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Deposition of TiO <sub/>2</sub> photocatalyst on polyethylene terephthalate or polyimide polymer films by reactive sputtering for flexible photocatalytic sheets
摘要： Polycrystalline anatase TiO2 films were deposited by rf reactive magnetron sputtering on polyethylene terephthalate (PET) or polyimide (PI) films with different buffer layers, such as SiO2 or Zn2SnOx (ZTO) between the TiO2 film and the substrate. Such TiO2/(SiO2 or ZTO)/(PET or PI) sheets with high transmittance in the visible region of light performed high photo-decomposition ability of CH3CHO under the UV irradiation of the black light centered at 352 nm. In the case of using SiO2 as the buffer layer, “nano-pore layer” was observed clearly in full area of the polymer substrates close to the buffer layers after the UV irradiation, whereas such degradation was suppressed drastically in the case of using ZTO as the buffer layer. Such photocatalytic sheets performed also photo-induced hydrophilicity by the UV irradiation, where the contact angle to pure water became around 5O under the UV irradiation. After additional deposition of SiO2 by the reactive sputtering under rather high total gas pressure of 3.0 Pa on the outermost surface of the TiO2 films, the photo-induced hydrophilicity was maintained for more than 98 days in the dark. Such 3-layerd SiO2/TiO2/ZTO on PET or PI substrates should be the promising flexible photocatalytic sheets with the retentional photo-induced hydrophilicity.
关键词： PET,TiO2,Photocatalyst,PI,Reactive Sputtering,Flexible substrate
更新于2025-11-19 16:51:07
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Fluorescent pH Probes based on PET Quenching of Long Fluorescence Lifetime Triangulenium Dyes Martin Rosenberg, Anne Kathrine R. Junker, Thomas Just S?rensen, and Bo W. Laursen*[a]
摘要： Azaoxatriangulenium dyes with long fluorescence lifetimes offer advantages in fluorescence lifetime imaging (FLIM), time-gated detection and polarization assays. However, the long excited state lifetimes are also expected to increase sensitivity to photoinduced electron transfer (PET) quenching, potentially increasing the on-off ratio of PET probes. We report the synthesis and investigation of the optical properties of azaoxatriangulenium salts substituted with phenol substituents for pH sensing. Two series of pH probes with the phenol hydroxy group placed in the ortho, meta, or para positions to azadioxatriangulenium (ADOTA) and diazaoxatriangulenium (DAOTA) chromophores are investigated. All the phenol substituted dyes possess pH responsive fluorescence signals in the biological relevant pH window (pH 6-9) due to efficient intramolecular PET from the phenolate form of the pendant arm. While the PET mechanism is partly suppressed in the phenol form the ADOTA derivatives, it is completely suppressed in the DAOTA derivatives. The long excited state lifetimes of the triangulenium dyes ensure efficient PET quenching leading to very high on-off ratios of the pH probes. The study clearly demonstrates effects of the position of the phenol/phenolate group relative to the chromophore on both PET quenching rates and pKa values.
关键词： PET probes,triangulenium,pH probes,photoinduced electron transfer,Fluorescent probes
更新于2025-10-22 19:40:53
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A reaction-based turn-on fluorescent sensor for the detection of Cu (II) with excellent sensitivity and selectivity: Synthesis, DFT calculations, kinetics and application in real water samples
摘要： A reaction-based turn-on fluorescent chemosensor RhB-Cu, starting from rhodamine B (RhB), for Cu2+ was easily synthesized in two steps. The sensor could selectively detect Cu2+ with a 100-fold fluorescence enhancement among the common metal ions, exhibiting an extremely low detection limit of 4.7 nM. To the best of our knowledge, this was the best record for the detection of Cu2+ with organic fluorescent sensors. There was a 1:1 binding stoichiometry between RhB-Cu and Cu2+ with an association constant of 6.42 × 104 M-1. Noteworthy, it could distinguish Cu2+ from Cu+, which was hard to realize in the previous studies. In addition, the detection mechanism was proposed based on mass spectrometric analysis and density functional theory (DFT) calculations. Kinetic studies were conducted to obtain the activation energy, enthalpy and entropy, so as to elucidate the solvent effect. Interestingly, the kinetic compensation effect (KCE) was uncovered in this work. Finally, RhB-Cu was proved to have the capability to work in real water samples. It would highly contribute to the even better design of fluorescent sensor for Cu2+ in future.
