cu]NOTA-pentixather were performed in chem-1 cells, stably transfected with hCXCR4. The stability of the tracer was evaluated in vitro and in vivo . Small-animal PET and biodistribution studies at different time points were performed in Daudi lymphoma-bearing severe combined immunodeficiency (SCID) mice. [ 64 Cu]NOTA-pentixather was rapidly radiolabeled at 60 °C with high radiochemical yields ≥90% and purities >99%. [ 64 Cu]NOTA-pentixather offered the highest affinity of the evaluated peptides in this study (IC 50  = 14.9 ± 2.1 nM), showed efficient CXCR4-targeting in vitro and was stable in blood and urine with high resistance to transchelation in ethylenediaminetetraacetic acid (EDTA) challenge studies. Due to the enhanced lipophilicity of [ 64 Cu]NOTA-pentixather (logP = -1.2), biodistribution studies showed some nonspecific accumulation in the liver and intestines. However, tumor accumulation (13.1 ± 1.5% ID/g, 1.5 h p.i.) was CXCR4-specific and higher than in all other organs and resulted in high resolution delineation of Daudi tumors in PET/CT images in vivo. [ 64 Cu]NOTA-pentixather was fast and efficiently radiolabeled, showed effective CXCR4-targeting, high stability in vitro and in vivo and resulted in high resolution PET/CT images accompanied with a suitable

Tier-1 assays for assessing the toxicity of insecticidal proteins produced by genetically engineered plants to non-target arthropods.

PubMed

Li, Yun-He; Romeis, Jörg; Wu, Kong-Ming; Peng, Yu-Fa

2014-04-01

In assessing an insect-resistant genetically engineered (IRGE) crop before its commercialization, researchers normally use so-called "Tier-1 assays" as the initial step to determine the effects of the crop on non-target organisms. In these tests, the insecticidal proteins (IPs) produced by the IRGEs are added to the diets of test organisms in the laboratory. Test organisms in such assays can be directly exposed to much higher concentrations of the test IPs than they would encounter in the field. The results of Tier-1 assays are thus more conservative than those generated in studies in which the organisms are exposed to the IPs by feeding on IRGE plant tissue or in the case of predators or parasites, by feeding on invertebrate prey or hosts that have fed on IRGE plant tissue. In this report, we consider three important factors that must be considered in Tier-1 assays: (i) methods for delivery of the IP to the test organisms; (ii) the need for and selection of compounds used as positive controls; and (iii) methods for monitoring the concentration, stability and bioactivity of the IP during the assay. We also analyze the existing data from Tier-1 assays regarding the toxicity of Bt Cry proteins to non-target arthropod species. The data indicate that the widely used Bt proteins have no direct toxicity to non-target organisms. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Targeted Peptide Measurements in Biology and Medicine: Best Practices for Mass Spectrometry-based Assay Development Using a Fit-for-Purpose Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carr, Steven A.; Abbateillo, Susan E.; Ackermann, Bradley L.

2014-01-14

Adoption of targeted mass spectrometry (MS) approaches such as multiple reaction monitoring (MRM) to study biological and biomedical questions is well underway in the proteomics community. Successful application depends on the ability to generate reliable assays that uniquely and confidently identify target peptides in a sample. Unfortunately, there is a wide range of criteria being applied to say that an assay has been successfully developed. There is no consensus on what criteria are acceptable and little understanding of the impact of variable criteria on the quality of the results generated. Publications describing targeted MS assays for peptides frequently do notmore » contain sufficient information for readers to establish confidence that the tests work as intended or to be able to apply the tests described in their own labs. Guidance must be developed so that targeted MS assays with established performance can be made widely distributed and applied by many labs worldwide. To begin to address the problems and their solutions, a workshop was held at the National Institutes of Health with representatives from the multiple communities developing and employing targeted MS assays. Participants discussed the analytical goals of their experiments and the experimental evidence needed to establish that the assays they develop work as intended and are achieving the required levels of performance. Using this “fit-for-purpose” approach, the group defined three tiers of assays distinguished by their performance and extent of analytical characterization. Computational and statistical tools useful for the analysis of targeted MS results were described. Participants also detailed the information that authors need to provide in their manuscripts to enable reviewers and readers to clearly understand what procedures were performed and to evaluate the reliability of the peptide or protein quantification measurements reported. This paper presents a summary of the meeting

Preclinical Evaluation of an Anti-Nectin-4 ImmunoPET Reagent in Tumor-Bearing Mice and Biodistribution Studies in Cynomolgus Monkeys.

PubMed

Campbell, Dean O; Noda, Akihiro; Verlinsky, Alla; Snyder, Josh; Fujita, Yuji; Murakami, Yoshihiro; Fushiki, Hiroshi; Miyoshi, Sosuke; Lacayo, Sergio; Cabral, Edward; Yang, Peng; Stover, David R; Joseph, Ingrid B J K

2016-10-01

Nectin-4 is selectively overexpressed in a variety of cancers and is currently under clinical investigation as a therapeutic target. A monoclonal antibody against nectin-4 (AGS-22M6) was evaluated as an Immuno-positron emission tomography (ImmunoPET) reagent. Its ability to assay nectin-4 expression as well as detect nectin-4 positive tumors in the liver and bone was evaluated using mouse models. The biodistribution of [(89)Zr]AGS-22M6 was evaluated in mice bearing tumors with varying levels of nectin-4 expression. An isogenic breast cancer tumor line was used to model metastatic liver and bone disease in mice. The biodistribution of [(18)F]AGS-22M6 in cynomolgus monkeys was evaluated. A positive correlation was demonstrated between tumor nectin-4 expression and [(89)Zr]AGS-22M6 uptake. Tumors in the liver and bone were detected and differentiated based on nectin-4 expression. [(18)F]AGS-22M6 showed limited uptake in cynomolgus monkey tissues. [(89)Zr]AGS-22M6 is a promising ImmunoPET reagent that can assay nectin-4 expression in both primary and metastatic lesions.

[Target volume margins for lung cancer: internal target volume/clinical target volume].

PubMed

Jouin, A; Pourel, N

2013-10-01

The aim of this study was to carry out a review of margins that should be used for the delineation of target volumes in lung cancer, with a focus on margins from gross tumour volume (GTV) to clinical target volume (CTV) and internal target volume (ITV) delineation. Our review was based on a PubMed literature search with, as a cornerstone, the 2010 European Organisation for Research and Treatment of Cancer (EORTC) recommandations by De Ruysscher et al. The keywords used for the search were: radiotherapy, lung cancer, clinical target volume, internal target volume. The relevant information was categorized under the following headings: gross tumour volume definition (GTV), CTV-GTV margin (first tumoural CTV then nodal CTV definition), in field versus elective nodal irradiation, metabolic imaging role through the input of the PET scanner for tumour target volume and limitations of PET-CT imaging for nodal target volume definition, postoperative radiotherapy target volume definition, delineation of target volumes after induction chemotherapy; then the internal target volume is specified as well as tumoural mobility for lung cancer and respiratory gating techniques. Finally, a chapter is dedicated to planning target volume definition and another to small cell lung cancer. For each heading, the most relevant and recent clinical trials and publications are mentioned. Copyright © 2013. Published by Elsevier SAS.

Design of a functional cyclic HSV1-TK reporter and its application to PET imaging of apoptosis

PubMed Central

Wang, Zhe; Wang, Fu; Hida, Naoki; Kiesewetter, Dale O; Tian, Jie; Niu, Gang; Chen, Xiaoyuan

2017-01-01

Positron emission tomography (PET) is a sensitive and noninvasive imaging method that is widely used to explore molecular events in living subjects. PET can precisely and quantitatively evaluate cellular apoptosis, which has a crucial role in various physiological and pathological processes. In this protocol, we describe the design and use of an engineered cyclic herpes simplex virus 1–thymidine kinase (HSV1-TK) PET reporter whose kinase activity is specifically switched on by apoptosis. The expression of cyclic TK (cTK) in healthy cells leads to inactive product, whereas the activation of apoptosis through the caspase-3 pathway cleaves cTK, thus restoring its activity and enabling PET imaging. In addition to detailing the design and construction of the cTK plasmid in this protocol, we include assays for evaluating the function and specificity of the cTK reporter in apoptotic cells, such as assays for measuring the cell uptake of PET tracer in apoptotic cells, correlating doxorubicin (Dox)-induced cell apoptosis to cTK function recovery, and in vivo PET imaging of cancer cell apoptosis, and we also include corresponding data acquisition methods. The time to build the entire cTK reporter is ~2–3 weeks. The selection of a stable cancer cell line takes ~4–6 weeks. The time to implement assays regarding cTK function in apoptotic cells and the in vivo imaging varies depending on the experiment. The cyclization strategy described in this protocol can also be adapted to create other reporter systems for broad biomedical applications. PMID:25927390

A fluorescence anisotropy assay to discover and characterize ligands targeting the maytansine site of tubulin.

PubMed

Menchon, Grégory; Prota, Andrea E; Lucena-Agell, Daniel; Bucher, Pascal; Jansen, Rolf; Irschik, Herbert; Müller, Rolf; Paterson, Ian; Díaz, J Fernando; Altmann, Karl-Heinz; Steinmetz, Michel O

2018-05-29

Microtubule-targeting agents (MTAs) like taxol and vinblastine are among the most successful chemotherapeutic drugs against cancer. Here, we describe a fluorescence anisotropy-based assay that specifically probes for ligands targeting the recently discovered maytansine site of tubulin. Using this assay, we have determined the dissociation constants of known maytansine site ligands, including the pharmacologically active degradation product of the clinical antibody-drug conjugate trastuzumab emtansine. In addition, we discovered that the two natural products spongistatin-1 and disorazole Z with established cellular potency bind to the maytansine site on β-tubulin. The high-resolution crystal structures of spongistatin-1 and disorazole Z in complex with tubulin allowed the definition of an additional sub-site adjacent to the pocket shared by all maytansine-site ligands, which could be exploitable as a distinct, separate target site for small molecules. Our study provides a basis for the discovery and development of next-generation MTAs for the treatment of cancer.

Fragment-Based Phenotypic Lead Discovery: Cell-Based Assay to Target Leishmaniasis.

PubMed

Ayotte, Yann; Bilodeau, François; Descoteaux, Albert; LaPlante, Steven R

2018-05-02

A rapid and practical approach for the discovery of new chemical matter for targeting pathogens and diseases is described. Fragment-based phenotypic lead discovery (FPLD) combines aspects of traditional fragment-based lead discovery (FBLD), which involves the screening of small-molecule fragment libraries to target specific proteins, with phenotypic lead discovery (PLD), which typically involves the screening of drug-like compounds in cell-based assays. To enable FPLD, a diverse library of fragments was first designed, assembled, and curated. This library of soluble, low-molecular-weight compounds was then pooled to expedite screening. Axenic cultures of Leishmania promastigotes were screened, and single hits were then tested for leishmanicidal activity against intracellular amastigote forms in infected murine bone-marrow-derived macrophages without evidence of toxicity toward mammalian cells. These studies demonstrate that FPLD can be a rapid and effective means to discover hits that can serve as leads for further medicinal chemistry purposes or as tool compounds for identifying known or novel targets. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

First-in-Human Human Epidermal Growth Factor Receptor 2-Targeted Imaging Using 89Zr-Pertuzumab PET/CT: Dosimetry and Clinical Application in Patients with Breast Cancer.

PubMed

Ulaner, Gary A; Lyashchenko, Serge K; Riedl, Christopher; Ruan, Shutian; Zanzonico, Pat B; Lake, Diana; Jhaveri, Komal; Zeglis, Brian; Lewis, Jason S; O'Donoghue, Joseph A

2018-06-01

In what we believe to be a first-in-human study, we evaluated the safety and dosimetry of 89 Zr-pertuzumab PET/CT for human epidermal growth factor receptor 2 (HER2)-targeted imaging in patients with HER2-positive breast cancer. Methods: Patients with HER2-positive breast cancer and evidence of distant metastases were enrolled in an institutional review board-approved prospective clinical trial. Pertuzumab was conjugated with deferoxamine and radiolabeled with 89 Zr. Patients underwent PET/CT with 74 MBq of 89 Zr-pertuzumab in a total antibody mass of 20-50 mg of pertuzumab. PET/CT, whole-body probe counts, and blood drawing were performed over 8 d to assess pharmacokinetics, biodistribution, and dosimetry. PET/CT images were evaluated for the ability to visualize HER2-positive metastases. Results: Six patients with HER2-positive metastatic breast cancer were enrolled and administered 89 Zr-pertuzumab. No toxicities occurred. Dosimetry estimates from OLINDA demonstrated that the organs receiving the highest doses (mean ± SD) were the liver (1.75 ± 0.21 mGy/MBq), the kidneys (1.27 ± 0.28 mGy/MBq), and the heart wall (1.22 ± 0.16 mGy/MBq), with an average effective dose of 0.54 ± 0.07 mSv/MBq. PET/CT demonstrated optimal imaging 5-8 d after administration. 89 Zr-pertuzumab was able to image multiple sites of malignancy and suggested that they were HER2-positive. In 2 patients with both known HER2-positive and HER2-negative primary breast cancers and brain metastases, 89 Zr-pertuzumab PET/CT suggested that the brain metastases were HER2-positive. In 1 of the 2 patients, subsequent resection of a brain metastasis proved HER2-positive disease, confirming that the 89 Zr-pertuzumab avidity was a true-positive result for HER2-positive malignancy. Conclusion: This first-in-human study demonstrated safety, dosimetry, biodistribution, and successful HER2-targeted imaging with 89 Zr-pertuzumab PET/CT. Potential clinical applications include assessment of the HER2 status

Quantitative assessment of atherosclerotic plaques on (18)F-FDG PET/MRI: comparison with a PET/CT hybrid system.

PubMed

Li, Xiang; Heber, Daniel; Rausch, Ivo; Beitzke, Dietrich; Mayerhoefer, Marius E; Rasul, Sazan; Kreissl, Michael; Mitthauser, Markus; Wadsak, Wolfgang; Hartenbach, Markus; Haug, Alexander; Zhang, Xiaoli; Loewe, Christian; Beyer, Thomas; Hacker, Marcus

2016-07-01

PET with (18)F-FDG has the potential to assess vascular macrophage metabolism. (18)F-FDG is most often used in combination with contrast-enhanced CT to localize increased metabolism to specific arterial lesions. Novel (18)F-FDG PET/MRI hybrid imaging shows high potential for the combined evaluation of atherosclerotic plaques, due to the superior morphological conspicuity of plaque lesions. The purpose of this study was to evaluate the reliability and accuracy of (18)F-FDG PET/MRI uptake quantification compared to PET/CT as a reference standard in patients with carotid atherosclerotic plaques. The study group comprised 34 consecutive oncological patients with carotid plaques who underwent both PET/CT and PET/MRI with (18)F-FDG on the same day. The presence of atherosclerotic plaques was confirmed by 3 T MRI scans. Maximum standardized uptake values (SUVmax) for carotid plaque lesions and the average SUV of the blood pool within the adjacent internal jugular vein were determined and target-to-blood ratios (TBRs, plaque to blood pool) were calculated. Atherosclerotic lesions with maximum colocalized focal FDG uptake were assessed in each patient. SUVmax values of carotid plaque lesions were significantly lower on PET/MRI than on PET/CT (2.3 ± 0.6 vs. 3.1 ± 0.6; P < 0.01), but were significantly correlated between PET/CT and PET/MRI (Spearman's r = 0.67, P < 0.01). In contrast, TBRmax values of plaque lesions were similar on PET/MRI and on PET/CT (2.2 ± 0.3 vs. 2.2 ± 0.3; P = 0.4), and again were significantly correlated between PET/MRI and PET/CT (Spearman's r = 0.73, P < 0.01). Considering the increasing trend in SUVmax and TBRmax values from early to delayed imaging time-points on PET/CT and PET/MRI, respectively, with continuous clearance of radioactivity from the blood, a slight underestimation of TBRmax values may also be expected with PET/MRI compared with PET/CT. SUVmax and TBRmax values are widely accepted reference

Performance Characteristics of qPCR Assays Targeting Human- and Ruminant-Associated Bacteroidetes for Microbial Source Tracking across Sixteen Countries on Six Continents

PubMed Central

2013-01-01

Numerous quantitative PCR assays for microbial fecal source tracking (MST) have been developed and evaluated in recent years. Widespread application has been hindered by a lack of knowledge regarding the geographical stability and hence applicability of such methods beyond the regional level. This study assessed the performance of five previously reported quantitative PCR assays targeting human-, cattle-, or ruminant-associated Bacteroidetes populations on 280 human and animal fecal samples from 16 countries across six continents. The tested cattle-associated markers were shown to be ruminant-associated. The quantitative distributions of marker concentrations in target and nontarget samples proved to be essential for the assessment of assay performance and were used to establish a new metric for quantitative source-specificity. In general, this study demonstrates that stable target populations required for marker-based MST occur around the globe. Ruminant-associated marker concentrations were strongly correlated with total intestinal Bacteroidetes populations and with each other, indicating that the detected ruminant-associated populations seem to be part of the intestinal core microbiome of ruminants worldwide. Consequently tested ruminant-targeted assays appear to be suitable quantitative MST tools beyond the regional level while the targeted human-associated populations seem to be less prevalent and stable, suggesting potential for improvements in human-targeted methods. PMID:23755882

P04.02 Analysis of 18F-DOPA PET imaging for target volume definition in patients with recurrent glioblastoma treated with proton therapy

PubMed Central

Amelio, D.; Scartoni, D.; Palucci, A.; Vennarini, S.; Giacomelli, I.; Lemoine, S.; Donner, D.; Farace, P.; Chierichetti, F.; Amichetti, M.

2017-01-01

Abstract Introduction: Target volume definition is of critical relevance when re-irradiation is delivered and steep dose gradient irradiation techniques, such as proton therapy (PT), are employed. Aim of the study is to investigate the impact of 18F-DOPA on target volume contouring in recurrent glioblastoma (rGBM) patients (pts) undergoing re-irradiation with PT. MATERIAL AND METHODS: We investigated the differences in volume and relationship of magnetic resonance imaging (MRI)- vs. DOPA PET-derived gross tumor volumes (GTVs) of 14 rGBM pts re-irradiated with PT between January and November 2016. All pts had been previously treated with photon radiotherapy (60 Gy) with concomitant and adjuvant temozolomide. All the pts received morphological MRI with contrast enhancement medium administration and 18F-DOPA PET-CT study. We used the pathological distribution of 18F-DOPA in brain tissue to identify the so-called Biological Tumor Volume (BTV). Such areas were assessed using a tumor to normal brain ratio > 2. Moreover, any area of contrast enhancement on MRI was used to identify the MRI-based GTV (MRGTV). Definitive GTV included MRGTV plus BTV. Clinical target volume was generated by adding to GTV a 3-mm uniform margin manually corrected in proximity of anatomical barriers. CTV was expanded by 4 mm to create planning target volume. All pts received 36 GyRBE in 18 fractions. Mean values of differently delineated GTVs were compared each other by paired Student’s t-test; p < 0.05 was considered significant. To further compare MRGTV and BTV, the overlapping (MRGTV ^ BTV) and the composite (MRGTV U BTV) volumes were calculated, and a concordance index (CI) was defined as the ratio between the overlap and composite volumes. Results: MRGTV (mean 14.9 ± 14.5 cc) was larger than BTV (mean 10.9 ± 9.8 cc) although this difference was not statistically significant. The composite volume (mean 20.9 ± 14.7 cc) was significantly larger than each single volume (p < 0

Development of a Rickettsia bellii-Specific TaqMan Assay Targeting the Citrate Synthase Gene.

PubMed

Hecht, Joy A; Allerdice, Michelle E J; Krawczak, Felipe S; Labruna, Marcelo B; Paddock, Christopher D; Karpathy, Sandor E

2016-11-01

Rickettsia bellii is a rickettsial species of unknown pathogenicity that infects argasid and ixodid ticks throughout the Americas. Many molecular assays used to detect spotted fever group (SFG) Rickettsia species do not detect R. bellii, so that infection with this bacterium may be concealed in tick populations when assays are used that screen specifically for SFG rickettsiae. We describe the development and validation of a R. bellii-specific, quantitative, real-time PCR TaqMan assay that targets a segment of the citrate synthase (gltA) gene. The specificity of this assay was validated against a panel of DNA samples that included 26 species of Rickettsia, Orientia, Ehrlichia, Anaplasma, and Bartonella, five samples of tick and human DNA, and DNA from 20 isolates of R. bellii, including 11 from North America and nine from South America. A R. bellii control plasmid was constructed, and serial dilutions of the plasmid were used to determine the limit of detection of the assay to be one copy per 4 µl of template DNA. This assay can be used to better determine the role of R. bellii in the epidemiology of tick-borne rickettsioses in the Western Hemisphere. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

In Vivo PET Assay of Tumor Glutamine Flux and Metabolism: In-Human Trial of 18F-(2S,4R)-4-Fluoroglutamine.

PubMed

Dunphy, Mark P S; Harding, James J; Venneti, Sriram; Zhang, Hanwen; Burnazi, Eva M; Bromberg, Jacqueline; Omuro, Antonio M; Hsieh, James J; Mellinghoff, Ingo K; Staton, Kevin; Pressl, Christina; Beattie, Bradley J; Zanzonico, Pat B; Gerecitano, John F; Kelsen, David P; Weber, Wolfgang; Lyashchenko, Serge K; Kung, Hank F; Lewis, Jason S

2018-05-01

Purpose To assess the clinical safety, pharmacokinetics, and tumor imaging characteristics of fluorine 18-(2S,4R)-4-fluoroglutamine (FGln), a glutamine analog radiologic imaging agent. Materials and Methods This study was approved by the institutional review board and conducted under a U.S. Food and Drug Administration-approved Investigational New Drug application in accordance with the Helsinki Declaration and the Health Insurance Portability and Accountability Act. All patients provided written informed consent. Between January 2013 and October 2016, 25 adult patients with cancer received an intravenous bolus of FGln tracer (mean, 244 MBq ± 118, <100 μg) followed by positron emission tomography (PET) and blood radioassays. Patient data were summarized with descriptive statistics. FGln biodistribution and plasma amino acid levels in nonfasting patients (n = 13) were compared with those from patients who fasted at least 8 hours before injection (n = 12) by using nonparametric one-way analysis of variance with Bonferroni correction. Tumor FGln avidity versus fluorodeoxyglucose (FDG) avidity in patients with paired PET scans (n = 15) was evaluated with the Fisher exact test. P < .05 was considered indicative of a statistically significant difference. Results FGln PET depicted tumors of different cancer types (breast, pancreas, renal, neuroendocrine, lung, colon, lymphoma, bile duct, or glioma) in 17 of the 25 patients, predominantly clinically aggressive tumors with genetic mutations implicated in abnormal glutamine metabolism. Acute fasting had no significant effect on FGln biodistribution and plasma amino acid levels. FGln-avid tumors were uniformly FDG-avid but not vice versa (P = .07). Patients experienced no adverse effects. Conclusion Preliminary human FGln PET trial results provide clinical validation of abnormal glutamine metabolism as a potential tumor biomarker for targeted radiotracer imaging in several different cancer types. © RSNA, 2018 Online

Impact of FDG-PET on radiation therapy volume delineation in non-small-cell lung cancer.

PubMed

Bradley, Jeffrey; Thorstad, Wade L; Mutic, Sasa; Miller, Tom R; Dehdashti, Farrokh; Siegel, Barry A; Bosch, Walter; Bertrand, Rudi J

2004-05-01

Locoregional failure remains a significant problem for patients receiving definitive radiation therapy alone or combined with chemotherapy for non-small-cell lung cancer (NSCLC). Positron emission tomography (PET) with [(18)F]fluoro-2-deoxy-d-glucose (FDG) has proven to be a valuable diagnostic and staging tool for NSCLC. This prospective study was performed to determine the impact of treatment simulation with FDG-PET and CT on radiation therapy target volume definition and toxicity profiles by comparison to simulation with computed tomography (CT) scanning alone. Twenty-six patients with Stages I-III NSCLC were studied. Each patient underwent sequential CT and FDG-PET simulation on the same day. Immobilization devices used for both simulations included an alpha cradle, a flat tabletop, 6 external fiducial markers, and a laser positioning system. A radiation therapist participated in both simulations to reproduce the treatment setup. Both the CT and fused PET/CT image data sets were transferred to the radiation treatment planning workstation for contouring. Each FDG-PET study was reviewed with the interpreting nuclear radiologist before tumor volumes were contoured. The fused PET/CT images were used to develop the three-dimensional conformal radiation therapy (3DCRT) plan. A second physician, blinded to the results of PET, contoured the gross tumor volumes (GTV) and planning target volumes (PTV) from the CT data sets, and these volumes were used to generate mock 3DCRT plans. The PTV was defined by a 10-mm margin around the GTV. The two 3DCRT plans for each patient were compared with respect to the GTV, PTV, mean lung dose, volume of normal lung receiving > or =20 Gy (V20), and mean esophageal dose. The FDG-PET findings altered the AJCC TNM stage in 8 of 26 (31%) patients; 2 patients were diagnosed with metastatic disease based on FDG-PET and received palliative radiation therapy. Of the 24 patients who were planned with 3DCRT, PET clearly altered the radiation

Reactivity assay of surface carboxyl chain-ends of poly(ethylene terephthalate) (PET) film and track-etched microporous membranes using fluorine labelled- and/or 3H-labelled derivatization reagents: tandem analysis by X-ray photoelectron spectroscopy (XPS) and liquid scintillation counting (LSC)

NASA Astrophysics Data System (ADS)

Deldime, Michèle; Dewez, Jean-Luc; Schneider, Yves-Jacques; Marchand-Brynaert, Jacqueline

1995-09-01

Poly(ethylene terephthalate) (PET) films and track-etched microporous membranes of two different porosities were pretreated by hydrolysis and/or oxidation in order to enhance the amount of carboxyl chain-ends displayed on their surface. The reactivity of these carboxyl functions was determined by derivatization assays in which the reactions were carried out under conditions likely to be encountered in the coupling of water-soluble biochemical signals on the surface of biomaterials. Original reagents, fluorine-labelled and/or 3H-labelled aminoacid compounds, were used. The derivatized PET samples were examined by X-ray photoelectron spectroscopy (XPS) to characterize their apparent surfaces, and by liquid scintillation counting (LSC) to quantify the amount of tags fixed on their open surfaces. Using this dual assay technique, we analyzed the surface of microporous membranes which are currently used as substrates for cell culture systems.

PET/MRI: Where Might It Replace PET/CT?

PubMed Central

Ehman, Eric C.; Johnson, Geoffrey B.; Villanueva-Meyer, Javier E.; Cha, Soonmee; Leynes, Andrew Palmera; Larson, Peder Eric Zufall; Hope, Thomas A.

2017-01-01

Simultaneous positron emission tomography and MRI (PET/MRI) is a technology that combines the anatomic and quantitative strengths of MR imaging with physiologic information obtained from PET. PET and computed tomography (PET/ CT) performed in a single scanning session is an established technology already in widespread and accepted use worldwide. Given the higher cost and complexity of operating and interpreting the studies obtained on a PET/MRI system, there has been question as to which patients would benefit most from imaging with PET/MRI versus PET/CT. In this article, we compare PET/MRI with PET/CT, detail the applications for which PET/MRI has shown promise and discuss impediments to future adoption. It is our hope that future work will prove the benefit of PET/MRI to specific groups of patients, initially those in which PET/CT and MRI are already performed, leveraging simultaneity and allowing for greater degrees of multiparametric evaluation. PMID:28370695

Noninvasive imaging of cationic lipid-mediated delivery of optical and PET reporter genes in living mice.

PubMed

Iyer, Meera; Berenji, Manijeh; Templeton, Nancy S; Gambhir, Sanjiv S

2002-10-01

Gene therapy involves the safe and effective delivery of one or more genes of interest to target cells in vivo. The advantages of using nonviral delivery systems include ease of preparation, low toxicity, and weak immunogenicity. Nonviral delivery methods, when combined with a noninvasive, clinically applicable imaging assay, will greatly aid in the optimization of gene therapy approaches for cancer. We demonstrate cationic lipid-mediated noninvasive monitoring of reporter gene expression of firefly (Photinus pyralis) luciferase (fl) and a mutant herpes simplex virus type I thymidine kinase (HSV1-sr39tk, tk) in living mice using a cooled charge coupled device (CCD) camera and positron emission tomography (PET), respectively. We observe a high level of fl and tk reporter gene expression predominantly in the lungs after a single injection of the extruded DOTAP:cholesterol DNA liposome complexes by way of the tail vein, seen to be time- and dose-dependent. We observe a good correlation between the in vivo bioluminescent signal and the ex vivo firefly luciferase enzyme (FL) activity in different organs. We further demonstrate the feasibility of noninvasively imaging both optical and PET reporter gene expression in the same animal using the CCD camera and microPET, respectively.

Imaging Alzheimer's disease pathophysiology with PET

PubMed Central

Schilling, Lucas Porcello; Zimmer, Eduardo R.; Shin, Monica; Leuzy, Antoine; Pascoal, Tharick A.; Benedet, Andréa L.; Borelli, Wyllians Vendramini; Palmini, André; Gauthier, Serge; Rosa-Neto, Pedro

2016-01-01

ABSTRACT Alzheimer's disease (AD) has been reconceptualised as a dynamic pathophysiological process characterized by preclinical, mild cognitive impairment (MCI), and dementia stages. Positron emission tomography (PET) associated with various molecular imaging agents reveals numerous aspects of dementia pathophysiology, such as brain amyloidosis, tau accumulation, neuroreceptor changes, metabolism abnormalities and neuroinflammation in dementia patients. In the context of a growing shift toward presymptomatic early diagnosis and disease-modifying interventions, PET molecular imaging agents provide an unprecedented means of quantifying the AD pathophysiological process, monitoring disease progression, ascertaining whether therapies engage their respective brain molecular targets, as well as quantifying pharmacological responses. In the present study, we highlight the most important contributions of PET in describing brain molecular abnormalities in AD. PMID:29213438

An integrated target sequence and signal amplification assay, reverse transcriptase-PCR-enzyme-linked immunosorbent assay, to detect and characterize flaviviruses.

PubMed

Chang, G J; Trent, D W; Vorndam, A V; Vergne, E; Kinney, R M; Mitchell, C J

1994-02-01

We previously described a reverse transcriptase-PCR using flavivirus genus-conserved and virus species-specific amplimers (D. W. Trent and G. J. Chang, p. 355-371, in Y. Becker and C. Darai; ed., Frontiers of Virology, vol. 1, 1992). Target amplification was improved by redesigning the amplimers, and a sensitive enzyme-linked immunosorbent assay (ELISA) technique has been developed to detect amplified digoxigenin (DIG)-modified DNA. A single biotin motif and multiple DIG motifs were incorporated into each amplicon, which permitted amplicon capture by a biotin-streptavidin interaction and detection with DIG-specific antiserum in a colorimetric ELISA. We evaluated the utility of this assay for detecting St. Louis encephalitis (SLE) viral RNA in infected mosquitoes and dengue viral RNA in human serum specimens. The reverse transcriptase-PCR-ELISA was as sensitive as isolation of SLE virus by cell culture in detecting SLE viral RNA in infected mosquitoes. The test was 89% specific and 95 to 100% sensitive for identification of dengue viral RNA in serum specimens compared with isolation of virus by Aedes albopictus C6/36 cell culture and identification by the indirect immunofluorescence assay.

An integrated target sequence and signal amplification assay, reverse transcriptase-PCR-enzyme-linked immunosorbent assay, to detect and characterize flaviviruses.

PubMed Central

Chang, G J; Trent, D W; Vorndam, A V; Vergne, E; Kinney, R M; Mitchell, C J

1994-01-01

We previously described a reverse transcriptase-PCR using flavivirus genus-conserved and virus species-specific amplimers (D. W. Trent and G. J. Chang, p. 355-371, in Y. Becker and C. Darai; ed., Frontiers of Virology, vol. 1, 1992). Target amplification was improved by redesigning the amplimers, and a sensitive enzyme-linked immunosorbent assay (ELISA) technique has been developed to detect amplified digoxigenin (DIG)-modified DNA. A single biotin motif and multiple DIG motifs were incorporated into each amplicon, which permitted amplicon capture by a biotin-streptavidin interaction and detection with DIG-specific antiserum in a colorimetric ELISA. We evaluated the utility of this assay for detecting St. Louis encephalitis (SLE) viral RNA in infected mosquitoes and dengue viral RNA in human serum specimens. The reverse transcriptase-PCR-ELISA was as sensitive as isolation of SLE virus by cell culture in detecting SLE viral RNA in infected mosquitoes. The test was 89% specific and 95 to 100% sensitive for identification of dengue viral RNA in serum specimens compared with isolation of virus by Aedes albopictus C6/36 cell culture and identification by the indirect immunofluorescence assay. PMID:7512096

Preliminary results of a prototype C-shaped PET designed for an in-beam PET system

NASA Astrophysics Data System (ADS)

Kim, Hyun-Il; Chung, Yong Hyun; Lee, Kisung; Kim, Kyeong Min; Kim, Yongkwon; Joung, Jinhun

2016-06-01

Positron emission tomography (PET) can be utilized in particle beam therapy to verify the dose distribution of the target volume as well as the accuracy of the treatment. We present an in-beam PET scanner that can be integrated into a particle beam therapy system. The proposed PET scanner consisted of 14 detector modules arranged in a C-shape to avoid blockage of the particle beam line by the detector modules. Each detector module was composed of a 9×9 array of 4.0 mm×4.0 mm×20.0 mm LYSO crystals optically coupled to four 29-mm-diameter PMTs using the photomultiplier-quadrant-sharing (PQS) technique. In this study, a Geant4 Application for Tomographic Emission (GATE) simulation study was conducted to design a C-shaped PET scanner and then experimental evaluation of the proposed design was performed. The spatial resolution and sensitivity were measured according to NEMA NU2-2007 standards and were 6.1 mm and 5.61 cps/kBq, respectively, which is in good agreement with our simulation, with an error rate of 12.0%. Taken together, our results demonstrate the feasibility of the proposed C-shaped in-beam PET system, which we expect will be useful for measuring dose distribution in particle therapy.

Comparison of Gull Feces-Specific Assays Targeting the 16S rRNA Genes of Catellicoccus marimammalium and Streptococcus spp.

PubMed Central

Ryu, Hodon; Griffith, John F.; Khan, Izhar U. H.; Hill, Stephen; Edge, Thomas A.; Toledo-Hernandez, Carlos; Gonzalez-Nieves, Joel

2012-01-01

Two novel gull-specific quantitative PCR (qPCR) assays were developed using 16S rRNA gene sequences from gull fecal clone libraries: a SYBR green assay targeting Streptococcus spp. (gull3) and a hydrolysis TaqMan assay targeting Catellicoccus marimammalium (gull4). The objectives of this study were to compare the host specificity of a previous C. marimammalium qPCR assay (gull2) with that of the new markers and to examine the presence of the three gull markers in environmental water samples from different geographic locations. Most of the gull fecal samples tested (n = 255) generated positive signals with the gull2 and gull4 assays (i.e., >86%), whereas only 28% were positive with gull3. Low prevalence and abundance of tested gull markers (0.6 to 15%) were observed in fecal samples from six nonavian species (n = 180 fecal samples), whereas the assays cross-reacted to some extent (13 to 31%) with other (nongull) avian fecal samples. The gull3 assay was positive against fecal samples from 11 of 15 avian species, including gull. Of the presumed gull-impacted water samples (n = 349), 86%, 59%, and 91% were positive with the gull2, the gull3, and the gull4 assays, respectively. Approximately 5% of 239 non-gull-impacted water samples were positive with the gull2 and the gull4 assays, whereas 21% were positive witg the gull3 assay. While the relatively high occurrence of gull2 and gull4 markers in waters impacted by gull feces suggests that these assays could be used in environmental monitoring studies, the data also suggest that multiple avian-specific assays will be needed to accurately assess the contribution of different avian sources in recreational waters. PMID:22226950

Comparison of PET/CT with Sequential PET/MRI Using an MR-Compatible Mobile PET System.

PubMed

Nakamoto, Ryusuke; Nakamoto, Yuji; Ishimori, Takayoshi; Fushimi, Yasutaka; Kido, Aki; Togashi, Kaori

2018-05-01

The current study tested a newly developed flexible PET (fxPET) scanner prototype. This fxPET system involves dual arc-shaped detectors based on silicon photomultipliers that are designed to fit existing MRI devices, allowing us to obtain fused PET and MR images by sequential PET and MR scanning. This prospective study sought to evaluate the image quality, lesion detection rate, and quantitative values of fxPET in comparison with conventional whole-body (WB) PET and to assess the accuracy of registration. Methods: Seventeen patients with suspected or known malignant tumors were analyzed. Approximately 1 h after intravenous injection of 18 F-FDG, WB PET/CT was performed, followed by fxPET and MRI. For reconstruction of fxPET images, MRI-based attenuation correction was applied. The quality of fxPET images was visually assessed, and the number of detected lesions was compared between the 2 imaging methods. SUV max and maximum average SUV within a 1 cm 3 spheric volume (SUV peak ) of lesions were also compared. In addition, the magnitude of misregistration between fxPET and MR images was evaluated. Results: The image quality of fxPET was acceptable for diagnosis of malignant tumors. There was no significant difference in detectability of malignant lesions between fxPET and WB PET ( P > 0.05). However, the fxPET system did not exhibit superior performance to the WB PET system. There were strong positive correlations between the 2 imaging modalities in SUV max (ρ = 0.88) and SUV peak (ρ = 0.81). SUV max and SUV peak measured with fxPET were approximately 1.1-fold greater than measured with WB PET. The average misregistration between fxPET and MR images was 5.5 ± 3.4 mm. Conclusion: Our preliminary data indicate that running an fxPET scanner near an existing MRI system provides visually and quantitatively acceptable fused PET/MR images for diagnosis of malignant lesions. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

Testing implications of varying targets for Bordetella pertussis: comparison of the FilmArray Respiratory Panel and the Focus B. pertussis PCR assay

PubMed Central

Jerris, Robert C; Williams, Sally R; MacDonald, Heather J; Ingebrigtsen, Danielle R; Westblade, Lars F; Rogers, Beverly B

2015-01-01

Background The FilmArray Respiratory Panel (RP) detects multiple pathogens, including Bordetella pertussis. The multiplex PCR system is appropriate for a core laboratory or point of care due to ease of use. The purpose of this study is to compare the analytical sensitivity of the FilmArray RP, which targets the promoter region of the B. pertussis toxin gene, with the Focus real-time PCR assay, which targets the insertion sequence IS481. Methods Seventy-one specimens from patients aged 1 month to 18 years, which had tested positive for B. pertussis using the Focus assay, were analysed using the FilmArray RP. Results Forty-six specimens were positive for B. pertussis by both the Focus and the FilmArray RP assays. Twenty-five specimens were negative for B. pertussis using the FilmArray RP assay, but positive using the Focus assay. Conclusions The FilmArray RP assays will detect approximately 1/3 less cases of B. pertussis than the Focus assay. PMID:25742911

Target-Specific Assay for Rapid and Quantitative Detection of Mycobacterium chimaera DNA

PubMed Central

Zozaya-Valdés, Enrique; Porter, Jessica L.; Coventry, John; Fyfe, Janet A. M.; Carter, Glen P.; Gonçalves da Silva, Anders; Schultz, Mark B.; Seemann, Torsten; Johnson, Paul D. R.; Stewardson, Andrew J.; Bastian, Ivan; Roberts, Sally A.; Howden, Benjamin P.; Williamson, Deborah A.

2017-01-01

ABSTRACT Mycobacterium chimaera is an opportunistic environmental mycobacterium belonging to the Mycobacterium avium-M. intracellulare complex. Although most commonly associated with pulmonary disease, there has been growing awareness of invasive M. chimaera infections following cardiac surgery. Investigations suggest worldwide spread of a specific M. chimaera clone, associated with contaminated hospital heater-cooler units used during the surgery. Given the global dissemination of this clone, its potential to cause invasive disease, and the laboriousness of current culture-based diagnostic methods, there is a pressing need to develop rapid and accurate diagnostic assays specific for M. chimaera. Here, we assessed 354 mycobacterial genome sequences and confirmed that M. chimaera is a phylogenetically coherent group. In silico comparisons indicated six DNA regions present only in M. chimaera. We targeted one of these regions and developed a TaqMan quantitative PCR (qPCR) assay for M. chimaera with a detection limit of 100 CFU/ml in whole blood spiked with bacteria. In vitro screening against DNA extracted from 40 other mycobacterial species and 22 bacterial species from 21 diverse genera confirmed the in silico-predicted specificity for M. chimaera. Screening 33 water samples from heater-cooler units with this assay highlighted the increased sensitivity of PCR compared to culture, with 15 of 23 culture-negative samples positive by M. chimaera qPCR. We have thus developed a robust molecular assay that can be readily and rapidly deployed to screen clinical and environmental specimens for M. chimaera. PMID:28381604

FDG-PET-based differential uptake volume histograms: a possible approach towards definition of biological target volumes.

PubMed

Devic, Slobodan; Mohammed, Huriyyah; Tomic, Nada; Aldelaijan, Saad; De Blois, François; Seuntjens, Jan; Lehnert, Shirley; Faria, Sergio

2016-06-01

Integration of fluorine-18 fludeoxyglucose ((18)F-FDG)-positron emission tomography (PET) functional data into conventional anatomically based gross tumour volume delineation may lead to optimization of dose to biological target volumes (BTV) in radiotherapy. We describe a method for defining tumour subvolumes using (18)F-FDG-PET data, based on the decomposition of differential uptake volume histograms (dUVHs). For 27 patients with histopathologically proven non-small-cell lung carcinoma (NSCLC), background uptake values were sampled within the healthy lung contralateral to a tumour in those image slices containing tumour and then scaled by the ratio of mass densities between the healthy lung and tumour. Signal-to-background (S/B) uptake values within volumes of interest encompassing the tumour were used to reconstruct the dUVHs. These were subsequently decomposed into the minimum number of analytical functions (in the form of differential uptake values as a function of S/B) that yielded acceptable net fits, as assessed by χ(2) values. Six subvolumes consistently emerged from the fitted dUVHs over the sampled volume of interest on PET images. Based on the assumption that each function used to decompose the dUVH may correspond to a single subvolume, the intersection between the two adjacent functions could be interpreted as a threshold value that differentiates them. Assuming that the first two subvolumes spread over the tumour boundary, we concentrated on four subvolumes with the highest uptake values, and their S/B thresholds [mean ± standard deviation (SD)] were 2.88 ± 0.98, 4.05 ± 1.55, 5.48 ± 2.06 and 7.34 ± 2.89 for adenocarcinoma, 3.01 ± 0.71, 4.40 ± 0.91, 5.99 ± 1.31 and 8.17 ± 2.42 for large-cell carcinoma and 4.54 ± 2.11, 6.46 ± 2.43, 8.87 ± 5.37 and 12.11 ± 7.28 for squamous cell carcinoma, respectively. (18)F-FDG-based PET data may potentially be used to identify BTV within the tumour in

PET/CT-guided treatment planning for paediatric cancer patients: a simulation study of proton and conventional photon therapy

PubMed Central

Brodin, N P; Björk-Eriksson, T; Birk Christensen, C; Kiil-Berthelsen, A; Aznar, M C; Hollensen, C; Markova, E; Munck af Rosenschöld, P

2015-01-01

Objective: To investigate the impact of including fluorine-18 fludeoxyglucose (18F-FDG) positron emission tomography (PET) scanning in the planning of paediatric radiotherapy (RT). Methods: Target volumes were first delineated without and subsequently re-delineated with access to 18F-FDG PET scan information, on duplicate CT sets. RT plans were generated for three-dimensional conformal photon RT (3DCRT) and intensity-modulated proton therapy (IMPT). The results were evaluated by comparison of target volumes, target dose coverage parameters, normal tissue complication probability (NTCP) and estimated risk of secondary cancer (SC). Results: Considerable deviations between CT- and PET/CT-guided target volumes were seen in 3 out of the 11 patients studied. However, averaging over the whole cohort, CT or PET/CT guidance introduced no significant difference in the shape or size of the target volumes, target dose coverage, irradiated volumes, estimated NTCP or SC risk, neither for IMPT nor 3DCRT. Conclusion: Our results imply that the inclusion of PET/CT scans in the RT planning process could have considerable impact for individual patients. There were no general trends of increasing or decreasing irradiated volumes, suggesting that the long-term morbidity of RT in childhood would on average remain largely unaffected. Advances in knowledge: 18F-FDG PET-based RT planning does not systematically change NTCP or SC risk for paediatric cancer patients compared with CT only. 3 out of 11 patients had a distinct change of target volumes when PET-guided planning was introduced. Dice and mismatch metrics are not sufficient to assess the consequences of target volume differences in the context of RT. PMID:25494657

Employment of colorimetric enzyme assay for monitoring expression and solubility of GST fusion proteins targeted to inclusion bodies.

PubMed

Mačinković, Igor S; Abughren, Mohamed; Mrkic, Ivan; Grozdanović, Milica M; Prodanović, Radivoje; Gavrović-Jankulović, Marija

2013-12-01

High levels of recombinant protein expression can lead to the formation of insoluble inclusion bodies. These complex aggregates are commonly solubilized in strong denaturants, such as 6-8M urea, although, if possible, solubilization under milder conditions could facilitate subsequent refolding and purification of bioactive proteins. Commercially available GST-tag assays are designed for quantitative measurement of GST activity under native conditions. GST fusion proteins accumulated in inclusion bodies are considered to be undetectable by such assays. In this work, solubilization of recombinantly produced proteins was performed in 4M urea. The activity of rGST was assayed in 2M urea and it was shown that rGST preserves 85% of its activity under such denaturing conditions. A colorimetric GST activity assay with 1-chloro-2, 4-dinitrobenzene (CDNB) was examined for use in rapid detection of expression targeted to inclusion bodies and for the identification of inclusion body proteins which can be solubilized in low concentrations of chaotropic agents. Applicability of the assay was evaluated by tracking protein expression of two GST-fused allergens of biopharmaceutical value in E. coli, GST-Der p 2 and GST-Mus a 5, both targeted to inclusion bodies. Copyright © 2013 Elsevier B.V. All rights reserved.

