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Lei Xing - One of the best experts on this subject based on the ideXlab platform.

  • th c 17a 02 new radioluminescence strategies based on cret cerenkov Radiation Energy transfer for imaging and therapy
    Medical Physics, 2014
    Co-Authors: Olga Volotskova, Conroy Sun, Guillem Pratx, Lei Xing
    Abstract:

    Purpose: Cerenkov photons are produced when charged particles, emitted from radionuclides, travel through a media with a speed greater than that of the light in the media. Cerenkov Radiation is mostly in the UV/Blue region and, thus, readily absorbed by biological tissue. Cerenkov Radiation Energy Transfer (CRET) is a wavelength-shifting phenomenon from blue Cerenkov light to more penetrating red wavelengths. We demonstrate the feasibility of in-depth imaging of CRET light originating from radionuclides realized by down conversion of gold nanoclusters (AuNCs, a novel particle composed of few atoms of gold coated with serum proteins) in vivo. Methods: Bovine Serum Albumin, Human Serum Albumin and Transferrin conjugated gold nanoclusters were synthesized, characterized and examined for CRET. Three different clinically used radiotracers: 18F-FDG, 90Y and 99mTc were used. Optical spectrum (440–750 nm) was recorded by sensitive bioluminescence imaging system at physiological temperature. Dose dependence (activity range from 0.5 up to 800uCi) and concentration dependence (0.01 to 1uM) studies were carried out. The compound was also imaged in a xenograft mouse model. Results: Only β+ and β--emitting radionuclides (18F-FDG, 90Y) are capable of CRET; no signal was found in 99mTc (γ-emitter). The emission peak of CRET by AuNCs was found to be ∼700 nm and was ∼3 fold times of background. In vitro studies showed a linear dependency between luminescence intensity and dose and concentration. CRET by gold nanoclusters was observed in xenografted mice injected with 100uCi of 18F-FDG. Conclusion: The unique optical, transport and chemical properties of AuNCs (gold nanoclusters) make them ideal candidates for in-vivo imaging applications. Development of new molecular imaging probes will allow us to achieve substantially improved spatiotemporal resolution, sensitivity and specificity for tumor imaging and detection.

  • su e qi 15 single point dosimetry by means of cerenkov Radiation Energy transfer cret
    Medical Physics, 2014
    Co-Authors: Olga Volotskova, C Jenkins, Lei Xing
    Abstract:

    Purpose: Cerenkov light is generated when a charged particles with Energy greater then 250 keV, moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons during the static megavoltage linear accelerator (LINAC) operational mode. Recently, Cerenkov Radiation gained considerable interest as possible candidate as a new imaging modality. Optical signals generated by Cerenkov Radiation may act as a surrogate for the absorbed superficial Radiation dose. We demonstrated a novel single point dosimetry method for megavoltage photon and electron therapy utilizing down conversion of Cerenkov photons. Methods: The custom build signal characterization system was used: a sample holder (probe) with adjacent light tight compartments was connected via fiber-optic cables to a photon counting photomultiplier tube (PMT). One compartment contains a medium only while the other contains medium and red-shifting nano-particles (Q-dots, nanoclusters). By taking the difference between the two signals (Cerenkov photons and CRET photons) we obtain a measure of the down-converted light, which we expect to be proportional to dose as measured with an adjacent ion chamber. Experimental results are compared to Monte Carlo simulations performed using the GEANT4 code. Results: The signal correlation between CR signal, CRET readings andmore » dose produced by LINAC at a single point were investigated. The experimental results were compared with simulations. The dose linearity, signal to noise ratio and dose rate dependence were tested with custom build CRET based probe. Conclusion: Performance characteristics of the proposed single point CRET based probe were evaluated. The direct use of the induced Cerenkov emission and CRET in an irradiated single point volume as an indirect surrogate for the imparted dose was investigated. We conclude that CRET is a promising optical based dosimetry method that offers advantages over those already proposed.« less

Zhuang Liu - One of the best experts on this subject based on the ideXlab platform.