关键词： fluorescent sensor,solvent effect,kinetic compensation effect (KCE),copper,density functional theory (DFT),PET mechanism
更新于2025-10-22 19:38:57
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Mini EXPLORER II: a prototype high-sensitivity PET/CT scanner for companion animal whole body and human brain scanning
摘要： As part of the EXPLORER total-body positron emission tomography (PET) project, we have designed and built a high-resolution, high-sensitivity PET/CT scanner which is expected to have excellent performance for companion animal whole body and human brain imaging. The PET component has a ring diameter of 52 cm and an axial field of view of 48.3 cm. The detector modules are composed of arrays of lutetium (yttrium) oxyorthosilicate (LYSO) crystals of dimensions 2.76x2.76x18.1 mm coupled to silicon photomultipliers (SiPMs) for read-out. The CT component is a 24 detector row CT scanner with a 50 kW X-ray tube. PET system time-of-flight resolution was measured to be 409±39 ps and average system energy resolution was 11.7%±1.5% at 511 keV. The NEMA NU2-2012 system sensitivity was found to be 52-54 kcps/MBq. Spatial resolution was 2.6 mm at 10mm from the center of the FOV and 2.0 mm rods were clearly resolved on a mini-Derenzo phantom. Peak noise-equivalent count (NEC) rate, using the NEMA NU 2-2012 phantom, was measured to be 314 kcps at 9.2 kBq/cc. The CT scanner passed the technical components of the American College of Radiology (ACR) accreditation tests. We have also performed scans of a Hoffman brain phantom and we show images from the first canine patient imaged on this device.
关键词： NEMA,PET/CT,EXPLORER,total-body PET,companion animal,brain
更新于2025-09-23 15:23:52
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Comparison of image quality and lesion detection between digital and analog PET/CT
摘要： Objective The purpose of this study was to compare image quality and lesion detection capability between a digital and an analog PET/CT system in oncological patients. Materials and methods One hundred oncological patients (62 men, 38 women; mean age of 65 ± 12 years) were prospectively included from January–June 2018. All patients, who accepted to be scanned by two systems, consecutively underwent a single day, dual imaging protocol (digital and analog PET/CT). Three nuclear medicine physicians evaluated image quality using a 4-point scale (?1, poor; 0, fair; 1, good; 2, excellent) and detection capability by counting the number of lesions with increased radiotracer uptake. Differences were considered significant for a p value <0.05. Results Improved image quality in the digital over the analog system was observed in 54% of the patients (p = 0.05, 95% CI, 44.2–63.5). The percentage of interrater concordance in lesion detection capability between the digital and analog systems was 97%, with an interrater measure agreement of κ = 0.901 (p < 0.0001). Although there was no significant difference in the total number of lesions detected by the two systems (digital: 5.03 ± 10.6 vs. analog: 4.53 ± 10.29; p = 0.7), the digital system detected more lesions in 22 of 83 of PET+ patients (26.5%) (p = 0.05, 95% CI, 17.9–36.7). In these 22 patients, all lesions detected by the digital PET/CT (and not by the analog PET/CT) were < 10 mm. Conclusion Digital PET/CT offers improved image quality and lesion detection capability over the analog PET/CT in oncological patients, and even better for sub-centimeter lesions.