(18)F-FDG PET-CT simulation for non-small-cell lung cancer: effect in patients already staged by PET-CT.

PubMed

Hanna, Gerard G; McAleese, Jonathan; Carson, Kathryn J; Stewart, David P; Cosgrove, Vivian P; Eakin, Ruth L; Zatari, Ashraf; Lynch, Tom; Jarritt, Peter H; Young, V A Linda; O'Sullivan, Joe M; Hounsell, Alan R

2010-05-01

Positron emission tomography (PET), in addition to computed tomography (CT), has an effect in target volume definition for radical radiotherapy (RT) for non-small-cell lung cancer (NSCLC). In previously PET-CT staged patients with NSCLC, we assessed the effect of using an additional planning PET-CT scan for gross tumor volume (GTV) definition. A total of 28 patients with Stage IA-IIIB NSCLC were enrolled. All patients had undergone staging PET-CT to ensure suitability for radical RT. Of the 28 patients, 14 received induction chemotherapy. In place of a RT planning CT scan, patients underwent scanning on a PET-CT scanner. In a virtual planning study, four oncologists independently delineated the GTV on the CT scan alone and then on the PET-CT scan. Intraobserver and interobserver variability were assessed using the concordance index (CI), and the results were compared using the Wilcoxon signed ranks test. PET-CT improved the CI between observers when defining the GTV using the PET-CT images compared with using CT alone for matched cases (median CI, 0.57 for CT and 0.64 for PET-CT, p = .032). The median of the mean percentage of volume change from GTV(CT) to GTV(FUSED) was -5.21% for the induction chemotherapy group and 18.88% for the RT-alone group. Using the Mann-Whitney U test, this was significantly different (p = .001). PET-CT RT planning scan, in addition to a staging PET-CT scan, reduces interobserver variability in GTV definition for NSCLC. The GTV size with PET-CT compared with CT in the RT-alone group increased and was reduced in the induction chemotherapy group.

18F-fluorodeoxyglucose positron emission tomography/computed tomography-based radiotherapy target volume definition in non-small-cell lung cancer: delineation by radiation oncologists vs. joint outlining with a PET radiologist?

PubMed

Hanna, Gerard G; Carson, Kathryn J; Lynch, Tom; McAleese, Jonathan; Cosgrove, Vivian P; Eakin, Ruth L; Stewart, David P; Zatari, Ashraf; O'Sullivan, Joe M; Hounsell, Alan R

2010-11-15

(18)F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has benefits in target volume (TV) definition in radiotherapy treatment planning (RTP) for non-small-cell lung cancer (NSCLC); however, an optimal protocol for TV delineation has not been determined. We investigate volumetric and positional variation in gross tumor volume (GTV) delineation using a planning PET/CT among three radiation oncologists and a PET radiologist. RTP PET/CT scans were performed on 28 NSCLC patients (Stage IA-IIIB) of which 14 patients received prior induction chemotherapy. Three radiation oncologists and one PET radiologist working with a fourth radiation oncologist independently delineated the GTV on CT alone (GTV(CT)) and on fused PET/CT images (GTV(PETCT)). The mean percentage volume change (PVC) between GTV(CT) and GTV(PETCT) for the radiation oncologists and the PVC between GTV(CT) and GTV(PETCT) for the PET radiologist were compared using the Wilcoxon signed-rank test. Concordance index (CI) was used to assess both positional and volume change between GTV(CT) and GTV(PETCT) in a single measurement. For all patients, a significant difference in PVC from GTV(CT) to GTV(PETCT) exists between the radiation oncologist (median, 5.9%), and the PET radiologist (median, -0.4%, p = 0.001). However, no significant difference in median concordance index (comparing GTV(CT) and GTV(FUSED) for individual cases) was observed (PET radiologist = 0.73; radiation oncologists = 0.66; p = 0.088). Percentage volume changes from GTV(CT) to GTV(PETCT) were lower for the PET radiologist than for the radiation oncologists, suggesting a lower impact of PET/CT in TV delineation for the PET radiologist than for the oncologists. Guidelines are needed to standardize the use of PET/CT for TV delineation in RTP. Copyright © 2010 Elsevier Inc. All rights reserved.

Precision Medicine and PET/Computed Tomography in Melanoma.

PubMed

Mena, Esther; Sanli, Yasemin; Marcus, Charles; Subramaniam, Rathan M

2017-10-01

Recent advances in genomic profiling and sequencing of melanoma have provided new insights into the development of the basis for molecular biology to more accurately subgroup patients with melanoma. The development of novel mutation-targeted and immunomodulation therapy as a major component of precision oncology has revolutionized the management and outcome of patients with metastatic melanoma. PET imaging plays an important role in noninvasively assessing the tumor biological behavior, to guide individualized treatment and assess response to therapy. This review summarizes the recent genomic discoveries in melanoma in the era of targeted therapy and their implications for functional PET imaging. Published by Elsevier Inc.

Multiplexed targeted mass spectrometry assays for prostate cancer-associated urinary proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Tujin; Quek, Sue-Ing; Gao, Yuqian

Biomarkers for effective early diagnosis and prognosis of prostate cancer are still lacking. Multiplexed assays for cancer-associated proteins could be useful for identifying biomarkers for cancer detection and stratification. Herein, we report the development of sensitive targeted mass spectrometry assays for simultaneous quantification of 10 prostate cancer-associated proteins in urine. The diagnostic utility of these markers was evaluated with an initial cohort of 20 clinical urine samples. Individual marker concentration was normalized against the measured urinary prostate-specific antigen level as a reference of prostate-specific secretion. The areas under the receiver-operating characteristic curves for the 10 proteins ranged from 0.75 formore » CXCL14 to 0.87 for CEACAM5. Furthermore, MMP9 level was found to be significantly higher in patients with high Gleason scores, suggesting a potential of MMP9 as a marker for risk level assessment. Taken together, our work illustrated the feasibility of accurate multiplexed measurements of low-abundance cancer-associated proteins in urine and provided a viable path forward for preclinical verification of candidate biomarkers for prostate cancer.« less

Pet Problems at Home: Pet Problems in the Community.

ERIC Educational Resources Information Center

Soltow, Willow

1984-01-01

Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…

Immuno-PET Imaging and Radioimmunotherapy of 64Cu-/177Lu-Labeled Anti-EGFR Antibody in Esophageal Squamous Cell Carcinoma Model.

PubMed

Song, In Ho; Lee, Tae Sup; Park, Yong Serk; Lee, Jin Sook; Lee, Byung Chul; Moon, Byung Seok; An, Gwang Il; Lee, Hae Won; Kim, Kwang Il; Lee, Yong Jin; Kang, Joo Hyun; Lim, Sang Moo

2016-07-01

Immuno-PET provides valuable information about tumor location, phenotype, susceptibility to therapy, and treatment response, especially to targeted radioimmunotherapy. In this study, we prepared antiepidermal growth factor receptor (EGFR) antibody via identical chelator, 3,6,9,15-tetraazabicyclo[9.3.1]-pentadeca-1(15),11,13-trience-3,6,9,-triacetic acid (PCTA), labeled with (64)Cu or (177)Lu to evaluate the EGFR expression levels using immuno-PET and the feasibility of radioimmunotherapy in an esophageal squamous cell carcinoma (ESCC) model. Cetuximab was conjugated with p-SCN-Bn-PCTA and radiolabeled with (64)Cu or (177)Lu. In vitro EGFR expression levels were determined and compared using flow cytometry and cell binding assay. In vivo EGFR expression levels were evaluated via immuno-PET imaging of (64)Cu-cetuximab and biodistribution analysis. Micro-SPECT/CT imaging, biodistribution, and radioimmunotherapy studies of (177)Lu-cetuximab were performed in the ESCC model. Therapeutic responses were monitored using (18)F-FDG PET and immunohistochemical staining. (64)Cu- or (177)Lu-labeled antibodies showed high radiolabeling yield (>98%), stability (>90%), and favorable immunoreactivity. In vitro EGFR status measured by cell binding assay was correlated with the flow cytometry data. Immuno-PET, micro-SPECT/CT, and biodistribution demonstrated specific uptake in ESCC tumors depending on the EGFR expression levels. Tumor accumulation of (64)Cu- and (177)Lu-cetuximab was peaked at 48 and 120 h, respectively. Radioimmunotherapy with (177)Lu-cetuximab showed significant inhibition of tumor growth (P < 0.01) and marked reduction of (18)F-FDG SUV compared with that of control (P < 0.05). Terminal deoxynucleotidyl transferase dUTP nick-end labeling positivity and Ki-67 staining indices increased and decreased, respectively, in the radioimmunotherapy group compared with other groups (P < 0.01). (64)Cu-cetuximab immuno-PET represented EGFR expression levels in ESCC tumors, and

Contribution of FDOPA PET to radiotherapy planning for advanced glioma

NASA Astrophysics Data System (ADS)

Dowson, Nicholas; Fay, Michael; Thomas, Paul; Jeffree, Rosalind; McDowall, Robert; Winter, Craig; Coulthard, Alan; Smith, Jye; Gal, Yaniv; Bourgeat, Pierrick; Salvado, Olivier; Crozier, Stuart; Rose, Stephen

2014-03-01

Despite radical treatment with surgery, radiotherapy and chemotherapy, advanced gliomas recur within months. Geographic misses in radiotherapy planning may play a role in this seemingly ineluctable recurrence. Planning is typically performed on post-contrast MRIs, which are known to underreport tumour volume relative to FDOPA PET scans. FDOPA PET fused with contrast enhanced MRI has demonstrated greater sensitivity and specificity than MRI alone. One sign of potential misses would be differences between gross target volumes (GTVs) defined using MRI alone and when fused with PET. This work examined whether such a discrepancy may occur. Materials and Methods: For six patients, a 75 minute PET scan using 3,4-dihydroxy-6-18F-fluoro-L-phynel-alanine (18F-FDOPA) was taken within 2 days of gadolinium enhanced MRI scans. In addition to standard radiotherapy planning by an experienced radiotherapy oncologist, a second gross target volume (GTV) was defined by an experienced nuclear medicine specialist for fused PET and MRI, while blinded to the radiotherapy plans. The volumes from standard radiotherapy planning were compared to the PET defined GTV. Results: The comparison indicated radiotherapy planning would change in several cases if FDOPA PET data was available. PET-defined contours were external to 95% prescribed dose for several patients. However, due to the radiotherapy margins, the discrepancies were relatively small in size and all received a dose of 50 Gray or more. Conclusions: Given the limited size of the discrepancies it is uncertain that geographic misses played a major role in patient outcome. Even so, the existence of discrepancies indicates that FDOPA PET could assist in better defining margins when planning radiotherapy for advanced glioma, which could be important for highly conformal radiotherapy plans.

Stroma Targeting Nuclear Imaging and Radiopharmaceuticals

PubMed Central

Shetty, Dinesh; Jeong, Jae-Min; Shim, Hyunsuk

2012-01-01

Malignant transformation of tumor accompanies profound changes in the normal neighboring tissue, called tumor stroma. The tumor stroma provides an environment favoring local tumor growth, invasion, and metastatic spreading. Nuclear imaging (PET/SPECT) measures biochemical and physiologic functions in the human body. In oncology, PET/SPECT is particularly useful for differentiating tumors from postsurgical changes or radiation necrosis, distinguishing benign from malignant lesions, identifying the optimal site for biopsy, staging cancers, and monitoring the response to therapy. Indeed, PET/SPECT is a powerful, proven diagnostic imaging modality that displays information unobtainable through other anatomical imaging, such as CT or MRI. When combined with coregistered CT data, [18F]fluorodeoxyglucose ([18F]FDG)-PET is particularly useful. However, [18F]FDG is not a target-specific PET tracer. This paper will review the tumor microenvironment targeting oncologic imaging such as angiogenesis, invasion, hypoxia, growth, and homing, and also therapeutic radiopharmaceuticals to provide a roadmap for additional applications of tumor imaging and therapy. PMID:22685650

Genome Editing-Enabled HTS Assays Expand Drug Target Pathways for Charcot–Marie–Tooth Disease

PubMed Central

2015-01-01

Copy number variation resulting in excess PMP22 protein causes the peripheral neuropathy Charcot–Marie–Tooth disease, type 1A. To broadly interrogate chemically sensitive transcriptional pathways controlling PMP22 protein levels, we used the targeting precision of TALEN-mediated genome editing to embed reporters within the genetic locus harboring the Peripheral Myelin Protein 22 (Pmp22) gene. Using a Schwann cell line with constitutively high endogenous levels of Pmp22, we obtained allelic insertion of secreted bioluminescent reporters with sufficient signal to enable a 1536-well assay. Our findings from the quantitative high-throughput screening (qHTS) of several thousand drugs and clinically investigated compounds using this assay design both overlapped and expanded results from a previous assay using a randomly inserted reporter gene controlled by a single regulatory element of the Pmp22 gene. A key difference was the identification of a kinase-controlled inhibitory pathway of Pmp22 transcription revealed by the activity of the Protein kinase C (PKC)-modulator bryostatin. PMID:25188731

Development and application of a quantitative multiplexed small GTPase activity assay using targeted proteomics.

PubMed

Zhang, Cheng-Cheng; Li, Ru; Jiang, Honghui; Lin, Shujun; Rogalski, Jason C; Liu, Kate; Kast, Juergen

2015-02-06

Small GTPases are a family of key signaling molecules that are ubiquitously expressed in various types of cells. Their activity is often analyzed by western blot, which is limited by its multiplexing capability, the quality of isoform-specific antibodies, and the accuracy of quantification. To overcome these issues, a quantitative multiplexed small GTPase activity assay has been developed. Using four different binding domains, this assay allows the binding of up to 12 active small GTPase isoforms simultaneously in a single experiment. To accurately quantify the closely related small GTPase isoforms, a targeted proteomic approach, i.e., selected/multiple reaction monitoring, was developed, and its functionality and reproducibility were validated. This assay was successfully applied to human platelets and revealed time-resolved coactivation of multiple small GTPase isoforms in response to agonists and differential activation of these isoforms in response to inhibitor treatment. This widely applicable approach can be used for signaling pathway studies and inhibitor screening in many cellular systems.

Target Volume Delineation in Oropharyngeal Cancer: Impact of PET, MRI, and Physical Examination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thiagarajan, Anuradha, E-mail: anu_thiagarajan@hotmail.com; Caria, Nicola; Schoeder, Heiko

2012-05-01

Introduction: Sole utilization of computed tomography (CT) scans in gross tumor volume (GTV) delineation for head-and-neck cancers is subject to inaccuracies. This study aims to evaluate contributions of magnetic resonance imaging (MRI), positron emission tomography (PET), and physical examination (PE) to GTV delineation in oropharyngeal cancer (OPC). Methods: Forty-one patients with OPC were studied. All underwent contrast-enhanced CT simulation scans (CECTs) that were registered with pretreatment PETs and MRIs. For each patient, three sets of primary and nodal GTV were contoured. First, reference GTVs (GTVref) were contoured by the treating radiation oncologist (RO) using CT, MRI, PET, and PE findings.more » Additional GTVs were created using fused CT/PET scans (GTVctpet) and CT/MRI scans (GTVctmr) by two other ROs blinded to GTVref. To compare GTVs, concordance indices (CI) were calculated by dividing the respective overlap volumes by overall volumes. To evaluate the contribution of PE, composite GTVs derived from CT, MRI, and PET (GTVctpetmr) were compared with GTVref. Results: For primary tumors, GTVref was significantly larger than GTVctpet and GTVctmr (p < 0.001). Although no significant difference in size was noted between GTVctpet and GTVctmr (p = 0.39), there was poor concordance between them (CI = 0.62). In addition, although CI (ctpetmr vs. ref) was low, it was significantly higher than CI (ctpet vs. ref) and CI (ctmr vs. ref) (p < 0.001), suggesting that neither modality should be used alone. Qualitative analyses to explain the low CI (ctpetmr vs. ref) revealed underestimation of mucosal disease when GTV was contoured without knowledge of PE findings. Similar trends were observed for nodal GTVs. However, CI (ctpet vs. ref), CI (ctmr vs. ref), and CI (ctpetmr vs. ref) were high (>0.75), indicating that although the modalities were complementary, the added benefit was small in the context of CECTs. In addition, PE did not aid greatly in nodal GTV

Target-Specific Assay for Rapid and Quantitative Detection of Mycobacterium chimaera DNA.

PubMed

Zozaya-Valdés, Enrique; Porter, Jessica L; Coventry, John; Fyfe, Janet A M; Carter, Glen P; Gonçalves da Silva, Anders; Schultz, Mark B; Seemann, Torsten; Johnson, Paul D R; Stewardson, Andrew J; Bastian, Ivan; Roberts, Sally A; Howden, Benjamin P; Williamson, Deborah A; Stinear, Timothy P

2017-06-01

Mycobacterium chimaera is an opportunistic environmental mycobacterium belonging to the Mycobacterium avium - M. intracellulare complex. Although most commonly associated with pulmonary disease, there has been growing awareness of invasive M. chimaera infections following cardiac surgery. Investigations suggest worldwide spread of a specific M. chimaera clone, associated with contaminated hospital heater-cooler units used during the surgery. Given the global dissemination of this clone, its potential to cause invasive disease, and the laboriousness of current culture-based diagnostic methods, there is a pressing need to develop rapid and accurate diagnostic assays specific for M. chimaera Here, we assessed 354 mycobacterial genome sequences and confirmed that M. chimaera is a phylogenetically coherent group. In silico comparisons indicated six DNA regions present only in M. chimaera We targeted one of these regions and developed a TaqMan quantitative PCR (qPCR) assay for M. chimaera with a detection limit of 100 CFU/ml in whole blood spiked with bacteria. In vitro screening against DNA extracted from 40 other mycobacterial species and 22 bacterial species from 21 diverse genera confirmed the in silico -predicted specificity for M. chimaera Screening 33 water samples from heater-cooler units with this assay highlighted the increased sensitivity of PCR compared to culture, with 15 of 23 culture-negative samples positive by M. chimaera qPCR. We have thus developed a robust molecular assay that can be readily and rapidly deployed to screen clinical and environmental specimens for M. chimaera . Copyright © 2017 American Society for Microbiology.

Quantitative assessment of human and pet exposure to Salmonella associated with dry pet foods.

PubMed

Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Ford, Randall M; Baker, Robert C; Pradhan, Abani K

2016-01-04

Recent Salmonella outbreaks associated with dry pet foods and treats highlight the importance of these foods as previously overlooked exposure vehicles for both pets and humans. In the last decade efforts have been made to raise the safety of this class of products, for instance by upgrading production equipment, cleaning protocols, and finished product testing. However, no comprehensive or quantitative risk profile is available for pet foods, thus limiting the ability to establish safety standards and assess the effectiveness of current and proposed Salmonella control measures. This study sought to develop an ingredients-to-consumer quantitative microbial exposure assessment model to: 1) estimate pet and human exposure to Salmonella via dry pet food, and 2) assess the impact of industry and household-level mitigation strategies on exposure. Data on prevalence and concentration of Salmonella in pet food ingredients, production process parameters, bacterial ecology, and contact transfer in the household were obtained through literature review, industry data, and targeted research. A probabilistic Monte Carlo modeling framework was developed to simulate the production process and basic household exposure routes. Under the range of assumptions adopted in this model, human exposure due to handling pet food is null to minimal if contamination occurs exclusively before extrusion. Exposure increases considerably if recontamination occurs post-extrusion during coating with fat, although mean ingested doses remain modest even at high fat contamination levels, due to the low percent of fat in the finished product. Exposure is highly variable, with the distribution of doses ingested by adult pet owners spanning 3Log CFU per exposure event. Child exposure due to ingestion of 1g of pet food leads to significantly higher doses than adult doses associated with handling the food. Recontamination after extrusion and coating, e.g., via dust or equipment surfaces, may also lead to

Polymerase chain reaction assay targeting cytochrome b gene for the detection of dog meat adulteration in meatball formulation.

PubMed

Rahman, Md Mahfujur; Ali, Md Eaqub; Hamid, Sharifah Bee Abd; Mustafa, Shuhaimi; Hashim, Uda; Hanapi, Ummi Kalthum

2014-08-01

A polymerase chain reaction (PCR) assay for the assessment of dog meat adulteration in meatballs was developed. The assay selectively amplified a 100-bp region of canine mitochondrial cytochrome b gene from pure, raw, processed and mixed backgrounds. The specificity of the assay was tested against 11 animals and 3 plants species, commonly available for meatball formulation. The stability of the assay was proven under extensively autoclaving conditions that breakdown target DNA. A blind test from ready to eat chicken and beef meatballs showed that the assay can repeatedly detect 0.2% canine meat tissues under complex matrices using 0.04 ng of dog DNA extracted from differentially treated meatballs. The simplicity, stability and sensitivity of the assay suggested that it could be used in halal food industry for the authentication of canine derivatives in processed foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

Commercial and PET radioisotope manufacturing with a medical cyclotron

NASA Astrophysics Data System (ADS)

Boothe, T. E.; McLeod, T. F.; Plitnikas, M.; Kinney, D.; Tavano, E.; Feijoo, Y.; Smith, P.; Szelecsényi, F.

1993-06-01

Mount Sinai has extensive experience in producing radionuclides for commercial sales and for incorporation into radiopharmaceuticals, including PET. Currently, an attempt is being made to supply radiochemicals to radiopharmaceutical manufacturers outside the hospital, to prepare radiopharmaceuticals for in-house use, and to prepare PET radiopharmaceuticals, such as 2-[F-18] FDG, for outside sales. This use for both commercial and PET manufacturing is atypical for a hospital-based cyclotron. To accomplish PET radiopharmaceutical sales, the hospital operates a nuclear pharmacy. A review of operational details for the past several years shows a continuing dependence on commercial sales which is reflected in research and developmental aspects and in staffing. Developmental efforts have centered primarily on radionuclide production, target development, and radiochemical processing optimization.

Perturbation Theory/Machine Learning Model of ChEMBL Data for Dopamine Targets: Docking, Synthesis, and Assay of New l-Prolyl-l-leucyl-glycinamide Peptidomimetics.

PubMed

Ferreira da Costa, Joana; Silva, David; Caamaño, Olga; Brea, José M; Loza, Maria Isabel; Munteanu, Cristian R; Pazos, Alejandro; García-Mera, Xerardo; González-Díaz, Humbert

2018-06-25

Predicting drug-protein interactions (DPIs) for target proteins involved in dopamine pathways is a very important goal in medicinal chemistry. We can tackle this problem using Molecular Docking or Machine Learning (ML) models for one specific protein. Unfortunately, these models fail to account for large and complex big data sets of preclinical assays reported in public databases. This includes multiple conditions of assays, such as different experimental parameters, biological assays, target proteins, cell lines, organism of the target, or organism of assay. On the other hand, perturbation theory (PT) models allow us to predict the properties of a query compound or molecular system in experimental assays with multiple boundary conditions based on a previously known case of reference. In this work, we report the first PTML (PT + ML) study of a large ChEMBL data set of preclinical assays of compounds targeting dopamine pathway proteins. The best PTML model found predicts 50000 cases with accuracy of 70-91% in training and external validation series. We also compared the linear PTML model with alternative PTML models trained with multiple nonlinear methods (artificial neural network (ANN), Random Forest, Deep Learning, etc.). Some of the nonlinear methods outperform the linear model but at the cost of a notable increment of the complexity of the model. We illustrated the practical use of the new model with a proof-of-concept theoretical-experimental study. We reported for the first time the organic synthesis, chemical characterization, and pharmacological assay of a new series of l-prolyl-l-leucyl-glycinamide (PLG) peptidomimetic compounds. In addition, we performed a molecular docking study for some of these compounds with the software Vina AutoDock. The work ends with a PTML model predictive study of the outcomes of the new compounds in a large number of assays. Therefore, this study offers a new computational methodology for predicting the outcome for any compound

Combined model-based and patient-specific dosimetry for 18F-DCFPyL, a PSMA-targeted PET agent.

PubMed

Plyku, Donika; Mena, Esther; Rowe, Steven P; Lodge, Martin A; Szabo, Zsolt; Cho, Steve Y; Pomper, Martin G; Sgouros, George; Hobbs, Robert F

2018-06-01

Prostate-specific membrane antigen (PSMA), a type-II integral membrane protein highly expressed in prostate cancer, has been extensively used as a target for imaging and therapy. Among the available PET radiotracers, the low molecular weight agents that bind to PSMA are proving particularly effective. We present the dosimetry results for 18 F-DCFPyL in nine patients with metastatic prostate cancer. Nine patients were imaged using sequential PET/CT scans at approximately 1, 12, 35 and 70 min, and a final PET/CT scan at approximately 120 min after intravenous administration of 321 ± 8 MBq (8.7 ± 0.2 mCi) of 18 F-DCFPyL. Time-integrated-activity coefficients were calculated and used as input in OLINDA/EXM software to obtain dose estimates for the majority of the major organs. The absorbed doses (AD) to the eye lens and lacrimal glands were calculated using Monte-Carlo models based on idealized anatomy combined with patient-specific volumes and activity from the PET/CT scans. Monte-Carlo based models were also developed for calculation of the dose to two major salivary glands (parotid and submandibular) using CT-based patient-specific gland volumes. The highest calculated mean AD per unit administered activity of 18 F was found in the lacrimal glands, followed by the submandibular glands, kidneys, urinary bladder wall, and parotid glands. The S-values for the lacrimal glands to the eye lens (0.42 mGy/MBq h), the tear film to the eye lens (1.78 mGy/MBq h) and the lacrimal gland self-dose (574.10 mGy/MBq h) were calculated. Average S-values for the salivary glands were 3.58 mGy/MBq h for the parotid self-dose and 6.78 mGy/MBq h for the submandibular self-dose. The resultant mean effective dose of 18 F-DCFPyL was 0.017 ± 0.002 mSv/MBq. 18 F-DCFPyL dosimetry in nine patients was obtained using novel models for the lacrimal and salivary glands, two organs with potentially dose-limiting uptake for therapy and diagnosis which lacked pre

Imaging Caspase-3 Activation as a Marker of Apoptosis-Targeted Treatment Response in Cancer

PubMed Central

Chen, Delphine L.; Engle, Jacquelyn T.; Griffin, Elizabeth A.; Miller, J. Philip; Chu, Wenhua; Zhou, Dong; Mach, Robert H.

2016-01-01

Purpose We tested whether positron emission tomography (PET) with the caspase-3 targeted isatin analog [18F]WC-4-116 could image caspase-3 activation in response to an apoptosis-inducing anticancer therapy. Procedures [18F]WC-4-116 uptake was determined in etoposide-treated EL4 cells. Biodistribution studies with [18F]WC-4-116 and [18F]ICMT-18, a non-caspase-3-targeted tracer, as well as [18F]WC-4-116 microPET imaging assessed responses in Colo205 tumor bearing mice treated with death receptor 5 (DR5) targeted agonist antibodies. Immunohistochemical staining and enzyme assays confirmed caspase-3 activation. Two-way analysis of variance or Student’s t-test assessed for treatment-related changes in tracer uptake. Results [18F]WC-4-116 increased 8 ± 2-fold in etoposide-treated cells. The [18F]WC-4-116 %ID/g also increased significantly in tumors with high caspase-3 enzyme activity (p < 0.05). [18F]ICMT-18 tumor uptake did not differ in tumors with high or low caspase-3 enzyme activity. Conclusions [18F]WC-4-116 uptake in vivo reflects increased caspase-3 activation and may be useful for detecting caspase-3 mediated apoptosis treatment responses in cancer. PMID:25344147

Characterization of an In-Beam PET Prototype for Proton Therapy With Different Target Compositions

NASA Astrophysics Data System (ADS)

Attanasi, Francesca; Belcari, Nicola; Moehrs, Sascha; Rosso, Valeria; Vecchio, Sara; Cirrone, G. A. Pablo; Cuttone, Giacomo; Lojacono, Piero; Romano, Francesco; Lanconelli, Nico; Del Guerra, Alberto

2010-06-01

At the University of Pisa, the DoPET (Dosimetry with a Positron Emission Tomograph) project has focused on the development and characterization of an ad hoc, scalable, dual-head PET prototype for in-beam treatment planning verification of the proton therapy. In this paper we report the first results obtained with our current prototype, consisting of two opposing lutetium yttrium orthosilicate (LYSO) detectors, each one covering an area of 4.5 × 4.5 cm2. We measured the β+-activation induced by 62 MeV proton beams at Catana facility (LNS, Catania, Italy) in several plastic phantoms. Experiments were performed to evaluate the possibility to extract accurate phantom geometrical information from the reconstructed PET images. The PET prototype proved its capability of locating small air cavities in homogeneous PMMA phantoms with a submillimetric accuracy and of distinguishing materials with different 16O and 12C content by back mapping phantom geometry through the separation of the isotope contributions. This could be very useful in the clinical practice as a tool to highlight anatomical or physiological organ variations among different treatment sessions and to discriminate different tissue types, thus providing feedbacks for the accuracy of dose deposition.

ImmunoPET imaging of tissue factor expression in pancreatic cancer with 89Zr-Df-ALT-836.

PubMed

Hernandez, Reinier; England, Christopher G; Yang, Yunan; Valdovinos, Hector F; Liu, Bai; Wong, Hing C; Barnhart, Todd E; Cai, Weibo

2017-10-28

Overexpression of tissue factor (TF) has been associated with increased tumor growth, tumor angiogenesis, and metastatic potential in many malignancies, including pancreatic cancer. Additionally, high TF expression was shown to strongly correlate with poor prognoses and decreased survival in pancreatic cancer patients. Herein, we exploited the potential targeting of TF for positron emission tomography (PET) imaging of pancreatic cancer. The TF-targeted tracer was developed through radiolabeling of the anti-human TF monoclonal antibody (ALT-836) with 89 Zr. The tracer was characterized by fluorescence microscopy and flow cytometry assays in BXPC-3 and PANC-1 cells, two pancreatic cancer cell lines with high and low TF expression levels, respectively. Non-invasive PET scans were acquired in tumor-bearing mice injected with 89 Zr-Df-ALT-836. Additionally, ex vivo biodistribution, blocking, and histological studies were performed to establish the affinity and specificity of 89 Zr-Df-ALT-836 for TF in vivo. 89 Zr-labeling of Df-ALT-836 was achieved in high yield and good specific activity. Flow cytometry and microscopy studies revealed no detectable difference in TF-binding affinity between ALT-836 and Df-ALT-836 in vitro. Longitudinal PET scans unveiled a lasting and prominent 89 Zr-Df-ALT-836 uptake in BXPC-3 tumors (peak at 31.5±6.0%ID/g at 48h post-injection; n=3), which was significantly abrogated (2.3±0.5%ID/g at 48h post-injection; n=3) when mice were pre-injected with a blocking dose (50mg/kg) of unlabeled ALT-836. Ex vivo biodistribution data confirmed the accuracy of the PET results, and histological analysis correlated high tumor uptake with in situ TF expression. Taken together, these results attest to the excellent affinity and TF-specificity of 89 Zr-Df-ALT-836. With elevated, persistent, and specific accumulation in TF-positive BXPC-3 tumors, PET imaging using 89 Zr-Df-ALT-836 promises to open new avenues for improving future diagnosis, stratification

Intensity-modulated salvage radiotherapy with simultaneous integrated boost for local recurrence of prostate carcinoma: a pilot study on the place of PET-choline for guiding target volume delineation.

PubMed

Wahart, Aurélien; Guy, Jean-Baptiste; Vallard, Alexis; Geissler, Benjamin; Ben Mrad, Majed; Falk, Alexander T; Prevot, Nathalie; de Laroche, Guy; Rancoule, Chloé; Chargari, Cyrus; Magné, Nicolas

2016-01-01

The aim of this study was to report the first cases of salvage radiotherapy (RT) using the intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) targeted on choline positron emission tomography (PET) uptake in a local recurrent prostate cancer, after a radical prostatectomy. Four patients received salvage irradiation for biochemical relapse that occurred after the initial radical prostatectomy. The relapse occurred from 10 months to 6 years with PSA levels ranging from 2.35 to 4.86 ng ml(-1). For each patient, an (18)F-choline PET-CT showed a focal choline uptake in prostatic fossa, with standardized uptake value calculated on the basis of predicted lean body mass (SUL) max of 3.3-6.8. No involved lymph node or distant metastases were diagnosed. IMRT doses were of 62.7 Gy (1.9 Gy/fraction, 33 fractions), with a SIB of 69.3 Gy (2.1 Gy/fraction, 33 fractions) to a PET-guided target volume. Acute toxicities were limited. We observed no gastrointestinal toxicity ≥grade 2 and only one grade 2 genitourinary toxicity. At 1-month follow-up evaluation, no complication and a decrease in PSA level (6.8-43.8% of the pre-therapeutic level) were reported. After 4 months, a decrease in PSA level was obtained for all the patients, ranging from 30% to 70%. At a median follow-up of 15 months, PSA level was controlled for all the patients, but one of them experienced a distant lymph node recurrence. Salvage irradiation to the prostate bed with SIB guided by PET-CT is feasible, with biological efficacy and no major acute toxicity. IMRT with PET-oriented SIB for salvage treatment of prostate cancer is possible, without major acute toxicity.

Scout-MRM: Multiplexed Targeted Mass Spectrometry-Based Assay without Retention Time Scheduling Exemplified by Dickeya dadantii Proteomic Analysis during Plant Infection.

PubMed

Rougemont, Blandine; Bontemps Gallo, Sébastien; Ayciriex, Sophie; Carrière, Romain; Hondermarck, Hubert; Lacroix, Jean Marie; Le Blanc, J C Yves; Lemoine, Jérôme

2017-02-07

Targeted mass spectrometry of a surrogate peptide panel is a powerful method to study the dynamics of protein networks, but chromatographic time scheduling remains a major limitation for dissemination and implementation of robust and large multiplexed assays. We unveil a Multiple Reaction Monitoring method (Scout-MRM) where the use of spiked scout peptides triggers complex transition lists, regardless of the retention time of targeted surrogate peptides. The interest of Scout-MRM method regarding the retention time independency, multiplexing capability, reproducibility, and putative interest in facilitating method transfer was illustrated by a 782-peptide-plex relative assay targeting 445 proteins of the phytopathogen Dickeya dadantii during plant infection.

Field evaluation of the photo-induced electron transfer fluorogenic primers (PET) real-time PCR for the detection of Plasmodium falciparum in Tanzania.

PubMed

Talundzic, Eldin; Maganga, Mussa; Masanja, Irene M; Peterson, David S; Udhayakumar, Venkatachalam; Lucchi, Naomi W

2014-01-27

Accurate diagnosis of malaria infections remains challenging, especially in the identification of submicroscopic infections. New molecular diagnostic tools that are inexpensive, sensitive enough to detect low-level infections and suitable in laboratory settings of resource-limited countries are required for malaria control and elimination programmes. Here the diagnostic potential of a recently developed photo-induced electron transfer fluorogenic primer (PET) real-time polymerase chain reaction (PCR) called PET-PCR was investigated. This study aimed to (i) evaluate the use of this assay as a method for the detection of both Plasmodium falciparum and other Plasmodium species infections in a developing country's diagnostic laboratory; and, (ii) determine the assay's sensitivity and specificity compared to a nested 18S rRNA PCR. Samples used in this study were obtained from a previous study conducted in the region of Iringa, Tanzania. A total of 303 samples from eight health facilities in Tanzania were utilized for this evaluation. All samples were screened using the multiplex PET-PCR assay designed to detect Plasmodium genus and P. falciparum initially in laboratory in Tanzania and then repeated at a reference laboratory at the CDC in the USA. Microscopy data was available for all the 303 samples. A subset of the samples were tested in a blinded fashion to find the sensitivity and specificity of the PET-PCR compared to the nested 18S rRNA PCR. Compared to microscopy, the PET-PCR assay was 59% more sensitive in detecting P. falciparum infections. The observed sensitivity and specificity were 100% (95% confidence interval (CI0.95) = 94-100%) and (CI0.95 = 96-100%), respectively, for the PET-PCR assay when compared to nested 18S rRNA PCR. When compared to 18S rRNA PCR, microscopy had a low sensitivity of 40% (CI0.95 = 23-61%) and specificity of 100% (CI0.95 = 96-100%). The PET-PCR results performed in the field laboratory in Tanzania were in 100

Avirulent Bacillus anthracis Strain with Molecular Assay Targets as Surrogate for Irradiation-Inactivated Virulent Spores.

PubMed

Plaut, Roger D; Staab, Andrea B; Munson, Mark A; Gebhardt, Joan S; Klimko, Christopher P; Quirk, Avery V; Cote, Christopher K; Buhr, Tony L; Rossmaier, Rebecca D; Bernhards, Robert C; Love, Courtney E; Berk, Kimberly L; Abshire, Teresa G; Rozak, David A; Beck, Linda C; Stibitz, Scott; Goodwin, Bruce G; Smith, Michael A; Sozhamannan, Shanmuga

2018-04-01

The revelation in May 2015 of the shipment of γ irradiation-inactivated wild-type Bacillus anthracis spore preparations containing a small number of live spores raised concern about the safety and security of these materials. The finding also raised doubts about the validity of the protocols and procedures used to prepare them. Such inactivated reference materials were used as positive controls in assays to detect suspected B. anthracis in samples because live agent cannot be shipped for use in field settings, in improvement of currently deployed detection methods or development of new methods, or for quality assurance and training activities. Hence, risk-mitigated B. anthracis strains are needed to fulfill these requirements. We constructed a genetically inactivated or attenuated strain containing relevant molecular assay targets and tested to compare assay performance using this strain to the historical data obtained using irradiation-inactivated virulent spores.

Development of two fluorine-18 labeled PET radioligands targeting PDE10A and in vivo PET evaluation in nonhuman primates.

PubMed

Stepanov, Vladimir; Takano, Akihiro; Nakao, Ryuji; Amini, Nahid; Miura, Shotaro; Hasui, Tomoaki; Kimura, Haruhide; Taniguchi, Takahiko; Halldin, Christer

2018-02-01

Phosphodiesterase 10A (PDE10A) is a member of the PDE enzyme family that degrades cyclic adenosine and guanosine monophosphates (cAMP and cGMP). Based on the successful development of [ 11 C]T-773 as PDE10A positron emission tomography (PET) radioligand, in this study our aim was to develop and evaluate fluorine-18 analogs of [ 11 C]T-773. [ 18 F]FM-T-773-d 2 and [ 18 F]FE-T-773-d 4 were synthesized from the same precursor used for 11 C-labeling of T-773 in a two-step approach via 18 F-fluoromethylation and 18 F-fluoroethylation, respectively, using corresponding deuterated synthons. A total of 12 PET measurements were performed in seven non-human primates. First, baseline PET measurements were performed using High Resolution Research Tomograph system with both [ 18 F]FM-T-773-d 2 and [ 18 F]FE-T-773-d 4 ; the uptake in whole brain and separate brain regions, as well as the specific binding and tissue ratio between putamen and cerebellum, was examined. Second, baseline and pretreatment PET measurements using MP-10 as the blocker were performed for [ 18 F]FM-T-773-d 2 including arterial blood sampling with radiometabolite analysis in four NHPs. Both [ 18 F]FM-T-773-d 2 and [ 18 F]FE-T-773-d 4 were successfully radiolabeled with an average molar activity of 293 ± 114 GBq/μmol (n=8) for [ 18 F]FM-T-773-d 2 and 209 ± 26 GBq/μmol (n=4) for [ 18 F]FE-T-773-d 4 , and a radiochemical yield of 10% (EOB, n=12, range 3%-16%). Both radioligands displayed high brain uptake (~5.5% of injected radioactivity for [ 18 F]FM-T-773-d 2 and ~3.5% for [ 18 F]FE-T-773-d 4 at the peak) and a fast washout. Specific binding reached maximum within 30 min for [ 18 F]FM-T-773-d 2 and after approximately 45 min for [ 18 F]FE-T-773-d 4 . [ 18 F]FM-T-773-d 2 data fitted well with kinetic compartment models. BP ND values obtained indirectly through compartment models were correlated well with those obtained by SRTM. BP ND calculated with SRTM was 1.0-1.7 in the putamen. The occupancy with 1

Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT.

PubMed

Wiesmüller, Marco; Quick, Harald H; Navalpakkam, Bharath; Lell, Michael M; Uder, Michael; Ritt, Philipp; Schmidt, Daniela; Beck, Michael; Kuwert, Torsten; von Gall, Carl C

2013-01-01

PET/MR hybrid scanners have recently been introduced, but not yet validated. The aim of this study was to compare the PET components of a PET/CT hybrid system and of a simultaneous whole-body PET/MR hybrid system with regard to reproducibility of lesion detection and quantitation of tracer uptake. A total of 46 patients underwent a whole-body PET/CT scan 1 h after injection and an average of 88 min later a second scan using a hybrid PET/MR system. The radioactive tracers used were (18)F-deoxyglucose (FDG), (18)F-ethylcholine (FEC) and (68)Ga-DOTATATE (Ga-DOTATATE). The PET images from PET/CT (PET(CT)) and from PET/MR (PET(MR)) were analysed for tracer-positive lesions. Regional tracer uptake in these foci was quantified using volumes of interest, and maximal and average standardized uptake values (SUV(max) and SUV(avg), respectively) were calculated. Of the 46 patients, 43 were eligible for comparison and statistical analysis. All lesions except one identified by PET(CT) were identified by PET(MR) (99.2 %). In 38 patients (88.4 %), the same number of foci were identified by PET(CT) and by PET(MR). In four patients, more lesions were identified by PET(MR) than by PET(CT), in one patient PET(CT) revealed an additional focus compared to PET(MR). The mean SUV(max) and SUV(avg) of all lesions determined by PET(MR) were by 21 % and 11 % lower, respectively, than the values determined by PET(CT) (p < 0.05), and a strong correlation between these variables was identified (Spearman rho 0.835; p < 0.01). PET/MR showed equivalent performance in terms of qualitative lesion detection to PET/CT. The differences demonstrated in quantitation of tracer uptake between PET(CT) and PET(MR) were minor, but statistically significant. Nevertheless, a more detailed study of the quantitative accuracy of PET(MR) and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations.

PET AND SPECT STUDIES IN CHILDREN WITH HEMISPHERIC LOW-GRADE GLIOMAS

PubMed Central

Juhász, Csaba; Bosnyák, Edit

2016-01-01

Molecular imaging is playing an increasing role in the pre-treatment evaluation of low-grade gliomas. While glucose positron emission tomography (PET) can be helpful to differentiate low-grade from high-grade tumors, PET imaging with amino acid radiotracers has several advantages, such as better differentiation between tumors and non-tumorous lesions, optimized biopsy targeting and improved detection of tumor recurrence. This review provides a brief overview of single photon emission computed tomography (SPECT) studies followed by a more detailed review of clinical applications of glucose and amino acid PET imaging in low-grade hemispheric gliomas. We discuss key differences in the performance of the most commonly utilized PET radiotracers and highlight the advantage of PET/MRI fusion to obtain optimal information about tumor extent, heterogeneity and metabolism. Recent data also suggest that simultaneous acquisition of PET/MR images and the combination of advanced MRI techniques with quantitative PET can further improve the pre- and post-treatment evaluation of pediatric brain tumors. PMID:27659825

PET and SPECT studies in children with hemispheric low-grade gliomas.

PubMed

Juhász, Csaba; Bosnyák, Edit

2016-10-01

Molecular imaging is playing an increasing role in the pretreatment evaluation of low-grade gliomas. While glucose positron emission tomography (PET) can be helpful to differentiate low-grade from high-grade tumors, PET imaging with amino acid radiotracers has several advantages, such as better differentiation between tumors and non-tumorous lesions, optimized biopsy targeting, and improved detection of tumor recurrence. This review provides a brief overview of single-photon emission computed tomography (SPECT) studies followed by a more detailed review of the clinical applications of glucose and amino acid PET imaging in low-grade hemispheric gliomas. We discuss key differences in the performance of the most commonly utilized PET radiotracers and highlight the advantage of PET/MRI fusion to obtain optimal information about tumor extent, heterogeneity, and metabolism. Recent data also suggest that simultaneous acquisition of PET/MR images and the combination of advanced MRI techniques with quantitative PET can further improve the pretreatment and post-treatment evaluation of pediatric brain tumors.

How to use PET/CT in the evaluation of response to radiotherapy.

PubMed

Decazes, Pierre; Thureau, Sébastien; Dubray, Bernard; Vera, Pierre

2018-06-01

Radiotherapy is a major treatment modality for many cancers. Tumor response after radiotherapy determines the subsequent steps of the patient's management (surveillance, adjuvant or salvage treatment and palliative care). Tumor response assessed during radiotherapy offers a promising opportunity to adapt the treatment plan to reduced or increased target volume, to specifically target sub-volumes with relevant biological characteristics (metabolism, hypoxia, proliferation, etc.) and to further spare the organs at risk. In addition to its role in the diagnosis and the initial staging, Positron Emission Tomography combined with a Computed Tomography (PET/CT) provides functional information and is therefore attractive to evaluate tumor response. The aim of this paper is to review the published data addressing PET/CT as an evaluation tool in irradiated tumors. Reports on PET/CT acquired at various times (during radiotherapy, after initial (chemo-) radiotherapy, after definitive radiotherapy and during posttreatment follow-up) in solid tumors (lung, head-and-neck, cervix, esophagus, prostate and rectum) were collected and reviewed. Various tracers and technical aspects are also discussed. 18F-FDG PET/CT has a well-established role in clinical routine after definitive chemo-radiotherapy for locally advanced head-and-neck cancers. 18F-choline PET/CT is indicated in prostate cancer patients with biochemical failure. 18F-FDG PET/CT is optional in many other circumstances and the clinical benefits of assessing tumor response with PET/CT remain a field of very active research. The combination of PET with Magnetic Resonance Imaging (PET/MRI) may prove to be valuable in irradiated rectal and cervix cancers. Tumor response can be evaluated by PET/CT with clinical consequences in multiple situations, notably in head and neck and prostate cancers, after radiotherapy. Further clinical evaluation for most cancers is still needed, possibly in association to MRI.

