Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Tumors under fire: Munich physicists generate highly energetic carbon beams using intense lasers

Oncologists have a dream: they want to use highly energetic ion beams in good quality and accurately defined dose for a pin-sharp and cost-effective radiation treatment of tumors.

Modern techniques based on intense laser pulses may in the future replace expensive conventional particle accelerators. A team of physicists of the Cluster of Excellence "Munich-Centre for Advanced Photonics" (MAP) lead by Prof. Dr. Dietrich Habs (Ludwig-Maximilian University Munich) in cooperation with scientists of the Max-Born-Institute in Berlin now succeeded to finally experimentally demonstrate a mechanism of laser-driven beam generation that has been predicted by theorists long time ago.

The pioneering results are published in the latest issue of Physical Review Letters.

Carbon beams are considered to be the most effective method of cancer therapy, as tumors are destroyed permanently with minimum trauma. Whereas conventional x-rays or electron beams cause significant damage to the surrounding healthy tissue on their pathway into the body, the high biological effectiveness of carbon beams can be precisely concentrated in the tumor, thus exclusively killing targeted cancer cells. Therefore, carbon ions are an outstanding tool for radiation therapy of deeply situated tumors located in highly sensitive regions like in the vicinity of the brain stem, where doctors would refuse to even contemplate surgical intervention. The generation of these beams is currently rather challenging, state-of-the-art are complex huge accelerator facilities which are extremely expensive in construction, operation and maintenance. Hence, the vast majority of today's cancer patients is unable to benefit from this kind of treatment. "As doctors we are dependent on the physicists' progress to develop a cheaper and more compact carbon beam source in order to make ion beam therapy available for everybody" Prof. Dr. Michael Molls points out, another MAP member and director of the TUM Department of Radiation Oncology.

Indeed, in recent years major advances have been achieved in the generation of highly energetic ion beams based on compact lasers instead of large-scale accelerator facilities. "The new technique allows an acceleration distance smaller than the diameter of a human hair," Habs explains. Such small distances are sufficient to accelerate ions to high energies when employing highly intense laser pulses. Not only the accelerator itself, but also the beam guide is being shrunken significantly, as the several tons of weight steering magnets can be replaced by small-sized mirrors. However, up to now no efficient method has been developed to transfer the same amount of energy from the laser to every single ion to allow for a well defined penetration depth of the particle beam in radiation therapy. This is what Prof. Habs and his team are working on. Andreas Henig carried out the first successful experiments together with Berlin physicists: "With the latest results we succeeded in an efficient ion beam generation, while simultaneously reducing the energy spread of the accelerated particles. We are very happy about this experimental break-through!"

The scientists generate the high energy ions by irradiating diamond-like carbon foils with intense laser pulses. Atoms located within the foil are split into electrons and ions by the strong electric field of the laser focus, a plasma is generated. The enormous laser intensity (about 1020 times more intense than the sun) strongly heats the electrons and separates them in an expanding cloud from the heavier and therefore slower ions. A huge charge separation field builds up, accelerating ions to velocities up to a tenth of light speed. However, up to now laser-accelerated ions exhibited a broad energy spectrum, whereas medical applications demand a well-defined particle energy to allow for a precise control of penetration depth and dose distribution in the body.

The group of Munich physicists is the first to experimentally demonstrate an acceleration process which allows all ions to fly with the same velocity. By changing the laser polarization from linear to circular and reducing the diamond-like carbon foil to only a few nanometers in thickness, an uncontrolled heating of the particles and subsequent foil expansion was avoided. Instead, the laser light now pushes the electrons collectively as a nanometer-thin layer in forward direction, dragging carbon ions with it. The whole foil is driven like a sail by the light pressure of the laser - a mechanism that has been predicted by theorists long time ago.

The accomplished results provide the first experimental proof and pave the way towards a cost-saving generation of the highly promising carbon ion beams. The next challenge for the physicists in the Cluster of Excellence is to further increase the energy of the laser-accelerated ion beam. At the moment it is not yet sufficient to penetrate the body far enough to reach deeply situated tumors. Nonetheless, Habs is excited: "Already in a few moths from now we will start irradiating single cells at our biomedical beamline here at the Max-Planck-Institute of Quantum Optics in Garching and will in parallel work hard to further enhance the parameters of the ion beam."

Original publication:
DOI: 10.1103/PhysRevLett.103.245003

Christine Kortenbruck | idw
Further information:

More articles from Physics and Astronomy:

nachricht Novel light sources made of 2D materials
28.10.2016 | Julius-Maximilians-Universität Würzburg

nachricht OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Steering a fusion plasma toward stability

28.10.2016 | Power and Electrical Engineering

Bioluminescent sensor causes brain cells to glow in the dark

28.10.2016 | Life Sciences

Activation of 2 genes linked to development of atherosclerosis

28.10.2016 | Life Sciences

More VideoLinks >>>