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 Hubble sees Neptune's mysterious shrinking storm
16.02.2018 | NASA/Goddard Space Flight Center

nachricht Supermassive black hole model predicts characteristic light signals at cusp of collision
15.02.2018 | Rochester Institute of Technology

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: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>