Planar optical waveguide based sandwich assay sensors and processes for the detection of biological targets including protein markers, pathogens and cellular debris

DOEpatents

Martinez, Jennifer S [Santa Fe, NM; Swanson, Basil I [Los Alamos, NM; Grace, Karen M [Los Alamos, NM; Grace, Wynne K [Los Alamos, NM; Shreve, Andrew P [Santa Fe, NM

2009-06-02

An assay element is described including recognition ligands bound to a film on a single mode planar optical waveguide, the film from the group of a membrane, a polymerized bilayer membrane, and a self-assembled monolayer containing polyethylene glycol or polypropylene glycol groups therein and an assay process for detecting the presence of a biological target is described including injecting a biological target-containing sample into a sensor cell including the assay element, with the recognition ligands adapted for binding to selected biological targets, maintaining the sample within the sensor cell for time sufficient for binding to occur between selected biological targets within the sample and the recognition ligands, injecting a solution including a reporter ligand into the sensor cell; and, interrogating the sample within the sensor cell with excitation light from the waveguide, the excitation light provided by an evanescent field of the single mode penetrating into the biological target-containing sample to a distance of less than about 200 nanometers from the waveguide thereby exciting the fluorescent-label in any bound reporter ligand within a distance of less than about 200 nanometers from the waveguide and resulting in a detectable signal.

Lung PET scan

MedlinePlus

... PET - chest; PET - lung; PET - tumor imaging; PET/CT - lung; Solitary pulmonary nodule - PET ... minutes. PET scans are performed along with a CT scan. This is because the combined information from ...

Efficiency gains in tracer identification for nuclear imaging: can in vivo LC-MS/MS evaluation of small molecules screen for successful PET tracers?

PubMed

Joshi, Elizabeth M; Need, Anne; Schaus, John; Chen, Zhaogen; Benesh, Dana; Mitch, Charles; Morton, Stuart; Raub, Thomas J; Phebus, Lee; Barth, Vanessa

2014-12-17

Positron emission tomography (PET) imaging has become a useful noninvasive technique to explore molecular biology within living systems; however, the utility of this method is limited by the availability of suitable radiotracers to probe specific targets and disease biology. Methods to identify potential areas of improvement in the ability to predict small molecule performance as tracers prior to radiolabeling would speed the discovery of novel tracers. In this retrospective analysis, we characterized the brain penetration or peak SUV (standardized uptake value), binding potential (BP), and brain exposure kinetics across a series of known, nonradiolabeled PET ligands using in vivo LC-MS/MS (liquid chromatography coupled to mass spectrometry) and correlated these parameters with the reported PET ligand performance in nonhuman primates and humans available in the literature. The PET tracers studied included those reported to label G protein-coupled receptors (GPCRs), intracellular enzymes, and transporters. Additionally, data for each tracer was obtained from a mouse brain uptake assay (MBUA), previously published, where blood-brain barrier (BBB) penetration and clearance parameters were assessed and compared against similar data collected on a broad compound set of central nervous system (CNS) therapeutic compounds. The BP and SUV identified via nonradiolabeled LC-MS/MS, while different from the published values observed in the literature PET tracer data, allowed for an identification of initial criteria values we sought to facilitate increased potential for success from our early discovery screening paradigm. Our analysis showed that successful, as well as novel, clinical PET tracers exhibited BP of greater than 1.5 and peak SUVs greater than approximately 150% at 5 min post dose in rodents. The brain kinetics appeared similar between both techniques despite differences in tracer dose, suggesting linearity across these dose ranges. The assessment of tracers in a

VPAC1 targeted 64Cu-TP3805 PET imaging of prostate cancer: preliminary evaluation in man

PubMed Central

Tripathi, Sushil; Trabulsi, Edouard J; Gomella, Leonard; Kim, Sung; McCue, Peter; Intenzo, Charles; Birbe, Ruth; Gandhe, Ashish; Kumar, Pardeep; Thakur, Mathew

2015-01-01

Objectives To evaluate 64Cu-TP3805 as a novel biomolecule, to PET image prostate cancer (PC), at the onset of which VPAC1, the superfamily of G-protein coupled receptors, is expressed in high density on PC cells, but not on normal cells. Methods 25 patients undergoing radical prostatectomy were PET/CT imaged preoperatively with 64Cu-TP3805. Standardized uptake values (SUVmax) were determined, malignant lesions (SUV > 1.0) counted, and compared with histologic findings. Whole mount pathology slides from 6 VPAC1 PET imaged patients, 3 BPH patients, one malignant and one benign lymph node underwent digital autoradiography (DAR) after 64Cu-TP3805 incubation and compared to H&E stained slides. Results In 25 patient PET imaging, 212 prostate gland lesions had SUVmax > 1.0 vs.127 lesions identified by histology of biopsy tissues. The status of the additional 85 PET identified prostate lesions remains to be determined. In 68 histological slides from 6 PET imaged patients, DAR identified 105/107 PC foci, 19/19 HGPIN, and ejaculatory ducts and verumontanum involved with cancer. Additionally, DAR found 9 PC lesions not previously identified histologically. The positive and negative lymph nodes were correctly identified and in 3/3 BPH patients and 5/5 cysts, DAR was negative. Conclusion This feasibility study demonstrated that 64Cu-TP3805 delineates PC in vivo and ex vivo, provided normal images for benign masses, and is worthy of further studies. PMID:26519886

Novel hexadentate and pentadentate chelators for 64Cu-based targeted PET imaging

PubMed Central

Sin, Inseok; Kang, Chisoo; Bandara, Nilantha; Sun, Xiang; Zhong, Yongliang; Rogers, Buck E.; Chong, Hyun-Soon

2014-01-01

A series of new hexadentate and pentadentate chelators were designed and synthesized as chelators of 64Cu. The new pentadentate and hexadentate chelators contain different types of donor groups and are expected to form neutral complexes with Cu(II). The new chelators were evaluated for complex kinetics and stability with 64Cu. The new chelators instantly bound to 64Cu with high labeling efficiency and maximum specific activity. All 64Cu-radiolabeled complexes in human serum remained intact for 2 days. The 64Cu-radiolabeled complexes were further challenged by EDTA in a 100-fold molar excess. Among the 64Cu-radiolabeled complexes evaluated, 64Cu-complex of the new chelator E was well tolerated with a minimal transfer of 64Cu to EDTA. 64Cu-radiolabeled complex of the new chelator E was further evaluated for biodistribution studies using mice and displayed rapid blood clearance and low organ uptake. 64Cu-chelator E produced a favorable in vitro and in vivo complex stability profiles comparable to 64Cu complex of the known hexadentate NOTA chelator. The in vitro and in vivo data highlight strong potential of the new chelator E for targeted PET imaging application. PMID:24657050

A versatile scalable PET processing system

DOE Office of Scientific and Technical Information (OSTI.GOV)

H. Dong, A. Weisenberger, J. McKisson, Xi Wenze, C. Cuevas, J. Wilson, L. Zukerman

2011-06-01

Positron Emission Tomography (PET) historically has major clinical and preclinical applications in cancerous oncology, neurology, and cardiovascular diseases. Recently, in a new direction, an application specific PET system is being developed at Thomas Jefferson National Accelerator Facility (Jefferson Lab) in collaboration with Duke University, University of Maryland at Baltimore (UMAB), and West Virginia University (WVU) targeted for plant eco-physiology research. The new plant imaging PET system is versatile and scalable such that it could adapt to several plant imaging needs - imaging many important plant organs including leaves, roots, and stems. The mechanical arrangement of the detectors is designed tomore » accommodate the unpredictable and random distribution in space of the plant organs without requiring the plant be disturbed. Prototyping such a system requires a new data acquisition system (DAQ) and data processing system which are adaptable to the requirements of these unique and versatile detectors.« less

Production of an 15O beam using a stable oxygen ion beam for in-beam PET imaging

NASA Astrophysics Data System (ADS)

Mohammadi, Akram; Yoshida, Eiji; Tashima, Hideaki; Nishikido, Fumihiko; Inaniwa, Taku; Kitagawa, Atsushi; Yamaya, Taiga

2017-03-01

In advanced ion therapy, the 15O ion beam is a promising candidate to treat hypoxic tumors and simultaneously monitor the delivered dose to a patient using PET imaging. This study aimed at production of an 15O beam by projectile fragmentation of a stable 16O beam in an optimal material, followed by in-beam PET imaging using a prototype OpenPET system, which was developed in the authors' group. The study was carried out in three steps: selection of the optimal target based on the highest production rate of 15O fragments; experimental production of the beam using the optimal target in the Heavy Ion Medical Accelerator Chiba (HIMAC) secondary beam course; and realization of in-beam PET imaging for the produced beam. The optimal target evaluations were done using the Monte Carlo simulation code PHITS. The fluence and mean energy of the secondary particles were simulated and the optimal target was selected based on the production rate of 15O fragments. The highest production rate of 15O was observed for a liquid hydrogen target, 3.27% for a 53 cm thick target from the 16O beam of 430 MeV/u. Since liquid hydrogen is not practically applicable in the HIMAC secondary beam course a hydrogen-rich polyethylene material, which was the second optimal target from the simulation results, was selected as the experimental target. Three polyethylene targets with thicknesses of 5, 11 or 14 cm were used to produce the 15O beam without any degrader in the beam course. The highest production rate was measured as around 0.87% for the 11 cm thick polyethylene target from the 16O beam of 430 MeV/u when the angular acceptance and momentum acceptance were set at ±13 mrad and ±2.5%, respectively. The purity of the produced beam for the three targets were around 75%, insufficient for clinical application, but it was increased to 97% by inserting a wedge shape aluminum degrader with a thickness of 1.76 cm into the beam course and that is sufficiently high. In-beam PET imaging was also

Multi-layer cube sampling for liver boundary detection in PET-CT images.

PubMed

Liu, Xinxin; Yang, Jian; Song, Shuang; Song, Hong; Ai, Danni; Zhu, Jianjun; Jiang, Yurong; Wang, Yongtian

2018-06-01

Liver metabolic information is considered as a crucial diagnostic marker for the diagnosis of fever of unknown origin, and liver recognition is the basis of automatic diagnosis of metabolic information extraction. However, the poor quality of PET and CT images is a challenge for information extraction and target recognition in PET-CT images. The existing detection method cannot meet the requirement of liver recognition in PET-CT images, which is the key problem in the big data analysis of PET-CT images. A novel texture feature descriptor called multi-layer cube sampling (MLCS) is developed for liver boundary detection in low-dose CT and PET images. The cube sampling feature is proposed for extracting more texture information, which uses a bi-centric voxel strategy. Neighbour voxels are divided into three regions by the centre voxel and the reference voxel in the histogram, and the voxel distribution information is statistically classified as texture feature. Multi-layer texture features are also used to improve the ability and adaptability of target recognition in volume data. The proposed feature is tested on the PET and CT images for liver boundary detection. For the liver in the volume data, mean detection rate (DR) and mean error rate (ER) reached 95.15 and 7.81% in low-quality PET images, and 83.10 and 21.08% in low-contrast CT images. The experimental results demonstrated that the proposed method is effective and robust for liver boundary detection.

Targeting Amino Acid Metabolism for Molecular Imaging of Inflammation Early After Myocardial Infarction.

PubMed

Thackeray, James T; Bankstahl, Jens P; Wang, Yong; Wollert, Kai C; Bengel, Frank M

2016-01-01

Acute tissue inflammation after myocardial infarction influences healing and remodeling and has been identified as a target for novel therapies. Molecular imaging holds promise for guidance of such therapies. The amino acid (11)C-methionine is a clinically approved agent which is thought to accumulate in macrophages, but not in healthy myocytes. We assessed the suitability of positron emission tomography (PET) with (11)C-methionine for imaging post-MI inflammation, from cell to mouse to man. Uptake assays demonstrated 7-fold higher (11)C-methionine uptake by polarized pro-inflammatory M1 macrophages over anti-inflammatory M2 subtypes (p<0.001). C57Bl/6 mice (n=27) underwent coronary artery ligation or no surgery. Serial (11)C-methionine PET was performed 3, 5 and 7d later. MI mice exhibited a perfusion defect in 32-50% of the left ventricle (LV). PET detected increased (11)C-methionine accumulation in the infarct territory at 3d (5.9±0.9%ID/g vs 4.7±0.9 in remote myocardium, and 2.6±0.5 in healthy mice; p<0.05 and <0.01 respectively), which declined by d7 post-MI (4.3±0.6 in infarct, 3.4±0.8 in remote; p=0.03 vs 3d, p=0.08 vs healthy). Increased (11)C-methionine uptake was associated with macrophage infiltration of damaged myocardium. Treatment with anti-integrin antibodies (anti-CD11a, -CD11b, -CD49d; 100µg) lowered macrophage content by 56% and (11)C-methionine uptake by 46% at 3d post-MI. A patient study at 3d after ST-elevation MI and early reperfusion confirmed elevated (11)C-methionine uptake in the hypoperfused myocardial region. Targeting of elevated amino acid metabolism in pro-inflammatory M1 macrophages enables PET imaging-derived demarcation of tissue inflammation after MI. (11)C-methionine-based molecular imaging may assist in the translation of novel image-guided, inflammation-targeted regenerative therapies.

Targeting Amino Acid Metabolism for Molecular Imaging of Inflammation Early After Myocardial Infarction

PubMed Central

Thackeray, James T.; Bankstahl, Jens P.; Wang, Yong; Wollert, Kai C.; Bengel, Frank M.

2016-01-01

Acute tissue inflammation after myocardial infarction influences healing and remodeling and has been identified as a target for novel therapies. Molecular imaging holds promise for guidance of such therapies. The amino acid 11C-methionine is a clinically approved agent which is thought to accumulate in macrophages, but not in healthy myocytes. We assessed the suitability of positron emission tomography (PET) with 11C-methionine for imaging post-MI inflammation, from cell to mouse to man. Uptake assays demonstrated 7-fold higher 11C-methionine uptake by polarized pro-inflammatory M1 macrophages over anti-inflammatory M2 subtypes (p<0.001). C57Bl/6 mice (n=27) underwent coronary artery ligation or no surgery. Serial 11C-methionine PET was performed 3, 5 and 7d later. MI mice exhibited a perfusion defect in 32-50% of the left ventricle (LV). PET detected increased 11C-methionine accumulation in the infarct territory at 3d (5.9±0.9%ID/g vs 4.7±0.9 in remote myocardium, and 2.6±0.5 in healthy mice; p<0.05 and <0.01 respectively), which declined by d7 post-MI (4.3±0.6 in infarct, 3.4±0.8 in remote; p=0.03 vs 3d, p=0.08 vs healthy). Increased 11C-methionine uptake was associated with macrophage infiltration of damaged myocardium. Treatment with anti-integrin antibodies (anti-CD11a, -CD11b, -CD49d; 100µg) lowered macrophage content by 56% and 11C-methionine uptake by 46% at 3d post-MI. A patient study at 3d after ST-elevation MI and early reperfusion confirmed elevated 11C-methionine uptake in the hypoperfused myocardial region. Targeting of elevated amino acid metabolism in pro-inflammatory M1 macrophages enables PET imaging-derived demarcation of tissue inflammation after MI. 11C-methionine-based molecular imaging may assist in the translation of novel image-guided, inflammation-targeted regenerative therapies. PMID:27570549

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404.

PubMed

Besemer, Abigail E; Titz, Benjamin; Grudzinski, Joseph J; Weichert, Jamey P; Kuo, John S; Robins, H Ian; Hall, Lance T; Bednarz, Bryan P

2017-07-06

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124 I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131 I-CLR1404 voxel-level dose distribution was calculated from the 124 I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131 I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq -1 (0.07-0.37 Gy GBq -1 ). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404

NASA Astrophysics Data System (ADS)

Besemer, Abigail E.; Titz, Benjamin; Grudzinski, Joseph J.; Weichert, Jamey P.; Kuo, John S.; Robins, H. Ian; Hall, Lance T.; Bednarz, Bryan P.

2017-08-01

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131I-CLR1404 voxel-level dose distribution was calculated from the 124I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq-1 (0.07-0.37 Gy GBq-1). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for standard

Faster experimental validation of microRNA targets using cold fusion cloning and a dual firefly-Renilla luciferase reporter assay.

PubMed

Alvarez, M Lucrecia

2014-01-01

Different target prediction algorithms have been developed to provide a list of candidate target genes for a given animal microRNAs (miRNAs). However, these computational approaches provide both false-positive and false-negative predictions. Therefore, the target genes of a specific miRNA identified in silico should be experimentally validated. In this chapter, we describe a step-by-step protocol for the experimental validation of a direct miRNA target using a faster Dual Firefly-Renilla Luciferase Reporter Assay. We describe how to construct reporter plasmids using the simple, fast, and highly efficient cold fusion cloning technology, which does not require ligase, phosphatase, or restriction enzymes. In addition, we provide a protocol for co-transfection of reporter plasmids with either miRNA mimics or miRNA inhibitors in human embryonic kidney 293 (HEK293) cells, as well as a description on how to measure Firefly and Renilla luciferase activity using the Dual-Glo Luciferase Assay kit. As an example of the use of this technology, we will validate glucose-6-phosphate dehydrogenase (G6PD) as a direct target of miR-1207-5p.

PET/PDT theranostics: synthesis and biological evaluation of a peptide-targeted gallium porphyrin.

PubMed

Bryden, Francesca; Savoie, Huguette; Rosca, Elena V; Boyle, Ross W

2015-03-21

The development of novel theranostic agents is an important step in the pathway towards personalised medicine, with the combination of diagnostic and therapeutic modalities into a single treatment agent naturally lending itself to the optimisation and personalisation of treatment. In pursuit of the goal of a molecular theranostic suitable for use as a PET radiotracer and a photosensitiser for PDT, a novel radiolabelled peptide-porphyrin conjugate targeting the α6β1-integrin has been developed. (69/71)Ga and (68)Ga labelling of an azide-functionalised porphyrin has been carried out in excellent yields, with subsequent bioconjugation to an alkyne-functionalised peptide demonstrated. α6β1-integrin expression of two cell lines has been evaluated by flow cytometry, and therapeutic potential of the conjugate demonstrated. Evaluation of the phototoxicity of the porphyrin-peptide theranostic conjugate in comparison to an untargeted control porphyrin in vitro, demonstrated significantly enhanced activity for a cell line with higher α6β1-integrin expression when compared with a cell line exhibiting lower α6β1-integrin expression.

Patterns-of-failure guided biological target volume definition for head and neck cancer patients: FDG-PET and dosimetric analysis of dose escalation candidate subregions.

PubMed

Mohamed, Abdallah S R; Cardenas, Carlos E; Garden, Adam S; Awan, Musaddiq J; Rock, Crosby D; Westergaard, Sarah A; Brandon Gunn, G; Belal, Abdelaziz M; El-Gowily, Ahmed G; Lai, Stephen Y; Rosenthal, David I; Fuller, Clifton D; Aristophanous, Michalis

2017-08-01

To identify the radio-resistant subvolumes in pretreatment FDG-PET by mapping the spatial location of the origin of tumor recurrence after IMRT for head-and-neck squamous cell cancer to the pretreatment FDG-PET/CT. Patients with local/regional recurrence after IMRT with available FDG-PET/CT and post-failure CT were included. For each patient, both pre-therapy PET/CT and recurrence CT were co-registered with the planning CT (pCT). A 4-mm radius was added to the centroid of mapped recurrence growth target volumes (rGTV's) to create recurrence nidus-volumes (NVs). The overlap between boost-tumor-volumes (BTV) representing different SUV thresholds/margins combinations and NVs was measured. Forty-seven patients were eligible. Forty-two (89.4%) had type A central high dose failure. Twenty-six (48%) of type A rGTVs were at the primary site and 28 (52%) were at the nodal site. The mean dose of type A rGTVs was 71Gy. BTV consisting of 50% of the maximum SUV plus 10mm margin was the best subvolume for dose boosting due to high coverage of primary site NVs (92.3%), low average relative volume to CTV1 (41%), and least average percent voxels outside CTV1 (19%). The majority of loco-regional recurrences originate in the regions of central-high-dose. When correlated with pretreatment FDG-PET, the majority of recurrences originated in an area that would be covered by additional 10mm margin on the volume of 50% of the maximum FDG uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a novel, fibrin-specific PET tracer.

PubMed

van Mourik, Tiemen R; Claesener, Michael; Nicolay, Klaas; Grüll, Holger

2017-05-30

Fibrin deposition is observed in several diseases such as atherosclerosis, deep vein thrombosis, and also tumors, where it contributes to the formation of mature tumor stroma. The aim of this study was to develop a gallium-labeled peptide tracer on the basis of the fibrin-targeting peptide Epep for PET imaging of fibrin deposition. For this purpose, the peptide Epep was modified with a NOTA moiety for radiolabeling with 67 Ga and 68 Ga and compared with the earlier validated 111 In-DOTA-Epep tracer. In vitro binding assays of 67 Ga-NOTA-Epep displayed an enhanced retention as compared to previously published data showing binding of 111 In-DOTA-Epep to human (84.0 ± 0.6 vs 66.6 ± 1.4 %Dose) and mouse derived fibrin clots (83.5 ± 1.7 vs 74.2 ± 2.4% Dose). In vivo blood kinetics displayed a bi-phasic elimination profile (t 1/2 , α  = 2.6 ± 1.0 minutes and t 1/2 , β  = 15.8 ± 1.3 minutes) and ex vivo biodistribution showed low blood values at 4 hours post injection and a low uptake in nontarget tissue (<0.2 %ID/g; kidneys, 1.9%ID/g). In conclusion, taking into account the ease of radiolabeling and the promising in vitro and in vivo studies, gallium-labeled Epep displays the potential for further development towards a PET tracer for fibrin deposition. Copyright © 2017 John Wiley & Sons, Ltd.

Post-PET ultrasound improves specificity of 18F-FDG-PET for recurrent differentiated thyroid cancer while maintaining sensitivity

PubMed Central

Kråkenes, Jostein; Brauckhoff, Katrin; Haugland, Hans Kristian; Heinecke, Achim; Akslen, Lars A; Varhaug, Jan Erik; Brauckhoff, Michael

2015-01-01

Background Positron emission tomography (PET) using fluor-18-deoxyglucose (18F-FDG) with or without computed tomography (CT) is generally accepted as the most sensitive imaging modality for diagnosing recurrent differentiated thyroid cancer (DTC) in patients with negative whole body scintigraphy with iodine-131 (I-131). Purpose To assess the potential incremental value of ultrasound (US) over 18F-FDG-PET-CT. Material and Methods Fifty-one consecutive patients with suspected recurrent DTC were prospectively evaluated using the following multimodal imaging protocol: (i) US before PET (pre-US) with or without fine needle biopsy (FNB) of suspicious lesions; (ii) single photon emission computed tomography (≥3 GBq I-131) with co-registered CT (SPECT-CT); (iii) 18F-FDG-PET with co-registered contrast-enhanced CT of the neck; (iv) US in correlation with the other imaging modalities (post-US). Postoperative histology, FNB, and long-term follow-up (median, 2.8 years) were taken as composite gold standard. Results Fifty-eight malignant lesions were identified in 34 patients. Forty lesions were located in the neck or upper mediastinum. On receiver operating characteristics (ROC) analysis, 18F-FDG-PET had a limited lesion-based specificity of 59% at a set sensitivity of 90%. Pre-US had poor sensitivity and specificity of 52% and 53%, respectively, increasing to 85% and 94% on post-US, with knowledge of the PET/CT findings (P < 0.05 vs. PET and pre-US). Multimodal imaging changed therapy in 15 out of 51 patients (30%). Conclusion In patients with suspected recurrent DTC, supplemental targeted US in addition to 18F-FDG-PET-CT increases specificity while maintainin sensitivity, as non-malignant FDG uptake in cervical lesions can be confirmed. PMID:25770086

[Positron-emission tomography (PET) and PET/CT in head and neck cancer - recommendations of an interdisciplinary consensus conference].

PubMed

Kohlfürst, S; Markitz, M; Raunik, W; Eckel, H E; Kresnik, E; Hausegger, K; Salzwimmer, M; Gaggl, A; Chiari, F; Lind, P

2009-02-01

Today's available therapeutic options in head and neck cancer patients have led to better treatment modalities tailored to the individually clinical staging of the patients towards a risk adapted tumour management. This, however, is only possible with an accurately pretherapeutic diagnostic regimen and closely posttherapeutic follow-up. These issues were discussed by nuclear medicine experts, otorhinolaryngologists, oral surgeons, radiologists, radio-oncologists and oncologists in a meeting that took place in Pörtschach, Austria, on 05 May 2006. The aim was to discuss the impact and indications of performing FDG PET/CT in patients with head and neck cancer and to outline possible future perspectives. FDG PET/CT is recommended for a better pretherapeutic staging in stage IV according to UICC and should be the method of choice in CUP with lymph node metastases. FDG PET/CT should be performed 3 - 4 months after radiation-/radiochemotherapy to diagnose viable tumour and to avoid false positive results. To evaluate the position and effectiveness of FDG PET/CT in therapy-monitoring further studies are needed. In case of radiation therapy FDG PET/CT allows a tailored treatment of patients with an accurate design of the target volume to reduce damage to the surrounding tissues. The interdisciplinary consensus reached by the experts is not intended to recommend standard guidelines in the management of head and neck cancer but to summarise and stress the impact of FDG PET/CT on the basis of the present literature and current clinical practise.

Multi-atlas attenuation correction supports full quantification of static and dynamic brain PET data in PET-MR

NASA Astrophysics Data System (ADS)

Mérida, Inés; Reilhac, Anthonin; Redouté, Jérôme; Heckemann, Rolf A.; Costes, Nicolas; Hammers, Alexander

2017-04-01

In simultaneous PET-MR, attenuation maps are not directly available. Essential for absolute radioactivity quantification, they need to be derived from MR or PET data to correct for gamma photon attenuation by the imaged object. We evaluate a multi-atlas attenuation correction method for brain imaging (MaxProb) on static [18F]FDG PET and, for the first time, on dynamic PET, using the serotoninergic tracer [18F]MPPF. A database of 40 MR/CT image pairs (atlases) was used. The MaxProb method synthesises subject-specific pseudo-CTs by registering each atlas to the target subject space. Atlas CT intensities are then fused via label propagation and majority voting. Here, we compared these pseudo-CTs with the real CTs in a leave-one-out design, contrasting the MaxProb approach with a simplified single-atlas method (SingleAtlas). We evaluated the impact of pseudo-CT accuracy on reconstructed PET images, compared to PET data reconstructed with real CT, at the regional and voxel levels for the following: radioactivity images; time-activity curves; and kinetic parameters (non-displaceable binding potential, BPND). On static [18F]FDG, the mean bias for MaxProb ranged between 0 and 1% for 73 out of 84 regions assessed, and exceptionally peaked at 2.5% for only one region. Statistical parametric map analysis of MaxProb-corrected PET data showed significant differences in less than 0.02% of the brain volume, whereas SingleAtlas-corrected data showed significant differences in 20% of the brain volume. On dynamic [18F]MPPF, most regional errors on BPND ranged from -1 to  +3% (maximum bias 5%) for the MaxProb method. With SingleAtlas, errors were larger and had higher variability in most regions. PET quantification bias increased over the duration of the dynamic scan for SingleAtlas, but not for MaxProb. We show that this effect is due to the interaction of the spatial tracer-distribution heterogeneity variation over time with the degree of accuracy of the attenuation maps. This

Multi-atlas attenuation correction supports full quantification of static and dynamic brain PET data in PET-MR.

PubMed

Mérida, Inés; Reilhac, Anthonin; Redouté, Jérôme; Heckemann, Rolf A; Costes, Nicolas; Hammers, Alexander

2017-04-07

In simultaneous PET-MR, attenuation maps are not directly available. Essential for absolute radioactivity quantification, they need to be derived from MR or PET data to correct for gamma photon attenuation by the imaged object. We evaluate a multi-atlas attenuation correction method for brain imaging (MaxProb) on static [ 18 F]FDG PET and, for the first time, on dynamic PET, using the serotoninergic tracer [ 18 F]MPPF. A database of 40 MR/CT image pairs (atlases) was used. The MaxProb method synthesises subject-specific pseudo-CTs by registering each atlas to the target subject space. Atlas CT intensities are then fused via label propagation and majority voting. Here, we compared these pseudo-CTs with the real CTs in a leave-one-out design, contrasting the MaxProb approach with a simplified single-atlas method (SingleAtlas). We evaluated the impact of pseudo-CT accuracy on reconstructed PET images, compared to PET data reconstructed with real CT, at the regional and voxel levels for the following: radioactivity images; time-activity curves; and kinetic parameters (non-displaceable binding potential, BP ND ). On static [ 18 F]FDG, the mean bias for MaxProb ranged between 0 and 1% for 73 out of 84 regions assessed, and exceptionally peaked at 2.5% for only one region. Statistical parametric map analysis of MaxProb-corrected PET data showed significant differences in less than 0.02% of the brain volume, whereas SingleAtlas-corrected data showed significant differences in 20% of the brain volume. On dynamic [ 18 F]MPPF, most regional errors on BP ND ranged from -1 to  +3% (maximum bias 5%) for the MaxProb method. With SingleAtlas, errors were larger and had higher variability in most regions. PET quantification bias increased over the duration of the dynamic scan for SingleAtlas, but not for MaxProb. We show that this effect is due to the interaction of the spatial tracer-distribution heterogeneity variation over time with the degree of accuracy of the attenuation

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain.

PubMed

Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

2015-05-01

The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was maintained. The change of gain of

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Jin Ho; Choi, Yong, E-mail: ychoi.image@gmail.com; Jung, Jiwoong

2015-05-15

Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. Themore » PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

Single-Center Experience with a Targeted Next Generation Sequencing Assay for Assessment of Relevant Somatic Alterations in Solid Tumors.

PubMed

Paasinen-Sohns, Aino; Koelzer, Viktor H; Frank, Angela; Schafroth, Julian; Gisler, Aline; Sachs, Melanie; Graber, Anne; Rothschild, Sacha I; Wicki, Andreas; Cathomas, Gieri; Mertz, Kirsten D

2017-03-01

Companion diagnostics rely on genomic testing of molecular alterations to enable effective cancer treatment. Here we report the clinical application and validation of the Oncomine Focus Assay (OFA), an integrated, commercially available next-generation sequencing (NGS) assay for the rapid and simultaneous detection of single nucleotide variants, short insertions and deletions, copy number variations, and gene rearrangements in 52 cancer genes with therapeutic relevance. Two independent patient cohorts were investigated to define the workflow, turnaround times, feasibility, and reliability of OFA targeted sequencing in clinical application and using archival material. Cohort I consisted of 59 diagnostic clinical samples from the daily routine submitted for molecular testing over a 4-month time period. Cohort II consisted of 39 archival melanoma samples that were up to 15years old. Libraries were prepared from isolated nucleic acids and sequenced on the Ion Torrent PGM sequencer. Sequencing datasets were analyzed using the Ion Reporter software. Genomic alterations were identified and validated by orthogonal conventional assays including pyrosequencing and immunohistochemistry. Sequencing results of both cohorts, including archival formalin-fixed, paraffin-embedded material stored up to 15years, were consistent with published variant frequencies. A concordance of 100% between established assays and OFA targeted NGS was observed. The OFA workflow enabled a turnaround of 3½ days. Taken together, OFA was found to be a convenient tool for fast, reliable, broadly applicable and cost-effective targeted NGS of tumor samples in routine diagnostics. Thus, OFA has strong potential to become an important asset for precision oncology. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

[18F](2S,4R)4-Fluoroglutamine PET Detects Glutamine Pool Size Changes in Triple Negative Breast Cancer in Response to Glutaminase Inhibition

PubMed Central

Pantel, Austin R.; Li, Shihong; Lieberman, Brian P.; Ploessl, Karl; Choi, Hoon; Blankemeyer, Eric; Lee, Hsiaoju; Kung, Hank F.; Mach, Robert H.

2017-01-01

Glutaminolysis is a metabolic pathway adapted by many aggressive cancers, including triple-negative breast cancers (TNBC), to utilize glutamine for survival and growth. In this study, we examined the utility of [18F](2S,4R)4-fluoroglutamine ([18F]4F-Gln) PET to measure tumor cellular glutamine pool size, whose change might reveal the pharmacodynamic (PD) effect of drugs targeting this cancer-specific metabolic pathway. High glutaminase (GLS) activity in TNBC tumors resulted in low cellular glutamine pool size assayed via high-resolution 1H magnetic resonance spectroscopy (MRS). GLS inhibition significantly increased glutamine pool size in TNBC tumors. MCF-7 tumors, with inherently low GLS activity compared to TNBC, displayed a larger baseline glutamine pool size that did not change as much in response to GLS inhibition. The tumor-to-blood-activity-ratios (T/B) obtained from [18F]4F-Gln PET images matched the distinct glutamine pool sizes of both tumor models at baseline. After a short course of GLS inhibitor treatment, the T/B values increased significantly in TNBC, but did not change in MCF-7 tumors. Across both tumor types and after GLS inhibitor or vehicle treatment, we observed a strong positive correlation between T/B values and tumor glutamine pool size measured using MRS (R2=0.71). In conclusion, [18F]4F-Gln PET tracked cellular glutamine pool size in breast cancers with differential GLS activity and detected increases in cellular glutamine pool size induced by GLS inhibitors. This study accomplished the first necessary step towards validating [18F]4F-Gln PET as a PD marker for glutaminase-targeting drugs. PMID:28202527

Performance of PCR-based assays targeting Bacteroidales genetic markers of human fecal pollution in sewage and fecal samples

EPA Science Inventory

There are numerous PCR-based methods available to characterize human fecal pollution in ambient waters. Each assay employs distinct oligonucleotides and many target different genes and microorganisms leading to potential variations in method performance. Laboratory comparisons ...

Triroc: A Multi-Channel SiPM Read-Out ASIC for PET/PET-ToF Application

NASA Astrophysics Data System (ADS)

Ahmad, Salleh; Fleury, Julien; de la Taille, Christophe; Seguin-Moreau, Nathalie; Dulucq, Frederic; Martin-Chassard, Gisele; Callier, Stephane; Thienpont, Damien; Raux, Ludovic

2015-06-01

Triroc is the latest addition to SiPM readout ASICs family developed at Weeroc, a start-up company from the Omega microelectronics group of IN2P3/CNRS. This chip is developed under the framework TRIMAGE European project which is aimed for building a cost effective tri-modal PET/MR/EEG brain scan. To ensure the flexibility and compatibility with any SiPM in the market, the ASIC is designed to be capable of accepting negative and positive polarity input signals. This 64-channel ASIC, is suitable for SiPM readout which requires high accuracy timing and charge measurements. Targeted applications would be PET prototyping with time-of-flight capability. Main features of Triroc includes high dynamic range ADC up to 2500 photoelectrons and TDC fine time binning of 40 ps. Triroc requires very minimal external components which means it is a good contender for compact multichannel PET prototyping. Triroc is designed by using AMS 0.35 μm SiGe technology and it was submitted in March 2014. The detail design of this chip will be presented.

Brain-inspired cheminformatics of drug-target brain interactome, synthesis, and assay of TVP1022 derivatives.

PubMed

Romero-Durán, Francisco J; Alonso, Nerea; Yañez, Matilde; Caamaño, Olga; García-Mera, Xerardo; González-Díaz, Humberto

2016-04-01

The use of Cheminformatics tools is gaining importance in the field of translational research from Medicinal Chemistry to Neuropharmacology. In particular, we need it for the analysis of chemical information on large datasets of bioactive compounds. These compounds form large multi-target complex networks (drug-target interactome network) resulting in a very challenging data analysis problem. Artificial Neural Network (ANN) algorithms may help us predict the interactions of drugs and targets in CNS interactome. In this work, we trained different ANN models able to predict a large number of drug-target interactions. These models predict a dataset of thousands of interactions of central nervous system (CNS) drugs characterized by > 30 different experimental measures in >400 different experimental protocols for >150 molecular and cellular targets present in 11 different organisms (including human). The model was able to classify cases of non-interacting vs. interacting drug-target pairs with satisfactory performance. A second aim focus on two main directions: the synthesis and assay of new derivatives of TVP1022 (S-analogues of rasagiline) and the comparison with other rasagiline derivatives recently reported. Finally, we used the best of our models to predict drug-target interactions for the best new synthesized compound against a large number of CNS protein targets. Copyright © 2015 Elsevier Ltd. All rights reserved.

PET imaging of β-glucuronidase activity by an activity-based 124I-trapping probe for the personalized glucuronide prodrug targeted therapy.

PubMed

Su, Yu-Cheng; Cheng, Ta-Chun; Leu, Yu-Ling; Roffler, Steve R; Wang, Jaw-Yuan; Chuang, Chih-Hung; Kao, Chien-Han; Chen, Kai-Chuan; Wang, Hsin-Ell; Cheng, Tian-Lu

2014-12-01

Beta-glucuronidase (βG) is a potential biomarker for cancer diagnosis and prodrug therapy. The ability to image βG activity in patients would assist in personalized glucuronide prodrug cancer therapy. However, whole-body imaging of βG activity for medical usage is not yet available. Here, we developed a radioactive βG activity-based trapping probe for positron emission tomography (PET). We generated a (124)I-tyramine-conjugated difluoromethylphenol beta-glucuronide probe (TrapG) to form (124)I-TrapG that could be selectively activated by βG for subsequent attachment of (124)I-tyramine to nucleophilic moieties near βG-expressing sites. We estimated the specificity of a fluorescent FITC-TrapG, the cytotoxicity of tyramine-TrapG, and the serum half-life of (124)I-TrapG. βG targeting of (124)I-TrapG in vivo was examined by micro-PET. The biodistribution of (131)I-TrapG was investigated in different organs. Finally, we imaged the endogenous βG activity and assessed its correlation with therapeutic efficacy of 9-aminocamptothecin glucuronide (9ACG) prodrug in native tumors. FITC-TrapG showed specific trapping at βG-expressing CT26 (CT26/mβG) cells but not in CT26 cells. The native TrapG probe possessed low cytotoxicity. (124)I-TrapG preferentially accumulated in CT26/mβG but not CT26 cells. Meanwhile, micro-PET and whole-body autoradiography results demonstrated that (124)I-TrapG signals in CT26/mβG tumors were 141.4-fold greater than in CT26 tumors. Importantly, Colo205 xenografts in nude mice that express elevated endogenous βG can be monitored by using infrared glucuronide trapping probes (NIR-TrapG) and suppressed by 9ACG prodrug treatment. (124)I-TrapG exhibited low cytotoxicity allowing long-term monitoring of βG activity in vivo to aid in the optimization of prodrug targeted therapy. ©2014 American Association for Cancer Research.

Multi-modal in cellulo evaluation of NPR-C targeted C-ANF-peptide and C-ANF-comb nanoparticles

NASA Astrophysics Data System (ADS)

Shokeen, Monica; Pressly, Eric; Connal, Luke; Liu, Yongjian; Hawker, Craig J.; Woodard, Pamela K.; Anderson, Carolyn J.; Achilefu, Samuel; Welch, Michael J.

2012-03-01

Natriuretic peptides (NPs) are clinical markers of heart disease that have anti-proliferative and anti-migratory effects on vascular smooth-muscle cells (VSMCs). In atherosclerosis, NPs participate in vascular remodeling, where the expression of NP clearance receptors (NPR-Cs) is upregulated both in the endothelium and in VSMCs[1-3]. In this study, we investigated the enhanced targeting potential of novel multifunctional nanoprobes conjugated with multiple copies of a C-type atrial natriuretic factor (C-ANF) peptide fragment to target NPR-C transfected cells. The cell binding results of the NPR-C targeted nanoprobes were compared with that of the C-ANF peptide fragment alone. The nanoprobe and peptide structures contain the chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) for labeling with the PET tracer, 64Cu, for radioactive assays and luminescent Eu (III) for confocal cell imaging. Cell assays performed with the radioactive nanoprobe and peptide demonstrated higher cell binding of the targeted nanoprobe comapred with the peptide alone (8.63+/-1.67 vs. 1.13+/-0.06). The targeting specificity of both moieties was tested by using the control cell lines NPR-A and NPR-B, and receptor mediated uptake was demonstrated by reduced uptake in the presence of excess unlabeled respective probes.

[18F-Fluorocholine PET-CT for localization of parathyroid adenomas].

PubMed

Kluijfhout, Wouter P; Vriens, Menno R; Borel Rinkes, Inne H M; Valk, Gerlof D; de Klerk, John M H; de Keizer, Bart

2015-01-01

18F-fluorocholine PET-CT is a new imaging modality for the localization of pathological parathyroid glands in patients with primary hyperparathyroidism. The PET-CT is a combination scan that uses both the physiological information from the PET and the anatomical information from the CT. Uptake of the radio-isotope 18F-fluorocholine is increased in pathological parathyroid glands. 18F-fluorocholine PET-CT helps clinicians to localize the pathological parathyroid glands where conventional modalities fail to do so. This enables surgeons to carry out targeted minimal invasive surgery. It may also prevent the patient having to undergo a more extensive exploration, with its associated risks, and alleviate the necessity of taking medications with side effects. Although the literature on this subject is still scarce, preliminary results are promising. As any hospital with a PET-CT can perform the scan, we expect that its use in patients with hyperparathyroidism will increase over the next few years.

An update on technical and methodological aspects for cardiac PET applications.

PubMed

Presotto, Luca; Busnardo, Elena; Gianolli, Luigi; Bettinardi, Valentino

2016-12-01

Positron emission tomography (PET) is indicated for a large number of cardiac diseases: perfusion and viability studies are commonly used to evaluate coronary artery disease; PET can also be used to assess sarcoidosis and endocarditis, as well as to investigate amyloidosis. Furthermore, a hot topic for research is plaque characterization. Most of these studies are technically very challenging. High count rates and short acquisition times characterize perfusion scans while very small targets have to be imaged in inflammation/infection and plaques examinations. Furthermore, cardiac PET suffers from respiratory and cardiac motion blur. Each type of studies has specific requirements from the technical and methodological point of view, thus PET systems with overall high performances are required. Furthermore, in the era of hybrid PET/computed tomography (CT) and PET/Magnetic Resonance Imaging (MRI) systems, the combination of complementary functional and anatomical information can be used to improve diagnosis and prognosis. Moreover, PET images can be qualitatively and quantitatively improved exploiting information from the other modality, using advanced algorithms. In this review we will report the latest technological and methodological innovations for PET cardiac applications, with particular reference to the state of the art of the hybrid PET/CT and PET/MRI. We will also report the most recent advancements in software, from reconstruction algorithms to image processing and analysis programs.

Bacterial Zoonoses Transmitted by Household Pets: State-of-the-Art and Future Perspectives for Targeted Research and Policy Actions.

PubMed

Damborg, P; Broens, E M; Chomel, B B; Guenther, S; Pasmans, F; Wagenaar, J A; Weese, J S; Wieler, L H; Windahl, U; Vanrompay, D; Guardabassi, L

2016-07-01

The close contact between household pets and people offers favourable conditions for bacterial transmission. In this article, the aetiology, prevalence, transmission, impact on human health and preventative measures are summarized for selected bacterial zoonoses transmissible by household pets. Six zoonoses representing distinct transmission routes were selected arbitrarily based on the available information on incidence and severity of pet-associated disease caused by zoonotic bacteria: bite infections and cat scratch disease (physical injuries), psittacosis (inhalation), leptospirosis (contact with urine), and campylobacteriosis and salmonellosis (faecal-oral ingestion). Antimicrobial resistance was also included due to the recent emergence of multidrug-resistant bacteria of zoonotic potential in dogs and cats. There is a general lack of data on pathogen prevalence in the relevant pet population and on the incidence of human infections attributable to pets. In order to address these gaps in knowledge, and to minimize the risk of human infection, actions at several levels are recommended, including: (1) coordinated surveillance of zoonotic pathogens and antimicrobial resistance in household pets, (2) studies to estimate the burden of human disease attributable to pets and to identify risk behaviours facilitating transmission, and (3) education of those in charge of pets, animal caretakers, veterinarians and human medical healthcare practitioners on the potential zoonotic risks associated with exposure to pets. Disease-specific recommendations include incentives to undertake research aimed at the development of new diagnostic tests, veterinary-specific antimicrobial products and vaccines, as well as initiatives to promote best practices in veterinary diagnostic laboratories and prudent antimicrobial usage. Copyright © 2016. Published by Elsevier Ltd.

NEMA NU 4-2008 Performance Measurements of Two Commercial Small-Animal PET Scanners: ClearPET and rPET-1

NASA Astrophysics Data System (ADS)

Canadas, Mario; Embid, Miguel; Lage, Eduardo; Desco, Manuel; Vaquero, Juan José; Perez, José Manuel

2011-02-01

In this work, we compare two commercial positron emission tomography (PET) scanners installed at CIEMAT (Madrid, Spain): the ClearPET and the rPET-1. These systems have significant geometrical differences, such as the axial field of view (110 mm on ClearPET versus 45.6 mm on rPET-1), the configuration of the detectors (whole ring on ClearPET versus one pair of planar blocks on rPET-1) and the use of an axial shift between ClearPET detector modules. We used an assessment procedure that fulfilled the recommendations of the National Electrical Manufacturers Association (NEMA) NU 4-2008 standard. The methodology includes studies of spatial resolution, sensitivity, scatter fraction, count losses and image quality. Our experiments showed a central spatial resolution of 1.5 mm (transaxial), 3.2 mm (axial) for the ClearPET and 1.5 mm (transaxial), 1.6 mm (axial) for the rPET-1, with a small variation across the transverse axis on both scanners ( 1 mm). The absolute sensitivity at the centre of the field of view was 4.7% for the ClearPET and 1.0% for the rPET-1. The peak noise equivalent counting rate for the mouse-sized phantom was 73.4 kcps reached at 0.51 MBq/mL on the ClearPET and 29.2 kcps at 1.35 MBq/mL on the rPET-1. The recovery coefficients measured using the image quality phantom ranged from 0.11 to 0.89 on the ClearPET and from 0.14 to 0.81 on the rPET-1. The overall performance shows that both the ClearPET and the rPET-1 systems are very suitable for preclinical research and imaging of small animals.

