• Laser flashes for cancer research

    From ScienceDaily@1:317/3 to All on Monday, March 14, 2022 22:30:40
    Laser flashes for cancer research
    Research team achieves milestone in proton irradiation

    Date:
    March 14, 2022
    Source:
    Helmholtz-Zentrum Dresden-Rossendorf
    Summary:
    Irradiation with fast protons is a more effective and less
    invasive cancer treatment than X-rays. However, modern proton
    therapy requires large particle accelerators, which has experts
    investigating alternative accelerator concepts, such as laser
    systems to accelerate protons. Such systems are deployed in
    preclinical studies to pave the way for optimal radiation therapy. A
    research team has now successfully tested irradiation with laser
    protons on animals.



    FULL STORY ========================================================================== Irradiation with fast protons is a more effective and less invasive
    cancer treatment than X-rays. However, modern proton therapy requires
    large particle accelerators, which has experts investigating alternative accelerator concepts, such as laser systems to accelerate protons. Such
    systems are deployed in preclinical studies to pave the way for
    optimal radiation therapy. A research team led by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now successfully tested irradiation with
    laser protons on animals for the first time, as the group reports in
    the journal Nature Physics.


    ========================================================================== Radiation therapy is one of the main cancer treatment methods. It usually leverages strong, focused X-ray light. Protons -- the nuclei of hydrogen
    atoms -- accelerated to high energies and bundled into small, precisely targetable bunches are an alternative. They can penetrate deep into the
    tissue where they deposit most of their energy in the tumor, destroying
    the cancer while leaving the surrounding tissue largely intact. This makes
    the method both more effective and less invasive than X-ray therapy. "The method is particularly suitable for irradiating tumors at the base of
    the skull, in the brain, and in the central nervous system," explains
    HZDR researcher Dr. Elke Beyreuther. "It is also used in pediatric cancer patients to reduce possible long-term effects." However, the method is significantly more complex than X-ray therapy as it requires elaborate accelerator facilities to generate the fast protons and transport them to
    the patient. This is why there are only a few proton therapy centers in Germany, including one at Dresden University Hospital. Currently, experts
    are working to steadily improve the method and adapt it to patients.

    Laser-based proton accelerators could make a decisive contribution here.

    Customized laser flashes "The approach is based on a high-power laser
    to generate strong and extremely short light pulses, which are fired
    at a thin plastic or metal foil," explains HZDR physicist Dr. Florian
    Kroll. The intensity of these flashes knocks swathes of electrons out
    of the foil, creating a strong electric field that can bundle protons
    into pulses and accelerate them to high energies. Fascinatingly, the
    scale of this process is miniscule: The acceleration path is merely a
    few micrometers long.

    "We have been working on the project for 15 years, but so far, the
    protons hadn't picked up enough energy for irradiation," Beyreuther
    reports. "Also, the pulse intensity was too variable, so we couldn't make
    sure we were delivering the right dose." But over the past few years, scientists finally achieved crucial improvements, in particular thanks
    to a better understanding of the interaction between the laser flashes
    and the foil. "Above all, the precise shape of the laser flashes is particularly important," Kroll explains. "We can now tailor them to
    create proton pulses that have sufficient energy and are also stable
    enough." New research requirements Finally, the parameters had been
    optimized to the point that the HZDR team was able to launch a crucial
    series of experiments: the first-ever, controlled irradiation of tumors
    in mice with laser-accelerated protons. The experiments were carried
    out in cooperation with experts from Dresden University Hospital at
    the OncoRay -- National Center for Radiation Research in Oncology and benchmarked with comparative experiments at the conventional proton
    therapy facility. "We found that our laser-driven proton source can
    generate biologically valuable data," Kroll reports. "This sets the stage
    for further studies that will allow us to test and optimize our method." Another special feature of laser-accelerated proton pulses is their
    enormous intensity. While in conventional proton therapy, the radiation
    dose is administered in a span of a few minutes, the laser-based process
    could occur within a millionth of a second. "There are indications that
    such a rapid dose administration helps spare the healthy surrounding
    tissue even better than before," explains Elke Beyreuther. "We want to
    follow up on these indications with our experimental setup and conduct preclinical studies to investigate when and how this rapid irradiation
    method should be used to gain an advantage in cancer therapy."

    ========================================================================== Story Source: Materials provided by
    Helmholtz-Zentrum_Dresden-Rossendorf. Note: Content may be edited for
    style and length.


    ========================================================================== Journal Reference:
    1. F. Kroll, F.-E. Brack, C. Bernert, S. Bock, E. Bodenstein,
    K. Bru"chner,
    T. Cowan, L. Gaus, R. Gebhardt, U. Helbig, L. Karsch, T. Kluge,
    S. Kraft, M. Krause, E. Lessmann, U. Masood, S. Meister,
    J. Metzkes-Ng, A. Nossula, J. Pawelke, J. Pietzsch, T. Pu"schel,
    M. Reimold, M. Rehwald, C. Richter, H.-P. Schlenvoigt, U. Schramm,
    M.E.P. Umlandt, T. Ziegler, K. Zeil, E.

    Beyreuthe. Tumor irradiation in mice with a laser-accelerated
    proton beam. Nature Physics, 2022 DOI: 10.1038/s41567-022-01520-3 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220314120654.htm

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