关键词： Analog PET/CT,Digital PET/CT,Image quality,Lesion detection capability
更新于2025-09-23 15:23:52
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Head-to-head comparison of the diagnostic performances of Rubidium-PET and SPECT with CZT camera for the detection of myocardial ischemia in a population of women and overweight individuals
摘要： Background. The aim of this study was to compare the diagnostic performances for the detection of myocardial ischemia of 82-Rb-PET-MPS and 99m-Tc-SPECT-MPS in overweight individuals and women. Methods and Results. Men with BMI ≥ 25 and women referred for MPS were considered for inclusion. All individuals underwent 99m-Tc-SPECT-MPS with CZT cameras and 82-Rb-PET-MPS in 3D-mode. Individuals with at least one positive MPS were referred for coronary angiography (CA) with FFR measurements. A criterion for positivity was a composite endpoint including significant stenosis on CA or, in the absence of CA, the occurrence of acute coronary event during the following year. 313 patients (46% women) with mean BMI of 31.8 ± 6.5 were included. Sensitivity for the detection of myocardial ischemia was higher with 82-Rb-PET-MPS compared with 99m-Tc-SPECT-MPS (85% vs. 57%, P < .05); specificity was equally high with both imaging techniques (93% vs. 94%, P > .05). 82-Rb-PET allowed for a more accurate detection of patients with a high-risk coronary artery disease (HR-CAD) than 99m-Tc-SPECT-MPS (AUC = 0.86 vs. 0.75, respectively; P = .04). Conclusions. In women and overweight individuals, 82-Rb-PET-MPS provides higher sensitivity for the detection of myocardial ischemia than 99m-Tc-SPECT-MPS thanks to a better image quality and an improved detection of HR-CAD.
关键词： CZT camera,MPI,Diagnostic and prognostic application,PET,Myocardial blood flow,SPECT,82-Rubidium,CAD
更新于2025-09-23 15:23:52
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Comparative assessment of linear least-squares, nonlinear least-squares, and Patlak graphical method for regional and local quantitative tracer kinetic modelling in cerebral dynamic <sup>18</sup> F-FDG PET
摘要： Purpose: Dynamic 18F-FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least-squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model parameters. Nevertheless, faster techniques, including linear least-squares (LLS) and Patlak graphical method, have been proposed to deal with high resolution noisy data, representing a more adaptable solution for routine clinical implementation. Former research investigating the relative performance of the available algorithms lack precise evaluation of kinetic parameter estimates under realistic acquisition conditions. Methods: The present study aims at the systematic comparison of the feasibility and pertinence of kinetic modelling of dynamic cerebral 18F-FDG PET using NLS, LLS, and Patlak method, based on numerical simulations and patient data. Numerical simulations were used to study and parameters estimation bias and variance under representative noise levels. Patient data allowed to assess the concordance between the three methods at the regional and voxel scale, and to evaluate the robustness of the estimations with respect to patient head motion. Results and Conclusions: Our findings indicate that at the regional level NLS and LLS provide kinetic parameter estimates ( and ) with similar bias and variance characteristics ( bias ± rel. std dev. 0.0±5.1% and 0.1%±4.9% for NLS and LLS respectively, bias ± rel. std dev. 0.1%±4.5% and -0.7%±4.4% for NLS and LLS respectively), NLS estimates being however slightly less sensitive to patient motion. At the voxel level, provided that patient motion is negligible or corrected, LLS offers an appealing alternative solution for local mapping, with high correlation with NLS values (Pearson’s r = 0.95 on actual data) in computations times less than two orders of magnitude lower. Last, Patlak method appears as the most robust and accurate technique for the estimation of values at the regional and voxel scale, with or without head motion. It provides low bias / low variance quantification (bias ± rel. std dev. -1.5±9.5% and -4.1±19.7% for Patlak and NLS respectively) as well as smooth parametric images suitable for visual assessment.