The influence of CT based attenuation correction on PET/CT registration: an evaluation study

NASA Astrophysics Data System (ADS)

Yaniv, Ziv; Wong, Kenneth H.; Banovac, Filip; Levy, Elliot; Cleary, Kevin

2007-03-01

We are currently developing a PET/CT based navigation system for guidance of biopsies and radiofrequency ablation (RFA) of early stage hepatic tumors. For these procedures, combined PET/CT data can potentially improve current interventions. The diagnostic efficacy of biopsies can potentially be improved by accurately targeting the region within the tumor that exhibits the highest metabolic activity. For RFA procedures the system can potentially enable treatment of early stage tumors, targeting tumors before structural abnormalities are clearly visible on CT. In both cases target definition is based on the metabolic data (PET), and navigation is based on the spatial data (CT), making the system highly dependent upon accurate spatial alignment between these data sets. In our institute all clinical data sets include three image volumes: one CT, and two PET volumes, with and without CT-based attenuation correction. This paper studies the effect of the CT-based attenuation correction on the registration process. From comparing the pairs of registrations from five data sets we observe that the point motion magnitude difference between registrations is on the same scale as the point motion magnitude in each one of the registrations, and that visual inspection cannot identify this discrepancy. We conclude that using non-rigid registration to align the PET and CT data sets is too variable, and most likely does not provide sufficient accuracy for interventional procedures.

Fusion of multi-tracer PET images for dose painting.

PubMed

Lelandais, Benoît; Ruan, Su; Denœux, Thierry; Vera, Pierre; Gardin, Isabelle

2014-10-01

PET imaging with FluoroDesoxyGlucose (FDG) tracer is clinically used for the definition of Biological Target Volumes (BTVs) for radiotherapy. Recently, new tracers, such as FLuoroThymidine (FLT) or FluoroMisonidazol (FMiso), have been proposed. They provide complementary information for the definition of BTVs. Our work is to fuse multi-tracer PET images to obtain a good BTV definition and to help the radiation oncologist in dose painting. Due to the noise and the partial volume effect leading, respectively, to the presence of uncertainty and imprecision in PET images, the segmentation and the fusion of PET images is difficult. In this paper, a framework based on Belief Function Theory (BFT) is proposed for the segmentation of BTV from multi-tracer PET images. The first step is based on an extension of the Evidential C-Means (ECM) algorithm, taking advantage of neighboring voxels for dealing with uncertainty and imprecision in each mono-tracer PET image. Then, imprecision and uncertainty are, respectively, reduced using prior knowledge related to defects in the acquisition system and neighborhood information. Finally, a multi-tracer PET image fusion is performed. The results are represented by a set of parametric maps that provide important information for dose painting. The performances are evaluated on PET phantoms and patient data with lung cancer. Quantitative results show good performance of our method compared with other methods. Copyright © 2014 Elsevier B.V. All rights reserved.

Current application and future perspectives of PSMA PET imaging in prostate cancer.

PubMed

Ceci, Francesco; Castellucci, Paolo; Fanti, Stefano

2018-03-08

As precision medicine evolves, the contribution of molecular imaging to the management of prostate cancer (PCa) patients, especially for Positron Emission Tomography (PET) imaging, is gaining importance. Highly successful approaches to measure the expression of the prostate specific membrane antigen (PSMA) have been introduced recently. PSMA, the glutamate carboxypeptidase II (GCP-II), is a membrane bound metallo-peptidase that is overexpressed in 90-100% of PCa cells. Due to its selective over-expression, PSMA is a reliable tissue marker for prostate cancer and is considered an ideal target for tumor specific imaging and therapy. A variety of PET and SPECT probes targeting this peptide receptor have been introduced. These are undergoing extensive clinical evaluations. Initial results attest to a high accuracy for disease detection compared conventional radiology (CT or MRI) and other nuclear medicine procedure (choline PET or fluciclovine PET). However, prospective evaluation of the impact on patient management for PSMA-ligand PET and its impact on patient outcome is currently missing. Finally, PSMA inhibitors can be radio-labeled with diagnostic (68Ga-PSMA-11), or therapeutic nuclides (177Lu/225Ac PSMA-617) to be used as theranostic agent. Initial results showed that PSMA-targeted radioligand therapy (RLT) can potentially delay disease progression in metastatic castrate-resistant PCa. This review aims to explore the current application of PSMA based imaging in prostate cancer, reporting about main advantages and limitations of this new theranostic procedure. The future perspectives and potential the applications of this agent will be also discussed.

18F-FNDP for PET Imaging of Soluble Epoxide Hydrolase.

PubMed

Horti, Andrew G; Wang, Yuchuan; Minn, Il; Lan, Xi; Wang, Jian; Koehler, Raymond C; Alkayed, Nabil J; Dannals, Robert F; Pomper, Martin G

2016-11-01

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme located within cytosol and peroxisomes that converts epoxides to the corresponding diols and hydrolyzes phosphate monoesters. It serves to inactivate epoxyeicosatrienoic acids (EETs), which are generated in the brain to couple neuronal activity and cerebral blood flow in normal and pathologic states. Altered regulation of sEH was observed previously in various neuropathologic disorders including vascular dementia and stroke. Inhibitors of sEH are pursued as agents to mitigate neuronal damage after stroke. We developed N-(3,3-diphenylpropyl)-6- 18 F-fluoronicotinamide ( 18 F-FNDP), which proved highly specific for imaging of sEH in the mouse and nonhuman primate brain with PET. 18 F-FNDP was synthesized from the corresponding bromo precursor. sEH inhibitory activity of 18 F-FNDP was measured using an sEH inhibitor screening assay kit. Biodistribution was undertaken in CD-1 mice. Binding specificity was assayed in CD-1 and sEH knock-out mice and Papio anubis (baboon) through pretreatment with an sEH inhibitor to block sEH binding. Dynamic PET imaging with arterial blood sampling was performed in 3 baboons, with regional tracer binding quantified using distribution volume. The metabolism of 18 F-FNDP in baboons was assessed using high-performance liquid chromatography. 18 F-FNDP (inhibition binding affinity constant, 1.73 nM) was prepared in 1 step in a radiochemical yield of 14% ± 7%, specific radioactivity in the range of 888-3,774 GBq/μmol, and a radiochemical purity greater than 99% using an automatic radiosynthesis module. The time of preparation was about 75 min. In CD-1 mice, regional uptake followed the pattern of striatum > cortex > hippocampus > cerebellum, consistent with the known brain distribution of sEH, with 5.2% injected dose per gram of tissue at peak uptake. Blockade of 80%-90% was demonstrated in all brain regions. Minimal radiotracer uptake was present in sEH knock-out mice. PET baboon

[Principles of PET].

PubMed

Beuthien-Baumann, B

2018-05-01

Positron emission tomography (PET) is a procedure in nuclear medicine, which is applied predominantly in oncological diagnostics. In the form of modern hybrid machines, such as PET computed tomography (PET/CT) and PET magnetic resonance imaging (PET/MRI) it has found wide acceptance and availability. The PET procedure is more than just another imaging technique, but a functional method with the capability for quantification in addition to the distribution pattern of the radiopharmaceutical, the results of which are used for therapeutic decisions. A profound knowledge of the principles of PET including the correct indications, patient preparation, and possible artifacts is mandatory for the correct interpretation of PET results.

Sigma metrics used to assess analytical quality of clinical chemistry assays: importance of the allowable total error (TEa) target.

PubMed

Hens, Koen; Berth, Mario; Armbruster, Dave; Westgard, Sten

2014-07-01

Six Sigma metrics were used to assess the analytical quality of automated clinical chemistry and immunoassay tests in a large Belgian clinical laboratory and to explore the importance of the source used for estimation of the allowable total error. Clinical laboratories are continually challenged to maintain analytical quality. However, it is difficult to measure assay quality objectively and quantitatively. The Sigma metric is a single number that estimates quality based on the traditional parameters used in the clinical laboratory: allowable total error (TEa), precision and bias. In this study, Sigma metrics were calculated for 41 clinical chemistry assays for serum and urine on five ARCHITECT c16000 chemistry analyzers. Controls at two analyte concentrations were tested and Sigma metrics were calculated using three different TEa targets (Ricos biological variability, CLIA, and RiliBÄK). Sigma metrics varied with analyte concentration, the TEa target, and between/among analyzers. Sigma values identified those assays that are analytically robust and require minimal quality control rules and those that exhibit more variability and require more complex rules. The analyzer to analyzer variability was assessed on the basis of Sigma metrics. Six Sigma is a more efficient way to control quality, but the lack of TEa targets for many analytes and the sometimes inconsistent TEa targets from different sources are important variables for the interpretation and the application of Sigma metrics in a routine clinical laboratory. Sigma metrics are a valuable means of comparing the analytical quality of two or more analyzers to ensure the comparability of patient test results.

Evaluation of quantitative polymerase chain reaction assays targeting Mycobacterium avium, M. intracellulare, and M. avium subspecies paratuberculosis in drinking water biofilms.

PubMed

Chern, Eunice C; King, Dawn; Haugland, Richard; Pfaller, Stacy

2015-03-01

Mycobacterium avium (MA), Mycobacterium intracellulare (MI), and Mycobacterium avium subsp. paratuberculosis (MAP) are difficult to culture due to their slow growing nature. A quantitative polymerase chain reaction (qPCR) method for the rapid detection of MA, MI, and MAP can be used to provide data supporting drinking water biofilms as potential sources of human exposure. The aim of this study was to characterize two qPCR assays targeting partial 16S rRNA gene sequences of MA and MI and use these assays, along with two previously reported MAP qPCR assays (IS900 and Target 251), to investigate Mycobacterium occurrence in kitchen faucet biofilms. MA and MI qPCR assays demonstrated 100% specificity and sensitivity when evaluated against 18 non-MA complex, 76 MA, and 17 MI isolates. Both assays detected approximately 1,000 cells from a diluted cell stock inoculated on a sampling swab 100% of the time. DNA analysis by qPCR indicated that 35.3, 56.9 and 11.8% of the 51 kitchen faucet biofilm samples collected contained MA, MI, and MAP, respectively. This study introduces novel qPCR assays designed to specifically detect MA and MI in biofilm. Results support the use of qPCR as an alternative to culture for detection and enumeration of MA, MI, and MAP in microbiologically complex samples.

Physics and applications of positron beams in an integrated PET/MR.

PubMed

Watson, Charles C; Eriksson, Lars; Kolb, Armin

2013-02-07

In PET/MR systems having the PET component within the uniform magnetic field interior to the MR, positron beams can be injected into the PET field of view (FOV) from unshielded emission sources external to it, as a consequence of the action of the Lorentz force on the transverse components of the positron's velocity. Such beams may be as small as a few millimeters in diameter, but extend 50 cm or more axially without appreciable divergence. Larger beams form 'phantoms' of annihilations in air that can be easily imaged, and that are essentially free of γ-ray attenuation and scatter effects, providing a unique tool for characterizing PET systems and reconstruction algorithms. Thin targets intersecting these beams can produce intense annihilation sources having the thickness of a sheet of paper, which are very useful for high resolution measurements, and difficult to achieve with conventional sources. Targeted beams can provide other point, line and surface sources for various applications, all without the need to have radioactivity within the FOV. In this paper we discuss the physical characteristics of positron beams in air and present examples of their applications.

Prospective evaluation of 18F-FACBC PET/CT and PET/MRI versus multiparametric MRI in intermediate- to high-risk prostate cancer patients (FLUCIPRO trial).

PubMed

Jambor, Ivan; Kuisma, Anna; Kähkönen, Esa; Kemppainen, Jukka; Merisaari, Harri; Eskola, Olli; Teuho, Jarmo; Perez, Ileana Montoya; Pesola, Marko; Aronen, Hannu J; Boström, Peter J; Taimen, Pekka; Minn, Heikki

2018-03-01

The purpose of this study was to evaluate 18 F-FACBC PET/CT, PET/MRI, and multiparametric MRI (mpMRI) in detection of primary prostate cancer (PCa). Twenty-six men with histologically confirmed PCa underwent PET/CT immediately after injection of 369 ± 10 MBq 18 F-FACBC (fluciclovine) followed by PET/MRI started 55 ± 7 min from injection. Maximum standardized uptake values (SUV max ) were measured for both hybrid PET acquisitions. A separate mpMRI was acquired within a week of the PET scans. Logan plots were used to calculate volume of distribution (V T ). The presence of PCa was estimated in 12 regions with radical prostatectomy findings as ground truth. For each imaging modality, area under the curve (AUC) for detection of PCa was determined to predict diagnostic performance. The clinical trial registration number is NCT02002455. In the visual analysis, 164/312 (53%) regions contained PCa, and 41 tumor foci were identified. PET/CT demonstrated the highest sensitivity at 87% while its specificity was low at 56%. The AUC of both PET/MRI and mpMRI significantly (p < 0.01) outperformed that of PET/CT while no differences were detected between PET/MRI and mpMRI. SUV max and V T of Gleason score (GS) >3 + 4 tumors were significantly (p < 0.05) higher than those for GS 3 + 3 and benign hyperplasia. A total of 442 lymph nodes were evaluable for staging, and PET/CT and PET/MRI demonstrated true-positive findings in only 1/7 patients with metastatic lymph nodes. Quantitative 18 F-FACBC imaging significantly correlated with GS but failed to outperform MRI in lesion detection. 18 F-FACBC may assist in targeted biopsies in the setting of hybrid imaging with MRI.

Professor Pet.

ERIC Educational Resources Information Center

Pet Information Bureau, New York, NY.

This manual outlines ways in which observation and care of classroom pet animals may be used to enrich the education of elementary school children. Part one deals with the benefits of having pets in the classroom. Part two illustrates ways in which pets can serve as valuable teaching tools and gives examples of lessons in which the use of pets can…

PET imaging in adaptive radiotherapy of prostate tumors.

PubMed

Beuthien-Baumann, Bettina; Koerber, Stefan A

2018-06-04

The integration of data from positron-emission-tomography, combined with computed tomography as PET/CT or combined with magnet resonance imaging as PET/MRI, into radiation treatment planning of prostate cancer is gaining higher impact with the development of more sensitive and specific radioligands. The classic PET-tracer for prostate cancer imaging are [11C]choline and [11C]acetate, which are currently outperformed by ligands binding to the prostate-specific- membrane-antigen (PSMA). [68Ga]PSMA-11, which is the most frequently applied tracer, has shown to detect lymph node metastases, local recurrences, distant metastases and intraprostatic foci with high sensitivity, even at relatively low PSA levels. The results from PET-imaging may influence radiotherapeutic (RT) management at different stages of the disease i.e. during primary staging or biochemical recurrence, when the detection of distant metastases may alter the curative treatment concept into a palliative approach. On the other hand, the clinical target volume could be adapted by visualizing lymph node metastases at locations, which might not have been suspicious on morphologic imaging alone. The treatment plan might contain a boost to the dominant intraprostatic lesion, which could be delineated by a combination of PET-tracer uptake and multiparametric MRI. Therefore, PSMA-PET imaging is well suited for being integrated into prostate radiation planning. However, further prospective trials evaluating the impact on oncological outcome are indicated.

ToxCast Assay Network (TCAN) Viewer: A Visualization Tool for High-throughput Assay Chemical Data (SOT)

EPA Science Inventory

USEPA’s ToxCast program has generated high-throughput bioactivity screening (HTS) data on thousands of chemicals. The ToxCast program has described and annotated the HTS assay battery with respect to assay design and target information (e.g., gene target). Recent stakeholder and ...

Field evaluation of the photo-induced electron transfer fluorogenic primers (PET) real-time PCR for the detection of Plasmodium falciparum in Tanzania

PubMed Central

2014-01-01

Background Accurate diagnosis of malaria infections remains challenging, especially in the identification of submicroscopic infections. New molecular diagnostic tools that are inexpensive, sensitive enough to detect low-level infections and suitable in laboratory settings of resource-limited countries are required for malaria control and elimination programmes. Here the diagnostic potential of a recently developed photo-induced electron transfer fluorogenic primer (PET) real-time polymerase chain reaction (PCR) called PET-PCR was investigated. This study aimed to (i) evaluate the use of this assay as a method for the detection of both Plasmodium falciparum and other Plasmodium species infections in a developing country’s diagnostic laboratory; and, (ii) determine the assay’s sensitivity and specificity compared to a nested 18S rRNA PCR. Methods Samples used in this study were obtained from a previous study conducted in the region of Iringa, Tanzania. A total of 303 samples from eight health facilities in Tanzania were utilized for this evaluation. All samples were screened using the multiplex PET-PCR assay designed to detect Plasmodium genus and P. falciparum initially in laboratory in Tanzania and then repeated at a reference laboratory at the CDC in the USA. Microscopy data was available for all the 303 samples. A subset of the samples were tested in a blinded fashion to find the sensitivity and specificity of the PET-PCR compared to the nested 18S rRNA PCR. Results Compared to microscopy, the PET-PCR assay was 59% more sensitive in detecting P. falciparum infections. The observed sensitivity and specificity were 100% (95% confidence interval (CI0.95) = 94-100%) and (CI0.95 = 96-100%), respectively, for the PET-PCR assay when compared to nested 18S rRNA PCR. When compared to 18S rRNA PCR, microscopy had a low sensitivity of 40% (CI0.95 = 23-61%) and specificity of 100% (CI0.95 = 96-100%). The PET-PCR results performed in the field laboratory

Assay Portal | Office of Cancer Clinical Proteomics Research

Cancer.gov

The CPTAC Assay Portal serves as a centralized public repository of "fit-for-purpose," multiplexed quantitative mass spectrometry-based proteomic targeted assays. Targeted proteomic assays eliminate issues that are commonly observed using conventional protein detection systems.

The development, past achievements, and future directions of brain PET

PubMed Central

Jones, Terry; Rabiner, Eugenii A

2012-01-01

The early developments of brain positron emission tomography (PET), including the methodological advances that have driven progress, are outlined. The considerable past achievements of brain PET have been summarized in collaboration with contributing experts in specific clinical applications including cerebrovascular disease, movement disorders, dementia, epilepsy, schizophrenia, addiction, depression and anxiety, brain tumors, drug development, and the normal healthy brain. Despite a history of improving methodology and considerable achievements, brain PET research activity is not growing and appears to have diminished. Assessments of the reasons for decline are presented and strategies proposed for reinvigorating brain PET research. Central to this is widening the access to advanced PET procedures through the introduction of lower cost cyclotron and radiochemistry technologies. The support and expertize of the existing major PET centers, and the recruitment of new biologists, bio-mathematicians and chemists to the field would be important for such a revival. New future applications need to be identified, the scope of targets imaged broadened, and the developed expertize exploited in other areas of medical research. Such reinvigoration of the field would enable PET to continue making significant contributions to advance the understanding of the normal and diseased brain and support the development of advanced treatments. PMID:22434067

Value of PET/CT and MR Lymphography in Treatment of Prostate Cancer Patients With Lymph Node Metastases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortuin, Ansje S., E-mail: A.Fortuin@rad.umcn.nl; Deserno, Willem M.L.L.G.; Meijer, Hanneke J.M.

2012-11-01

Purpose: To determine the clinical value of two novel molecular imaging techniques: {sup 11}C-choline positron emission tomography (PET)/computed tomography (CT) and ferumoxtran-10 enhanced magnetic resonance imaging (magnetic resonance lymphography [MRL]) for lymph node (LN) treatment in prostate cancer (PCa) patients. Therefore, we evaluated the ability of PET/CT and MRL to assess the number, size, and location of LN metastases in patients with primary or recurrent PCa. Methods and Materials: A total of 29 patients underwent MRL and PET/CT for LN evaluation. The MRL and PET/CT data were analyzed independently. The number, size, and location of the LN metastases were determined.more » The location was described as within or outside the standard clinical target volume for elective pelvic irradiation as defined by the Radiation Therapy Oncology Group. Subsequently, the results from MRL and PET/CT were compared. Results: Of the 738 LNs visible on MRL, 151 were positive in 23 of 29 patients. Of the 132 LNs visible on PET/CT, 34 were positive in 13 of 29 patients. MRL detected significantly more positive LNs (p < 0.001) in more patients than PET/CT (p = 0.002). The mean diameter of the detected suspicious LNs on MRL was significantly smaller than those detected by PET/CT, 4.9 mm and 8.4 mm, respectively (p < 0.0001). In 14 (61%) of 23 patients, suspicious LNs were found outside the clinical target volume with MRL and in 4 (31%) of 13 patients with PET/CT. Conclusion: In patients with PCa, both molecular imaging techniques, MRL and {sup 11}C-choline PET/CT, can detect LNs suspicious for metastasis, irrespective of the existing size and shape criteria for CT and conventional magnetic resonance imaging. On MRL and PET/CT, 61% and 31% of the suspicious LNs were located outside the conventional clinical target volume. Therefore, these techniques could help to individualize treatment selection and enable image-guided radiotherapy for patients with PCa LN metastases.« less

Automation of (64)Cu production at Turku PET Centre.

PubMed

Elomaa, Viki-Veikko; Jurttila, Jori; Rajander, Johan; Solin, Olof

2014-07-01

At Turku PET Centre automation for handling solid targets for the production of (64)Cu has been built. The system consists of a module for moving the target from the irradiation position into a lead transport shield and a robotic-arm assisted setup for moving the target within radiochemistry laboratory. The main motivation for designing automation arises from radiation hygiene. Copyright © 2014 Elsevier Ltd. All rights reserved.

5-HT Radioligands for Human Brain Imaging With PET and SPECT

PubMed Central

Paterson, Louise M.; Kornum, Birgitte R.; Nutt, David J.; Pike, Victor W.; Knudsen, Gitte M.

2014-01-01

The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging. PMID:21674551

Joint PET-MR respiratory motion models for clinical PET motion correction

NASA Astrophysics Data System (ADS)

Manber, Richard; Thielemans, Kris; Hutton, Brian F.; Wan, Simon; McClelland, Jamie; Barnes, Anna; Arridge, Simon; Ourselin, Sébastien; Atkinson, David

2016-09-01

Patient motion due to respiration can lead to artefacts and blurring in positron emission tomography (PET) images, in addition to quantification errors. The integration of PET with magnetic resonance (MR) imaging in PET-MR scanners provides complementary clinical information, and allows the use of high spatial resolution and high contrast MR images to monitor and correct motion-corrupted PET data. In this paper we build on previous work to form a methodology for respiratory motion correction of PET data, and show it can improve PET image quality whilst having minimal impact on clinical PET-MR protocols. We introduce a joint PET-MR motion model, using only 1 min per PET bed position of simultaneously acquired PET and MR data to provide a respiratory motion correspondence model that captures inter-cycle and intra-cycle breathing variations. In the model setup, 2D multi-slice MR provides the dynamic imaging component, and PET data, via low spatial resolution framing and principal component analysis, provides the model surrogate. We evaluate different motion models (1D and 2D linear, and 1D and 2D polynomial) by computing model-fit and model-prediction errors on dynamic MR images on a data set of 45 patients. Finally we apply the motion model methodology to 5 clinical PET-MR oncology patient datasets. Qualitative PET reconstruction improvements and artefact reduction are assessed with visual analysis, and quantitative improvements are calculated using standardised uptake value (SUVpeak and SUVmax) changes in avid lesions. We demonstrate the capability of a joint PET-MR motion model to predict respiratory motion by showing significantly improved image quality of PET data acquired before the motion model data. The method can be used to incorporate motion into the reconstruction of any length of PET acquisition, with only 1 min of extra scan time, and with no external hardware required.

Positron Emission Tomography (PET)

DOE R&D Accomplishments Database

Welch, M. J.

1990-01-01

Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

Copper Loading of Preformed Nanoparticles for PET-Imaging Applications.

PubMed

Lu, Hoang D; Wang, Leon Z; Wilson, Brian K; McManus, Simon A; Jumai'an, Jenny; Padakanti, Prashanth K; Alavi, Abass; Mach, Robert H; Prud'homme, Robert K

2018-01-31

Nanoparticles (NP) are promising contrast agents for positron emission tomography (PET) radionuclide imaging that can increase signal intensity by localizing clusters of PET radionuclides together. However, methods to load NPs with PET radionuclides suffer from harsh loading conditions or poor loading efficacies or result in NP surface modifications that alter targeting in vivo. We present the formation of water-dispersible, polyethylene glycol coated NPs that encapsulate phthalocyanines into NP cores at greater than 50 wt % loading, using the self-assembly technique Flash NanoPrecipitation. Particles from 70 to 160 nm are produced. Phthalocyanine NPs rapidly and spontaneously chelate metals under mild conditions and can act as sinks for PET radionuclides such as 64-Cu to produce PET-active NPs. NPs chelate copper(II) with characteristic rates of 1845 M -1 h -1 at pH 6 and 37 °C, which produced >90% radionuclide chelation within 1 h. NP physical properties, such as core composition, core fluidity, and size, can be tuned to modulate chelation kinetics. These NPs retain 64 Cu even in the presence of the strong chelator ethylene diamine tetraacetic acid. The development of these constructs for rapid and facile radionuclide labeling expands the applications of NP-based PET imaging.

Dynamic neurotransmitter interactions measured with PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiffer, W.K.; Dewey, S.L.

2001-04-02

Positron emission tomography (PET) has become a valuable interdisciplinary tool for understanding physiological, biochemical and pharmacological functions at a molecular level in living humans, whether in a healthy or diseased state. The utility of tracing chemical activity through the body transcends the fields of cardiology, oncology, neurology and psychiatry. In this, PET techniques span radiochemistry and radiopharmaceutical development to instrumentation, image analysis, anatomy and modeling. PET has made substantial contributions in each of these fields by providing a,venue for mapping dynamic functions of healthy and unhealthy human anatomy. As diverse as the disciplines it bridges, PET has provided insight intomore » an equally significant variety of psychiatric disorders. Using the unique quantitative ability of PET, researchers are now better able to non-invasively characterize normally occurring neurotransmitter interactions in the brain. With the knowledge that these interactions provide the fundamental basis for brain response, many investigators have recently focused their efforts on an examination of the communication between these chemicals in both healthy volunteers and individuals suffering from diseases classically defined as neurotransmitter specific in nature. In addition, PET can measure the biochemical dynamics of acute and sustained drug abuse. Thus, PET studies of neurotransmitter interactions enable investigators to describe a multitude of specific functional interactions in the human brain. This information can then be applied to understanding side effects that occur in response to acute and chronic drug therapy, and to designing new drugs that target multiple systems as opposed to single receptor types. Knowledge derived from PET studies can be applied to drug discovery, research and development (for review, see (Fowler et al., 1999) and (Burns et al., 1999)). Here, we will cover the most substantial contributions of PET to

Approaches using molecular imaging technology - use of PET in clinical microdose studies§

PubMed Central

Wagner, Claudia C; Langer, Oliver

2013-01-01

Positron emission tomography (PET) imaging uses minute amounts of radiolabeled drug tracers and thereby meets the criteria for clinical microdose studies. The advantage of PET, when compared to other analytical methods used in microdose studies, is that the pharmacokinetics (PK) of a drug can be determined in the tissue targeted for drug treatment. PET microdosing already offers interesting applications in clinical oncology and in the development of central nervous system pharmaceuticals and is extending its range of application to many other fields of pharmaceutical medicine. Although requirements for preclinical safety testing for microdose studies have been cut down by regulatory authorities, radiopharmaceuticals increasingly need to be produced under good manufacturing practice (GMP) conditions, which increases the costs of PET microdosing studies. Further challenges in PET microdosing include combining PET with other ultrasensitive analytical methods, such as accelerator mass spectrometry (AMS), to gain plasma PK data of drugs, beyond the short PET examination periods. Finally, conducting clinical PET studies with radiolabeled drugs both at micro- and therapeutic doses is encouraged to answer the question of dose linearity in clinical microdosing. PMID:20887762

Approaches using molecular imaging technology -- use of PET in clinical microdose studies.

PubMed

Wagner, Claudia C; Langer, Oliver

2011-06-19

Positron emission tomography (PET) imaging uses minute amounts of radiolabeled drug tracers and thereby meets the criteria for clinical microdose studies. The advantage of PET, when compared to other analytical methods used in microdose studies, is that the pharmacokinetics (PK) of a drug can be determined in the tissue targeted for drug treatment. PET microdosing already offers interesting applications in clinical oncology and in the development of central nervous system pharmaceuticals and is extending its range of application to many other fields of pharmaceutical medicine. Although requirements for preclinical safety testing for microdose studies have been cut down by regulatory authorities, radiopharmaceuticals increasingly need to be produced under good manufacturing practice (GMP) conditions, which increases the costs of PET microdosing studies. Further challenges in PET microdosing include combining PET with other ultrasensitive analytical methods, such as accelerator mass spectrometry (AMS), to gain plasma PK data of drugs, beyond the short PET examination periods. Finally, conducting clinical PET studies with radiolabeled drugs both at micro- and therapeutic doses is encouraged to answer the question of dose linearity in clinical microdosing. Copyright © 2010 Elsevier B.V. All rights reserved.

FDG-PET/CT imaging for tumor staging and definition of tumor volumes in radiation treatment planning in non-small cell lung cancer.

PubMed

Zheng, Yuanda; Sun, Xiaojiang; Wang, Jian; Zhang, Lingnan; DI, Xiaoyun; Xu, Yaping

2014-04-01

18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has the potential to improve the staging and radiation treatment (RT) planning of various tumor sites. However, from a clinical standpoint, questions remain with regard to what extent PET/CT changes the target volume and whether PET/CT reduces interobserver variability in target volume delineation. The present study analyzed the use of FDG-PET/CT images for staging and evaluated the impact of FDG-PET/CT on the radiotherapy volume delineation compared with CT in patients with non-small cell lung cancer (NSCLC) who were candidates for radiotherapy. Intraobserver variation in delineating tumor volumes was also observed. In total, 23 patients with stage I-III NSCLC were enrolled and treated with fractionated RT-based therapy with or without chemotherapy. FDG-PET/CT scans were acquired within two weeks prior to RT. PET and CT data sets were sent to the treatment planning system, Pinnacle, through compact discs. The CT and PET images were subsequently fused by means of a dedicated RT planning system. Gross tumor volume (GTV) was contoured by four radiation oncologists on CT (GTV-CT) and PET/CT images (GTV-PET/CT). The resulting volumes were analyzed and compared. For the first phase, two radiation oncologists outlined the contours together, achieving a final consensus. Based on PET/CT, changes in tumor-node-metastasis categories occurred in 8/23 cases (35%). Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in 12/20 patients (60%) in comparison with CT targeting. The most prominent changes in GTV were observed in cases with atelectasis. For the second phase, the variation in delineating tumor volumes was assessed by four observers. The mean ratio of largest to smallest CT-based GTV was 2.31 (range, 1.01-5.96). The addition of the PET results reduced the mean ratio to 1.46 (range, 1.02-2.27). PET/CT fusion images may have a

Distribution of intravenously administered acetylcholinesterase inhibitor and acetylcholinesterase activity in the adrenal gland: 11C-donepezil PET study in the normal rat.

PubMed

Watabe, Tadashi; Naka, Sadahiro; Ikeda, Hayato; Horitsugi, Genki; Kanai, Yasukazu; Isohashi, Kayako; Ishibashi, Mana; Kato, Hiroki; Shimosegawa, Eku; Watabe, Hiroshi; Hatazawa, Jun

2014-01-01

Acetylcholinesterase (AChE) inhibitors have been used for patients with Alzheimer's disease. However, its pharmacokinetics in non-target organs other than the brain has not been clarified yet. The purpose of this study was to evaluate the relationship between the whole-body distribution of intravenously administered (11)C-Donepezil (DNP) and the AChE activity in the normal rat, with special focus on the adrenal glands. The distribution of (11)C-DNP was investigated by PET/CT in 6 normal male Wistar rats (8 weeks old, body weight  = 220 ± 8.9 g). A 30-min dynamic scan was started simultaneously with an intravenous bolus injection of (11)C-DNP (45.0 ± 10.7 MBq). The whole-body distribution of the (11)C-DNP PET was evaluated based on the Vt (total distribution volume) by Logan-plot analysis. A fluorometric assay was performed to quantify the AChE activity in homogenized tissue solutions of the major organs. The PET analysis using Vt showed that the adrenal glands had the 2nd highest level of (11)C-DNP in the body (following the liver) (13.33 ± 1.08 and 19.43 ± 1.29 ml/cm(3), respectively), indicating that the distribution of (11)C-DNP was the highest in the adrenal glands, except for that in the excretory organs. The AChE activity was the third highest in the adrenal glands (following the small intestine and the stomach) (24.9 ± 1.6, 83.1 ± 3.0, and 38.5 ± 8.1 mU/mg, respectively), indicating high activity of AChE in the adrenal glands. We demonstrated the whole-body distribution of (11)C-DNP by PET and the AChE activity in the major organs by fluorometric assay in the normal rat. High accumulation of (11)C-DNP was observed in the adrenal glands, which suggested the risk of enhanced cholinergic synaptic transmission by the use of AChE inhibitors.

Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy

NASA Astrophysics Data System (ADS)

Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

2016-06-01

A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra

An atypical sarcoidosis involvement in FDG PET/CT

PubMed Central

Robin, Philippe; Benigni, Paolo; Feger, Benoit; Salaun, Pierre-Yves; Abgral, Ronan

2016-01-01

Abstract Rationale: Sarcoidosis is an idiopathic systemic inflammatory granulomatous disorder comprised of epithelioid and multinucleated giant cells with little necrosis which involve various organs. Laryngeal involvement is extremely rare, with a prevalence of about 0.5 to 1%. Diagnoses: Here we present a case of laryngeal involvement of sarcoidosis demonstrated on 18F-Fluorodesoxyglucose Positron-Emission Tomography/Computed Tomography (FDG PET/CT). Patient concerns: A 63 year-old man suffering from dysphonia was referred to our department for characterization of laryngeal lesion suspicious for cancer with non-informative biopsy, the sample was not sufficient for diagnosis. Interventions: FDG PET/CT showed a pathological uptake on the right vocal cord, but also highlighted a bilateral uptake in intrathoracic hilar lymphadenopathy areas, typically found in several inflammatory diseases. Outcomes: New laryngeal targeted biopsies revealed non-caseating epithelioid granulomas suggesting sarcoidosis involvement. After 6 months of systemic steroid treatment, FDG PET/CT showed a significant decrease of the laryngeal uptake. Lessons: This case shows the usefulness of FDG PET/CT to accurately assess inflammatory activity in rare extra-pulmonary sarcoidosis involvement. Moreover, this case emphasizes that FDG PET/CT is an interesting tool for assessing therapeutic efficacy of inflammatory diseases such as sarcoidosis. PMID:28033265

CPTAC Team Releases Targeted Proteomic Assays for Ovarian Cancer | Office of Cancer Clinical Proteomics Research

Cancer.gov

Pacific Northwest National Laboratory (PNNL) investigators in the Clinical Proteomic Tumor Analysis Consortium (CPTAC) of the National Cancer Institute (NCI), announces the public release of 98 targeted mass spectrometry-based assays for ovarian cancer research studies.  Chosen based on proteogenomic observations from the recently published multi-institutional collaborative project between PNNL and Johns Hopkins University that comprehensively examined the collections of proteins in the tumors of ovarian cancer patients (highlighted in a paper in

CT-guided automated detection of lung tumors on PET images

NASA Astrophysics Data System (ADS)

Cui, Yunfeng; Zhao, Binsheng; Akhurst, Timothy J.; Yan, Jiayong; Schwartz, Lawrence H.

2008-03-01

The calculation of standardized uptake values (SUVs) in tumors on serial [ 18F]2-fluoro-2-deoxy-D-glucose ( 18F-FDG) positron emission tomography (PET) images is often used for the assessment of therapy response. We present a computerized method that automatically detects lung tumors on 18F-FDG PET/Computed Tomography (CT) images using both anatomic and metabolic information. First, on CT images, relevant organs, including lung, bone, liver and spleen, are automatically identified and segmented based on their locations and intensity distributions. Hot spots (SUV >= 1.5) on 18F-FDG PET images are then labeled using the connected component analysis. The resultant "hot objects" (geometrically connected hot spots in three dimensions) that fall into, reside at the edges or are in the vicinity of the lungs are considered as tumor candidates. To determine true lesions, further analyses are conducted, including reduction of tumor candidates by the masking out of hot objects within CT-determined normal organs, and analysis of candidate tumors' locations, intensity distributions and shapes on both CT and PET. The method was applied to 18F-FDG-PET/CT scans from 9 patients, on which 31 target lesions had been identified by a nuclear medicine radiologist during a Phase II lung cancer clinical trial. Out of 31 target lesions, 30 (97%) were detected by the computer method. However, sensitivity and specificity were not estimated because not all lesions had been marked up in the clinical trial. The method effectively excluded the hot spots caused by mediastinum, liver, spleen, skeletal muscle and bone metastasis.

Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR.

PubMed

Catalano, Onofrio A; Coutinho, Artur M; Sahani, Dushyant V; Vangel, Mark G; Gee, Michael S; Hahn, Peter F; Witzel, Thomas; Soricelli, Andrea; Salvatore, Marco; Catana, Ciprian; Mahmood, Umar; Rosen, Bruce R; Gervais, Debra

2017-04-01

Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer. Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test. The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02). PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

Signalling and chemosensitivity assays in melanoma: is mutated status a prerequisite for targeted therapy?

PubMed

Passeron, Thierry; Lacour, Jean-Philippe; Allegra, Maryline; Ségalen, Coralie; Deville, Anne; Thyss, Antoine; Giacchero, Damien; Ortonne, Jean-Paul; Bertolotto, Corine; Ballotti, Robert; Bahadoran, Philippe

2011-12-01

Selection for targeted therapies in melanoma is currently based on the search for mutations in selected genes. We aimed at evaluating the interest of signalling and chemosensitivity studies in addition to genotyping for assessing the best suitable treatment in an individual patient. We extracted genomic DNA and melanoma cells from tumor tissue of a skin metastasis of a 17-year-old woman with stage IV melanoma progressing despite three successive lines of treatment. Despite the absence of mutation in BRAF, NRAS cKIT, the MAPK pathway was activated and a significant response to sorafenib, a mitogen-activated protein kinase (MAPK)/RAF inhibitor, was found in signalling and chemosensitivity assays. A treatment combining sorafenib and dacarbazine produced a partial response for 9 months, with marked necrosis in some lesions. Chemosensitivity assays and signalling pathway studies could be of great value in addition to genotyping for assessing the most appropriate treatment in melanoma. © 2011 John Wiley & Sons A/S.

Antibody-based PET imaging of amyloid beta in mouse models of Alzheimer's disease

PubMed Central

Sehlin, Dag; Fang, Xiaotian T.; Cato, Linda; Antoni, Gunnar; Lannfelt, Lars; Syvänen, Stina

2016-01-01

Owing to their specificity and high-affinity binding, monoclonal antibodies have potential as positron emission tomography (PET) radioligands and are currently used to image various targets in peripheral organs. However, in the central nervous system, antibody uptake is limited by the blood–brain barrier (BBB). Here we present a PET ligand to be used for diagnosis and evaluation of treatment effects in Alzheimer's disease. The amyloid β (Aβ) antibody mAb158 is radiolabelled and conjugated to a transferrin receptor antibody to enable receptor-mediated transcytosis across the BBB. PET imaging of two different mouse models with Aβ pathology clearly visualize Aβ in the brain. The PET signal increases with age and correlates closely with brain Aβ levels. Thus, we demonstrate that antibody-based PET ligands can be successfully used for brain imaging. PMID:26892305

MicroPET imaging and transgenic models: a blueprint for Alzheimer's disease clinical research.

PubMed

Zimmer, Eduardo R; Parent, Maxime J; Cuello, A Claudio; Gauthier, Serge; Rosa-Neto, Pedro

2014-11-01

Over the past decades, developments in neuroimaging have significantly contributed to the understanding of Alzheimer's disease (AD) pathophysiology. Specifically, positron emission tomography (PET) imaging agents targeting amyloid deposition have provided unprecedented opportunities for refining in vivo diagnosis, monitoring disease propagation, and advancing AD clinical trials. Furthermore, the use of a miniaturized version of PET (microPET) in transgenic (Tg) animals has been a successful strategy for accelerating the development of novel radiopharmaceuticals. However, advanced applications of microPET focusing on the longitudinal propagation of AD pathophysiology or therapeutic strategies remain in their infancy. This review highlights what we have learned from microPET imaging in Tg models displaying amyloid and tau pathology, and anticipates cutting-edge applications with high translational value to clinical research. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simultaneous PET/MR imaging with a radio frequency-penetrable PET insert

PubMed Central

Grant, Alexander M.; Lee, Brian J.; Chang, Chen-Ming; Levin, Craig S.

2017-01-01

Purpose A brain sized radio-frequency (RF)-penetrable PET insert has been designed for simultaneous operation with MRI systems. This system takes advantage of electro-optical coupling and battery power to electrically float the PET insert relative to the MRI ground, permitting RF signals to be transmitted through small gaps between the modules that form the PET ring. This design facilitates the use of the built-in body coil for RF transmission, and thus could be inserted into any existing MR site wishing to achieve simultaneous PET/MR imaging. The PET detectors employ non-magnetic silicon photomultipliers in conjunction with a compressed sensing signal multiplexing scheme, and optical fibers to transmit analog PET detector signals out of the MRI room for decoding, processing, and image reconstruction. Methods The PET insert was first constructed and tested in a laboratory benchtop setting, where tomographic images of a custom resolution phantom were successfully acquired. The PET insert was then placed within a 3T body MRI system, and tomographic resolution/contrast phantom images were acquired both with only the B0 field present, and under continuous pulsing from different MR imaging sequences. Results The resulting PET images have comparable contrast-to-noise ratios (CNR) under all MR pulsing conditions: the maximum percent CNR relative difference for each rod type among all four PET images acquired in the MRI system has a mean of 14.0±7.7%. MR images were successfully acquired through the RF-penetrable PET shielding using only the built-in MR body coil, suggesting that simultaneous imaging is possible without significant mutual interference. Conclusions These results show promise for this technology as an alternative to costly integrated PET/MR scanners; a PET insert that is compatible with any existing clinical MRI system could greatly increase the availability, accessibility, and dissemination of PET/MR. PMID:28102949

Initial clinical evaluation of PET-based ion beam therapy monitoring under consideration of organ motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurz, Christopher, E-mail: christopher.kurz@physik.uni-muenchen.de; Bauer, Julia; Unholtz, Daniel

2016-02-15

Purpose: Intrafractional organ motion imposes considerable challenges to scanned ion beam therapy and demands for a thorough verification of the applied treatment. At the Heidelberg Ion-Beam Therapy Center (HIT), the scanned ion beam delivery is verified by means of postirradiation positron-emission-tomography (PET) imaging. This work presents a first clinical evaluation of PET-based treatment monitoring in ion beam therapy under consideration of target motion. Methods: Three patients with mobile liver lesions underwent scanned carbon ion irradiation at HIT and postirradiation PET/CT (x-ray-computed-tomography) imaging with a commercial scanner. Respiratory motion was recorded during irradiation and subsequent image acquisition. This enabled a time-resolvedmore » (4D) calculation of the expected irradiation-induced activity pattern and, for one patient where an additional 4D CT was acquired at the PET/CT scanner after treatment, a motion-compensated PET image reconstruction. For the other patients, PET data were reconstructed statically. To verify the treatment, calculated prediction and reconstructed measurement were compared with a focus on the ion beam range. Results: Results in the current three patients suggest that for motion amplitudes in the order of 2 mm there is no benefit from incorporating respiratory motion information into PET-based treatment monitoring. For a target motion in the order of 10 mm, motion-related effects become more severe and a time-resolved modeling of the expected activity distribution can lead to an improved data interpretation if a sufficient number of true coincidences is detected. Benefits from motion-compensated PET image reconstruction could not be shown conclusively at the current stage. Conclusions: The feasibility of clinical PET-based treatment verification under consideration of organ motion has been shown for the first time. Improvements in noise-robust 4D PET image reconstruction are deemed necessary to enhance the

PET/CT versus body coil PET/MRI: how low can you go?

PubMed

Appenzeller, P; Mader, C; Huellner, M W; Schmidt, D; Schmid, D; Boss, A; von Schulthess, G; Veit-Haibach, P

2013-08-01

The purpose of this study was to evaluate if positron emission tomography (PET)/magnetic resonance imaging (MRI) with just one gradient echo sequence using the body coil is diagnostically sufficient compared with a standard, low-dose non-contrast-enhanced PET/computed tomography (CT) concerning overall diagnostic accuracy, lesion detectability, size and conspicuity evaluation. Sixty-three patients (mean age 58 years, range 19-86 years; 23 women, 40 men) referred for either staging or restaging/follow-up of various malignant tumours (malignant melanoma, lung cancer, breast cancer, Hodgkin's lymphoma, non-Hodgkin's lymphoma, CUP, gynaecology tumours, pleural mesothelioma, oesophageal cancer, colorectal cancer, stomach cancer) were prospectively included. Imaging was conducted using a tri-modality PET/CT-MR set-up (full ring, time-of-flight Discovery PET/CT 690, 3 T Discovery MR 750, both GE Healthcare, Waukesha, WI). All patients were positioned on a dedicated PET/CT- and MR-compatible examination table, allowing for patient transport from the MR system to the PET/CT without patient movement. In accordance with RECIST 1.1 criteria, measurements of the maximum lesion diameters on CT and MR images were obtained. In lymph nodes, the short axis was measured. A four-point scale was used for assessment of lesion conspicuity: 1 (>25 % of lesion borders definable), 2 (25-50 %), 3 (50-75 %) and 4 (>75 %). For each lesion the corresponding anatomical structure was noted based on anatomical information of the spatially co-registered PET/CT and PET/MRI image sections. Additionally, lesions were divided into three categories: "tumour mass", "lymph nodes" and "lesions". Differences in overall lesion detectability and conspicuity in PET/CT and PET/MRI, as well as differences in detectability based on the localisation and lesion type, were analysed by Wilcoxon signed rank test. A total of 126 PET-positive lesions were evaluated. Overall, no statistically significant

PET imaging of cardiomyocyte apoptosis in a rat myocardial infarction model.

