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

11.12.2009
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:
http://www.munich-photonics.de
http://www.ha.physik.uni-muenchen.de/index.html

More articles from Physics and Astronomy:

nachricht Temperature-controlled fiber-optic light source with liquid core
20.06.2018 | Leibniz-Institut für Photonische Technologien e. V.

nachricht New material for splitting water
19.06.2018 | American Institute of Physics

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>