  • core shell taox mno2 nanoparticles as a nano radiosensitizer for effective cancer radiotherapy
    Journal of Materials Chemistry B, 2018
    Co-Authors: Fei Gong, Jiawen Chen, Xiao Han, Jiayue Zhao, Mengyun Wang, Liangzhu Feng, Zhuang Liu, Liang Cheng
    Abstract:

    Improving tumor oxygenation and concentrating X-ray Radiation Energy inside the tumor have received considerable attention in cancer radiotherapy. Herein, core–shell tantalum oxide@manganese dioxide (TaOx@MnO2) nanostructures are prepared as an efficient radiosensitizer for enhancing radiotherapy (RT). In these nanostructures, the TaOx core serves as a RT sensitizer that efficiently concentrates X-ray Radiation Energy inside the tumor, while the MnO2 shell may trigger the decomposition of endogenous H2O2 in the tumor microenvironment (TME) to generate oxygen and overcome hypoxia-associated Radiation resistance. In vitro and in vivo experiments demonstrated that the synthesized TaOx@MnO2-PEG nanostructures could accomplish an excellent synergistic radiotherapy sensitization effect. Furthermore, TaOx@MnO2-PEG nanoparticles could also serve as promising agents for MR/CT dual-modal imaging. In brief, our study highlights a new type of multifunctional radiosensitizer agent to enhance radiotherapy treatment by means of simultaneously concentrating Radiation Energy inside tumors and overcoming tumor hypoxia, promising for applications in tumor radiotherapy.

  • taox decorated perfluorocarbon nanodroplets as oxygen reservoirs to overcome tumor hypoxia and enhance cancer radiotherapy
    Biomaterials, 2017
    Co-Authors: Guosheng Song, Chao Liang, Kai Yang, Xuejiao Song, Ziliang Dong, Zhuang Liu
    Abstract:

    Cancer radiotherapy (RT) is a clinically used tumor treatment strategy applicable for a wide range of solid tumors. However, during RT treatment of tumors, only a small portion of applied ionizing irRadiation Energy is absorbed by the tumor, in which the largely hypoxic microenvironment also limits the anti-tumor efficacy of RT. In this work, we rationally fabricate polyethylene glycol (PEG) stabilized perfluorocarbon (PFC) nano-droplets decorated with TaOx nanoparticles (TaOx@PFC-PEG) as a multifunctional RT sensitizer. The obtained TaOx@PFC-PEG nanoparticles on one hand can absorb X-ray by TaOx to concentrate Radiation Energy within tumor cells, on the other hand after saturating PFC with oxygen will act as an oxygen reservoir to gradually release oxygen and improve tumor oxygenation. As the result, remarkably enhanced in vivo RT treatment is achieved with TaOx@PFC-PEG nanoparticles in our mouse tumor model experiments. Our work thus presents a new nanotechnology strategy to enhance RT-induced tumor treatment by simultaneously concentrating Radiation Energy within tumors and improving tumor oxygenation, using one multifunctional agent.

  • perfluorocarbon loaded hollow bi2se3 nanoparticles for timely supply of oxygen under near infrared light to enhance the radiotherapy of cancer
    Advanced Materials, 2016
    Co-Authors: Guosheng Song, Chao Liang, Kai Yang, Liang Cheng, Qi Zhao, Zhuang Liu
    Abstract:

    Hollow Bi2 Se3 nanoparticles prepared by a cation exchange method are loaded with perfluorocarbon as an oxygen carrier. With these nanoparticles, a promising concept is demonstrated to enhance radiotherapy by not only using their X-ray-absorbing ability to locally concentrate Radiation Energy in the tumor, but also employing near-infrared light to trigger burst release of oxygen from the nanoparticles to overcome hypoxia-associated radio-resistance.

  • core shell mnse bi2se3 fabricated via a cation exchange method as novel nanotheranostics for multimodal imaging and synergistic thermoradiotherapy
    Advanced Materials, 2015
    Co-Authors: Guosheng Song, Chao Liang, Kai Yang, Liang Cheng, Hua Gong, Xianchuang Zheng, Xiqun Jiang, Zhuang Liu
    Abstract:

    MnSe@Bi2 Se3 core-shell nanostructures with highly integrated imaging and therapy functions are fabricated by a simple cation exchange method. Using those nanoparticles as a theranostic agent, a promise concept is further demonstrated to enhance conventional radiotherapy by: i) using X-ray absorbing agents to locally concentrate Radiation Energy and ii) employing near-infrared-light-triggered photothermal therapy to overcome hypoxia-associated radioresistance.

Chen Lin - One of the best experts on this subject based on the ideXlab platform.