PubMed

Ma, Hui; Liu, Shaoyu; Xiong, Ying; Zhang, Zhanwen; Sun, Aixia; Su, Shu; Liang, Hong; Yuan, Gongjun; Tang, Ganghua

2018-06-23

Cardiomyocyte apoptosis has been observed in several cardiovascular diseases and contributes to the subsequent cardiac remodeling processes and progression to heart failure. Consequently, apoptosis imaging is helpful for noninvasively detecting the disease progression and providing treatment guidance. Here, we tested 18 F-labeled 2-(5-fluoropentyl)-2-methyl-malonic acid ( 18 F-ML-10) and 18 F-labeled 2-(3-fluoropropyl)-2-methyl-malonic acid ( 18 F-ML-8) for apoptosis imaging in rat models of myocardial infarction (MI) and compared them with 18 F-fluorodeoxyglucose ( 18 F-FDG). MI was induced in Sprague-Dawley rats by permanent left coronary artery ligation. Procedural success was confirmed by echocardiography and positron emission tomography (PET) imaging with 18 F-FDG. In vivo PET imaging with 18 F-ML-10 and 18 F-ML-8 was performed in the MI models at different time points after operation. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays and immunohistochemical analyses were used to evaluate myocardial apoptosis. In vitro cell binding assays were performed to validate 18 F-ML-8 binding to apoptotic cardiomyocytes. PET imaging demonstrated high 18 F-ML-10 and 18 F-ML-8 uptake where 18 F-FDG uptake was absent. The focal accumulation of the two tracers was high on days 1 and 3 but was not notable on days 5 and 7 after surgery. The infarct-to-lung uptake ratio was 4.29 ± 0.30 for 18 F-ML-10 and 3.51 ± 0.18 for 18 F-ML-8 (n = 6, analyzed by averaging the uptake ratios on postoperative days 1 and 3, P < 0.05). The TUNEL results showed that myocardial cell apoptosis was closely related to the focal uptake of the apoptotic tracers in the infarct area. In addition, the apoptosis rates calculated from the TUNEL results were better correlated with 18 F-ML-8 uptake than with 18 F-ML-10 uptake. Ex vivo cell binding assays demonstrated that 18 F-ML-8 accumulated in apoptotic cells but not in necrotic or normal cells. PET imaging

Cerenkov Luminescence Imaging as a Modality to Evaluate Antibody-Based PET Radiotracers

PubMed Central

D’Souza, Jimson W.; Hensley, Harvey; Doss, Mohan; Beigarten, Charles; Torgov, Michael; Olafsen, Tove; Yu, Jian Q.

2017-01-01

Antibodies, and engineered antibody fragments, labeled with radioisotopes are being developed as radiotracers for the detection and phenotyping of diseases such as cancer. The development of antibody-based radiotracers requires extensive characterization of their in vitro and in vivo properties, including their ability to target tumors in an antigen-selective manner. In this study, we investigated the use of Cerenkov luminescence imaging (CLI) as compared with PET as a modality for evaluating the in vivo behavior of antibody-based radiotracers. Methods: The anti–prostate-specific membrane antigen (PSMA) huJ591 antibody (IgG; 150 kDa) and its minibody (Mb; 80 kDa) format were functionalized with the chelator 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid (NODAGA) and radiolabeled with the positron-emitting radionuclide 64Cu (half-life, 12.7 h). Immunoreactive preparations of the radiolabeled antibodies were injected into NCr nu/nu mice harboring PSMA-positive CWR22Rv1 and PSMA-negative PC-3 tumor xenografts. Tumor targeting was evaluated by both PET and CLI. Results: 64Cu-NODAGA-PSMA-IgG and 64Cu-NODAGA-PSMA-Mb retained the ability to bind cell surface PSMA, and both radiotracers exhibited selective uptake into PSMA-positive tumors. Under the experimental conditions used, PSMA-selective uptake of 64Cu-NODAGA-PSMA-IgG and 64Cu-NODAGA-PSMA-Mb was observed by CLI as early as 3 h after injection, with tumor-to-background ratios peaking at 24 (IgG) and 16 (Mb) h after injection. Targeting data generated by CLI correlated with that generated by PET and necropsy. Conclusion: CLI provided a rapid and simple assessment of the targeting specificity and pharmacokinetics of the antibody-based PET radiotracers that correlated well with the behavior observed by standard PET imaging. Moreover, CLI provided clear discrimination between uptake kinetics of an intact IgG and its small-molecular-weight derivative Mb. These data support the use of CLI for the evaluation of

Real-time FDG PET Guidance during Biopsies and Radiofrequency Ablation Using Multimodality Fusion with Electromagnetic Navigation

PubMed Central

Kadoury, Samuel; Abi-Jaoudeh, Nadine; Levy, Elliot B.; Maass-Moreno, Roberto; Krücker, Jochen; Dalal, Sandeep; Xu, Sheng; Glossop, Neil; Wood, Bradford J.

2011-01-01

Purpose: To assess the feasibility of combined electromagnetic device tracking and computed tomography (CT)/ultrasonography (US)/fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) fusion for real-time feedback during percutaneous and intraoperative biopsies and hepatic radiofrequency (RF) ablation. Materials and Methods: In this HIPAA-compliant, institutional review board–approved prospective study with written informed consent, 25 patients (17 men, eight women) underwent 33 percutaneous and three intraoperative biopsies of 36 FDG-avid targets between November 2007 and August 2010. One patient underwent biopsy and RF ablation of an FDG-avid hepatic focus. Targets demonstrated heterogeneous FDG uptake or were not well seen or were totally inapparent at conventional imaging. Preprocedural FDG PET scans were rigidly registered through a semiautomatic method to intraprocedural CT scans. Coaxial biopsy needle introducer tips and RF ablation electrode guider needle tips containing electromagnetic sensor coils were spatially tracked through an electromagnetic field generator. Real-time US scans were registered through a fiducial-based method, allowing US scans to be fused with intraprocedural CT and preacquired FDG PET scans. A visual display of US/CT image fusion with overlaid coregistered FDG PET targets was used for guidance; navigation software enabled real-time biopsy needle and needle electrode navigation and feedback. Results: Successful fusion of real-time US to coregistered CT and FDG PET scans was achieved in all patients. Thirty-one of 36 biopsies were diagnostic (malignancy in 18 cases, benign processes in 13 cases). RF ablation resulted in resolution of targeted FDG avidity, with no local treatment failure during short follow-up (56 days). Conclusion: Combined electromagnetic device tracking and image fusion with real-time feedback may facilitate biopsies and ablations of focal FDG PET abnormalities that would be challenging with

Drug Target Validation Methods in Malaria - Protein Interference Assay (PIA) as a Tool for Highly Specific Drug Target Validation.

PubMed

Meissner, Kamila A; Lunev, Sergey; Wang, Yuan-Ze; Linzke, Marleen; de Assis Batista, Fernando; Wrenger, Carsten; Groves, Matthew R

2017-01-01

The validation of drug targets in malaria and other human diseases remains a highly difficult and laborious process. In the vast majority of cases, highly specific small molecule tools to inhibit a proteins function in vivo are simply not available. Additionally, the use of genetic tools in the analysis of malarial pathways is challenging. These issues result in difficulties in specifically modulating a hypothetical drug target's function in vivo. The current "toolbox" of various methods and techniques to identify a protein's function in vivo remains very limited and there is a pressing need for expansion. New approaches are urgently required to support target validation in the drug discovery process. Oligomerisation is the natural assembly of multiple copies of a single protein into one object and this self-assembly is present in more than half of all protein structures. Thus, oligomerisation plays a central role in the generation of functional biomolecules. A key feature of oligomerisation is that the oligomeric interfaces between the individual parts of the final assembly are highly specific. However, these interfaces have not yet been systematically explored or exploited to dissect biochemical pathways in vivo. This mini review will describe the current state of the antimalarial toolset as well as the potentially druggable malarial pathways. A specific focus is drawn to the initial efforts to exploit oligomerisation surfaces in drug target validation. As alternative to the conventional methods, Protein Interference Assay (PIA) can be used for specific distortion of the target protein function and pathway assessment in vivo. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A comparative study of the target volume definition in radiotherapy with «Slow CT Scan» vs. 4D PET/CT Scan in early stages non-small cell lung cancer.

PubMed

Molla, M; Anducas, N; Simó, M; Seoane, A; Ramos, M; Cuberas-Borros, G; Beltran, M; Castell, J; Giralt, J

To evaluate the use of 4D PET/CT to quantify tumor respiratory motion compared to the «Slow»-CT (CTs) in the radiotherapy planning process. A total of 25 patients with inoperable early stage non small cell lung cancer (NSCLC) were included in the study. Each patient was imaged with a CTs (4s/slice) and 4D PET/CT. The adequacy of each technique for respiratory motion capture was evaluated using the volume definition for each of the following: Internal target volume (ITV) 4D and ITVslow in relation with the volume defined by the encompassing volume of 4D PET/CT and CTs (ITVtotal). The maximum distance between the edges of the volume defined by each technique to that of the total volume was measured in orthogonal beam's eye view. The ITV4D showed less differences in relation with the ITVtotal in both the cranio-caudal and the antero-posterior axis compared to the ITVslow. The maximum differences were 0.36mm in 4D PET/CTand 0.57mm in CTs in the antero-posterior axis. 4D PET/CT resulted in the definition of more accurate (ITV4D/ITVtotal 0.78 vs. ITVs/ITVtotal 0.63), and larger ITVs (19.9 cc vs. 16.3 cc) than those obtained with CTs. Planning with 4D PET/CT in comparison with CTs, allows incorporating tumor respiratory motion and improving planning radiotherapy of patients in early stages of lung cancer. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Multi-laboratory evaluations of the performance of Catellicoccus marimammalium PCR assays developed to target gull fecal sources

USGS Publications Warehouse

Sinigalliano, Christopher D.; Ervin, Jared S.; Van De Werfhorst, Laurie C.; Badgley, Brian D.; Ballestée, Elisenda; Bartkowiaka, Jakob; Boehm, Alexandria B.; Byappanahalli, Muruleedhara N.; Goodwin, Kelly D.; Gourmelon, Michèle; Griffith, John; Holden, Patricia A.; Jay, Jenny; Layton, Blythe; Lee, Cheonghoon; Lee, Jiyoung; Meijer, Wim G.; Noble, Rachel; Raith, Meredith; Ryu, Hodon; Sadowsky, Michael J.; Schriewer, Alexander; Wang, Dan; Wanless, David; Whitman, Richard; Wuertz, Stefan; Santo Domingo, Jorge W.

2013-01-01

Here we report results from a multi-laboratory (n = 11) evaluation of four different PCR methods targeting the 16S rRNA gene of Catellicoccus marimammalium originally developed to detect gull fecal contamination in coastal environments. The methods included a conventional end-point PCR method, a SYBR® Green qPCR method, and two TaqMan® qPCR methods. Different techniques for data normalization and analysis were tested. Data analysis methods had a pronounced impact on assay sensitivity and specificity calculations. Across-laboratory standardization of metrics including the lower limit of quantification (LLOQ), target detected but not quantifiable (DNQ), and target not detected (ND) significantly improved results compared to results submitted by individual laboratories prior to definition standardization. The unit of measure used for data normalization also had a pronounced effect on measured assay performance. Data normalization to DNA mass improved quantitative method performance as compared to enterococcus normalization. The MST methods tested here were originally designed for gulls but were found in this study to also detect feces from other birds, particularly feces composited from pigeons. Sequencing efforts showed that some pigeon feces from California contained sequences similar to C. marimammalium found in gull feces. These data suggest that the prevalence, geographic scope, and ecology of C. marimammalium in host birds other than gulls require further investigation. This study represents an important first step in the multi-laboratory assessment of these methods and highlights the need to broaden and standardize additional evaluations, including environmentally relevant target concentrations in ambient waters from diverse geographic regions.

18F-FDG PET/MRI fusion in characterizing pancreatic tumors: comparison to PET/CT.

PubMed

Tatsumi, Mitsuaki; Isohashi, Kayako; Onishi, Hiromitsu; Hori, Masatoshi; Kim, Tonsok; Higuchi, Ichiro; Inoue, Atsuo; Shimosegawa, Eku; Takeda, Yutaka; Hatazawa, Jun

2011-08-01

To demonstrate that positron emission tomography (PET)/magnetic resonance imaging (MRI) fusion was feasible in characterizing pancreatic tumors (PTs), comparing MRI and computed tomography (CT) as mapping images for fusion with PET as well as fused PET/MRI and PET/CT. We retrospectively reviewed 47 sets of (18)F-fluorodeoxyglucose ((18)F -FDG) PET/CT and MRI examinations to evaluate suspected or known pancreatic cancer. To assess the ability of mapping images for fusion with PET, CT (of PET/CT), T1- and T2-weighted (w) MR images (all non-contrast) were graded regarding the visibility of PT (5-point confidence scale). Fused PET/CT, PET/T1-w or T2-w MR images of the upper abdomen were evaluated to determine whether mapping images provided additional diagnostic information to PET alone (3-point scale). The overall quality of PET/CT or PET/MRI sets in diagnosis was also assessed (3-point scale). These PET/MRI-related scores were compared to PET/CT-related scores and the accuracy in characterizing PTs was compared. Forty-three PTs were visualized on CT or MRI, including 30 with abnormal FDG uptake and 13 without. The confidence score for the visibility of PT was significantly higher on T1-w MRI than CT. The scores for additional diagnostic information to PET and overall quality of each image set in diagnosis were significantly higher on the PET/T1-w MRI set than the PET/CT set. The diagnostic accuracy was higher on PET/T1-w or PET/T2-w MRI (93.0 and 90.7%, respectively) than PET/CT (88.4%), but statistical significance was not obtained. PET/MRI fusion, especially PET with T1-w MRI, was demonstrated to be superior to PET/CT in characterizing PTs, offering better mapping and fusion image quality.

Two Variants of a High-Throughput Fluorescent Microplate Assay of Polysaccharide Endotransglycosylases.

PubMed

Kováčová, Kristína; Farkaš, Vladimír

2016-04-01

Polysaccharide endotransglycosylases (PETs) are the cell wall-modifying enzymes of fungi and plants. They catalyze random endo-splitting of the polysaccharide donor molecule and transfer of the newly formed reducing sugar residue to the nonreducing end of an acceptor molecule which can be a polysaccharide or an oligosaccharide. Owing to their important role in the cell wall formation, the inhibition of PETs represents an attractive strategy in the fight against fungal infections. We have elaborated two variants of a versatile high-throughput microplate fluorimetric assay that could be used for effective identification of PETs and screening of their inhibitors. Both assays use the respective polysaccharides as the donors and sulforhodamine-labeled oligosaccharides as the acceptors but differ from each other by mode of how the labeled polysaccharide products of transglycosylation are separated from the unreacted oligosaccharide acceptors. In the first variant, the reactions take place in a layer of agar gel laid on the bottoms of the wells of a microtitration plate. After the reaction, the high-Mr transglycosylation products are precipitated with 66 % ethanol and retained within the gel while the low-Mr products and the unreacted acceptors are washed out. In the second variant, the donor polysaccharides are adsorbed to the surface of a microplate well and remain adsorbed there also after becoming labeled in the course of the transglycosylation reaction whereas the unused low-Mr acceptors are washed out. As a proof of versatility, assays of heterologously expressed transglycosylases ScGas1, ScCrh1, and ScCrh2 from the yeast Saccharomyces cerevisiae, CaPhr1 and CaPhr2 from Candida albicans, and of a plant xyloglucan endotransglycosylase (XET) are demonstrated.

SU-D-201-07: Exploring the Utility of 4D FDG-PET/CT Scans in Design of Radiation Therapy Planning Compared with 3D PET/CT: A Prospective Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, C; Yin, Y

2015-06-15

Purpose: A method using four-dimensional(4D) PET/CT in design of radiation treatment planning was proposed and the target volume and radiation dose distribution changes relative to standard three-dimensional (3D) PET/CT were examined. Methods: A target deformable registration method was used by which the whole patient’s respiration process was considered and the effect of respiration motion was minimized when designing radiotherapy planning. The gross tumor volume of a non-small-cell lung cancer was contoured on the 4D FDG-PET/CT and 3D PET/CT scans by use of two different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; another technique using amore » constant threshold of standardized uptake value (SUV) greater than 2.5. The target volume and radiotherapy dose distribution between VOL3D and VOL4D were analyzed. Results: For all phases, the average automatic and manually GTV volume was 18.61 cm3 (range, 16.39–22.03 cm3) and 31.29 cm3 (range, 30.11–35.55 cm3), respectively. The automatic and manually volume of merged IGTV were 27.82 cm3 and 49.37 cm3, respectively. For the manual contour, compared to 3D plan the mean dose for the left, right, and total lung of 4D plan have an average decrease 21.55%, 15.17% and 15.86%, respectively. The maximum dose of spinal cord has an average decrease 2.35%. For the automatic contour, the mean dose for the left, right, and total lung have an average decrease 23.48%, 16.84% and 17.44%, respectively. The maximum dose of spinal cord has an average decrease 1.68%. Conclusion: In comparison to 3D PET/CT, 4D PET/CT may better define the extent of moving tumors and reduce the contouring tumor volume thereby optimize radiation treatment planning for lung tumors.« less

PET/CT scanners: a hardware approach to image fusion.

PubMed

Townsend, David W; Beyer, Thomas; Blodgett, Todd M

2003-07-01

New technology that combines positron tomography with x-ray computed tomography (PET/CT) is available from all major vendors of PET imaging equipment: CTI, Siemens, GE, Philips. Although not all vendors have made the same design choices as those described in this review all have in common that their high performance design places a commercial CT scanner in tandem with a commercial PET scanner. The level of physical integration is actually less than that of the original prototype design where the CT and PET components were mounted on the same rotating support. There will undoubtedly be a demand for PET/CT technology with a greater level of integration, and at a reduced cost. This may be achieved through the design of a scanner specifically for combined anatomical and functional imaging, rather than a design combining separate CT and PET scanners, as in the current approaches. By avoiding the duplication of data acquisition and image reconstruction functions, for example, a more integrated design should also allow cost savings over current commercial PET/CT scanners. The goal is then to design and build a device specifically for imaging the function and anatomy of cancer in the most optimal and effective way, without conceptualizing it as combined PET and CT. The development of devices specifically for imaging a particular disease (eg, cancer) differs from the conventional approach of, for example, an all-purpose anatomical imaging device such as a CT scanner. This new concept targets more of a disease management approach rather than the usual division into the medical specialties of radiology (anatomical imaging) and nuclear medicine (functional imaging). Copyright 2003 Elsevier Inc. All rights reserved.

Joint Segmentation of Anatomical and Functional Images: Applications in Quantification of Lesions from PET, PET-CT, MRI-PET, and MRI-PET-CT Images

PubMed Central

Bagci, Ulas; Udupa, Jayaram K.; Mendhiratta, Neil; Foster, Brent; Xu, Ziyue; Yao, Jianhua; Chen, Xinjian; Mollura, Daniel J.

2013-01-01

We present a novel method for the joint segmentation of anatomical and functional images. Our proposed methodology unifies the domains of anatomical and functional images, represents them in a product lattice, and performs simultaneous delineation of regions based on random walk image segmentation. Furthermore, we also propose a simple yet effective object/background seed localization method to make the proposed segmentation process fully automatic. Our study uses PET, PET-CT, MRI-PET, and fused MRI-PET-CT scans (77 studies in all) from 56 patients who had various lesions in different body regions. We validated the effectiveness of the proposed method on different PET phantoms as well as on clinical images with respect to the ground truth segmentation provided by clinicians. Experimental results indicate that the presented method is superior to threshold and Bayesian methods commonly used in PET image segmentation, is more accurate and robust compared to the other PET-CT segmentation methods recently published in the literature, and also it is general in the sense of simultaneously segmenting multiple scans in real-time with high accuracy needed in routine clinical use. PMID:23837967

Solid-Phase Biological Assays for Drug Discovery

NASA Astrophysics Data System (ADS)

Forsberg, Erica M.; Sicard, Clémence; Brennan, John D.

2014-06-01

In the past 30 years, there has been a significant growth in the use of solid-phase assays in the area of drug discovery, with a range of new assays being used for both soluble and membrane-bound targets. In this review, we provide some basic background to typical drug targets and immobilization protocols used in solid-phase biological assays (SPBAs) for drug discovery, with emphasis on particularly labile biomolecular targets such as kinases and membrane-bound receptors, and highlight some of the more recent approaches for producing protein microarrays, bioaffinity columns, and other devices that are central to small molecule screening by SPBA. We then discuss key applications of such assays to identify drug leads, with an emphasis on the screening of mixtures. We conclude by highlighting specific advantages and potential disadvantages of SPBAs, particularly as they relate to particular assay formats.

Towards a high sensitivity small animal PET system based on CZT detectors (Conference Presentation)

NASA Astrophysics Data System (ADS)

Abbaszadeh, Shiva; Levin, Craig

2017-03-01

Small animal positron emission tomography (PET) is a biological imaging technology that allows non-invasive interrogation of internal molecular and cellular processes and mechanisms of disease. New PET molecular probes with high specificity are under development to target, detect, visualize, and quantify subtle molecular and cellular processes associated with cancer, heart disease, and neurological disorders. However, the limited uptake of these targeted probes leads to significant reduction in signal. There is a need to advance the performance of small animal PET system technology to reach its full potential for molecular imaging. Our goal is to assemble a small animal PET system based on CZT detectors and to explore methods to enhance its photon sensitivity. In this work, we reconstruct an image from a phantom using a two-panel subsystem consisting of six CZT crystals in each panel. For image reconstruction, coincidence events with energy between 450 and 570 keV were included. We are developing an algorithm to improve sensitivity of the system by including multiple interaction events.

Respiratory Motion Management in PET/CT: Applications and Clinical Usefulness.

PubMed

Guerra, Luca; Ponti, Elena De; Morzenti, Sabrina; Spadavecchia, Chiara; Crivellaro, Cinzia

2017-01-01

Breathing movement can introduce heavy bias in both image quality and quantitation in PET/CT. The aim of this paper is a review of the literature to evaluate the benefit of respiratory gating in terms of image quality, quantification and lesion detectability. A review of the literature published in the last 10 years and dealing with gated PET/CT technique has been performed, focusing on improvement in quantification, lesion detectability and diagnostic accuracy in neoplastic lesion. In addition, the improvement in the definition of radiotherapy planning has been evaluated. There is a consistent increase of the Standardized Uptake Value (SUV) in gated PET images when compared to ungated ones, particularly for lesions located in liver and in lung. Respiratory gating can also increase sensitivity, specificity and accuracy of PET/CT. Gated PET/CT can be used for radiation therapy planning, reducing the uncertainty in target definition, optimizing the volume to be treated and reducing the possibility of "missing" during the dose delivery. Moreover, new technologies, able to define the movement of lesions and organs directly from the PET sinogram, can solve some problems that currently are limiting the clinical use of gated PET/CT (i.e.: extended acquisition time, radiation exposure). The published literature demonstrated that respiratory gating PET/CT is a valid technique to improve quantification, lesion detectability of lung and liver tumors and can better define the radiotherapy planning of moving lesions and organs. If new technical improvements for motion compensation will be clinically validated, gated technique could be applied routinely in any PET/CT scan. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Measurements from a Compact Cost-Effective Beamline for the THC14 PET Cyclotron

NASA Astrophysics Data System (ADS)

Dehnel, M. P.; Theroux, J.; Christensen, T.; Stewart, T. M.; Roeder, M.; Sirot, P.; Fasse, D.; Brasile, J. P.; Raoult, F.; Buckley, K.

2009-03-01

The THC14 PET Cyclotron produced by THALES specifies two compact cost-effective beamlines for high current PET radioisotope production. The design and development of the beamline system was reported previously in NIM B 261 (2007) pp 809-812. This paper describes the successful testing of this compact beamline at the first installation. A series of measurement data are presented starting from low current scintillator image data, higher current beam diagnostic data (baffles, collimators, targets) and finally a simultaneous dual beam run on Faraday Cups. The beamline system has proven to be a flexible and valuable tool for optimizing high current beam intensity distribution on target in a well-instrumented manner. This ability to tailor the beam characteristics for the target is particularly important as high power targets are developed which can handle very high beam currents.

89Zr-DFO-AMG102 Immuno-PET to Determine Local Hepatocyte Growth Factor Protein Levels in Tumors for Enhanced Patient Selection.

PubMed

Price, Eric W; Carnazza, Kathryn E; Carlin, Sean D; Cho, Andrew; Edwards, Kimberly J; Sevak, Kuntal K; Glaser, Jonathan M; de Stanchina, Elisa; Janjigian, Yelena Y; Lewis, Jason S

2017-09-01

The hepatocyte growth factor (HGF) binding antibody rilotumumab (AMG102) was modified for use as a 89 Zr-based immuno-PET imaging agent to noninvasively determine the local levels of HGF protein in tumors. Because recent clinical trials of HGF-targeting therapies have been largely unsuccessful in several different cancers (e.g., gastric, brain, lung), we have synthesized and validated 89 Zr-DFO-AMG102 as a companion diagnostic for improved identification and selection of patients having high local levels of HGF in tumors. To date, patient selection has not been performed using the local levels of HGF protein in tumors. Methods: The chelator p -SCN-Bn-DFO was conjugated to AMG102, radiolabeling with 89 Zr was performed in high radiochemical yields and purity (>99%), and binding affinity of the modified antibody was confirmed using an enzyme-linked immunosorbent assay (ELISA)-type binding assay. PET imaging, biodistribution, autoradiography and immunohistochemistry, and ex vivo HGF ELISA experiments were performed on murine xenografts of U87MG (HGF-positive, MET-positive) and MKN45 (HGF-negative, MET-positive) and 4 patient-derived xenografts (MET-positive, HGF unknown). Results: Tumor uptake of 89 Zr-DFO-AMG102 at 120 h after injection in U87MG xenografts (HGF-positive) was high (36.8 ± 7.8 percentage injected dose per gram [%ID/g]), whereas uptake in MKN45 xenografts (HGF-negative) was 5.0 ± 1.3 %ID/g and a control of nonspecific human IgG 89 Zr-DFO-IgG in U87MG tumors was 11.5 ± 3.3 %ID/g, demonstrating selective uptake in HGF-positive tumors. Similar experiments performed in 4 different gastric cancer patient-derived xenograft models showed low uptake of 89 Zr-DFO-AMG102 (∼4-7 %ID/g), which corresponded with low HGF levels in these tumors (ex vivo ELISA). Autoradiography, immunohistochemical staining, and HGF ELISA assays confirmed that elevated levels of HGF protein were present only in U87MG tumors and that 89 Zr-DFO-AMG102 uptake was closely correlated

PET response assessment in apatinib-treated radioactive iodine-refractory thyroid cancer.

PubMed

Wang, Chen; Zhang, Xin; Yang, Xue; Li, Hui; Cui, Ruixue; Guan, Wenmin; Li, Xin; Zhu, Zhaohui; Lin, Yansong

2018-06-01

This work evaluated the use of the positron emission tomography (PET)/computed tomography (CT) technique to assess the early therapeutic response and predict the prognosis of patients with radioactive iodine-refractory differentiated thyroid cancer (RAIR-DTC) who underwent apatinib therapy. Standardised uptake value (SUV), metabolic tumour volume (MTV) and total lesion glycolysis (TLG), derived from 18 F-FDG PET/CT and SUV from 68 Ga-NOTA-PRGD2 PET/CT were evaluated. Tumour response was evaluated using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Sixteen of 20 patients achieved partial response (PR) and four of 20 had stable disease (SD) after apatinib therapy. Six progression-free survival (PFS) events occurred. A strong correlation was observed between the best change in the sum of the longest diameters of target lesions (ΔCT%) and 18 F-FDG PET/CT indices after the completion of the first treatment cycle (ΔMTV% ( P  = 0.0019), ΔTLG% ( P  = 0.0021) and ΔSUVmax% ( P  = 0.0443)). A significant difference in PFS was observed between patients with ΔMTV% <-45% and ≥-45% ( P  = 0.0019) and between patients with ΔTLG% <-80% and ≥-80% ( P  = 0.0065). Ten of 11 patients presented a decrease in SUVmax on 68 Ga-NOTA-PRGD2 PET/CT after two cycles of apatinib therapy and showed PR, whereas one patient presenting an increase in SUVmax only showed SD as the best response. When a cut-off value of the target/background ratio at -20% was used, two PFS curves showed a significant difference ( P  = 0.0016). Hence, early assessment by 18 F-FDG and 68 Ga-NOTA-PRGD2 PET/CT was effective in the prediction and evaluation of RAIR-DTC treated with apatinib. © 2018 Society for Endocrinology.

MO-AB-BRA-06: Dynamic FLT PET for Investigating Potential Synergistic Therapeutic Targets During Anti-Angiogenic Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarpelli, M; Perlman, S; Liu, G

2016-06-15

Purpose: Novel treatment strategies for metastatic cancer patients involve synergistically combining treatments with the hope of improving outcomes. This study investigated changes in tumor proliferative and vascular characteristics derived from dynamic [F-18]FLT PET during antiangiogenic treatment with the goal of identifying synergistic treatment opportunities. Methods: Patients with various solid cancers underwent continuous three-week cycles of anti-angiogenic treatment with intermittent dosing (two-weeks-on/one-week-off). Patients received up to six dynamic FLT PET/CT scans (days 0, 14, and 21 of cycle 1 (C1) and cycle 3 (C3)). Tumor proliferative (Kflt, net uptake rate) and vascular parameters (K1 blood-to-tissue transfer; Vb, vascular fraction) were calculatedmore » using a two-tissue compartment four-rate parameter kinetic model. Relative changes in these parameters, from day 0 to 14 (TxResp) and day 14 to 21 (offTxResp), were calculated. Significant differences were tested using Wilcoxon signed-rank test and significant correlations were tested using Spearman correlation. Results: Thirty patients were evaluable for C1 offTxResp with median values for Kflt, K1, and Vb of +30%, +35% and +30%, respectively. The fractions of patients with positive C1 offTxResp were: 21/30 for Ki, 24/30 for K1, 21/30 for Vb, and 12/30 had positive offTxResp for all three kinetic parameters. The offTxResp in C3 was not significantly different from C1 for any of the kinetic parameters. Significant correlations were found between TxResp and offTxResp in C1 for Kflt (ρ=-0.52, p=0.014), K1 (ρ=−0.61, p=0.003) and Vb (ρ=−0.80, p<0.001). Similar correlations were found for Kflt (ρ=-1, p=0.017) and K1 (ρ=−1, p=0.017) for the five patients evaluable in C3. Conclusion: Dynamic FLT PET showed evidence of distinct vascular and proliferative increases during off treatment weeks that could potentially be targeted with synergistic therapy. Early changes in kinetic parameters were

A new highly sensitive and specific real-time PCR assay targeting the malate dehydrogenase gene of Kingella kingae and application to 201 pediatric clinical specimens.

PubMed

Houmami, Nawal El; Durand, Guillaume André; Bzdrenga, Janek; Darmon, Anne; Minodier, Philippe; Seligmann, Hervé; Raoult, Didier; Fournier, Pierre-Edouard

2018-06-06

Kingella kingae is a significant pediatric pathogen responsible for bone and joint infections, occult bacteremia, and endocarditis in early childhood. Past efforts to detect this bacterium by culture and broad-range 16S rRNA gene polymerase chain reaction (PCR) assays from clinical specimens have proven unsatisfactory and were gradually let out for the benefit of specific real-time PCR tests targeting the groEL gene and RTX locus of K. kingae by the late 2000s. However, recent studies showed that real-time PCR (RT-PCR) assays targeting the Kingella sp. RTX locus that are currently available for the diagnosis of K. kingae infection lack of specificity because they could not distinguish between K. kingae and the recently described K. negevensis species. Furthermore, in silico analysis of the groEL gene from a large collection of 45 K. kingae strains showed that primers and probes from K. kingae groEL -based RT-PCR assays display a few mismatches with K. kingae groEL variations that may result in a decreased detection sensitivity, especially in paucibacillary clinical specimens. In order to provide an alternative to groEL - and RTX-targeting RT-PCR assays that may suffer from suboptimal specificity and sensitivity, a K. kingae -specific RT-PCR assay targeting the malate dehydrogenase ( mdh ) gene was developed for predicting no mismatch against 18 variants of the K. kingae mdh gene from 20 distinct sequences types of K. kingae This novel K. kingae -specific RT-PCR assay demonstrated a high specificity and sensitivity and was successfully used to diagnose K. kingae infections and carriage in 104 clinical specimens from children aged between 7 months and 7 years old. Copyright © 2018 American Society for Microbiology.

Parametric PET/MR Fusion Imaging to Differentiate Aggressive from Indolent Primary Prostate Cancer with Application for Image-Guided Prostate Cancer Biopsies

DTIC Science & Technology

2013-10-01

AD_________________ Award Number: W81XWH-12-1-0597 TITLE: Parametric PET /MR Fusion Imaging to...Parametric PET /MR Fusion Imaging to Differentiate Aggressive from Indolent Primary Prostate Cancer with Application for Image-Guided Prostate Cancer Biopsies...The study investigates whether fusion PET /MRI imaging with 18F-choline PET /CT and diffusion-weighted MRI can be successfully applied to target prostate

Detailed comparison of amyloid PET and CSF biomarkers for identifying early Alzheimer disease

PubMed Central

Zetterberg, Henrik; Mattsson, Niklas; Johansson, Per; Minthon, Lennart; Blennow, Kaj; Olsson, Mattias

2015-01-01

Objective: To compare the diagnostic accuracy of CSF biomarkers and amyloid PET for diagnosing early-stage Alzheimer disease (AD). Methods: From the prospective, longitudinal BioFINDER study, we included 122 healthy elderly and 34 patients with mild cognitive impairment who developed AD dementia within 3 years (MCI-AD). β-Amyloid (Aβ) deposition in 9 brain regions was examined with [18F]-flutemetamol PET. CSF was analyzed with INNOTEST and EUROIMMUN ELISAs. The results were replicated in 146 controls and 64 patients with MCI-AD from the Alzheimer's Disease Neuroimaging Initiative study. Results: The best CSF measures for identifying MCI-AD were Aβ42/total tau (t-tau) and Aβ42/hyperphosphorylated tau (p-tau) (area under the curve [AUC] 0.93–0.94). The best PET measures performed similarly (AUC 0.92–0.93; anterior cingulate, posterior cingulate/precuneus, and global neocortical uptake). CSF Aβ42/t-tau and Aβ42/p-tau performed better than CSF Aβ42 and Aβ42/40 (AUC difference 0.03–0.12, p < 0.05). Using nonoptimized cutoffs, CSF Aβ42/t-tau had the highest accuracy of all CSF/PET biomarkers (sensitivity 97%, specificity 83%). The combination of CSF and PET was not better than using either biomarker separately. Conclusions: Amyloid PET and CSF biomarkers can identify early AD with high accuracy. There were no differences between the best CSF and PET measures and no improvement when combining them. Regional PET measures were not better than assessing the global Aβ deposition. The results were replicated in an independent cohort using another CSF assay and PET tracer. The choice between CSF and amyloid PET biomarkers for identifying early AD can be based on availability, costs, and doctor/patient preferences since both have equally high diagnostic accuracy. Classification of evidence: This study provides Class III evidence that amyloid PET and CSF biomarkers identify early-stage AD equally accurately. PMID:26354982

Intelligent MoS2 Nanotheranostic for Targeted and Enzyme-/pH-/NIR-Responsive Drug Delivery To Overcome Cancer Chemotherapy Resistance Guided by PET Imaging.

PubMed

Dong, Xinghua; Yin, Wenyan; Zhang, Xiao; Zhu, Shuang; He, Xiao; Yu, Jie; Xie, Jiani; Guo, Zhao; Yan, Liang; Liu, Xiangfeng; Wang, Qing; Gu, Zhanjun; Zhao, Yuliang

2018-01-31

Chemotherapy resistance remains a major hurdle for cancer therapy in clinic because of the poor cellular uptake and insufficient intracellular release of drugs. Herein, an intelligent, multifunctional MoS 2 nanotheranostic (MoS 2 -PEI-HA) ingeniously decorated with biodegradable hyaluronic acid (HA) assisted by polyethyleneimine (PEI) is reported to combat drug-resistant breast cancer (MCF-7-ADR) after loading with the chemotherapy drug doxorubicin (DOX). HA can not only target CD44-overexpressing MCF-7-ADR but also be degraded by hyaluronidase (HAase) that is concentrated in the tumor microenvironment, thus accelerating DOX release. Furthermore, MoS 2 with strong near-infrared (NIR) photothermal conversion ability can also promote the release of DOX in the acidic tumor environment at a mild 808 nm laser irradiation, achieving a superior antitumor activity based on the programmed response to HAase and NIR laser actuator. Most importantly, HA targeting combined with mild NIR laser stimuli, rather than using hyperthermia, can potently downregulate the expression of drug-resistance-related P-glycoprotein (P-gp), resulting in greatly enhanced intracellular drug accumulation, thus achieving drug resistance reversal. After labeled with 64 Cu by a simple chelation strategy, MoS 2 was employed for real-time positron emission tomography (PET) imaging of MCF-7-ADR tumor in vivo. This multifunctional nanoplatform paves a new avenue for PET imaging-guided spatial-temporal-controlled accurate therapy of drug-resistant cancer.

Pet-Related Infections.

PubMed

Day, Michael J

2016-11-15

Physicians and veterinarians have many opportunities to partner in promoting the well-being of people and their pets, especially by addressing zoonotic diseases that may be transmitted between a pet and a human family member. Common cutaneous pet-acquired zoonoses are dermatophytosis (ringworm) and sarcoptic mange (scabies), which are both readily treated. Toxoplasmosis can be acquired from exposure to cat feces, but appropriate hygienic measures can minimize the risk to pregnant women. Persons who work with animals are at increased risk of acquiring bartonellosis (e.g., cat-scratch disease); control of cat fleas is essential to minimize the risk of these infections. People and their pets share a range of tick-borne diseases, and exposure risk can be minimized with use of tick repellent, prompt tick removal, and appropriate tick control measures for pets. Pets such as reptiles, amphibians, and backyard poultry pose a risk of transmitting Salmonella species and are becoming more popular. Personal hygiene after interacting with these pets is crucial to prevent Salmonella infections. Leptospirosis is more often acquired from wildlife than infected dogs, but at-risk dogs can be protected with vaccination. The clinical history in the primary care office should routinely include questions about pets and occupational or other exposure to pet animals. Control and prevention of zoonoses are best achieved by enhancing communication between physicians and veterinarians to ensure patients know the risks of and how to prevent zoonoses in themselves, their pets, and other people.

A targeted next-generation sequencing assay for the molecular diagnosis of genetic disorders with orodental involvement

PubMed Central

Prasad, Megana K; Geoffroy, Véronique; Vicaire, Serge; Jost, Bernard; Dumas, Michael; Le Gras, Stéphanie; Switala, Marzena; Gasse, Barbara; Laugel-Haushalter, Virginie; Paschaki, Marie; Leheup, Bruno; Droz, Dominique; Dalstein, Amelie; Loing, Adeline; Grollemund, Bruno; Muller-Bolla, Michèle; Lopez-Cazaux, Séréna; Minoux, Maryline; Jung, Sophie; Obry, Frédéric; Vogt, Vincent; Davideau, Jean-Luc; Davit-Beal, Tiphaine; Kaiser, Anne-Sophie; Moog, Ute; Richard, Béatrice; Morrier, Jean-Jacques; Duprez, Jean-Pierre; Odent, Sylvie; Bailleul-Forestier, Isabelle; Rousset, Monique Marie; Merametdijan, Laure; Toutain, Annick; Joseph, Clara; Giuliano, Fabienne; Dahlet, Jean-Christophe; Courval, Aymeric; El Alloussi, Mustapha; Laouina, Samir; Soskin, Sylvie; Guffon, Nathalie; Dieux, Anne; Doray, Bérénice; Feierabend, Stephanie; Ginglinger, Emmanuelle; Fournier, Benjamin; de la Dure Molla, Muriel; Alembik, Yves; Tardieu, Corinne; Clauss, François; Berdal, Ariane; Stoetzel, Corinne; Manière, Marie Cécile; Dollfus, Hélène; Bloch-Zupan, Agnès

2016-01-01

Background Orodental diseases include several clinically and genetically heterogeneous disorders that can present in isolation or as part of a genetic syndrome. Due to the vast number of genes implicated in these disorders, establishing a molecular diagnosis can be challenging. We aimed to develop a targeted next-generation sequencing (NGS) assay to diagnose mutations and potentially identify novel genes mutated in this group of disorders. Methods We designed an NGS gene panel that targets 585 known and candidate genes in orodental disease. We screened a cohort of 101 unrelated patients without a molecular diagnosis referred to the Reference Centre for Oro-Dental Manifestations of Rare Diseases, Strasbourg, France, for a variety of orodental disorders including isolated and syndromic amelogenesis imperfecta (AI), isolated and syndromic selective tooth agenesis (STHAG), isolated and syndromic dentinogenesis imperfecta, isolated dentin dysplasia, otodental dysplasia and primary failure of tooth eruption. Results We discovered 21 novel pathogenic variants and identified the causative mutation in 39 unrelated patients in known genes (overall diagnostic rate: 39%). Among the largest subcohorts of patients with isolated AI (50 unrelated patients) and isolated STHAG (21 unrelated patients), we had a definitive diagnosis in 14 (27%) and 15 cases (71%), respectively. Surprisingly, COL17A1 mutations accounted for the majority of autosomal-dominant AI cases. Conclusions We have developed a novel targeted NGS assay for the efficient molecular diagnosis of a wide variety of orodental diseases. Furthermore, our panel will contribute to better understanding the contribution of these genes to orodental disease. Trial registration numbers NCT01746121 and NCT02397824. PMID:26502894

PET/CT in Radiation Therapy Planning.

PubMed

Specht, Lena; Berthelsen, Anne Kiil

2018-01-01

Radiation therapy (RT) is an important component of the management of lymphoma patients. Most lymphomas are metabolically active and accumulate 18 F-fluorodeoxyglucose (FDG). Positron emission tomography with computer tomography (PET/CT) imaging using FDG is used routinely in staging and treatment evaluation. FDG-PET/CT imaging is now also used routinely for contouring the target for RT, and has been shown to change the irradiated volume significantly compared with CT imaging alone. Modern advanced imaging techniques with image fusion and motion management in combination with modern highly conformal RT techniques have increased the precision of RT, and have made it possible to reduce dramatically the risks of long-term side effects of treatment while maintaining the high cure rates for these diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

J-PET: A New Technology for the Whole-body PET Imaging

NASA Astrophysics Data System (ADS)

Niedźwiecki, S.; Białas, P.; Curceanu, C.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Gorgol, M.; Hiesmayr, B. C.; Jasińska, B.; Kapłon, Ł.; Kisielewska-Kamińska, D.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krawczyk, N.; Krzemień, W.; Kubicz, E.; Mohammed, M.; Pawlik-Niedźwiecka, M.; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Sharma, S.; Shopa, R. Y.; Silarski, M.; Skurzok, M.; Wieczorek, A.; Wiślicki, W.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET built from plastic scintillators. J-PET prototype consists of 192 detection modules arranged axially in three layers forming a cylindrical diagnostic chamber with the inner diameter of 85 cm and the axial field-of-view of 50 cm. An axial arrangement of long strips of plastic scintillators, their small light attenuation, superior timing properties, and relative ease of the increase of the axial field-of-view opens promising perspectives for the cost effective construction of the whole-body PET scanner, as well as construction of MR and CT compatible PET inserts. Present status of the development of the J-PET tomograph will be presented and discussed.

Imaging of Tumor Characteristics and Molecular Pathways With PET: Developments Over the Last Decade Toward Personalized Cancer Therapy.