关键词： kinetic analysis,18F-FDG PET,cerebral glucose metabolism,quantification
更新于2025-09-23 15:23:52
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PET/CT with Fluorodeoxyglucose During Neoadjuvant
摘要： Objective: The aim of the present study is to evaluate the accuracy of Positron Emission Tomography/Computed Tomography (PET/CT) with Fluorodeoxyglucose ([18F]FDG) to predict treatment response in patients with locally advanced rectal cancer (LARC) during neoadjuvant chemoradiotherapy. Patients and methods: Forty-one LARC patients performed [18F]FDG-PET/CT at baseline (PET0). All patients received continuous capecitabine concomitant to radiotherapy on the pelvis, followed by intermittent capecitabine until two weeks before curative surgery. [18F]FDG-PET/CT was also carried out at 40 Gy-time (PET1) and at the end of neoadjuvant therapy (PET2). PET imaging was analysed semi-quantitatively through the measurement of maximal standardised uptake value (SUVmax) and the tumour volume (TV). Histology was expressed through pTNM and Dworak tumor regression grading. Patients were categorised into responder (downstaging or downsizing) and non-responder (stable or progressive disease by comparison pretreatment parameters with clinical/pathological characteristics posttreatment/after surgery). Logistic regression was used to evaluate SUVmax and TV absolute and percent reduction as predictors of response rate using gender, age, and CEA as covariates. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Survivals were compared by the Log-Rank test. Results: Twenty-three responders (9 ypCR, 14 with downstaged disease) and 18 non-responders showed differences in terms of both early and posttreatment SUVmax percent reduction (median comparison: responder = 63.2%, non-responder = 44.2%, p = 0.04 and responder = 76.9%, non-responder = 61.6%, p = 0.06 respectively). The best predictive cut-offs of treatment response for early and post-treatment SUVmax percent reduction were ≥57% and ≥66% from baseline (p = 0.02 and p = 0.01 respectively). Conclusions: [18F]FDG-PET/CT is a reliable technique for evaluating therapy response during neoadjuvant treatment in LARC, through a categorical classification of the SUV max reduction during treatment.
关键词： neoadjuvant therapy,PET/CT,rectal cancer,fluorodeoxyglucose
更新于2025-09-23 15:23:52
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Evaluation of patient effective dose in a PET/CT test
摘要： The positron emission tomography (PET)/computed tomography (CT) technique generates high doses in patients because two radiodiagnostic modalities are used in a single examination. In this study, the absorbed and effective doses generated by CT scans and by the incorporation of radiopharmaceutical solution were evaluated in 19 organs. It was found that 78.2% of the effective dose in PET/CT examinations comes from the CT scan. With an activity of 3.33 MBq/kg, 18F-FDG contributes 21.8% of the final effective dose.
关键词： Patient dosimetry,PET/CT,Computed tomography
更新于2025-09-23 15:23:52
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Flexible all-organic photorefractive devices
摘要： The objective of the present study is to demonstrate and evaluate the photorefractive (PR) performance of an all-organic PR device with a self-assembled monolayer (SAM)-modified organic conductive electrode of PEDOT:PSS coated on polyethylene terephthalate (PET). The PR composite consisted of a triphenylamine-based photoconductive polymer: poly(4-(diphenylamino)benzylacrylate) (PDAA), triphenylamine photoconductive plasticizer: (4-(diphenylamino)phenyl)methanol (TPAOH), nonlinear optical dye based on aminocyanostyrene: (4-asacycloheptylbenzylidenemalononitrile) (7-DCST), and soluble fullerene: [6, 6]-phenyl C61 butyric acid-methyl ester (PCBM). For comparison with the all-organic PR device, the PR performances using PET/ITO, glass/ITO, and glass/PEDOT:PSS substrates were also evaluated. The PR performance at an applied electric field of 40 V μm-1: diffraction efficiency and the response time of the PR device using PET/PEDOT:PSS-SAM substrate were 21.9%, and 390 ms, respectively. As a result of repeating bending test on this all-organic PR device, we found that the flexible PR device with PET/PEDOT:PSS-SAM substrate had a potential to withstand bending 10,000 times and revealed that the change in the haze value strongly influenced the degradation of PR performance.
关键词： All-organic,Photorefractive polymer,ITO-free device,PET substrate,PEDOT:PSS,Flexible
更新于2025-09-23 15:23:52