  • terahertz Radiation enhanced by target ablation during the interaction of high intensity laser pulse and micron thickness metal foil
    Physics of Plasmas, 2020
    Co-Authors: Siyuan Zhang, Y R Shou, Zheng Gong, Yixing Geng, Weimin Wang, X Q Yan, Chen Lin
    Abstract:

    When an ultra-intense relativistic laser is irradiated on a solid target, terahertz (THz) pulses can be generated by coherent transition Radiation when the laser-driven electron beams cross the rear surface of the target. The Radiation Energy depends on the number and Energy of the electrons. By introducing a milli-joule picosecond ablation laser pulse, an underdense preplasma with a scale length of micrometers is generated at the front surface of the target. Electron beams with more charge and higher Energy can be produced during the interaction between the following main laser pulse and the preplasma, which enhance the THz Radiation and affect the Radiation angle. Two dimensional particle-in-cell simulations demonstrate the improvement of electron beams and a nearly tenfold enhancement of THz Radiation Energy is observed.

K N Firsov - One of the best experts on this subject based on the ideXlab platform.

  • high efficiency room temperature znse fe 2 laser with a high pulsed Radiation Energy
    Applied Physics B, 2016
    Co-Authors: A E Dormidonov, K N Firsov, E M Gavrishchuk, Yu S Kazantsev, I G Kononov, V B Ikonnikov, T V Kotereva, D V Savin, N A Timofeeva
    Abstract:

    Characteristics of a ZnSe:Fe2+ laser operating at room temperature of active polycrystalline elements with large transversal dimensions are investigated. The active elements had a shape of plates with diameters D = 25–63 mm and width of ~4 mm, doped from two sides with iron ions by the diffusion method. The plates were doped in the process of hot isostatic pressing at an argon pressure of 100 MPa and temperature of 1250 °C for 75–151 h. The laser was pumped by a non-chain electrodischarge HF laser operated in a single-pulse mode. The employment of active elements with greater transversal dimensions resulted in a suppressed transversal parasitic oscillation at large diameters of the pumping spot. The generation Energy of 1.43 J with the slope efficiency ηslope = 53 % and the total efficiency with respect to the Energy absorbed in an active element ηabs ≈ 48 % was obtained on the sample of diameter D = 63 mm.

  • laser on single crystal znse fe2 with high pulse Radiation Energy at room temperature
    Laser Physics Letters, 2016
    Co-Authors: K N Firsov, E M Gavrishchuk, Yu S Kazantsev, I G Kononov, M P Frolov, Yu V Korostelin, A A Maneshkin, S D Velikanov, I M Yutkin
    Abstract:

    A laser on single-crystal ZnSe:Fe2+ was investigated at room temperature. Pumping of the laser was performed by a pulsed electrodischarge HF laser. In experiments, the spot diameter of HF laser Radiation incident to the surface of the crystal varied from 5.6 to 17 mm. Generation Energy of ~1.2 J was obtained and the efficiency with respect to the Energy arriving at the crystal was η in ≈ 25%. The slope efficiency with respect to the Energy absorbed in the crystal at large spot dimensions was η slope = 45%.

  • increasing the Radiation Energy of znse fe2 laser at room temperature
    Laser Physics Letters, 2014
    Co-Authors: K N Firsov, E M Gavrishchuk, Yu S Kazantsev, I G Kononov, S A Rodin
    Abstract:

    Characteristics of the laser on a polycrystalline ZnSe?:?Fe2+ sample pumped by the Radiation of a non-chain electro-discharge HF laser at room temperature are investigated. The Radiation spot of the HF laser on a surface of an active element had an elliptical shape with the axes a ? b = 2.8???3.2 ? 8.25???9.5?mm. A maximal generation Energy E = 192?mJ was obtained at the efficiency with respect to the Energy absorbed in the sample ?abs = 23% at the dimensions of the pumping spot a ? b = 6.8???7.5?mm. In this case, a maximal slope efficiency with respect to the absorbed Energy was ?sl = 29%. At the spot dimensions a ? b = 2.8???3.2?mm the slope efficiency was ?sl = 34%. Possibilities of a further increase of the generation Energy of a ZnSe?:?Fe2+ laser pumped by Radiation of the HF laser at room temperature are discussed.

Guosheng Song - One of the best experts on this subject based on the ideXlab platform.