PubMed

Marcu, Loredana Gabriela; Moghaddasi, Leyla; Bezak, Eva

2018-05-04

Improvements in personalized therapy are made possible by the advances in molecular biology that led to developments in molecular imaging, allowing highly specific in vivo imaging of biological processes. Positron emission tomography (PET) is the most specific and sensitive imaging technique for in vivo molecular targets and pathways, offering quantification and evaluation of functional properties of the targeted anatomy. This work is an integrative research review that summarizes and evaluates the accumulated current status of knowledge of recent advances in PET imaging for cancer diagnosis and treatment, concentrating on novel radiotracers and evaluating their advantages and disadvantages in cancer characterization. Medline search was conducted, limited to English publications from 2007 onward. Identified manuscripts were evaluated for most recent developments in PET imaging of cancer hypoxia, angiogenesis, proliferation, and clonogenic cancer stem cells (CSC). There is an expansion observed from purely metabolic-based PET imaging toward antibody-based PET to achieve more information on cancer characteristics to identify hypoxia, proangiogenic factors, CSC, and others. 64 Cu-ATSM, for example, can be used both as a hypoxia and a CSC marker. Progress in the field of functional imaging will possibly lead to more specific tumor targeting and personalized treatment, increasing tumor control and improving quality of life. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of 18F-FDG PET/CT and PET/MRI in patients with multiple myeloma

PubMed Central

Sachpekidis, Christos; Hillengass, Jens; Goldschmidt, Hartmut; Mosebach, Jennifer; Pan, Leyun; Schlemmer, Heinz-Peter; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

2015-01-01

PET/MRI represents a promising hybrid imaging modality with several potential clinical applications. Although PET/MRI seems highly attractive in the diagnostic approach of multiple myeloma (MM), its role has not yet been evaluated. The aims of this prospective study are to evaluate the feasibility of 18F-FDG PET/MRI in detection of MM lesions, and to investigate the reproducibility of bone marrow lesions detection and quantitative data of 18F-FDG uptake between the functional (PET) component of PET/CT and PET/MRI in MM patients. The study includes 30 MM patients. All patients initially underwent 18F-FDG PET/CT (60 min p.i.), followed by PET/MRI (120 min p.i.). PET/CT and PET/MRI data were assessed and compared based on qualitative (lesion detection) and quantitative (SUV) evaluation. The hybrid PET/MRI system provided good image quality in all cases without artefacts. PET/MRI identified 65 of the 69 lesions, which were detectable with PET/CT (94.2%). Quantitative PET evaluations showed the following mean values in MM lesions: SUVaverage=5.5 and SUVmax=7.9 for PET/CT; SUVaverage=3.9 and SUVmax=5.8 for PET/MRI. Both SUVaverage and SUVmax were significantly higher on PET/CT than on PET/MRI. Spearman correlation analysis demonstrated a strong correlation between both lesional SUVaverage (r=0.744) and lesional SUVmax (r=0.855) values derived from PET/CT and PET/MRI. Regarding detection of myeloma skeletal lesions, PET/MRI exhibited equivalent performance to PET/CT. In terms of tracer uptake quantitation, a significant correlation between the two techniques was demonstrated, despite the statistically significant differences in lesional SUVs between PET/CT and PET/MRI. PMID:26550538

New SPECT and PET Radiopharmaceuticals for Imaging Cardiovascular Disease

PubMed Central

Sogbein, Oyebola O.; Pelletier-Galarneau, Matthieu; Schindler, Thomas H.; Wei, Lihui; Wells, R. Glenn; Ruddy, Terrence D.

2014-01-01

Nuclear cardiology has experienced exponential growth within the past four decades with converging capacity to diagnose and influence management of a variety of cardiovascular diseases. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with technetium-99m radiotracers or thallium-201 has dominated the field; however new hardware and software designs that optimize image quality with reduced radiation exposure are fuelling a resurgence of interest at the preclinical and clinical levels to expand beyond MPI. Other imaging modalities including positron emission tomography (PET) and magnetic resonance imaging (MRI) continue to emerge as powerful players with an expanded capacity to diagnose a variety of cardiac conditions. At the forefront of this resurgence is the development of novel target vectors based on an enhanced understanding of the underlying pathophysiological process in the subcellular domain. Molecular imaging with novel radiopharmaceuticals engineered to target a specific subcellular process has the capacity to improve diagnostic accuracy and deliver enhanced prognostic information to alter management. This paper, while not comprehensive, will review the recent advancements in radiotracer development for SPECT and PET MPI, autonomic dysfunction, apoptosis, atherosclerotic plaques, metabolism, and viability. The relevant radiochemistry and preclinical and clinical development in addition to molecular imaging with emerging modalities such as cardiac MRI and PET-MR will be discussed. PMID:24901002

PSMA-PET based radiotherapy: a review of initial experiences, survey on current practice and future perspectives.

PubMed

Zschaeck, Sebastian; Lohaus, Fabian; Beck, Marcus; Habl, Gregor; Kroeze, Stephanie; Zamboglou, Constantinos; Koerber, Stefan Alexander; Debus, Jürgen; Hölscher, Tobias; Wust, Peter; Ganswindt, Ute; Baur, Alexander D J; Zöphel, Klaus; Cihoric, Nikola; Guckenberger, Matthias; Combs, Stephanie E; Grosu, Anca Ligia; Ghadjar, Pirus; Belka, Claus

2018-05-11

68 Gallium prostate specific membrane antigen (PSMA) ligand positron emission tomography (PET) is an increasingly used imaging modality in prostate cancer, especially in cases of tumor recurrence after curative intended therapy. Owed to the novelty of the PSMA-targeting tracers, clinical evidence on the value of PSMA-PET is moderate but rapidly increasing. State of the art imaging is pivotal for radiotherapy treatment planning as it may affect dose prescription, target delineation and use of concomitant therapy.This review summarizes the evidence on PSMA-PET imaging from a radiation oncologist's point of view. Additionally a short survey containing twelve examples of patients and 6 additional questions was performed in seven mayor academic centers with experience in PSMA ligand imaging and the findings are reported here.

Reproducibility of 18F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR

PubMed Central

Fischer, B M; Aznar, M C; Hansen, A E; Vogelius, I R; Löfgren, J; Andersen, F L; Loft, A; Kjaer, A; Højgaard, L; Specht, L

2015-01-01

Objective: To investigate reproducibility of fluorine-18 fludeoxyglucose (18F-FDG) uptake on 18F-FDG positron emission tomography (PET)/CT and 18F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). Methods: 30 patients with HNSCC were included in this prospective study. The patients were scanned twice before radiotherapy treatment with both PET/CT and PET/MR. Patients were scanned on the same scanners, 3 days apart and according to the same protocol. Metabolic tumour activity was measured by the maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively), and total lesion glycolysis from the metabolic tumour volume defined from ≥50% SUVmax. Bland–Altman analysis with limits of agreement, coefficient of variation (CV) from the two modalities were performed in order to test the reproducibility. Furthermore, CVs from SUVmax and SUVpeak were compared. The area under the curve from cumulative SUV–volume histograms were measured and tested for reproducibility of the distribution of 18F-FDG uptake. Results: 24 patients had two pre-treatment PET/CT scans and 21 patients had two pre-treatment PET/MR scans available for further analyses. Mean difference for SUVmax, peak and mean was approximately 4% for PET/CT and 3% for PET/MR, with 95% limits of agreement less than ±20%. CV was small (5–7%) for both modalities. There was no significant difference in CVs between PET/CT and PET/MR (p = 0.31). SUVmax was not more reproducible than SUVpeak (p = 0.09). Conclusion: 18F-FDG uptake in PET/CT and PET/MR is highly reproducible and we found no difference in reproducibility between PET/CT and PET/MR. Advances in knowledge: This is the first report to test reproducibility of PET/CT and PET/MR. PMID:25634069

Viewing another person's body as a target object: a behavioural and PET study of pointing.

PubMed

Cleret de Langavant, Laurent; Trinkler, Iris; Remy, Philippe; Thirioux, Bérangère; McIntyre, Joseph; Berthoz, Alain; Dupoux, Emmanuel; Bachoud-Lévi, Anne-Catherine

2012-07-01

Humans usually point at objects to communicate with other persons, although they generally avoid pointing at the other's body. Moreover, patients with heterotopagnosia after left parietal damage cannot point at another person's body parts, although they can point at objects and at their own body parts and although they can grasp the others' body parts. Strikingly, their performance gradually improves for figurative human body targets. Altogether, this suggests that the body of another real person holds a specific status in communicative pointing. Here, we test in healthy individuals whether performance for communicative pointing is influenced by the communicative capacity of the target. In Experiment 1, pointing at another real person's body parts was compared to pointing at objects, and in Experiment 2, the person was replaced by a manikin. While reaction times for pointing at objects were shorter compared to pointing at other person's body parts, they were similar for objects and manikin body parts. By adapting Experiment 1 to PET-scan imaging (Experiment 3), we showed that, compared to pointing at objects, the brain network for pointing at other person's body parts involves the left posterior intraparietal sulcus, lesion of which could cause heterotopagnosia. Taken together, our results indicate that the specificity of pointing at another person's body goes beyond the visuo-spatial features of the human body and might rather rely on its communicative capacity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Feasibility of FDG-PET in myocarditis: Comparison to CMR using integrated PET/MRI.

PubMed

Nensa, Felix; Kloth, Julia; Tezgah, Ercan; Poeppel, Thorsten D; Heusch, Philipp; Goebel, Juliane; Nassenstein, Kai; Schlosser, Thomas

2018-06-01

Besides cardiac sarcoidosis, FDG-PET is rarely used in the diagnosis of myocardial inflammation, while cardiac MRI (CMR) is the actual imaging reference for the workup of myocarditis. Using integrated PET/MRI in patients with suspected myocarditis, we prospectively compared FDG-PET to CMR and the feasibility of integrated FDG-PET/MRI in myocarditis. A total of 65 consecutive patients with suspected myocarditis were prospectively assessed using integrated cardiac FDG-PET/MRI. Studies comprised T2-weighted imaging, late gadolinium enhancement (LGE), and simultaneous PET acquisition. Physiological glucose uptake in the myocardium was suppressed using dietary preparation. FDG-PET/MRI was successful in 55 of 65 enrolled patients: two patients were excluded due to claustrophobia and eight patients due to failed inhibition of myocardial glucose uptake. Compared with CMR (LGE and/or T2), sensitivity and specificity of PET was 74% and 97%. Overall spatial agreement between PET and CMR was κ = 0.73. Spatial agreement between PET and T2 (κ = 0.75) was higher than agreement between PET and LGE (κ = 0.64) as well as between LGE and T2 (κ = 0.56). In patients with suspected myocarditis, FDG-PET is in good agreement with CMR findings.

SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Y; Bowsher, J; Yan, S

2014-06-01

Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medicalmore » Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better

Development and Evaluation of a Quantitative PCR Assay Targeting Sandhill Crane (Grus canadensis) Fecal Pollution

PubMed Central

Ryu, Hodon; Lu, Jingrang; Vogel, Jason; Elk, Michael; Chávez-Ramírez, Felipe; Ashbolt, Nicholas

2012-01-01

While the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters. Bacteria from crane excreta were dominated by bacilli and proteobacteria, with a notable paucity of sequences homologous to Bacteroidetes and Clostridia. The Crane1 marker targeted a dominant clade of unclassified Lactobacillales sequences closely related to Catellicoccus marimammalium. The host distribution of the Crane1 marker was relatively high, being positive for 69% (66/96) of the crane excreta samples tested. The assay also showed high host specificity, with 95% of the nontarget fecal samples (i.e., n = 553; 20 different free-range hosts) being negative. Of the presumed crane-impacted water samples (n = 16), 88% were positive for the Crane1 assay, whereas none of the water samples not impacted by cranes were positive (n = 165). Bayesian statistical models of the Crane1 MST marker demonstrated high confidence in detecting true-positive signals and a low probability of false-negative signals from environmental water samples. Altogether, these data suggest that the newly developed marker could be used in environmental monitoring studies to study crane fecal pollution dynamics. PMID:22492437

ChIA-PET2: a versatile and flexible pipeline for ChIA-PET data analysis

PubMed Central

Li, Guipeng; Chen, Yang; Snyder, Michael P.; Zhang, Michael Q.

2017-01-01

ChIA-PET2 is a versatile and flexible pipeline for analyzing different types of ChIA-PET data from raw sequencing reads to chromatin loops. ChIA-PET2 integrates all steps required for ChIA-PET data analysis, including linker trimming, read alignment, duplicate removal, peak calling and chromatin loop calling. It supports different kinds of ChIA-PET data generated from different ChIA-PET protocols and also provides quality controls for different steps of ChIA-PET analysis. In addition, ChIA-PET2 can use phased genotype data to call allele-specific chromatin interactions. We applied ChIA-PET2 to different ChIA-PET datasets, demonstrating its significantly improved performance as well as its ability to easily process ChIA-PET raw data. ChIA-PET2 is available at https://github.com/GuipengLi/ChIA-PET2. PMID:27625391

Development of a Ga-68 labeled PET tracer with short linker for prostate-specific membrane antigen (PSMA) targeting.

PubMed

Moon, Sung-Hyun; Hong, Mee Kyung; Kim, Young Ju; Lee, Yun-Sang; Lee, Dong Soo; Chung, June-Key; Jeong, Jae Min

2018-05-15

Glu-Urea-Lys (GUL) derivatives have been reported as prostate-specific membrane antigen (PSMA) agent. We developed derivatives of GUL conjugated with NOTA or DOTA via a thiourea linker and tested their feasibility as PSMA imaging agents after labeling with 68 Ga. NOTA-GUL and DOTA-GUL were synthesized and labeled with 68 Ga using generator-eluted 68 GaCl 3 in 0.1 M HCl in the presence of 1 M NaOAc at pH 5.5. The stabilities of 68 Ga-labeled compounds in human serum were tested at 37.5 °C. A competitive binding assay was performed using the PSMA-positive prostate cancer cell line 22Rv1 and [ 125 I]MIP-1072 (PSMA-specific binding agent) as a tracer. Biodistribution and micro-PET studies were performed using 22Rv1-xenograft BALB/c nude mice. The radiolabeling efficiency of NOTA-GUL (>99%) was higher than that of DOTA-GUL (92%). The IC 50 of Ga-NOTA-GUL was 18.3 nM. In the biodistribution study, tumor uptake of 68 Ga-NOTA-GUL (5.40% ID/g) was higher than that of 68 Ga-DOTA-GUL (4.66% ID/g) at 1 h. Tumor/muscle and tumor/blood uptake ratios of 68 Ga-NOTA-GUL (31.8 and 135, respectively) were significantly higher than those of 68 Ga-DOTA-GUL (16.1 and 31.1, respectively). The tumor/kidney uptake ratio of 68 Ga-NOTA-GUL was 3.4-fold higher than that of 68 Ga-DOTA-GUL. 68 Ga-NOTA-GUL showed specific uptake to PSMA positive tumor xenograft and was blocked by co-injection of the cold ligand. In conclusion, we successfully synthesized 68 Ga-NOTA-GUL and 68 Ga-DOTA-GUL for prostate cancer imaging. 68 Ga-NOTA-GUL showed better radiochemical and biodistribution results. 68 Ga-NOTA-GUL may be a promising PSMA targeting radiopharmaceutical. Copyright © 2018 Elsevier Ltd. All rights reserved.

The pet connection: pets as a conduit for social capital?

PubMed

Wood, Lisa; Giles-Corti, Billie; Bulsara, Max

2005-09-01

There is growing interest across a range of disciplines in the relationship between pets and health, with a range of therapeutic, physiological, psychological and psychosocial benefits now documented. While much of the literature has focused on the individual benefits of pet ownership, this study considered the potential health benefits that might accrue to the broader community, as encapsulated in the construct of social capital. A random survey of 339 adult residents from Perth, Western Australia were selected from three suburbs and interviewed by telephone. Pet ownership was found to be positively associated with some forms of social contact and interaction, and with perceptions of neighbourhood friendliness. After adjustment for demographic variables, pet owners scored higher on social capital and civic engagement scales. The results suggest that pet ownership provides potential opportunities for interactions between neighbours and that further research in this area is warranted. Social capital is another potential mechanism by which pets exert an influence on human health.

A Prospective Study of {sup 18}FDG-PET With CT Coregistration for Radiation Treatment Planning of Lymphomas and Other Hematologic Malignancies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terezakis, Stephanie A.; Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland; Schöder, Heiko

2014-06-01

Purpose: This prospective single-institution study examined the impact of positron emission tomography (PET) with the use of 2-[{sup 18}F] fluoro-2-deoxyglucose and computed tomography (CT) scan radiation treatment planning (TP) on target volume definition in lymphoma. Methods and Materials: 118 patients underwent PET/CT TP during June 2007 to May 2009. Gross tumor volume (GTV) was contoured on CT-only and PET/CT studies by radiation oncologists (ROs) and nuclear medicine physicians (NMPs) for 95 patients with positive PET scans. Treatment plans and dose-volume histograms were generated for CT-only and PET/CT for 95 evaluable sites. Paired t test statistics and Pearson correlation coefficients weremore » used for analysis. Results: 70 (74%) patients had non-Hodgkin lymphoma, 10 (11%) had Hodgkin lymphoma, 12 (10%) had plasma-cell neoplasm, and 3 (3%) had other hematologic malignancies. Forty-three (45%) presented with relapsed/refractory disease. Forty-five (47%) received no prior chemotherapy. The addition of PET increased GTV as defined by ROs in 38 patients (median, 27%; range, 5%-70%) and decreased GTV in 41 (median, 39.5%; range, 5%-80%). The addition of PET increased GTV as defined by NMPs in 27 patients (median, 26.5%; range, 5%-95%) and decreased GTV in 52 (median, 70%; range, 5%-99%). The intraobserver correlation between CT-GTV and PET-GTV was higher for ROs than for NMPs (0.94, P<.01 vs 0.89, P<.01). On the basis of Bland-Altman plots, the PET-GTVs defined by ROs were larger than those defined by NMPs. On evaluation of clinical TPs, only 4 (4%) patients had inadequate target coverage (D95 <95%) of the PET-GTV defined by NMPs. Conclusions: Significant differences between the RO and NMP volumes were identified when PET was coregistered to CT for radiation planning. Despite this, the PET-GTV defined by ROs and NMPs received acceptable prescription dose in nearly all patients. However, given the potential for a marginal miss, consultation with an

Sustainable Engineering and Improved Recycling of PET for High-Value Applications: Transforming Linear PET to Lightly Branched PET with a Novel, Scalable Process

NASA Astrophysics Data System (ADS)

Pierre, Cynthia; Torkelson, John

2009-03-01

A major challenge for the most effective recycling of poly(ethylene terephthalate) concerns the fact that initial melt processing of PET into a product leads to substantial degradation of molecular weight. Thus, recycled PET has insufficient melt viscosity for reuse in high-value applications such as melt-blowing of PET bottles. Academic and industrial research has tried to remedy this situation by synthesis and use of ``chain extenders'' that can lead to branched PET (with higher melt viscosity than the linear recycled PET) via condensation reactions with functional groups on the PET. Here we show that simple processing of PET via solid-state shear pulverization (SSSP) leads to enhanced PET melt viscosity without need for chemical additives. We hypothesize that this branching results from low levels of chain scission accompanying SSSP, leading to formation of polymeric radicals that participate in chain transfer and combination reactions with other PET chains and thereby to in situ branch formation. The pulverized PET exhibits vastly enhanced crystallization kinetics, eliminating the need to employ cold crystallization to achieve maximum PET crystallinity. Results of SSSP processing of PET will be compared to results obtained with poly(butylene terephthalate).

Veterinarians' role for pet owners facing pet loss

PubMed Central

Fernandez-Mehler, P.; Gloor, P.; Sager, E.; Lewis, F. I.; Glaus, T. M

2013-01-01

Owners' satisfaction with, and expectations from, their veterinarians around euthanasia, including questions on disposal of pet remains subject to animal species, clients' gender, age, family conditions, area of living and type of veterinary clinic visited were evaluated by questionnaire. Questionnaires were to be filled out by clients consecutively visiting the individual practices and hospitals for any kind of consultations. Of 2350 questionnaires distributed, 2008 were returned and available for analysis. Owner satisfaction concerning the procedure of euthanasia was high (92 per cent, 1173/1272). After the event of euthanasia, 14 per cent (170/1250) had changed their veterinarian, even though 75 per cent of these 170 had been satisfied with the procedure. Most owners (88 per cent) expected veterinarians to talk about their pet's final destination, and 38 per cent expected this to happen early in the pet's life. For 81 per cent clients, the veterinarian was the primary informant about the possibilities concerning the disposal of pet remains, and 33 per cent indicated their veterinarian as the contact person to talk about pet loss. Area of living, or veterinary specialisation, only marginally influenced the answers. Veterinarians play an important role to inform their clients concerning questions around euthanasia and the care of pet remains, and to support them during the process of mourning. PMID:23492929

Distribution of lymph node metastases on FDG-PET/CT in inoperable or unresectable oesophageal cancer patients and the impact on target volume definition in radiation therapy.

PubMed

Machiels, Melanie; Wouterse, Sanne J; Geijsen, Elisabeth D; van Os, Rob M; Bennink, Roel J; van Laarhoven, Hanneke Wm; Hulshof, Maarten Ccm

2016-08-01

Definitive chemoradiotherapy (dCRT) is standard care for localised inoperable/unresectable oesophageal tumours. Many surgical series have reported on distribution of lymph node metastases (LNM) in resected patients. However, no data is available on the distribution of at-risk LN regions in this more unfavourable patient group. This study aimed to determine the spread of LNM using FDG-PET/CT, to compare it with the distribution in surgical series and to define its impact on the definition of elective LN irradiation (ENI). FDG-PET/CT images of patients with oesophageal cancer treated with dCRT (from 2003 to 2013) were reviewed to identify the anatomic distribution of FDG-avid LNs. Tumours were divided according to proximal, mid-thoracic or distal localisation. About 105 consecutive patients entered analysis. The highest numbers of FDG-avid LNs in proximal tumours were at LN station 101R (45%) and 106recL (35%). For mid-thoracic tumours at 104R (30%) and 105 (30%). For tumours located in the distal oesophagus, the most common sites were along the lesser curvature of the stomach (21%) and the left gastric artery (21%). Except for the supraclavicular and pretracheal nodes, there were no positive locoregional LNM found outside the standard surgical resection area. Our results show a good correlation between the distribution of nodal volumes at risk in surgical series and on FDG-PET/CT. The results can be used to determine target definition in dCRT for oesophageal cancer. For mid-thoracic tumours, the current target delineation guidelines may be extended based on the risk of node involvement, but more clinical studies are needed to determine if the potential harm of expanding the CTV outweighs the potential benefit. © 2016 The Royal Australian and New Zealand College of Radiologists.

Prediction of Multi-Target Networks of Neuroprotective Compounds with Entropy Indices and Synthesis, Assay, and Theoretical Study of New Asymmetric 1,2-Rasagiline Carbamates

PubMed Central

Romero Durán, Francisco J.; Alonso, Nerea; Caamaño, Olga; García-Mera, Xerardo; Yañez, Matilde; Prado-Prado, Francisco J.; González-Díaz, Humberto

2014-01-01

In a multi-target complex network, the links (Lij) represent the interactions between the drug (di) and the target (tj), characterized by different experimental measures (Ki, Km, IC50, etc.) obtained in pharmacological assays under diverse boundary conditions (cj). In this work, we handle Shannon entropy measures for developing a model encompassing a multi-target network of neuroprotective/neurotoxic compounds reported in the CHEMBL database. The model predicts correctly >8300 experimental outcomes with Accuracy, Specificity, and Sensitivity above 80%–90% on training and external validation series. Indeed, the model can calculate different outcomes for >30 experimental measures in >400 different experimental protocolsin relation with >150 molecular and cellular targets on 11 different organisms (including human). Hereafter, we reported by the first time the synthesis, characterization, and experimental assays of a new series of chiral 1,2-rasagiline carbamate derivatives not reported in previous works. The experimental tests included: (1) assay in absence of neurotoxic agents; (2) in the presence of glutamate; and (3) in the presence of H2O2. Lastly, we used the new Assessing Links with Moving Averages (ALMA)-entropy model to predict possible outcomes for the new compounds in a high number of pharmacological tests not carried out experimentally. PMID:25255029

Prediction of multi-target networks of neuroprotective compounds with entropy indices and synthesis, assay, and theoretical study of new asymmetric 1,2-rasagiline carbamates.

PubMed

Romero Durán, Francisco J; Alonso, Nerea; Caamaño, Olga; García-Mera, Xerardo; Yañez, Matilde; Prado-Prado, Francisco J; González-Díaz, Humberto

2014-09-24

In a multi-target complex network, the links (L(ij)) represent the interactions between the drug (d(i)) and the target (t(j)), characterized by different experimental measures (K(i), K(m), IC50, etc.) obtained in pharmacological assays under diverse boundary conditions (c(j)). In this work, we handle Shannon entropy measures for developing a model encompassing a multi-target network of neuroprotective/neurotoxic compounds reported in the CHEMBL database. The model predicts correctly >8300 experimental outcomes with Accuracy, Specificity, and Sensitivity above 80%-90% on training and external validation series. Indeed, the model can calculate different outcomes for >30 experimental measures in >400 different experimental protocolsin relation with >150 molecular and cellular targets on 11 different organisms (including human). Hereafter, we reported by the first time the synthesis, characterization, and experimental assays of a new series of chiral 1,2-rasagiline carbamate derivatives not reported in previous works. The experimental tests included: (1) assay in absence of neurotoxic agents; (2) in the presence of glutamate; and (3) in the presence of H2O2. Lastly, we used the new Assessing Links with Moving Averages (ALMA)-entropy model to predict possible outcomes for the new compounds in a high number of pharmacological tests not carried out experimentally.

Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

PubMed

Rakvongthai, Yothin; El Fakhri, Georges

2017-07-01

Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensory analysis of pet foods.

PubMed

Koppel, Kadri

2014-08-01

Pet food palatability depends first and foremost on the pet and is related to the pet food sensory properties such as aroma, texture and flavor. Sensory analysis of pet foods may be conducted by humans via descriptive or hedonic analysis, pets via acceptance or preference tests, and through a number of instrumental analysis methods. Sensory analysis of pet foods provides additional information on reasons behind palatable and unpalatable foods as pets lack linguistic capabilities. Furthermore, sensory analysis may be combined with other types of information such as personality and environment factors to increase understanding of acceptable pet foods. Most pet food flavor research is proprietary and, thus, there are a limited number of publications available. Funding opportunities for pet food studies would increase research and publications and this would help raise public awareness of pet food related issues. This mini-review addresses current pet food sensory analysis literature and discusses future challenges and possibilities. © 2014 Society of Chemical Industry.

PSMA PET and radionuclide therapy in prostate cancer

PubMed Central

Bouchelouche, Kirsten; Turkbey, Baris; Choyke, Peter L.

2016-01-01

Prostate cancer (Pca) is the most common malignancy in men and a major cause of cancer death. Accurate imaging plays an important role in diagnosis, staging, restaging, detection of biochemical recurrence, and for therapy of PCa patients. Since no effective treatment is available for advanced PCa, there is an urgent need to develop new and more effective therapeutic strategies. In order to optimize treatment outcome, especially in high risk PCa patients, therapy of PCa is moving rapidly towards personalization. Medical imaging, including positron emission tomography (PET)/computed tomography (CT), plays an important role in personalized medicine in oncology. In the recent years, much focus has been on prostate specific membrane antigen (PSMA) as a promising target for imaging and therapy with radionuclides, since it is upregulated in most PCa. In the prostate, one potential role for PSMA PET imaging is to help guiding focal therapy. Several studies have shown great potential of PSMA PET/CT for initial staging, lymph node staging, and detection of recurrence of PCa, even at very low PSA values after primary therapy. Furthermore, studies have shown that PSMA PET/CT has a higher detection rate than choline PET/CT. Radiolabeled PSMA ligands for therapy show promise in several studies with metastatic PCa, and is an area of active investigation. The “Image and treat” strategy, with radiolabeled PSMA ligands, has the potential to improve the treatment outcome of PCa patients, and is paving the way for precision medicine in PCa. The aim of this review is to give an overview of recent advancement in PSMA PET and radionuclide therapy of PCa. PMID:27825432

The Petit Rat (pet/pet), a New Semilethal Mutant Dwarf Rat with Thymic and Testicular Anomalies

PubMed Central

Chiba, Junko; Suzuki, Katsushi; Suzuki, Hiroetsu

2008-01-01

The petit rat (pet/pet) is a recently discovered semilethal mutant dwarf. The neonatal pet/pet rats had a low body weight and small thymus and testis. During the first 3 d after birth, 50% of the male and 80% of the female pet/pet pups were lost or found dead. Surviving pet/pet rats showed marked retardation of postnatal growth, and their body weights were 41% (female rats) and 32% (male rats) of those of normal rats at the adult stage. The pet/pet rats exhibited proportional dwarfism, and their longitudinal bones were shorter than those of controls without skeletal malformations. Most organs of male pet/pet rats, especially the thymus, testis, adipose tissue surrounding the kidney, and accessory sex organs, weighed markedly less at 140 d of age than did those of their normal counterparts. The thymus of pet/pet rats was small with abnormal thymic follicles. Testes from pet/pet rats exhibited 2 patterns of abnormal histology. Spermatogenesis was present in testes that were only slightly anomalous, but the seminiferous tubules were reduced in diameter. In severely affected testes, most of the seminiferous tubules showed degeneration, and interstitial tissue was increased. Plasma growth hormone concentrations did not differ between pet/pet and normal male rats. The dwarf phenotype of pet/pet rats was inherited as an autosomal recessive trait. These results indicate that the pet/pet rat has a semilethal growth-hormone-independent dwarf phenotype that is accompanied by thymic and testicular anomalies and low birth weight. PMID:19149412

The petit rat (pet/pet), a new semilethal mutant dwarf rat with thymic and testicular anomalies.

PubMed

Chiba, Junko; Suzuki, Katsushi; Suzuki, Hiroetsu

2008-12-01

The petit rat (pet/pet) is a recently discovered semilethal mutant dwarf. The neonatal pet/pet rats had a low body weight and small thymus and testis. During the first 3 d after birth, 50% of the male and 80% of the female pet/pet pups were lost or found dead. Surviving pet/pet rats showed marked retardation of postnatal growth, and their body weights were 41% (female rats) and 32% (male rats) of those of normal rats at the adult stage. The pet/pet rats exhibited proportional dwarfism, and their longitudinal bones were shorter than those of controls without skeletal malformations. Most organs of male pet/pet rats, especially the thymus, testis, adipose tissue surrounding the kidney, and accessory sex organs, weighed markedly less at 140 d of age than did those of their normal counterparts. The thymus of pet/pet rats was small with abnormal thymic follicles. Testes from pet/pet rats exhibited 2 patterns of abnormal histology. Spermatogenesis was present in testes that were only slightly anomalous, but the seminiferous tubules were reduced in diameter. In severely affected testes, most of the seminiferous tubules showed degeneration, and interstitial tissue was increased. Plasma growth hormone concentrations did not differ between pet/pet and normal male rats. The dwarf phenotype of pet/pet rats was inherited as an autosomal recessive trait. These results indicate that the pet/pet rat has a semilethal growth-hormone-independent dwarf phenotype that is accompanied by thymic and testicular anomalies and low birth weight.

TaqMan based real time PCR assay targeting EML4-ALK fusion transcripts in NSCLC.

PubMed

Robesova, Blanka; Bajerova, Monika; Liskova, Kvetoslava; Skrickova, Jana; Tomiskova, Marcela; Pospisilova, Sarka; Mayer, Jiri; Dvorakova, Dana

2014-07-01

Lung cancer with the ALK rearrangement constitutes only a small fraction of patients with non-small cell lung cancer (NSCLC). However, in the era of molecular-targeted therapy, efficient patient selection is crucial for successful treatment. In this context, an effective method for EML4-ALK detection is necessary. We developed a new highly sensitive variant specific TaqMan based real time PCR assay applicable to RNA from formalin-fixed paraffin-embedded tissue (FFPE). This assay was used to analyze the EML4-ALK gene in 96 non-selected NSCLC specimens and compared with two other methods (end-point PCR and break-apart FISH). EML4-ALK was detected in 33/96 (34%) specimens using variant specific real time PCR, whereas in only 23/96 (24%) using end-point PCR. All real time PCR positive samples were confirmed with direct sequencing. A total of 46 specimens were subsequently analyzed by all three detection methods. Using variant specific real time PCR we identified EML4-ALK transcript in 17/46 (37%) specimens, using end-point PCR in 13/46 (28%) specimens and positive ALK rearrangement by FISH was detected in 8/46 (17.4%) specimens. Moreover, using variant specific real time PCR, 5 specimens showed more than one EML4-ALK variant simultaneously (in 2 cases the variants 1+3a+3b, in 2 specimens the variants 1+3a and in 1 specimen the variant 1+3b). In one case of 96 EML4-ALK fusion gene and EGFR mutation were detected. All simultaneous genetic variants were confirmed using end-point PCR and direct sequencing. Our variant specific real time PCR assay is highly sensitive, fast, financially acceptable, applicable to FFPE and seems to be a valuable tool for the rapid prescreening of NSCLC patients in clinical practice, so, that most patients able to benefit from targeted therapy could be identified. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Antibodies and antimatter: the resurgence of immuno-PET.

PubMed

Wu, Anna M

2009-01-01

The completion of the human genome, coupled with parallel major research efforts in proteomics and systems biology, has led to a flood of information on the roles of individual genes and proteins in normal physiologic processes and their disruptions in disease. In practical terms, this information has opened the door to increasingly targeted therapies as specific molecular markers are identified and validated. The ongoing transition from empiric to molecular medicine has engendered a need for corresponding molecular diagnostics, including noninvasive molecular imaging. Convergence of knowledge regarding key biomarkers that define normal biologic processes and disease with protein and imaging technology makes this an opportune time to revisit the combination of antibodies and PET, or immuno-PET.

Prostate-specific membrane antigen for prostate cancer theranostics: from imaging to targeted therapy.

PubMed

Arsenault, Frédéric; Beauregard, Jean-Mathieu; Pouliot, Frédéric

2018-06-22

In recent years, major advances in molecular imaging of prostate cancers (PCa) were made with the development and clinical validation of highly accurate PET tracers to stage and restage the disease. Prostate-specific membrane antigen (PSMA) is a transmembrane protein highly expressed in PCa, and its expression has led to the development of PSMA-binding radiopharmaceuticals for molecular imaging or radioligand therapy (RLT). We herein review the recent literature published on diagnostic and therapeutic (i.e. theranostic) PSMA tracers. Development in small PSMA-targeted molecules labeled with gallium-68 and fluorine-18 show promising results for primary staging and detection of disease at biochemical recurrence using PET/computed tomography (PET/CT). Studies show a higher sensitivity and specificity, along with an improved detection rate over conventional imaging (CT scan and bone scan) or choline PET tracers, especially for restaging after prostate-specific antigen failure following loco-regional therapy. In addition, some PSMA tracers can be labeled with beta-minus and alpha particle emitters, yielding encouraging response rates and low toxicity, and potentially offering a new line of targeted therapy for metastatic castration-resistant PCa. PSMA-targeted tracers have shown unprecedented accuracy to stage and restage PCa using PET/CT. Given their specific biodistribution toward PCa tissue, PSMA RLT now offers new therapeutic possibilities to target metastatic PCa. Prospective multicenter randomized studies investigating the clinical impact management impacts of PSMA-targeted molecules are urgently needed.

Pets for Handicapped Children.

ERIC Educational Resources Information Center

Frith, Greg H.

1982-01-01

Pets can provide valuable learning for handicapped children, but selection of a type of pet should consider cost, availability and care, parents' attitudes, locality, the animal's susceptibility to training, pet's life expectancy, and the child's handicap and emotional maturity. Suggested pet-related activities are listed. (CL)

DNA Meter: Energy Tunable, Quantitative Hybridization Assay

PubMed Central

Braunlin, William; Völker, Jens; Plum, G. Eric; Breslauer, Kenneth J.

2015-01-01

We describe a novel hybridization assay that employs a unique class of energy tunable, bulge loop-containing competitor strands (C*) that hybridize to a probe strand (P). Such initial “pre-binding” of a probe strand modulates its effective “availability” for hybridizing to a target site (T). More generally, the assay described here is based on competitive binding equilibria for a common probe strand (P) between such tunable competitor strands (C*) and a target strand (T). We demonstrate that loop variable, energy tunable families of C*P complexes exhibit enhanced discrimination between targets and mismatched targets, thereby reducing false positives/negatives. We refer to a C*P complex between a C* competitor single strand and the probe strand as a “tuning fork,” since the C* strand exhibits branch points (forks) at the duplex-bulge interfaces within the complex. By varying the loop to create families of such “tuning forks,” one can construct C*P “energy ladders” capable of resolving small differences within the target that may be of biological/functional consequence. The methodology further allows quantification of target strand concentrations, a determination heretofore not readily available by conventional hybridization assays. The dual ability of this tunable assay to discriminate and quantitate targets provides the basis for developing a technology we refer to as a “DNA Meter.” Here we present data that establish proof-of-principle for an in solution version of such a DNA Meter. We envision future applications of this tunable assay that incorporate surface bound/spatially resolved DNA arrays to yield enhanced discrimination and sensitivity. PMID:23529692

Quantitative PET Imaging of Tissue Factor Expression Using 18F-Labeled Active Site-Inhibited Factor VII.

PubMed

Nielsen, Carsten H; Erlandsson, Maria; Jeppesen, Troels E; Jensen, Mette M; Kristensen, Lotte K; Madsen, Jacob; Petersen, Lars C; Kjaer, Andreas

2016-01-01

Tissue factor (TF) is upregulated in many solid tumors, and its expression is linked to tumor angiogenesis, invasion, metastasis, and prognosis. A noninvasive assessment of tumor TF expression status is therefore of obvious clinical relevance. Factor VII is the natural ligand to TF. Here we report the development of a new PET tracer for specific imaging of TF using an (18)F-labeled derivative of factor VII. Active site-inhibited factor VIIa (FVIIai) was obtained by inactivation with phenylalanine-phenylalanine-arginine-chloromethyl ketone. FVIIai was radiolabeled with N-succinimidyl 4-(18)F-fluorobenzoate and purified. The corresponding product, (18)F-FVIIai, was injected into nude mice with subcutaneous human pancreatic xenograft tumors (BxPC-3) and investigated using small-animal PET/CT imaging 1, 2, and 4 h after injection. Ex vivo biodistribution was performed after the last imaging session, and tumor tissue was preserved for molecular analysis. A blocking experiment was performed in a second set of mice. The expression pattern of TF in the tumors was visualized by immunohistochemistry and the amount of TF in tumor homogenates was measured by enzyme-linked immunosorbent assay and correlated with the uptake of (18)F-FVIIai in the tumors measured in vivo by PET imaging. The PET images showed high uptake of (18)F-FVIIai in the tumor regions, with a mean uptake of 2.5 ± 0.3 percentage injected dose per gram (%ID/g) (mean ± SEM) 4 h after injection of 7.3-9.3 MBq of (18)F-FVIIai and with an average maximum uptake in the tumors of 7.1 ± 0.7 %ID/g at 4 h. In comparison, the muscle uptake was 0.2 ± 0.01 %ID/g at 4 h. At 4 h, the tumors had the highest uptake of any organ. Blocking with FVIIai significantly reduced the uptake of (18)F-FVIIai from 2.9 ± 0.1 to 1.4 ± 0.1 %ID/g (P < 0.001). The uptake of (18)F-FVIIai measured in vivo by PET imaging correlated (r = 0.72, P < 0.02) with TF protein level measured ex vivo. (18)F-FVIIai is a promising PET tracer for

Bacteriophage cocktail for biocontrol of Salmonella in dried pet food.

PubMed

Heyse, Serena; Hanna, Leigh Farris; Woolston, Joelle; Sulakvelidze, Alexander; Charbonneau, Duane

2015-01-01

Human salmonellosis has been associated with contaminated pet foods and treats. Therefore, there is interest in identifying novel approaches for reducing the risk of Salmonella contamination within pet food manufacturing environments. The use of lytic bacteriophages shows promise as a safe and effective way to mitigate Salmonella contamination in various food products. Bacteriophages are safe, natural, highly targeted antibacterial agents that specifically kill bacteria and can be targeted to kill food pathogens without affecting other microbiota. In this study, we show that a cocktail containing six bacteriophages had a broadspectrum activity in vitro against a library of 930 Salmonella enterica strains representing 44 known serovars. The cocktail was effective against 95% of the strains in this tested library. In liquid culture dose-ranging experiments, bacteriophage cocktail concentrations of ≥10(8) PFU/ml inactivated more than 90% of the Salmonella population (10(1) to 10(3) CFU/ml). Dried pet food inoculated with a mixture containing equal proportions of Salmonella serovars Enteritidis (ATCC 4931), Montevideo (ATCC 8387), Senftenberg (ATCC 8400), and Typhimurium (ATCC 13311) and then surface treated with the six-bacteriophage cocktail (≥2.5 ± 1.5 × 10(6) PFU/g) achieved a greater than 1-log (P < 0.001) reduction compared with the phosphate-buffered saline-treated control in measured viable Salmonella within 60 min. Moreover, this bacteriophage cocktail reduced natural contamination in samples taken from an undistributed lot of commercial dried dog food that tested positive for Salmonella. Our results indicate that bacteriophage biocontrol of S. enterica in dried pet food is technically feasible.

Towards integration of PET/MR hybrid imaging into radiation therapy treatment planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulus, Daniel H., E-mail: daniel.paulus@imp.uni-erlangen.de; Thorwath, Daniela; Schmidt, Holger

2014-07-15

Purpose: Multimodality imaging has become an important adjunct of state-of-the-art radiation therapy (RT) treatment planning. Recently, simultaneous PET/MR hybrid imaging has become clinically available and may also contribute to target volume delineation and biological individualization in RT planning. For integration of PET/MR hybrid imaging into RT treatment planning, compatible dedicated RT devices are required for accurate patient positioning. In this study, prototype RT positioning devices intended for PET/MR hybrid imaging are introduced and tested toward PET/MR compatibility and image quality. Methods: A prototype flat RT table overlay and two radiofrequency (RF) coil holders that each fix one flexible body matrixmore » RF coil for RT head/neck imaging have been evaluated within this study. MR image quality with the RT head setup was compared to the actual PET/MR setup with a dedicated head RF coil. PET photon attenuation and CT-based attenuation correction (AC) of the hardware components has been quantitatively evaluated by phantom scans. Clinical application of the new RT setup in PET/MR imaging was evaluated in anin vivo study. Results: The RT table overlay and RF coil holders are fully PET/MR compatible. MR phantom and volunteer imaging with the RT head setup revealed high image quality, comparable to images acquired with the dedicated PET/MR head RF coil, albeit with 25% reduced SNR. Repositioning accuracy of the RF coil holders was below 1 mm. PET photon attenuation of the RT table overlay was calculated to be 3.8% and 13.8% for the RF coil holders. With CT-based AC of the devices, the underestimation error was reduced to 0.6% and 0.8%, respectively. Comparable results were found within the patient study. Conclusions: The newly designed RT devices for hybrid PET/MR imaging are PET and MR compatible. The mechanically rigid design and the reproducible positioning allow for straightforward CT-based AC. The systematic evaluation within this study

Review of Gallium-68 PSMA PET/CT Imaging in the Management of Prostate Cancer

PubMed Central

Lenzo, Nat P.; Meyrick, Danielle; Turner, J. Harvey

2018-01-01

Over 90% of prostate cancers over-express prostate specific membrane antigen (PSMA) and these tumor cells may be accurately targeted for diagnosis by 68Ga-PSMA-positron emission tomography/computed tomography (68Ga-PSMA-PET/CT) imaging. This novel molecular imaging modality appears clinically to have superseded CT, and appears superior to MR imaging, for the detection of metastatic disease. 68Ga-PSMA PET/CT has the ability to reliably stage prostate cancer at presentation and can help inform an optimal treatment approach. Novel diagnostic applications of 68Ga-PSMA PET/CT include guiding biopsy to improve sampling accuracy, and guiding surgery and radiotherapy. In addition to facilitating the management of metastatic castrate resistant prostate cancer (mCRPC), 68Ga-PSMA can select patients who may benefit from targeted systemic radionuclide therapy. 68Ga-PSMA is the diagnostic positron-emitting theranostic pair with the beta emitter Lutetium-177 PSMA (177Lu-PSMA) and alpha-emitter Actinium-225 PSMA (225Ac-PSMA) which can both be used to treat PSMA-avid metastases of prostate cancer in the molecular tumor-targeted approach of theranostic nuclear oncology. PMID:29439481

Basic study of entire whole-body PET scanners based on the OpenPET geometry

NASA Astrophysics Data System (ADS)

Yoshida, Eiji; Yamaya, Taiga; Nishikido, Fumihiko; Inadama, Naoko; Murayama, Hideo

2010-09-01

A conventional PET scanner has a 15-25 cm axial field-of-view (FOV) and images a whole body using about six bed positions. An OpenPET geometry can extend the axial FOV with a limited number of detectors. The entire whole-body PET scanner must be able to process a large amount of data effectively. In this work, we study feasibility of the fully 3D entire whole-body PET scanner using the GATE simulation. The OpenPET has 12 block detector rings with the ring diameter of 840 mm and each block detector ring consists of 48 depth-of-interaction (DOI) detectors. The OpenPET has the axial length of 895.95 mm with five parts of 58.95 mm open gaps. The OpenPET has higher single data loss than a conventional PET scanner at grouping circuits. NECR of the OpenPET decreases by single data loss. But single data loss is mitigated by separating the axially arranged detector into two parts. Also, multiple coincidences are found to be important for the entire whole-body PET scanner. The entire whole-body PET scanner with the OpenPET geometry promises to provide a large axial FOV with the open space and to have sufficient performance values. But single data loss at the grouping circuits and multiple coincidences are limited to the peak noise equivalent count rate (NECR) for the entire whole-body PET scanner.

Targeted Lymphoma Cell Death by Novel Signal Transduction Modifications

DTIC Science & Technology

2009-07-01

metabolic activity), and iPET imaging (a highly sensitive method to assess in vivo tumor-targeting). We have b egun to de velop the DOTA conj...inhibition augmented the cytotoxic potential of peptide 5. • We have begun to develop DOTA -c onjugated peptide 5 and 41 in anticipation of immuno-PET

Molecular detection and characterization of Cryptosporidium species in household dogs, pet shop puppies, and dogs kept in a school of veterinary nursing in Japan.

PubMed

Itoh, Naoyuki; Oohashi, Yoshino; Ichikawa-Seki, Madoka; Itagaki, Tadashi; Ito, Yoichi; Saeki, Hideharu; Kanai, Kazutaka; Chikazawa, Seishiro; Hori, Yasutomo; Hoshi, Fumio; Higuchi, Seiichi

2014-03-01

Members of Cryptosporidium species, which are protozoan parasites, are prevalent worldwide and can cause diarrhoea in both humans and animals, including dogs. In addition, the Cryptosporidium species harboured in dogs have the potential for zoonotic transmission. The purpose of the present study was to determine the prevalence of Cryptosporidium species infection and perform molecular characterization of isolates in household dogs, pet shop puppies, and dogs kept in a school of veterinary nursing in Japan. Fresh faecal samples were collected once from 529 household dogs (aged from 2 months to 18 years old, from 9 veterinary clinics located in 6 different regions), 471 pet shop puppies (≤ 3 months old, from 4 pet shops located in 2 different regions), and 98 dogs (aged from 2 to 11 years old) kept in a veterinary nursing school. A nested polymerase chain reaction (PCR) assay targeting the 18S rRNA gene was employed for the detection of Cryptosporidium species, and 111 random samples of PCR amplicons (approximately 500-bp) were sequenced for the molecular characterization of the isolates. The prevalences of Cryptosporidium species in household dogs, pet shop puppies, and veterinary nursing school dogs were 7.2%, 31.6%, and 18.4%, respectively. In household dogs, no significant correlation was observed between the prevalence of Cryptosporidium species and the age (≤ 6 months vs. >6 months), living conditions (indoor vs. outdoor), faecal conditions (formed vs. unformed), and location of residence. In pet shop puppies, the prevalence of Cryptosporidium species was not related to faecal condition; however, the prevalence significantly differed among the pet shops. All of the 111 sequence samples (26 from household dogs, 75 from pet shop puppies, and 10 from veterinary nursing school dogs) were identified as Cryptosporidium canis. The present study demonstrates a high prevalence of Cryptosporidium species infections in pet shop puppies and dogs of a veterinary nursing

Dual gated PET/CT imaging of small targets of the heart: method description and testing with a dynamic heart phantom.

PubMed

Kokki, Tommi; Sipilä, Hannu T; Teräs, Mika; Noponen, Tommi; Durand-Schaefer, Nicolas; Klén, Riku; Knuuti, Juhani

2010-01-01

In PET imaging respiratory and cardiac contraction motions interfere the imaging of heart. The aim was to develop and evaluate dual gating method for improving the detection of small targets of the heart. The method utilizes two independent triggers which are sent periodically into list mode data based on respiratory and ECG cycles. An algorithm for generating dual gated segments from list mode data was developed. The test measurements showed that rotational and axial movements of point source can be separated spatially to different segments with well-defined borders. The effect of dual gating on detection of small moving targets was tested with a moving heart phantom. Dual gated images showed 51% elimination (3.6 mm out of 7.0 mm) of contraction motion of hot spot (diameter 3 mm) and 70% elimination (14 mm out of 20 mm) of respiratory motion. Averaged activity value of hot spot increases by 89% when comparing to non-gated images. Patient study of suspected cardiac sarcoidosis shows sharper spatial myocardial uptake profile and improved detection of small myocardial structures such as papillary muscles. The dual gating method improves detection of small moving targets in a phantom and it is feasible in clinical situations.

A heterodimeric [RGD-Glu-[(64)Cu-NO2A]-6-Ahx-RM2] αvβ3/GRPr-targeting antagonist radiotracer for PET imaging of prostate tumors.

PubMed

Durkan, Kubra; Jiang, Zongrun; Rold, Tammy L; Sieckman, Gary L; Hoffman, Timothy J; Bandari, Rajendra Prasad; Szczodroski, Ashley F; Liu, Liqin; Miao, Yubin; Reynolds, Tamila Stott; Smith, Charles J

2014-02-01

In the present study, we describe a (64)Cu-radiolabeled heterodimeric peptide conjugate for dual αvβ3/GRPr (αvβ3 integrin/gastrin releasing peptide receptor) targeting of the form [RGD-Glu-[(64)Cu-NO2A]-6-Ahx-RM2] (RGD: the amino acid sequence [Arg-Gly-Asp], a nonregulatory peptide used for αvβ3 integrin receptor targeting; Glu: glutamic acid; NO2A: 1,4,7-triazacyclononane-1,4-diacetic acid; 6-Ahx: 6-amino hexanoic acid; and RM2: (D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2), an antagonist analogue of bombesin (BBN) peptide used for GRPr targeting). RGD-Glu-6Ahx-RM2] was conjugated to a NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) complexing agent to produce [RGD-Glu-[NO2A]-6-Ahx-RM2], which was purified by reversed-phase high-performance liquid chromatography (RP-HPLC) and characterized by electrospray ionization-mass spectrometry (ESI-MS). Radiolabeling of the conjugate with (64)Cu produced [RGD-Glu-[(64)Cu-NO2A]-6-Ahx-RM2 in high radiochemical yield (≥95%). In vivo behavior of the radiolabeled peptide conjugate was investigated in normal CF-1 mice and in the PC-3 human prostate cancer experimental model. A competitive displacement receptor binding assay in human prostate PC-3 cells using (125)I-[Tyr(4)]BBN as the radioligand showed high binding affinity of [RGD-Glu-[(nat)Cu-NO2A]-6-Ahx-RM2] conjugate for the GRPr (3.09±0.34 nM). A similar assay in human, glioblastoma U87-MG cells using (125)I-Echistatin as the radioligand indicated a moderate receptor-binding affinity for the αvβ3 integrin (518±37.5 nM). In vivo studies of [RGD-Glu-[(64)Cu-NO2A]-6-Ahx-RM2] showed high accumulation (4.86±1.01 %ID/g, 1h post-intravenous injection (p.i.)) and prolonged retention (4.26±1.23 %ID/g, 24h p.i.) of tracer in PC-3 tumor-bearing mice. Micro-positron emission tomography (microPET) molecular imaging studies produced high-quality, high contrast images in PC-3 tumor-bearing mice at 4h p.i. The favorable pharmacokinetics and enhanced tumor uptake of (64)Cu

[Target volume segmentation of PET images by an iterative method based on threshold value].

PubMed

Castro, P; Huerga, C; Glaría, L A; Plaza, R; Rodado, S; Marín, M D; Mañas, A; Serrada, A; Núñez, L

2014-01-01

An automatic segmentation method is presented for PET images based on an iterative approximation by threshold value that includes the influence of both lesion size and background present during the acquisition. Optimal threshold values that represent a correct segmentation of volumes were determined based on a PET phantom study that contained different sizes spheres and different known radiation environments. These optimal values were normalized to background and adjusted by regression techniques to a two-variable function: lesion volume and signal-to-background ratio (SBR). This adjustment function was used to build an iterative segmentation method and then, based in this mention, a procedure of automatic delineation was proposed. This procedure was validated on phantom images and its viability was confirmed by retrospectively applying it on two oncology patients. The resulting adjustment function obtained had a linear dependence with the SBR and was inversely proportional and negative with the volume. During the validation of the proposed method, it was found that the volume deviations respect to its real value and CT volume were below 10% and 9%, respectively, except for lesions with a volume below 0.6 ml. The automatic segmentation method proposed can be applied in clinical practice to tumor radiotherapy treatment planning in a simple and reliable way with a precision close to the resolution of PET images. Copyright © 2013 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

64Cu-PSMA-617: A novel PSMA-targeted radio-tracer for PET imaging in gastric adenocarcinoma xenografted mice model.

PubMed

Han, Xue-Di; Liu, Chen; Liu, Fei; Xie, Qing-Hua; Liu, Te-Li; Guo, Xiao-Yi; Xu, Xiao-Xia; Yang, Xing; Zhu, Hua; Yang, Zhi

2017-09-26

Here, we report that it's feasible for imaging gastric adenocarcinoma mice model with prostate-specific membrane antigen (PSMA) targeting imaging agents, which could potentially provide an alternate and readily translational tool for managing gastric adenocarcinoma. DKFZ-PSMA-617, a PSMA targeting ligand reported recently, was chosen to be radio-labeled with nuclide 64 Cu. 64 Cu-PSMA-617 was radio-synthesized in high radio-chemical yield and specific activity up to 19.3 GBq/µmol. It showed good stability in vitro . The specificity of 64 Cu-PSMA-617 was confirmed by cell uptake experiments in PSMA (+) LNCaP cell and PSMA (-) PC-3 and gastric adenocarcinoma BGC-823 cells. Micro-PET imaging in BGC-823 and PC-3 xenografts nude mice was evaluated ( n = 4). And the tumors were visualized and better tumor-to-background achieved till 24 h. Co-administration of N- [[[(1S)-1-Carboxy-3-methylbutyl]amino]-carbonyl]-L-glutamic acid (ZJ-43) can substantially block the uptake in those tumors. Dissected tumor tissues were analyzed by auto-radiography and immunohistochemistry, and these results confirmed the PSMA expression in neo-vasculature which explained the target molecular imaging of 64 Cu-PSMA-617. All those results suggested 64 Cu-PSMA-617 may serve as a novel radio-tracer for tumor imaging more than prostate cancer.

64Cu-PSMA-617: A novel PSMA-targeted radio-tracer for PET imaging in gastric adenocarcinoma xenografted mice model

PubMed Central

Han, Xue-Di; Liu, Chen; Liu, Fei; Xie, Qing-Hua; Liu, Te-Li; Guo, Xiao-Yi; Xu, Xiao-Xia; Yang, Xing; Zhu, Hua; Yang, Zhi

2017-01-01

Here, we report that it’s feasible for imaging gastric adenocarcinoma mice model with prostate-specific membrane antigen (PSMA) targeting imaging agents, which could potentially provide an alternate and readily translational tool for managing gastric adenocarcinoma. DKFZ-PSMA-617, a PSMA targeting ligand reported recently, was chosen to be radio-labeled with nuclide 64Cu. 64Cu-PSMA-617 was radio-synthesized in high radio-chemical yield and specific activity up to 19.3 GBq/µmol. It showed good stability in vitro. The specificity of 64Cu-PSMA-617 was confirmed by cell uptake experiments in PSMA (+) LNCaP cell and PSMA (-) PC-3 and gastric adenocarcinoma BGC-823 cells. Micro-PET imaging in BGC-823 and PC-3 xenografts nude mice was evaluated (n = 4). And the tumors were visualized and better tumor-to-background achieved till 24 h. Co-administration of N- [[[(1S)-1-Carboxy-3-methylbutyl]amino]-carbonyl]-L-glutamic acid (ZJ-43) can substantially block the uptake in those tumors. Dissected tumor tissues were analyzed by auto-radiography and immunohistochemistry, and these results confirmed the PSMA expression in neo-vasculature which explained the target molecular imaging of 64Cu-PSMA-617. All those results suggested 64Cu-PSMA-617 may serve as a novel radio-tracer for tumor imaging more than prostate cancer. PMID:29088775

Childhood Attachment to Pets: Associations between Pet Attachment, Attitudes to Animals, Compassion, and Humane Behaviour

PubMed Central

Hawkins, Roxanne D.; Williams, Joanne M.

2017-01-01

Attachment to pets has an important role in children’s social, emotional, and cognitive development, mental health, well-being, and quality of life. This study examined associations between childhood attachment to pets and caring and friendship behaviour, compassion, and attitudes towards animals. This study also examined socio-demographic differences, particularly pet ownership and pet type. A self-report survey of over one thousand 7 to 12 year-olds in Scotland, UK, revealed that the majority of children are strongly attached to their pets, but attachment scores differ depending on pet type and child gender. Analysis revealed that attachment to pets is facilitated by compassion and caring and pet-directed friendship behaviours and that attachment to pets significantly predicts positive attitudes towards animals. The findings have implications for the promotion of prosocial and humane behaviour. Encouraging children to participate in pet care behaviour may promote attachment between children and their pet, which in turn may have a range of positive outcomes for both children (such as reduced aggression, better well-being, and quality of life) and pets (such as humane treatment). This study enhances our understanding of childhood pet attachment and has implications for humane education and promoting secure emotional attachments in childhood. PMID:28481256

Childhood Attachment to Pets: Associations between Pet Attachment, Attitudes to Animals, Compassion, and Humane Behaviour.

PubMed

Hawkins, Roxanne D; Williams, Joanne M; Scottish Society For The Prevention Of Cruelty To Animals Scottish Spca

2017-05-06

Attachment to pets has an important role in children's social, emotional, and cognitive development, mental health, well-being, and quality of life. This study examined associations between childhood attachment to pets and caring and friendship behaviour, compassion, and attitudes towards animals. This study also examined socio-demographic differences, particularly pet ownership and pet type. A self-report survey of over one thousand 7 to 12 year-olds in Scotland, UK, revealed that the majority of children are strongly attached to their pets, but attachment scores differ depending on pet type and child gender. Analysis revealed that attachment to pets is facilitated by compassion and caring and pet-directed friendship behaviours and that attachment to pets significantly predicts positive attitudes towards animals. The findings have implications for the promotion of prosocial and humane behaviour. Encouraging children to participate in pet care behaviour may promote attachment between children and their pet, which in turn may have a range of positive outcomes for both children (such as reduced aggression, better well-being, and quality of life) and pets (such as humane treatment). This study enhances our understanding of childhood pet attachment and has implications for humane education and promoting secure emotional attachments in childhood.

Pet Health

MedlinePlus

... Before getting a pet, think carefully about which animal is best for your family. What is each ... Does anyone have pet allergies? What type of animal suits your lifestyle and budget? Once you own ...

Accurate inclusion mass screening: a bridge from unbiased discovery to targeted assay development for biomarker verification.

PubMed

Jaffe, Jacob D; Keshishian, Hasmik; Chang, Betty; Addona, Theresa A; Gillette, Michael A; Carr, Steven A

2008-10-01

Verification of candidate biomarker proteins in blood is typically done using multiple reaction monitoring (MRM) of peptides by LC-MS/MS on triple quadrupole MS systems. MRM assay development for each protein requires significant time and cost, much of which is likely to be of little value if the candidate biomarker is below the detection limit in blood or a false positive in the original discovery data. Here we present a new technology, accurate inclusion mass screening (AIMS), designed to provide a bridge from unbiased discovery to MS-based targeted assay development. Masses on the software inclusion list are monitored in each scan on the Orbitrap MS system, and MS/MS spectra for sequence confirmation are acquired only when a peptide from the list is detected with both the correct accurate mass and charge state. The AIMS experiment confirms that a given peptide (and thus the protein from which it is derived) is present in the plasma. Throughput of the method is sufficient to qualify up to a hundred proteins/week. The sensitivity of AIMS is similar to MRM on a triple quadrupole MS system using optimized sample preparation methods (low tens of ng/ml in plasma), and MS/MS data from the AIMS experiments on the Orbitrap can be directly used to configure MRM assays. The method was shown to be at least 4-fold more efficient at detecting peptides of interest than undirected LC-MS/MS experiments using the same instrumentation, and relative quantitation information can be obtained by AIMS in case versus control experiments. Detection by AIMS ensures that a quantitative MRM-based assay can be configured for that protein. The method has the potential to qualify large number of biomarker candidates based on their detection in plasma prior to committing to the time- and resource-intensive steps of establishing a quantitative assay.

Development of a sensitive and quantitative diagnostic assay for fish nervous necrosis virus based on two-target real-time PCR.

PubMed

Dalla Valle, L; Toffolo, V; Lamprecht, M; Maltese, C; Bovo, G; Belvedere, P; Colombo, L

2005-10-31

The aim of the present work was to develop two new independent SYBR Green I-based real-time PCR assays for both detection and quantification of betanodavirus, an RNA virus that infects several species of marine teleost fish causing massive mortalities in larvae and juveniles. The assays utilized two pairs of primers targeting highly conserved regions of both the RNA molecules forming the betanodavirus genome: RNA1 encoding the RNA-dependent RNA polymerase (RdRP) and RNA2 encoding the coat protein (CP). The specificity of amplifications was monitored by the melting analysis and agarose gel electrophoresis of the amplified products. The applicability of these assays was confirmed with 21 betanodavirus strains, covering all the four main clades. In addition, a BLAST (NCBI) search with the primer sequences showed no genomic cross-reactivity with other viruses. The new assays were able to quantify concentrations of betanodavirus genes ranging from 10(1) to 10(8) copies per reaction. The intra-assay coefficients of variation (CV) of threshold cycle (Ct) values of the assays were 1.5% and 1.4% for CP and RdRP RNAs, respectively. The inter-assay CVs of Ct values were 2.3% and 2.4% for CP and RdRP RNAs, respectively. Moreover, regression analysis showed a significant correlation (R2>0.97) between genome number, as determined by real-time PCR assays and the corresponding virus titer expressed as TCID50/ml of two different betanodavirus strains propagated in cell culture. The two assays were compared with a previously established one-step RT-PCR assay and with the classical virus isolation test and found to be more sensitive. In conclusion, the developed real-time RT-PCR assays are a reliable, specific and sensitive tool for the quantitative diagnosis of betanodavirus.

Quantitative and Visual Assessments toward Potential Sub-mSv or Ultrafast FDG PET Using High-Sensitivity TOF PET in PET/MRI.

PubMed

Behr, Spencer C; Bahroos, Emma; Hawkins, Randall A; Nardo, Lorenzo; Ravanfar, Vahid; Capbarat, Emily V; Seo, Youngho

2018-06-01

Newer high-performance time-of-flight (TOF) positron emission tomography (PET) systems have the capability to preserve diagnostic image quality with low count density, while maintaining a high raw photon detection sensitivity that would allow for a reduction in injected dose or rapid data acquisition. To assess this, we performed quantitative and visual assessments of the PET images acquired using a highly sensitive (23.3 cps/kBq) large field of view (25-cm axial) silicon photomultiplier (SiPM)-based TOF PET (400-ps timing resolution) integrated with 3 T-MRI in comparison to PET images acquired on non-TOF PET/x-ray computed tomography (CT) systems. Whole-body 2-deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG) PET/CT was acquired for 15 patients followed by whole body PET/magnetic resonance imaging (MRI) with an average injected dose of 325 ± 84 MBq. The PET list mode data from PET/MRI were reconstructed using full datasets (4 min/bed) and reduced datasets (2, 1, 0.5, and 0.25 min/bed). Qualitative assessment between PET/CT and PET/MR images were made. A Likert-type scale between 1 and 5, 1 for non-diagnostic, 3 equivalent to PET/CT, and 5 superior quality, was used. Maximum and mean standardized uptake values (SUV max and SUV mean ) of normal tissues and lesions detected were measured and compared. Mean visual assessment scores were 3.54 ± 0.32, 3.62 ± 0.38, and 3.69 ± 0.35 for the brain and 3.05 ± 0.49, 3.71 ± 0.45, and 4.14 ± 0.44 for the whole-body maximum intensity projections (MIPs) for 1, 2, and 4 min/bed PET/MR images, respectively. The SUV mean values for normal tissues were lower and statistically significant for images acquired at 4, 2, 1, 0.5, and 0.25 min/bed on the PET/MR, with values of - 18 ± 28 % (p < 0.001), - 16 ± 29 % (p = 0.001), - 16 ± 31 % (p = 0.002), - 14 ± 35 % (p < 0.001), and - 13 ± 34 % (p = 0.002), respectively. SUV max and SUV peak values of all lesions were

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis.

PubMed

Jin, H; Yuan, L; Li, C; Kan, Y; Hao, R; Yang, J

2014-03-01

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection. Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis. In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

Correlation of inflammation assessed by 18F-FDG PET, active mineral deposition assessed by 18F-fluoride PET, and vascular calcification in atherosclerotic plaque: a dual-tracer PET/CT study.

PubMed

Derlin, Thorsten; Tóth, Zoltán; Papp, László; Wisotzki, Christian; Apostolova, Ivayla; Habermann, Christian R; Mester, Janos; Klutmann, Susanne

2011-07-01

Formation and progression of atherosclerotic plaque is a dynamic and complex process involving various pathophysiologic steps including inflammation and calcification. The purpose of this study was to compare macrophage activity as determined by (18)F-FDG PET and ongoing mineral deposition as measured by (18)F-sodium fluoride PET in atherosclerotic plaque and to correlate these findings with calcified plaque burden as assessed by CT. Forty-five patients were examined by whole-body (18)F-FDG PET, (18)F-sodium fluoride PET, and CT. Tracer uptake in various arterial segments was analyzed both qualitatively and semiquantitatively by measuring the blood-pool-corrected standardized uptake value (target-to-background ratio [TBR]). The pattern of tracer uptake in atherosclerotic lesions was compared after color-coded multistudy image fusion of PET and CT studies. The Fisher exact test and the Spearman correlation coefficient r(s) were used for statistical analysis of image-based results and cardiovascular risk factors. Intra- and interrater reproducibility were evaluated using the Cohen κ. (18)F-sodium fluoride uptake was observed at 105 sites in 27 (60%) of the 45 study patients, and mean TBR was 2.3 ± 0.7. (18)F-FDG uptake was seen at 124 sites in 34 (75.6%) patients, and mean TBR was 1.5 ± 0.3. Calcified atherosclerotic lesions were observed at 503 sites in 34 (75.6%) patients. Eighty-one (77.1%) of the 105 lesions with marked (18)F-sodium fluoride uptake and only 18 (14.5%) of the 124 lesions with (18)F-FDG accumulation were colocalized with arterial calcification. Coincident uptake of both (18)F-sodium fluoride and (18)F-FDG was observed in only 14 (6.5%) of the 215 arterial lesions with radiotracer accumulation. PET/CT with (18)F-FDG and (18)F-sodium fluoride may allow evaluation of distinct pathophysiologic processes in atherosclerotic lesions and might provide information on the complex interactions involved in formation and progression of atherosclerotic plaque.

PET imaging of αvβ3 integrin expression in tumours with 68Ga-labelled mono-, di- and tetrameric RGD peptides

PubMed Central

Yim, Cheng-Bin; Franssen, Gerben M.; Schuit, Robert C.; Luurtsema, Gert; Liu, Shuang; Oyen, Wim J. G.; Boerman, Otto C.

2010-01-01

Purpose Due to the restricted expression of αvβ3 in tumours, αvβ3 is considered a suitable receptor for tumour targeting. In this study the αvβ3-binding characteristics of 68Ga-labelled monomeric, dimeric and tetrameric RGD peptides were determined and compared with their 111In-labelled counterparts. Methods A monomeric (E-c(RGDfK)), a dimeric (E-[c(RGDfK)]2) and a tetrameric (E{E[c(RGDfK)]2}2) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with 68Ga. In vitro αvβ3-binding characteristics were determined in a competitive binding assay. In vivo αvβ3-targeting characteristics of the compounds were assessed in mice with subcutaneously growing SK-RC-52 xenografts. In addition, microPET images were acquired using a microPET/CT scanner. Results The IC50 values for the Ga(III)-labelled DOTA-E-c(RGDfK), DOTA-E-[c(RGDfK)]2 and DOTA-E{E[c(RGDfK)]2}2 were 23.9 ± 1.22, 8.99 ± 1.20 and 1.74 ± 1.18 nM, respectively, and were similar to those of the In(III)-labelled mono-, di- and tetrameric RGD peptides (26.6 ± 1.15, 3.34 ± 1.16 and 1.80 ± 1.37 nM, respectively). At 2 h post-injection, tumour uptake of the 68Ga-labelled mono-, di- and tetrameric RGD peptides (3.30 ± 0.30, 5.24 ± 0.27 and 7.11 ± 0.67%ID/g, respectively) was comparable to that of their 111In-labelled counterparts (2.70 ± 0.29, 5.61 ± 0.85 and 7.32 ± 2.45%ID/g, respectively). PET scans were in line with the biodistribution data. On all PET scans, the tumour could be clearly visualised. Conclusion The integrin affinity and the tumour uptake followed the order of DOTA-tetramer > DOTA-dimer > DOTA-monomer. The 68Ga-labelled tetrameric RGD peptide has excellent characteristics for imaging of αvβ3 expression with PET. Electronic supplementary material The online version of this article (doi:10.1007/s00259-010-1615-x) contains supplementary material, which is available to authorized users. PMID:20857099

Identification of Five Novel Salmonella Typhi-Specific Genes as Markers for Diagnosis of Typhoid Fever Using Single-Gene Target PCR Assays.

PubMed

Goay, Yuan Xin; Chin, Kai Ling; Tan, Clarissa Ling Ling; Yeoh, Chiann Ying; Ja'afar, Ja'afar Nuhu; Zaidah, Abdul Rahman; Chinni, Suresh Venkata; Phua, Kia Kien

2016-01-01

Salmonella Typhi ( S . Typhi) causes typhoid fever which is a disease characterised by high mortality and morbidity worldwide. In order to curtail the transmission of this highly infectious disease, identification of new markers that can detect the pathogen is needed for development of sensitive and specific diagnostic tests. In this study, genomic comparison of S . Typhi with other enteric pathogens was performed, and 6 S . Typhi genes, that is, STY0201, STY0307, STY0322, STY0326, STY2020, and STY2021, were found to be specific in silico . Six PCR assays each targeting a unique gene were developed to test the specificity of these genes in vitro . The diagnostic sensitivities and specificities of each assay were determined using 39 S . Typhi, 62 non-Typhi Salmonella , and 10 non- Salmonella clinical isolates. The results showed that 5 of these genes, that is, STY0307, STY0322, STY0326, STY2020, and STY2021, demonstrated 100% sensitivity (39/39) and 100% specificity (0/72). The detection limit of the 5 PCR assays was 32 pg for STY0322, 6.4 pg for STY0326, STY2020, and STY2021, and 1.28 pg for STY0307. In conclusion, 5 PCR assays using STY0307, STY0322, STY0326, STY2020, and STY2021 were developed and found to be highly specific at single-gene target resolution for diagnosis of typhoid fever.

Is non-attenuation-corrected PET inferior to body attenuation-corrected PET or PET/CT in lung cancer?

NASA Astrophysics Data System (ADS)

Maintas, Dimitris; Houzard, Claire; Ksyar, Rachid; Mognetti, Thomas; Maintas, Catherine; Scheiber, Christian; Itti, Roland

2006-12-01

It is considered that one of the great strengths of PET imaging is the ability to correct for body attenuation. This enables better lesion uptake quantification and quality of PET images. The aim of this work is to compare the sensitivity of non-attenuation-corrected (NAC) PET images, the gamma photons (GPAC) and CT attenuation-corrected (CTAC) images in detecting and staging of lung cancer. We have studied 66 patients undergoing PET/CT examinations for detecting and staging NSC lung cancer. The patients were injected with 18-FDG; 5 MBq/kg under fasting conditions and examination was started 60 min later. Transmission data were acquired by a spiral CT X-ray tube and by gamma photons emitting Cs-137l source and were used for the patient body attenuation correction without correction for respiratory motion. In 55 of 66 patients we performed both attenuation correction procedures and in 11 patients only CT attenuation correction. In seven patients with solitary nodules PET was negative and in 59 patients with lung cancer PET/CT was positive for pulmonary or other localization. In the group of 55 patients we found 165 areas of focal increased 18-FDG uptake in NAC, 165 in CTAC and 164 in GPAC PET images.In the patients with only CTAC we found 58 areas of increased 18-FDG uptake on NAC and 58 areas lesions on CTAC. In the patients with positive PET we found 223 areas of focal increased uptake in NAC and 223 areas in CTAC images. The sensitivity of NAC was equal to the sensitivity of CTAC and GPAC images. The visualization of peripheral lesions was better in NAC images and the lesions were better localized in attenuation-corrected images. In three lesions of the thorax the localization was better in GPAC and fused images than in CTAC images.

Non-input analysis for incomplete trapping irreversible tracer with PET.

PubMed

Ohya, Tomoyuki; Kikuchi, Tatsuya; Fukumura, Toshimitsu; Zhang, Ming-Rong; Irie, Toshiaki

2013-07-01

When using metabolic trapping type tracers, the tracers are not always trapped in the target tissue; i.e., some are completely trapped in the target, but others can be eliminated from the target tissue at a measurable rate. The tracers that can be eliminated are termed 'incomplete trapping irreversible tracers'. These incomplete trapping irreversible tracers may be clinically useful when the tracer β-value, the ratio of the tracer (metabolite) elimination rate to the tracer efflux rate, is under approximately 0.1. In this study, we propose a non-input analysis for incomplete trapping irreversible tracers based on the shape analysis (Shape), a non-input analysis used for irreversible tracers. A Monte Carlo simulation study based on experimental monkey data with two actual PET tracers (a complete trapping irreversible tracer [(11)C]MP4A and an incomplete trapping irreversible tracer [(18)F]FEP-4MA) was performed to examine the effects of the environmental error and the tracer elimination rate on the estimation of the k3-parameter (corresponds to metabolic rate) using Shape (original) and modified Shape (M-Shape) analysis. The simulation results were also compared with the experimental results obtained with the two PET tracers. When the tracer β-value was over 0.03, the M-Shape method was superior to the Shape method for the estimation of the k3-parameter. The simulation results were also in reasonable agreement with the experimental ones. M-Shape can be used as the non-input analysis of incomplete trapping irreversible tracers for PET study. Copyright © 2013 Elsevier Inc. All rights reserved.

Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification.

PubMed

Wang, Shouyi; Bowen, Stephen R; Chaovalitwongse, W Art; Sandison, George A; Grabowski, Thomas J; Kinahan, Paul E

2014-02-21

compensation when clinicians quantitatively assess PET/CT for therapy target definition and response assessment.

Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

NASA Astrophysics Data System (ADS)

Wang, Shouyi; Bowen, Stephen R.; Chaovalitwongse, W. Art; Sandison, George A.; Grabowski, Thomas J.; Kinahan, Paul E.

2014-02-01

when clinicians quantitatively assess PET/CT for therapy target definition and response assessment.

Hybrid FDG-PET/MR compared to FDG-PET/CT in adult lymphoma patients.

PubMed

Atkinson, Wendy; Catana, Ciprian; Abramson, Jeremy S; Arabasz, Grae; McDermott, Shanaugh; Catalano, Onofrio; Muse, Victorine; Blake, Michael A; Barnes, Jeffrey; Shelly, Martin; Hochberg, Ephraim; Rosen, Bruce R; Guimaraes, Alexander R

2016-07-01

The goal of this study is to evaluate the diagnostic performance of simultaneous FDG-PET/MR including diffusion compared to FDG-PET/CT in patients with lymphoma. Eighteen patients with a confirmed diagnosis of non-Hodgkin's (NHL) or Hodgkin's lymphoma (HL) underwent an IRB-approved, single-injection/dual-imaging protocol consisting of a clinical FDG-PET/CT and subsequent FDG-PET/MR scan. PET images from both modalities were reconstructed iteratively. Attenuation correction was performed using low-dose CT data for PET/CT and Dixon-MR sequences for PET/MR. Diffusion-weighted imaging was performed. SUVmax was measured and compared between modalities and the apparent diffusion coefficient (ADC) using ROI analysis by an experienced radiologist using OsiriX. Strength of correlation between variables was measured using the Pearson correlation coefficient (r p). Of the 18 patients included in this study, 5 had HL and 13 had NHL. The median age was 51 ± 14.8 years. Sixty-five FDG-avid lesions were identified. All FDG-avid lesions were visible with comparable contrast, and therefore initial and follow-up staging was identical between both examinations. SUVmax from FDG-PET/MR [(mean ± sem) (21.3 ± 2.07)] vs. FDG-PET/CT (mean 23.2 ± 2.8) demonstrated a strongly positive correlation [r s = 0.95 (0.94, 0.99); p < 0.0001]. There was no correlation found between ADCmin and SUVmax from FDG-PET/MR [r = 0.17(-0.07, 0.66); p = 0.09]. FDG-PET/MR offers an equivalent whole-body staging examination as compared with PET/CT with an improved radiation safety profile in lymphoma patients. Correlation of ADC to SUVmax was weak, understating their lack of equivalence, but not undermining their potential synergy and differing importance.

In Vivo PET Imaging of HDL in Multiple Atherosclerosis Models.

PubMed

Pérez-Medina, Carlos; Binderup, Tina; Lobatto, Mark E; Tang, Jun; Calcagno, Claudia; Giesen, Luuk; Wessel, Chang Ho; Witjes, Julia; Ishino, Seigo; Baxter, Samantha; Zhao, Yiming; Ramachandran, Sarayu; Eldib, Mootaz; Sánchez-Gaytán, Brenda L; Robson, Philip M; Bini, Jason; Granada, Juan F; Fish, Kenneth M; Stroes, Erik S G; Duivenvoorden, Raphaël; Tsimikas, Sotirios; Lewis, Jason S; Reiner, Thomas; Fuster, Valentín; Kjær, Andreas; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

2016-08-01

The goal of this study was to develop and validate a noninvasive imaging tool to visualize the in vivo behavior of high-density lipoprotein (HDL) by using positron emission tomography (PET), with an emphasis on its plaque-targeting abilities. HDL is a natural nanoparticle that interacts with atherosclerotic plaque macrophages to facilitate reverse cholesterol transport. HDL-cholesterol concentration in blood is inversely associated with risk of coronary heart disease and remains one of the strongest independent predictors of incident cardiovascular events. Discoidal HDL nanoparticles were prepared by reconstitution of its components apolipoprotein A-I (apo A-I) and the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine. For radiolabeling with zirconium-89 ((89)Zr), the chelator deferoxamine B was introduced by conjugation to apo A-I or as a phospholipid-chelator (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-deferoxamine B). Biodistribution and plaque targeting of radiolabeled HDL were studied in established murine, rabbit, and porcine atherosclerosis models by using PET combined with computed tomography (PET/CT) imaging or PET combined with magnetic resonance imaging. Ex vivo validation was conducted by radioactivity counting, autoradiography, and near-infrared fluorescence imaging. Flow cytometric assessment of cellular specificity in different tissues was performed in the murine model. We observed distinct pharmacokinetic profiles for the two (89)Zr-HDL nanoparticles. Both apo A-I- and phospholipid-labeled HDL mainly accumulated in the kidneys, liver, and spleen, with some marked quantitative differences in radioactivity uptake values. Radioactivity concentrations in rabbit atherosclerotic aortas were 3- to 4-fold higher than in control animals at 5 days' post-injection for both (89)Zr-HDL nanoparticles. In the porcine model, increased accumulation of radioactivity was observed in lesions by using in vivo PET imaging. Irrespective of the

Effect of respiratory gating on reducing lung motion artifacts in PET imaging of lung cancer.

PubMed

Nehmeh, S A; Erdi, Y E; Ling, C C; Rosenzweig, K E; Squire, O D; Braban, L E; Ford, E; Sidhu, K; Mageras, G S; Larson, S M; Humm, J L

2002-03-01

Positron emission tomography (PET) has shown an increase in both sensitivity and specificity over computed tomography (CT) in lung cancer. However, motion artifacts in the 18F fluorodioxydoglucose (FDG) PET images caused by respiration persists to be an important factor in degrading PET image quality and quantification. Motion artifacts lead to two major effects: First, it affects the accuracy of quantitation, producing a reduction of the measured standard uptake value (SUV). Second, the apparent lesion volume is overestimated. Both impact upon the usage of PET images for radiation treatment planning. The first affects the visibility, or contrast, of the lesion. The second results in an increase in the planning target volume, and consequently a greater radiation dose to the normal tissues. One way to compensate for this effect is by applying a multiple-frame capture technique. The PET data are then acquired in synchronization with the respiratory motion. Reduction in smearing due to gating was investigated in both phantoms and patient studies. Phantom studies showed a dependence of the reduction in smearing on the lesion size, the motion amplitude, and the number of bins used for data acquisition. These studies also showed an improvement in the target-to-background ratio, and a more accurate measurement of the SUV. When applied to one patient, respiratory gating showed a 28% reduction in the total lesion volume, and a 56.5% increase in the SUV. This study was conducted as a proof of principle that a gating technique can effectively reduce motion artifacts in PET image acquisition.

Competitive Advantage of PET/MRI

PubMed Central

Jadvar, Hossein; Colletti, Patrick M.

2013-01-01

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. PMID:23791129

Competitive advantage of PET/MRI.

PubMed

Jadvar, Hossein; Colletti, Patrick M

2014-01-01

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

PET imaging of urokinase-type plasminogen activator receptor (uPAR) in prostate cancer: current status and future perspectives.

PubMed

Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

2016-01-01

Overexpression of urokinase-type plasminogen activator receptors (uPAR) represents an important biomarker for aggressiveness in most common malignant diseases, including prostate cancer (PC). Accordingly, uPAR expression either assessed directly in malignant PC tissue or assessed directly in plasma (intact/cleaved forms)-provides independent additional clinical information to that contributed by PSA, Gleason score, and other relevant pathological and clinical parameters. In this respect, non-invasive molecular imaging by positron emission tomography (PET) offers a very attractive technology platform, which can provide the required quantitative information on the uPAR expression profile, without the need for invasive procedures and the risk of missing the target due to tumor heterogeneity. These observations support non-invasive PET imaging of uPAR in PC as a clinically relevant diagnostic and prognostic imaging method. In this review, we will focus on the recent development of uPAR PET and the relevance within prostate cancer imaging. Novel antibody and small-molecule radiotracers-targeting uPAR, including a series of uPAR-targeting PET ligands, based on the high affinity peptide ligand AE105, have been synthesized and tested in vitro and in vivo in preclinical murine xenograft models and, recently, in a first-ever clinical uPAR PET study in cancer patients, including patients with PC. In this phase I study, a high and specific uptake of the tracer 64 Cu-DOTA-AE105 was found in both primary tumors and lymph node metastases. The results are encouraging and support large-scale clinical trials to determine the utility of uPAR PET in the management of patients with PC with the goal of improving outcome.

Tube-Forming Assays.

PubMed

Brown, Ryan M; Meah, Christopher J; Heath, Victoria L; Styles, Iain B; Bicknell, Roy

2016-01-01

Angiogenesis involves the generation of new blood vessels from the existing vasculature and is dependent on many growth factors and signaling events. In vivo angiogenesis is dynamic and complex, meaning assays are commonly utilized to explore specific targets for research into this area. Tube-forming assays offer an excellent overview of the molecular processes in angiogenesis. The Matrigel tube forming assay is a simple-to-implement but powerful tool for identifying biomolecules involved in angiogenesis. A detailed experimental protocol on the implementation of the assay is described in conjunction with an in-depth review of methods that can be applied to the analysis of the tube formation. In addition, an ImageJ plug-in is presented which allows automatic quantification of tube images reducing analysis times while removing user bias and subjectivity.

Reproducibility of Quantitative Brain Imaging Using a PET-Only and a Combined PET/MR System

PubMed Central

Lassen, Martin L.; Muzik, Otto; Beyer, Thomas; Hacker, Marcus; Ladefoged, Claes Nøhr; Cal-González, Jacobo; Wadsak, Wolfgang; Rausch, Ivo; Langer, Oliver; Bauer, Martin

2017-01-01

The purpose of this study was to test the feasibility of migrating a quantitative brain imaging protocol from a positron emission tomography (PET)-only system to an integrated PET/MR system. Potential differences in both absolute radiotracer concentration as well as in the derived kinetic parameters as a function of PET system choice have been investigated. Five healthy volunteers underwent dynamic (R)-[11C]verapamil imaging on the same day using a GE-Advance (PET-only) and a Siemens Biograph mMR system (PET/MR). PET-emission data were reconstructed using a transmission-based attenuation correction (AC) map (PET-only), whereas a standard MR-DIXON as well as a low-dose CT AC map was applied to PET/MR emission data. Kinetic modeling based on arterial blood sampling was performed using a 1-tissue-2-rate constant compartment model, yielding kinetic parameters (K1 and k2) and distribution volume (VT). Differences for parametric values obtained in the PET-only and the PET/MR systems were analyzed using a 2-way Analysis of Variance (ANOVA). Comparison of DIXON-based AC (PET/MR) with emission data derived from the PET-only system revealed average inter-system differences of −33 ± 14% (p < 0.05) for the K1 parameter and −19 ± 9% (p < 0.05) for k2. Using a CT-based AC for PET/MR resulted in slightly lower systematic differences of −16 ± 18% for K1 and −9 ± 10% for k2. The average differences in VT were −18 ± 10% (p < 0.05) for DIXON- and −8 ± 13% for CT-based AC. Significant systematic differences were observed for kinetic parameters derived from emission data obtained from PET/MR and PET-only imaging due to different standard AC methods employed. Therefore, a transfer of imaging protocols from PET-only to PET/MR systems is not straightforward without application of proper correction methods. Clinical Trial Registration: www.clinicaltrialsregister.eu, identifier 2013-001724-19 PMID:28769742

Radiosynthesis and initial characterization of a PDE10A specific PET tracer [18F]AMG 580 in non-human primates.

PubMed

Hwang, Dah-Ren; Hu, Essa; Allen, Jennifer R; Davis, Carl; Treanor, James; Miller, Silke; Chen, Hang; Shi, Bingzhi; Narayanan, Tanjorie K; Barret, Olivier; Alagille, David; Yu, Zhigang; Slifstein, Mark

2015-08-01

Phosphodiesterase 10A (PDE10A) is an intracellular enzyme responsible for the breakdown of cyclic nucleotides which are important second messengers for neurotransmission. Inhibition of PDE10A has been identified as a potential target for treatment of various neuropsychiatric disorders. To assist drug development, we have identified a selective PDE10A positron emission tomography (PET) tracer, AMG 580. We describe here the radiosynthesis of [(18)F]AMG 580 and in vitro and in vivo characterization results. The potency and selectivity were determined by in vitro assay using [(3)H]AMG 580 and baboon brain tissues. [(18)F]AMG 580 was prepared by a 1-step [(18)F]fluorination procedure. Dynamic brain PET scans were performed in non-human primates. Regions-of-interest were defined on individuals' MRIs and transferred to the co-registered PET images. Data were analyzed using two tissue compartment analysis (2TC), Logan graphical (Logan) analysis with metabolite-corrected input function and the simplified reference tissue model (SRTM) method. A PDE10A inhibitor and unlabeled AMG 580 were used to demonstrate the PDE10A specificity. KD was estimated by Scatchard analysis of high and low affinity PET scans. AMG 580 has an in vitro KD of 71.9 pM. Autoradiography showed specific uptake in striatum. Mean activity of 121 ± 18 MBq was used in PET studies. In Rhesus, the baseline BPND for putamen and caudate was 3.38 and 2.34, respectively, via 2TC, and 3.16, 2.34 via Logan, and 2.92, and 2.01 via SRTM. A dose dependent decrease of BPND was observed by the pre-treatment with a PDE10A inhibitor. In baboons, 0.24 mg/kg dose of AMG 580 resulted in about 70% decrease of BPND. The in vivo KD of [(18)F]AMG 580 was estimated to be around 0.44 nM in baboons. [(18)F]AMG 580 is a selective and potent PDE10A PET tracer with excellent specific striatal binding in non-human primates. It warrants further evaluation in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

Feasibility of a semi-automated contrast-oriented algorithm for tumor segmentation in retrospectively gated PET images: phantom and clinical validation.

PubMed

Carles, Montserrat; Fechter, Tobias; Nemer, Ursula; Nanko, Norbert; Mix, Michael; Nestle, Ursula; Schaefer, Andrea

2015-12-21

PET/CT plays an important role in radiotherapy planning for lung tumors. Several segmentation algorithms have been proposed for PET tumor segmentation. However, most of them do not take into account respiratory motion and are not well validated. The aim of this work was to evaluate a semi-automated contrast-oriented algorithm (COA) for PET tumor segmentation adapted to retrospectively gated (4D) images. The evaluation involved a wide set of 4D-PET/CT acquisitions of dynamic experimental phantoms and lung cancer patients. In addition, segmentation accuracy of 4D-COA was compared with four other state-of-the-art algorithms. In phantom evaluation, the physical properties of the objects defined the gold standard. In clinical evaluation, the ground truth was estimated by the STAPLE (Simultaneous Truth and Performance Level Estimation) consensus of three manual PET contours by experts. Algorithm evaluation with phantoms resulted in: (i) no statistically significant diameter differences for different targets and movements (Δφ = 0.3 ± 1.6 mm); (ii) reproducibility for heterogeneous and irregular targets independent of user initial interaction and (iii) good segmentation agreement for irregular targets compared to manual CT delineation in terms of Dice Similarity Coefficient (DSC = 0.66 ± 0.04), Positive Predictive Value (PPV  = 0.81 ± 0.06) and Sensitivity (Sen. = 0.49 ± 0.05). In clinical evaluation, the segmented volume was in reasonable agreement with the consensus volume (difference in volume (%Vol) = 40 ± 30, DSC = 0.71 ± 0.07 and PPV = 0.90 ± 0.13). High accuracy in target tracking position (ΔME) was obtained for experimental and clinical data (ΔME(exp) = 0 ± 3 mm; ΔME(clin) 0.3 ± 1.4 mm). In the comparison with other lung segmentation methods, 4D-COA has shown the highest volume accuracy in both experimental and clinical data. In conclusion, the accuracy in volume delineation, position tracking and its robustness on highly irregular target movements

Feasibility of a semi-automated contrast-oriented algorithm for tumor segmentation in retrospectively gated PET images: phantom and clinical validation

NASA Astrophysics Data System (ADS)

Carles, Montserrat; Fechter, Tobias; Nemer, Ursula; Nanko, Norbert; Mix, Michael; Nestle, Ursula; Schaefer, Andrea

2015-12-01

PET/CT plays an important role in radiotherapy planning for lung tumors. Several segmentation algorithms have been proposed for PET tumor segmentation. However, most of them do not take into account respiratory motion and are not well validated. The aim of this work was to evaluate a semi-automated contrast-oriented algorithm (COA) for PET tumor segmentation adapted to retrospectively gated (4D) images. The evaluation involved a wide set of 4D-PET/CT acquisitions of dynamic experimental phantoms and lung cancer patients. In addition, segmentation accuracy of 4D-COA was compared with four other state-of-the-art algorithms. In phantom evaluation, the physical properties of the objects defined the gold standard. In clinical evaluation, the ground truth was estimated by the STAPLE (Simultaneous Truth and Performance Level Estimation) consensus of three manual PET contours by experts. Algorithm evaluation with phantoms resulted in: (i) no statistically significant diameter differences for different targets and movements (Δ φ =0.3+/- 1.6 mm); (ii) reproducibility for heterogeneous and irregular targets independent of user initial interaction and (iii) good segmentation agreement for irregular targets compared to manual CT delineation in terms of Dice Similarity Coefficient (DSC  =  0.66+/- 0.04 ), Positive Predictive Value (PPV  =  0.81+/- 0.06 ) and Sensitivity (Sen.  =  0.49+/- 0.05 ). In clinical evaluation, the segmented volume was in reasonable agreement with the consensus volume (difference in volume (%Vol)  =  40+/- 30 , DSC  =  0.71+/- 0.07 and PPV  =  0.90+/- 0.13 ). High accuracy in target tracking position (Δ ME) was obtained for experimental and clinical data (Δ ME{{}\\text{exp}}=0+/- 3 mm; Δ ME{{}\\text{clin}}=0.3+/- 1.4 mm). In the comparison with other lung segmentation methods, 4D-COA has shown the highest volume accuracy in both experimental and clinical data. In conclusion, the accuracy in volume

Evaluation of PeneloPET Simulations of Biograph PET/CT Scanners

NASA Astrophysics Data System (ADS)

Abushab, K. M.; Herraiz, J. L.; Vicente, E.; Cal-González, J.; España, S.; Vaquero, J. J.; Jakoby, B. W.; Udías, J. M.

2016-06-01

Monte Carlo (MC) simulations are widely used in positron emission tomography (PET) for optimizing detector design, acquisition protocols, and evaluating corrections and reconstruction methods. PeneloPET is a MC code based on PENELOPE, for PET simulations which considers detector geometry, acquisition electronics and materials, and source definitions. While PeneloPET has been successfully employed and validated with small animal PET scanners, it required a proper validation with clinical PET scanners including time-of-flight (TOF) information. For this purpose, we chose the family of Biograph PET/CT scanners: the Biograph True-Point (B-TP), Biograph True-Point with TrueV (B-TPTV) and the Biograph mCT. They have similar block detectors and electronics, but a different number of rings and configuration. Some effective parameters of the simulations, such as the dead-time and the size of the reflectors in the detectors, were adjusted to reproduce the sensitivity and noise equivalent count (NEC) rate of the B-TPTV scanner. These parameters were then used to make predictions of experimental results such as sensitivity, NEC rate, spatial resolution, and scatter fraction (SF), from all the Biograph scanners and some variations of them (energy windows and additional rings of detectors). Predictions agree with the measured values for the three scanners, within 7% (sensitivity and NEC rate) and 5% (SF). The resolution obtained for the B-TPTV is slightly better (10%) than the experimental values. In conclusion, we have shown that PeneloPET is suitable for simulating and investigating clinical systems with good accuracy and short computational time, though some effort tuning of a few parameters of the scanners modeled may be needed in case that the full details of the scanners studied are not available.

Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging

PubMed Central

Pike, Victor W.

2017-01-01

The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets. PMID:27087244

The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations

PubMed Central

Liu, Yiyan

2016-01-01

Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-d-glucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. Published clinical observations were discordant regarding the role of FDG PET/CT in diagnosing and staging RCC, and FDG PET/CT is not recommended for this purpose based on current national and international guidelines. However, quantitative FDG PET/CT imaging may facilitate the prediction of the degree of tumor differentiation and allows for prognosis of the disease. FDG PET/CT has potency as an imaging biomarker to provide useful information about patient’s survival. FDG PET/CT can be effectively used for postoperative surveillance and restaging with high sensitivity, specificity, and accuracy, as early diagnosis of recurrent/metastatic disease can drastically affect therapeutic decision and alter outcome of patients. FDG uptake is helpful for differentiating benign or bland emboli from tumor thrombosis in RCC patients. FDG PET/CT also has higher sensitivity and accuracy when compared with bone scan to detect RCC metastasis to the bone. FDG PET/CT can play a strong clinical role in the management of recurrent and metastatic RCC. In monitoring the efficacy of new target therapy such as tyrosine kinase inhibitors (TKIs) treatment for advanced RCC, FDG PET/CT has been increasingly used to assess the therapeutic efficacy, and change in FDG uptake is a strong indicator of biological response to TKI. PMID:27656421

Development of a Targeted Next-Generation Sequencing Assay to Detect Diagnostically Relevant Mutations of JAK2, CALR, and MPL in Myeloproliferative Neoplasms.

PubMed

Frawley, Thomas; O'Brien, Cathal P; Conneally, Eibhlin; Vandenberghe, Elisabeth; Percy, Melanie; Langabeer, Stephen E; Haslam, Karl

2018-02-01

The classical Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), consisting of polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are a heterogeneous group of neoplasms that harbor driver mutations in the JAK2, CALR, and MPL genes. The detection of mutations in these genes has been incorporated into the recent World Health Organization (WHO) diagnostic criteria for MPN. Given a pressing clinical need to screen for mutations in these genes in a routine diagnostic setting, a targeted next-generation sequencing (NGS) assay for the detection of MPN-associated mutations located in JAK2 exon 14, JAK2 exon 12, CALR exon 9, and MPL exon 10 was developed to provide a single platform alternative to reflexive, stepwise diagnostic algorithms. Polymerase chain reaction (PCR) primers were designed to target mutation hotspots in JAK2 exon 14, JAK2 exon 12, MPL exon 10, and CALR exon 9. Multiplexed PCR conditions were optimized by using qualitative PCR followed by NGS. Diagnostic genomic DNA from 35 MPN patients, known to harbor driver mutations in one of the target genes, was used to validate the assay. One hundred percent concordance was observed between the previously-identified mutations and those detected by NGS, with no false positives, nor any known mutations missed (specificity = 100%, CI = 0.96, sensitivity = 100%, CI = 0.89). Improved resolution of mutation sequences was also revealed by NGS analysis. Detection of diagnostically relevant driver mutations of MPN is enhanced by employing a targeted multiplex NGS approach. This assay presents a robust solution to classical MPN mutation screening, providing an alternative to time-consuming sequential analyses.

PET/CT aids the staging of and radiotherapy planning for early-stage extranodal natural killer/T-cell lymphoma, nasal type: A case series

PubMed Central

2011-01-01

Extranodal natural killer/T-cell lymphoma (ENKTL), nasal type, is a rare form of non-Hodgkin lymphoma. Treatment of ENKTL primarily relies on radiation; thus, proper delineation of target volumes is critical. Currently, the ideal modalities for delineation of gross tumor volume for ENKTL are unknown. We describe three consecutive cases of localized ENKTL that presented to the Nova Scotia Cancer Centre in Halifax, Nova Scotia. All patients had a planning CT and MRI as well as a planning FDG-PET/CT in the radiotherapy treatment position, wearing immobilization masks. All patients received radiation alone. In two patients, PET/CT changed not only the stage, but also the target volume requiring treatment. The third patient was unable to tolerate an MRI, but was able to undergo PET/CT, which improved the accuracy of the target volume. PET/CT aided the staging of and radiotherapy planning for our patients and appears to be a promising tool in the treatment of ENKTL. PMID:22208903

Biotechnological advances in the diagnosis of little-known parasitoses of pets.

PubMed

Traversa, Donato; Otranto, Domenico

2009-01-01

Dogs, cats, and horses are popular pets in many countries of the World and they have lived in close proximity with human beings for thousands of years. The effect of pet ownership on human health is well known and there is significant merit in preserving the health and welfare of these animals. Some infections caused by parasitic nematodes and arthropods of dogs, cats, and horses are now spreading in several areas of the world. This is the case of canine spirocercosis, feline aelurostrongylosis, and equine gastro-intestinal and nasal nematode and botfly infections. These diseases affect animal health and welfare and may be life-threatening. In spite these infections causing illnesses of major importance in clinical practice are spreading in new geographical foci, they are little known and underestimated also as an effect of difficulties in traditional diagnostics. Importantly, the limited reliability of conventional methodologies has also limited our knowledge of epidemiology, ecology, and biology of these parasitoses. This article reviews the DNA-based assays that have been recently developed for diagnosing these neglected pet parasitic diseases focusing on the advantages they have over classical techniques. Moreover, the opportunities for further epidemiological, ecological, and biological investigations are discussed.

The spatial distribution of pet dogs and pet cats on the island of Ireland

PubMed Central

2011-01-01

Background There is considerable international research regarding the link between human demographics and pet ownership. In several international studies, pet ownership was associated with household demographics including: the presence of children in the household, urban/rural location, level of education and age/family structure. What is lacking across all these studies, however, is an understanding of how these pets are spatially distributed throughout the regions under study. This paper describes the spatial distribution of pet dog and pet cat owning households on the island of Ireland. Results In 2006, there were an estimated 640,620 pet dog owning households and 215,542 pet cat owning households in Ireland. These estimates are derived from logistic regression modelling, based on household composition to determine pet dog ownership and the type of house to determine pet cat ownership. Results are presented using chloropleth maps. There is a higher density of pet dog owning households in the east of Ireland and in the cities than the west of Ireland and rural areas. However, in urban districts there are a lower proportion of households owning pet dogs than in rural districts. There are more households with cats in the urban areas, but the proportion of households with cats is greater in rural areas. Conclusions The difference in spatial distribution of dog ownership is a reflection of a generally higher density of households in the east of Ireland and in major cities. The higher proportion of ownership in the west is understandable given the higher proportion of farmers and rural dwellings in this area. Spatial representation allows us to visualise the impact of human household distribution on the density of both pet dogs and pet cats on the island of Ireland. This information can be used when analysing risk of disease spread, for market research and for instigating veterinary care. PMID:21663606

The spatial distribution of pet dogs and pet cats on the island of Ireland.

PubMed

Downes, Martin J; Clegg, Tracy A; Collins, Daniel M; McGrath, Guy; More, Simon J

2011-06-10

There is considerable international research regarding the link between human demographics and pet ownership. In several international studies, pet ownership was associated with household demographics including: the presence of children in the household, urban/rural location, level of education and age/family structure. What is lacking across all these studies, however, is an understanding of how these pets are spatially distributed throughout the regions under study. This paper describes the spatial distribution of pet dog and pet cat owning households on the island of Ireland. In 2006, there were an estimated 640,620 pet dog owning households and 215,542 pet cat owning households in Ireland. These estimates are derived from logistic regression modelling, based on household composition to determine pet dog ownership and the type of house to determine pet cat ownership. Results are presented using chloropleth maps. There is a higher density of pet dog owning households in the east of Ireland and in the cities than the west of Ireland and rural areas. However, in urban districts there are a lower proportion of households owning pet dogs than in rural districts. There are more households with cats in the urban areas, but the proportion of households with cats is greater in rural areas. The difference in spatial distribution of dog ownership is a reflection of a generally higher density of households in the east of Ireland and in major cities. The higher proportion of ownership in the west is understandable given the higher proportion of farmers and rural dwellings in this area. Spatial representation allows us to visualise the impact of human household distribution on the density of both pet dogs and pet cats on the island of Ireland. This information can be used when analysing risk of disease spread, for market research and for instigating veterinary care.

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters.

PubMed

Mhlanga, Joyce C; Carrino, John A; Lodge, Martin; Wang, Hao; Wahl, Richard L

2014-12-01

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with (18)F-FDG. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological (18)F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73 ± 7.7 years). Six patients served as the control group (53.7 ± 9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r = 0.86. p = 0.007; r = 0.94, p = 0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7 ± 6.6 vs. 32.2 ± 0.4, p = 0.02; 37.5 ± 5.4 vs. 32.2 ± 0.4, p = 0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8 ± 4.2 vs. 18 ± 1.8, p = 0.13; 22.8 ± 5.38 vs. 20.1 ± 1.54, p = 0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9 ± 31.3 vs. 0, p = 0.03). Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted.

Evacuating People and Their Pets: Older Floridians' Need for and Proximity to Pet-Friendly Shelters.

PubMed

Douglas, Rachel; Kocatepe, Ayberk; Barrett, Anne E; Ozguven, Eren Erman; Gumber, Clayton

2017-10-04

Pets influence evacuation decisions, but little is known about pet-friendly emergency shelters' availability or older adults' need for them. Our study addresses this issue, focusing on the most densely populated area of Florida (Miami-Dade)-the state with the oldest population and greatest hurricane susceptibility. We use Geographic Information Systems (GIS)-based methodology to identify the shortest paths to pet-friendly shelters, based on distance and congested and uncongested travel times-taking into account the older population's spatial distribution. Logistic regression models using the 2013 American Housing Survey's Disaster Planning Module examine anticipated shelter use as a function of pet ownership and requiring pet evacuation assistance. Thirty-four percent of older adults in the Miami-Dade area have pets-35% of whom report needing pet evacuation assistance. However, GIS accessibility measures show that travel time factors are likely to impede older adults' use of the area's few pet-friendly shelters. Logistic regression results reveal that pet owners are less likely to report anticipating shelter use; however, the opposite holds for pet owners reporting they would need help evacuating their pets-they anticipate using shelters. High pet shelter need coupled with low availability exacerbates older adults' heightened vulnerability during Florida's hurricane season. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A sensitive assay using a native protein substrate for screening HIV-1 maturation inhibitors targeting the protease cleavage site between the matrix and capsid.

PubMed

Lee, Sook-Kyung; Cheng, Nancy; Hull-Ryde, Emily; Potempa, Marc; Schiffer, Celia A; Janzen, William; Swanstrom, Ronald

2013-07-23

The matrix/capsid processing site in the HIV-1 Gag precursor is likely the most sensitive target to inhibit HIV-1 replication. We have previously shown that modest incomplete processing at the site leads to a complete loss of virion infectivity. In the study presented here, a sensitive assay based on fluorescence polarization that can monitor cleavage at the MA/CA site in the context of the folded protein substrate is described. The substrate, an MA/CA fusion protein, was labeled with the fluorescein-based FlAsH (fluorescein arsenical hairpin) reagent that binds to a tetracysteine motif (CCGPCC) that was introduced within the N-terminal domain of CA. By limiting the size of CA and increasing the size of MA (with an N-terminal GST fusion), we were able to measure significant differences in polarization values as a function of HIV-1 protease cleavage. The sensitivity of the assay was tested in the presence of increasing amounts of an HIV-1 protease inhibitor, which resulted in a gradual decrease in the fluorescence polarization values demonstrating that the assay is sensitive in discerning changes in protease processing. The high-throughput screening assay validation in 384-well plates showed that the assay is reproducible and robust with an average Z' value of 0.79 and average coefficient of variation values of <3%. The robustness and reproducibility of the assay were further validated using the LOPAC(1280) compound library, demonstrating that the assay provides a sensitive high-throughput screening platform that can be used with large compound libraries for identifying novel maturation inhibitors targeting the MA/CA site of the HIV-1 Gag polyprotein.

SU-E-J-124: 18F-FDG PET Imaging to Improve RT Treatment Outcome for Locally Advanced Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shusharina, N; Khan, F; Sharp, G

2015-06-15

Purpose: To investigate spatial correlation between high uptake regions of pre- and 10-days-post therapy{sup 1} {sup 8}F-FDG PET in recurrent lung cancer and to evaluate the feasibility of dose escalation boosting only regions with high FDG uptake identified on baseline PET. Methods: Nineteen patients with stages II– IV inoperable lung cancer were selected. Volumes of interest (VOI) on pre-therapy FDG-PET were defined using an isocontour at ≥50% of SUVmax. VOI of pre- and post-therapy PET images were correlated for the extent of overlap. A highly optimized IMRT plan to 60 Gy prescribed to PTV defined on the planning CT wasmore » designed using clinical dose constraints for the organs at risk. A boost of 18 Gy was prescribed to the VOI defined on baseline PET. A composite plan of the total 78 Gy was compared with the base 60 Gy plan. Increases in dose to the lungs, spinal cord and heart were evaluated. IMRT boost plan was compared with proton RT and SBRT boost plans. Results: Overlap fraction of baseline PET VOI with the VOI on 10 days-post therapy PET was 0.8 (95% CI: 0.7 – 0.9). Using baseline VOI as a boosting volume, dose could be escalated to 78 Gy for 15 patients without compromising the dose constraints. For 4 patients, the dose limiting factors were V20Gy and Dmean for the total lung, and Dmax for the spinal cord. An increase of the dose to OARs correlated significantly with the relative size of the boost volume. Conclusion: VOI defined on baseline 18F-FDG PET by the SUVmax-≥50% isocontour may be a biological target volume for escalated radiation dose. Dose escalation to this volume may provide improved tumor control without breaching predefined dose constraints for OARs. The best treatment outcome may be achieved with proton RT for large targets and with SBRT for small targets.« less

The potential advantages of (18)FDG PET/CT-based target volume delineation in radiotherapy planning of head and neck cancer.

PubMed

Moule, Russell N; Kayani, Irfan; Moinuddin, Syed A; Meer, Khalda; Lemon, Catherine; Goodchild, Kathleen; Saunders, Michele I

2010-11-01

This study investigated two fixed threshold methods to delineate the target volume using (18)FDG PET/CT before and during a course of radical radiotherapy in locally advanced squamous cell carcinoma of the head and neck. Patients were enrolled into the study between March 2006 and May 2008. (18)FDG PET/CT scans were carried out 72h prior to the start of radiotherapy and then at 10, 44 and 66Gy. Functional volumes were delineated according to the SUV Cut Off (SUVCO) (2.5, 3.0, 3.5, and 4.0bwg/ml) and percentage of the SUVmax (30%, 35%, 40%, 45%, and 50%) thresholds. The background (18)FDG uptake and the SUVmax within the volumes were also assessed. Primary and lymph node volumes for the eight patients significantly reduced with each increase in the delineation threshold (for example 2.5-3.0bwg/ml SUVCO) compared to the baseline threshold at each imaging point. There was a significant reduction in the volume (p⩽0.0001-0.01) after 36Gy compared to the 0Gy by the SUVCO method. There was a negative correlation between the SUVmax within the primary and lymph node volumes and delivered radiation dose (p⩽0.0001-0.011) but no difference in the SUV within the background reference region. The volumes delineated by the PTSUVmax method increased with the increase in the delivered radiation dose after 36Gy because the SUVmax within the region of interest used to define the edge of the volume was equal or less than the background (18)FDG uptake and the software was unable to effectively differentiate between tumour and background uptake. The changes in the target volumes delineated by the SUVCO method were less susceptible to background (18)FDG uptake compared to those delineated by the PTSUVmax and may be more helpful in radiotherapy planning. The best method and threshold have still to be determined within institutions, both nationally and internationally. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Experimental verification of a 4D MLEM reconstruction algorithm used for in-beam PET measurements in particle therapy

NASA Astrophysics Data System (ADS)

Stützer, K.; Bert, C.; Enghardt, W.; Helmbrecht, S.; Parodi, K.; Priegnitz, M.; Saito, N.; Fiedler, F.

2013-08-01

In-beam positron emission tomography (PET) has been proven to be a reliable technique in ion beam radiotherapy for the in situ and non-invasive evaluation of the correct dose deposition in static tumour entities. In the presence of intra-fractional target motion an appropriate time-resolved (four-dimensional, 4D) reconstruction algorithm has to be used to avoid reconstructed activity distributions suffering from motion-related blurring artefacts and to allow for a dedicated dose monitoring. Four-dimensional reconstruction algorithms from diagnostic PET imaging that can properly handle the typically low counting statistics of in-beam PET data have been adapted and optimized for the characteristics of the double-head PET scanner BASTEI installed at GSI Helmholtzzentrum Darmstadt, Germany (GSI). Systematic investigations with moving radioactive sources demonstrate the more effective reduction of motion artefacts by applying a 4D maximum likelihood expectation maximization (MLEM) algorithm instead of the retrospective co-registration of phasewise reconstructed quasi-static activity distributions. Further 4D MLEM results are presented from in-beam PET measurements of irradiated moving phantoms which verify the accessibility of relevant parameters for the dose monitoring of intra-fractionally moving targets. From in-beam PET listmode data sets acquired together with a motion surrogate signal, valuable images can be generated by the 4D MLEM reconstruction for different motion patterns and motion-compensated beam delivery techniques.

The MiniPET: a didactic PET system

NASA Astrophysics Data System (ADS)

Pedro, R.; Silva, J.; Gurriana, L.; Silva, J. M.; Maio, A.; Soares Augusto, J.

2013-03-01

The MiniPET project aims to design and build a small PET system. It consists of two 4 × 4 matrices of 16 LYSO scintillator crystals and two PMTs with 16 channels resulting in a low cost system with the essential functionality of a clinical PET instrument. It is designed to illustrate the physics of the PET technique and to provide a didactic platform for the training of students and nuclear imaging professionals as well as for scientific outreach. The PET modules can be configured to test for the coincidence of 511 keV gamma rays. The model has a flexible mechanical setup [1] and can simulate 14 diferent ring geometries, from a configuration with as few as 18 detectors per ring (ring radius phi=51 mm), up to a geometry with 70 detectors per ring (phi=200 mm). A second version of the electronic system [2] allowed measurement and recording of the energy deposited in 4 detector channels by photons from a 137Cs radioactive source and by photons resulting of the annihilation of positrons from a 22Na radioactive source. These energy spectra are used for detector performance studies, as well as angular dependency studies. In this paper, the mechanical setup, the front-end high-speed analog electronics, the digital acquisition and control electronics implemented in a FPGA, as well as the data-transfer interface between the FPGA board and a host PC are described. Recent preliminary results obtained with the 4 active channels in the prototype are also presented.

Nucleic Acid Amplification Based Diagnostic of Lyme (Neuro-)borreliosis – Lost in the Jungle of Methods, Targets, and Assays?

PubMed Central

Nolte, Oliver

2012-01-01

Laboratory based diagnosis of infectious diseases usually relies on culture of the disease causing micro-organism, followed by identification and susceptibility testing. Since Borrelia burgdorferi sensu lato, the etiologic agent of Lyme disease or Lyme borreliosis, requires very specific culture conditions (e.g. specific liquid media, long term cul-ture) traditional bacteriology is often not done on a routine basis. Instead, confirmation of the clinical diagnosis needs ei-ther indirect techniques (like serology or measurement of cellular activity in the presence of antigens) or direct but culture independent techniques, like microscopy or nucleic acid amplification techniques (NAT), with polymerase chain reaction (PCR) being the most frequently applied NAT method in routine laboratories. NAT uses nucleic acids of the disease causing micro-organism as template for amplification, isolated from various sources of clinical specimens. Although the underlying principle, adoption of the enzymatic process running during DNA duplication prior to prokaryotic cell division, is comparatively easy, a couple of ‘pitfalls’ is associated with the technique itself as well as with interpretation of the results. At present, no commercial, CE-marked and sufficiently validated PCR assay is available. A number of homebrew assays have been published, which are different in terms of target (i.e. the gene targeted by the amplification primers), method (nested PCR, PCR followed by hybridization, real-time PCR) and validation criteria. Inhibitory compounds may lead to false negative results, if no appropriate internal control is included. Carry-over of amplicons, insufficient handling and workflow and/or insufficiently validated targets/primers may result in false positive results. Different targets may yield different analytical sensitivity, depending, among other factors, of the redundancy of a target gene in the genome. Per-formance characteristics (e.g. analytical sensitivity and

Selected PET radiomic features remain the same.

PubMed

Tsujikawa, Tetsuya; Tsuyoshi, Hideaki; Kanno, Masafumi; Yamada, Shizuka; Kobayashi, Masato; Narita, Norihiko; Kimura, Hirohiko; Fujieda, Shigeharu; Yoshida, Yoshio; Okazawa, Hidehiko

2018-04-17

We investigated whether PET radiomic features are affected by differences in the scanner, scan protocol, and lesion location using 18 F-FDG PET/CT and PET/MR scans. SUV, TMR, skewness, kurtosis, entropy, and homogeneity strongly correlated between PET/CT and PET/MR images. SUVs were significantly higher on PET/MR 0-2 min and PET/MR 0-10 min than on PET/CT in gynecological cancer ( p = 0.008 and 0.008, respectively), whereas no significant difference was observed between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images in oral cavity/oropharyngeal cancer. TMRs on PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min increased in this order in gynecological cancer and oral cavity/oropharyngeal cancer. In contrast to conventional and histogram indices, 4 textural features (entropy, homogeneity, SRE, and LRE) were not significantly different between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images. 18 F-FDG PET radiomic features strongly correlated between PET/CT and PET/MR images. Dixon-based attenuation correction on PET/MR images underestimated tumor tracer uptake more significantly in oral cavity/oropharyngeal cancer than in gynecological cancer. 18 F-FDG PET textural features were affected less by differences in the scanner and scan protocol than conventional and histogram features, possibly due to the resampling process using a medium bin width. Eight patients with gynecological cancer and 7 with oral cavity/oropharyngeal cancer underwent a whole-body 18 F-FDG PET/CT scan and regional PET/MR scan in one day. PET/MR scans were performed for 10 minutes in the list mode, and PET/CT and 0-2 min and 0-10 min PET/MR images were reconstructed. The standardized uptake value (SUV), tumor-to-muscle SUV ratio (TMR), skewness, kurtosis, entropy, homogeneity, short-run emphasis (SRE), and long-run emphasis (LRE) were compared between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images.

Intranasal Opioid Administration in Rhesus Monkeys: PET Imaging and Antinociception.

PubMed

Saccone, Phillip A; Lindsey, Angela M; Koeppe, Robert A; Zelenock, Kathy A; Shao, Xia; Sherman, Phillip; Quesada, Carole A; Woods, James H; Scott, Peter J H

2016-11-01

The goal of this study was to evaluate the effects of intranasally administered opioids in rhesus monkeys using the tail-withdrawal assay, and to correlate these effects with measures of receptor occupancy using positron emission tomography (PET) imaging. Initial experiments characterized the antinociceptive effects of intranasal (IN) fentanyl and buprenorphine relative to intramuscular (IM) injection. Fentanyl (0.010-0.032 mg/kg) and buprenorphine (0.1-1.0 mg/kg) produced dose-dependent increases in tail-withdrawal latency that did not differ between routes of delivery. The second experiment compared the ability of IN and intravenous (IV) naloxone (NLX) to block the antinociceptive effects IV fentanyl, and to measure receptor occupancy at equipotent doses of NLX using PET imaging. IN and IV NLX (0.0032-0.032 mg/kg) produced dose-dependent decreases in fentanyl-induced antinociception. Again, there was no difference observed in overall potency between routes. PET imaging showed that IV and IN NLX produced similar decreases in receptor occupancy as measured by [ 11 C]carfentanil blocking, although there was a trend for IV NLX to produce marginally greater occupancy changes. This study validated the first procedures to evaluate the IN effects of opioids in rhesus monkeys. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

A fully automatic approach for multimodal PET and MR image segmentation in gamma knife treatment planning.

PubMed

Rundo, Leonardo; Stefano, Alessandro; Militello, Carmelo; Russo, Giorgio; Sabini, Maria Gabriella; D'Arrigo, Corrado; Marletta, Francesco; Ippolito, Massimo; Mauri, Giancarlo; Vitabile, Salvatore; Gilardi, Maria Carla

2017-06-01

Nowadays, clinical practice in Gamma Knife treatments is generally based on MRI anatomical information alone. However, the joint use of MRI and PET images can be useful for considering both anatomical and metabolic information about the lesion to be treated. In this paper we present a co-segmentation method to integrate the segmented Biological Target Volume (BTV), using [ 11 C]-Methionine-PET (MET-PET) images, and the segmented Gross Target Volume (GTV), on the respective co-registered MR images. The resulting volume gives enhanced brain tumor information to be used in stereotactic neuro-radiosurgery treatment planning. GTV often does not match entirely with BTV, which provides metabolic information about brain lesions. For this reason, PET imaging is valuable and it could be used to provide complementary information useful for treatment planning. In this way, BTV can be used to modify GTV, enhancing Clinical Target Volume (CTV) delineation. A novel fully automatic multimodal PET/MRI segmentation method for Leksell Gamma Knife ® treatments is proposed. This approach improves and combines two computer-assisted and operator-independent single modality methods, previously developed and validated, to segment BTV and GTV from PET and MR images, respectively. In addition, the GTV is utilized to combine the superior contrast of PET images with the higher spatial resolution of MRI, obtaining a new BTV, called BTV MRI . A total of 19 brain metastatic tumors, undergone stereotactic neuro-radiosurgery, were retrospectively analyzed. A framework for the evaluation of multimodal PET/MRI segmentation is also presented. Overlap-based and spatial distance-based metrics were considered to quantify similarity concerning PET and MRI segmentation approaches. Statistics was also included to measure correlation among the different segmentation processes. Since it is not possible to define a gold-standard CTV according to both MRI and PET images without treatment response assessment

Enhancement of PET Images

NASA Astrophysics Data System (ADS)

Davis, Paul B.; Abidi, Mongi A.

1989-05-01

PET is the only imaging modality that provides doctors with early analytic and quantitative biochemical assessment and precise localization of pathology. In PET images, boundary information as well as local pixel intensity are both crucial for manual and/or automated feature tracing, extraction, and identification. Unfortunately, the present PET technology does not provide the necessary image quality from which such precise analytic and quantitative measurements can be made. PET images suffer from significantly high levels of radial noise present in the form of streaks caused by the inexactness of the models used in image reconstruction. In this paper, our objective is to model PET noise and remove it without altering dominant features in the image. The ultimate goal here is to enhance these dominant features to allow for automatic computer interpretation and classification of PET images by developing techniques that take into consideration PET signal characteristics, data collection, and data reconstruction. We have modeled the noise steaks in PET images in both rectangular and polar representations and have shown both analytically and through computer simulation that it exhibits consistent mapping patterns. A class of filters was designed and applied successfully. Visual inspection of the filtered images show clear enhancement over the original images.

Parametric PET/MR Fusion Imaging to Differentiate Aggressive from Indolent Primary Prostate Cancer with Application for Image-Guided Prostate Cancer Biopsies

DTIC Science & Technology

2014-10-01

Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The study investigates whether fusion PET/MRI imaging with 18F- choline PET/CT and...imaging with 18F- choline PET/CT and diffusion-weighted MRI can be successfully applied to target prostate cancer using image-guided prostate...Completed task. The 18F- choline synthesis was implemented and optimized for routine radiotracer production. RDRC committee approval as part of the IRB

Principles of PET/MR Imaging.

PubMed

Disselhorst, Jonathan A; Bezrukov, Ilja; Kolb, Armin; Parl, Christoph; Pichler, Bernd J

2014-06-01

Hybrid PET/MR systems have rapidly progressed from the prototype stage to systems that are increasingly being used in the clinics. This review provides an overview of developments in hybrid PET/MR systems and summarizes the current state of the art in PET/MR instrumentation, correction techniques, and data analysis. The strong magnetic field requires considerable changes in the manner by which PET images are acquired and has led, among others, to the development of new PET detectors, such as silicon photomultipliers. During more than a decade of active PET/MR development, several system designs have been described. The technical background of combined PET/MR systems is explained and related challenges are discussed. The necessity for PET attenuation correction required new methods based on MR data. Therefore, an overview of recent developments in this field is provided. Furthermore, MR-based motion correction techniques for PET are discussed, as integrated PET/MR systems provide a platform for measuring motion with high temporal resolution without additional instrumentation. The MR component in PET/MR systems can provide functional information about disease processes or brain function alongside anatomic images. Against this background, we point out new opportunities for data analysis in this new field of multimodal molecular imaging. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

A Radiofluorinated Divalent Cystine Knot Peptide for Tumor PET Imaging

DOE PAGES

Jiang, Lei; Kimura, Richard H.; Ma, Xiaowei; ...

2014-04-09

A divalent knottin containing two separate integrin binding epitopes (RGD) in the adjacent loops, 3-4A, was recently developed and reported in our previous publication. In the current study, 3-4A was radiofluorinated with a 4-nitrophenyl 2- 18F-fluoropropinate ( 18F-NFP) group and the resulting divalent positron emission tomography (PET) probe, 18F-FP–3-4A, was evaluated as a novel imaging probe to detect integrin αvβ3 positive tumors in living animals. Knottin 3-4A was synthesized by solid phase peptide synthesis, folded, and site-specifically conjugated with 18/19F-NFP to produce the fluorinated peptide 18/19F-fluoropropinate-3-4A ( 18/19F-FP–3-4A). The stability of 18F-FP–3-4A was tested in both phosphate buffered saline (PBS)more » buffer and mouse serum. Cell uptake assays of the radiolabeled peptides were performed using U87MG cells. In addition, small animal PET imaging and biodistribution studies of 18F-FP–3-4A were performed in U87MG tumor-bearing mice. The receptor targeting specificity of the radiolabeled peptide was also verified by coinjecting the probe with a blocking peptide cyclo(RGDyK). Our study showed that 18F-FP–3-4A exhibited excellent stability in PBS buffer (pH 7.4) and mouse serum. Small animal PET imaging and biodistribution data revealed that 18F-FP–3-4A exhibited rapid and good tumor uptake (3.76 ± 0.59% ID/g and 2.22 ± 0.62% ID/g at 0.5 and 1 h, respectively). 18F-FP–3-4A was rapidly cleared from the normal tissues, resulting in excellent tumor-to-normal tissue contrasts. For example, liver uptake was only 0.39 ± 0.07% ID/g and the tumor to liver ratio was 5.69 at 1 h p.i. Furthermore, coinjection of cyclo(RGDyK) with 18F-FP–3-4A significantly inhibited tumor uptake (0.41 ± 0.12 vs 1.02 ± 0.19% ID/g at 2.5 h) in U87MG xenograft models, demonstrating specific accumulation of the probe in the tumor. In summary, the divalent probe 18F-FP–3-4A is characterized by rapid and high tumor uptake and excellent tumor

In vitro antioxidant activity of pet ether extract of black pepper

PubMed Central

Singh, Ramnik; Singh, Narinder; Saini, B.S.; Rao, Harwinder Singh

2008-01-01

Objective: To investigate the in vitro antioxidant activity of different fractions (R1, R2 and R3) obtained from pet ether extract of black pepper fruits (Piper nigrum Linn.) Materials and Methods: The fractions R1, R2 and R3 were eluted from pet ether and ethyl acetate in the ratio of 6:4, 5:5 and 4:6, respectively. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. Results: The free radical scavenging activity of the different fractions of pet ether extract of P. nigrum (PEPN) increased in a concentration dependent manner. The R3 and R2 fraction of PEPN in 500 µg/ml inhibited the peroxidation of a linoleic acid emulsion by 60.48±3.33% and 58.89±2.51%, respectively. In DPPH free radical scavenging assay, the activity of R3 and R2 were found to be almost similar. The R3 (100µg/ml) fraction of PEPN inhibited 55.68±4.48% nitric oxide radicals generated from sodium nitroprusside, whereas curcumin in the same concentration inhibited 84.27±4.12%. Moreover, PEPN scavenged the superoxide radical generated by the Xanthine/Xanthine oxidase system. The fraction R2 and R3 in the doses of 1000µg/ml inhibited 61.04±5.11% and 63.56±4.17%, respectively. The hydroxyl radical was generated by Fenton's reaction. The amounts of total phenolic compounds were determined and 56.98 µg pyrocatechol phenol equivalents were detected in one mg of R3. Conclusions: P. nigrum could be considered as a potential source of natural antioxidant. PMID:20040947

Clinical Nononcologic Applications of PET/CT and PET/MRI in Musculoskeletal, Orthopedic, and Rheumatologic Imaging.

PubMed

Gholamrezanezhad, Ali; Basques, Kyle; Batouli, Ali; Matcuk, George; Alavi, Abass; Jadvar, Hossein

2018-06-01

With improvements in PET/CT and PET/MRI over the last decade, as well as increased understanding of the pathophysiology of musculoskeletal diseases, there is an emerging potential for PET as a primary or complementary modality in the management of rheumatologic and orthopedic conditions. We discuss the role of PET/CT and PET/MRI in nononcologic musculoskeletal disorders, including inflammatory and infectious conditions and postoperative complications. There is great potential for an increased role for PET to serve as a primary or complementary modality in the management of orthopedic and rheumatologic disorders.

Coregistered FDG PET/CT-based textural characterization of head and neck cancer for radiation treatment planning.

PubMed

Yu, Huan; Caldwell, Curtis; Mah, Katherine; Mozeg, Daniel

2009-03-01

Coregistered fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has shown potential to improve the accuracy of radiation targeting of head and neck cancer (HNC) when compared to the use of CT simulation alone. The objective of this study was to identify textural features useful in distinguishing tumor from normal tissue in head and neck via quantitative texture analysis of coregistered 18F-FDG PET and CT images. Abnormal and typical normal tissues were manually segmented from PET/CT images of 20 patients with HNC and 20 patients with lung cancer. Texture features including some derived from spatial grey-level dependence matrices (SGLDM) and neighborhood gray-tone-difference matrices (NGTDM) were selected for characterization of these segmented regions of interest (ROIs). Both K nearest neighbors (KNNs) and decision tree (DT)-based KNN classifiers were employed to discriminate images of abnormal and normal tissues. The area under the curve (AZ) of receiver operating characteristics (ROC) was used to evaluate the discrimination performance of features in comparison to an expert observer. The leave-one-out and bootstrap techniques were used to validate the results. The AZ of DT-based KNN classifier was 0.95. Sensitivity and specificity for normal and abnormal tissue classification were 89% and 99%, respectively. In summary, NGTDM features such as PET Coarseness, PET Contrast, and CT Coarseness extracted from FDG PET/CT images provided good discrimination performance. The clinical use of such features may lead to improvement in the accuracy of radiation targeting of HNC.

PSMA-Based [(18)F]DCFPyL PET/CT Is Superior to Conventional Imaging for Lesion Detection in Patients with Metastatic Prostate Cancer.

PubMed

Rowe, Steven P; Macura, Katarzyna J; Mena, Esther; Blackford, Amanda L; Nadal, Rosa; Antonarakis, Emmanuel S; Eisenberger, Mario; Carducci, Michael; Fan, Hong; Dannals, Robert F; Chen, Ying; Mease, Ronnie C; Szabo, Zsolt; Pomper, Martin G; Cho, Steve Y

2016-06-01

Current standard of care conventional imaging modalities (CIM) such as X-ray computed tomography (CT) and bone scan can be limited for detection of metastatic prostate cancer and therefore improved imaging methods are an unmet clinical need. We evaluated the utility of a novel second-generation low molecular weight radiofluorinated prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) radiotracer, [(18)F]DCFPyL, in patients with metastatic prostate cancer. Nine patients with suspected prostate cancer recurrence, eight with CIM evidence of metastatic prostate cancer and one with biochemical recurrence, were imaged with [(18)F]DCFPyL PET/CT. Eight of the patients had contemporaneous CIM for comparison. A lesion-by-lesion comparison of the detection of suspected sites of metastatic prostate cancer was carried out between PET and CIM. Statistical analysis for estimated proportions of inter-modality agreement for detection of metastatic disease was calculated accounting for intra-patient correlation using general estimating equation (GEE) intercept-only regression models. One hundred thirty-nine sites of PET positive [(18)F]DCFPyL uptake (138 definite, 1 equivocal) for metastatic disease were detected in the eight patients with available comparison CIM. By contrast, only 45 lesions were identified on CIM (30 definite, 15 equivocal). When lesions were negative or equivocal on CIM, it was estimated that a large portion of these lesions or 0.72 (95 % confidence interval (CI) 0.55-0.84) would be positive on [(18)F]DCFPyL PET. Conversely, of those lesions negative or equivocal on [(18)F]DCFPyL PET, it was estimated that only a very small proportion or 0.03 (95 % CI 0.01-0.07) would be positive on CIM. Delayed 2-h-post-injection time point PET yielded higher tumor radiotracer uptake and higher tumor-to-background ratios than an earlier 1-h-post-injection time point. A novel PSMA-targeted PET radiotracer, [(18)F]DCFPyL, was able to a large

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters

PubMed Central

Mhlanga, Joyce C.; Carrino, John A.; Lodge, Martin; Wang, Hao

2015-01-01

Purpose The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with 18F-FDG. Methods Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological 18F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Results Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73±7.7 years). Six patients served as the control group (53.7±9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r=0.86. p =0.007; r=0.94, p=0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7±6.6 vs. 32.2±0.4, p=0.02; 37.5±5.4 vs. 32.2±0.4, p=0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8±4.2 vs. 18±1.8, p= 0.13; 22.8±5.38 vs. 20.1±1.54, p=0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9±31.3 vs. 0, p=0.03). Conclusion Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted. PMID:25134669

The loss-of-allele assay for ES cell screening and mouse genotyping.

PubMed

Frendewey, David; Chernomorsky, Rostislav; Esau, Lakeisha; Om, Jinsop; Xue, Yingzi; Murphy, Andrew J; Yancopoulos, George D; Valenzuela, David M

2010-01-01

Targeting vectors used to create directed mutations in mouse embryonic stem (ES) cells consist, in their simplest form, of a gene for drug selection flanked by mouse genomic sequences, the so-called homology arms that promote site-directed homologous recombination between the vector and the target gene. The VelociGene method for the creation of targeted mutations in ES cells employs targeting vectors, called BACVecs, that are based on bacterial artificial chromosomes. Compared with conventional short targeting vectors, BacVecs provide two major advantages: (1) their much larger homology arms promote high targeting efficiencies without the need for isogenicity or negative selection strategies; and (2) they enable deletions and insertions of up to 100kb in a single targeting event, making possible gene-ablating definitive null alleles and other large-scale genomic modifications. Because of their large arm sizes, however, BACVecs do not permit screening by conventional assays, such as long-range PCR or Southern blotting, that link the inserted targeting vector to the targeted locus. To exploit the advantages of BACVecs for gene targeting, we inverted the conventional screening logic in developing the loss-of-allele (LOA) assay, which quantifies the number of copies of the native locus to which the mutation was directed. In a correctly targeted ES cell clone, the LOA assay detects one of the two native alleles (for genes not on the X or Y chromosome), the other allele being disrupted by the targeted modification. We apply the same principle in reverse as a gain-of-allele assay to quantify the copy number of the inserted targeting vector. The LOA assay reveals a correctly targeted clone as having lost one copy of the native target gene and gained one copy of the drug resistance gene or other inserted marker. The combination of these quantitative assays makes LOA genotyping unequivocal and amenable to automated scoring. We use the quantitative polymerase chain reaction

Artefacts of PET/CT images

PubMed Central

Pettinato, C; Nanni, C; Farsad, M; Castellucci, P; Sarnelli, A; Civollani, S; Franchi, R; Fanti, S; Marengo, M; Bergamini, C

2006-01-01

Positron emission tomography (PET) is a non-invasive imaging modality, which is clinically widely used both for diagnosis and accessing therapy response in oncology, cardiology and neurology. Fusing PET and CT images in a single dataset would be useful for physicians who could read the functional and the anatomical aspects of a disease in a single shot. The use of fusion software has been replaced in the last few years by integrated PET/CT systems, which combine a PET and a CT scanner in the same gantry. CT images have the double function to correct PET images for attenuation and can fuse with PET for a better visualization and localization of lesions. The use of CT for attenuation correction yields several advantages in terms of accuracy and patient comfort, but can also introduce several artefacts on PET-corrected images. PET/CT image artefacts are due primarily to metallic implants, respiratory motion, use of contrast media and image truncation. This paper reviews different types artefacts and their correction methods. PET/CT improves image quality and image accuracy. However, to avoid possible pitfalls the simultaneous display of both Computed Tomography Attenuation Corrected (CTAC) and non corrected PET images, side by side with CT images is strongly recommended. PMID:21614340

Data-driven gating in PET: Influence of respiratory signal noise on motion resolution.

PubMed

Büther, Florian; Ernst, Iris; Frohwein, Lynn Johann; Pouw, Joost; Schäfers, Klaus Peter; Stegger, Lars

2018-05-21

Data-driven gating (DDG) approaches for positron emission tomography (PET) are interesting alternatives to conventional hardware-based gating methods. In DDG, the measured PET data themselves are utilized to calculate a respiratory signal, that is, subsequently used for gating purposes. The success of gating is then highly dependent on the statistical quality of the PET data. In this study, we investigate how this quality determines signal noise and thus motion resolution in clinical PET scans using a center-of-mass-based (COM) DDG approach, specifically with regard to motion management of target structures in future radiotherapy planning applications. PET list mode datasets acquired in one bed position of 19 different radiotherapy patients undergoing pretreatment [ 18 F]FDG PET/CT or [ 18 F]FDG PET/MRI were included into this retrospective study. All scans were performed over a region with organs (myocardium, kidneys) or tumor lesions of high tracer uptake and under free breathing. Aside from the original list mode data, datasets with progressively decreasing PET statistics were generated. From these, COM DDG signals were derived for subsequent amplitude-based gating of the original list mode file. The apparent respiratory shift d from end-expiration to end-inspiration was determined from the gated images and expressed as a function of signal-to-noise ratio SNR of the determined gating signals. This relation was tested against additional 25 [ 18 F]FDG PET/MRI list mode datasets where high-precision MR navigator-like respiratory signals were available as reference signal for respiratory gating of PET data, and data from a dedicated thorax phantom scan. All original 19 high-quality list mode datasets demonstrated the same behavior in terms of motion resolution when reducing the amount of list mode events for DDG signal generation. Ratios and directions of respiratory shifts between end-respiratory gates and the respective nongated image were constant over all

Development of a PET Scanner for Simultaneously Imaging Small Animals with MRI and PET

PubMed Central

Thompson, Christopher J; Goertzen, Andrew L; Thiessen, Jonathan D; Bishop, Daryl; Stortz, Greg; Kozlowski, Piotr; Retière, Fabrice; Zhang, Xuezhu; Sossi, Vesna

2014-01-01

Recently, positron emission tomography (PET) is playing an increasingly important role in the diagnosis and staging of cancer. Combined PET and X-ray computed tomography (PET-CT) scanners are now the modality of choice in cancer treatment planning. More recently, the combination of PET and magnetic resonance imaging (MRI) is being explored in many sites. Combining PET and MRI has presented many challenges since the photo-multiplier tubes (PMT) in PET do not function in high magnetic fields, and conventional PET detectors distort MRI images. Solid state light sensors like avalanche photo-diodes (APDs) and more recently silicon photo-multipliers (SiPMs) are much less sensitive to magnetic fields thus easing the compatibility issues. This paper presents the results of a group of Canadian scientists who are developing a PET detector ring which fits inside a high field small animal MRI scanner with the goal of providing simultaneous PET and MRI images of small rodents used in pre-clinical medical research. We discuss the evolution of both the crystal blocks (which detect annihilation photons from positron decay) and the SiPM array performance in the last four years which together combine to deliver significant system performance in terms of speed, energy and timing resolution. PMID:25120157