A precise understanding of how ion beams affect biological tissue is of great importance for both radiotherapy applications and the assessment of radioprotection risks, e.g. to astronauts on long term missions in space. The radiation biology and biophysics research groups headed by Professor Markus Löbrich (TU Darmstadt) and Professor Marco Durante (GSI) respectively were the first to conduct experimental high resolution analyses on the 3D lesion distribution induced by high energy ion beams in biological tissue and to compare these with theoretical model predictions.
The biological effects of radiation consist in the damage caused to genetic information (DNA) contained in every cell nucleus. However, cells feature powerful repair mechanisms that can undo a lot of the damage caused by radiation.
That ion beams can induce greater effects than conventional photon (e.g. X ray) radiation can be explained by the extremely high energy they emit over a very small space around the ions’ path. In other words, ion beams can induce highly complex local damage that is far more resistant to repair efforts than the damage caused by photon radiation.
The conceptions favoured to date of ion beam induced 3D lesion patterns are based above all on theoretical considerations deduced from measurements of physical properties. There are no measurement data available for biological systems.
In a joint research project, scientists at the TU Darmstadt and GSI Hemholtzzentrum für Schwerionenforschung were the first to analyse 3D lesion distribution in biological tissue on the submicrometre level and to compare their findings with theoretical predictions. The radiation experiments at GSI used high energy ion beams with the same characteristics as the cosmic radiation in space.
Identification with marker
The analyses were conducted on a tissue with a particularly high density of cell nuclei, facilitating a virtually continuous detection of DNA damage. The identification of damage involved the use of a marker for the most serious form of biological damage, the DNA double strand break, causing the irreversible loss of key genetic information. This experimental approach can visualise the traces of ion induced DNA damage over many cells. The measurements show clearly the concentration of damage at the centre of the ion path and a rapidly declining lesion frequency away from this.
Effects predicted to greater precision
On the one hand, these biological findings confirm the assumptions of 3D lesion distribution based on measured physical properties. On the other, they can be used for a critical analysis and quasi calibration of the various prediction models. These data provide an essential constituent of a model for the prediction of radiation efficacy that was developed by GSI physicists and applied for treatment planning at the ion beam therapy centres in Heidelberg, Marburg, Pavia, and Shanghai for their tumour treatment schedules.
All details can be found in “Direct Measurement of the 3-Dimensional DNA Lesion Distribution Induced by Energetic Charged Particles in a Mouse Model Tissue” by Johanna Mirsch, Francesco Tommasino, Antonia Frohns, Sandro Conrad, Marco Durante, Michael Scholz, Thomas Friedrich, and Markus Löbrich published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS):
MI-Nr. 62e/2015, ml/feu
http://www.pnas.org/content/early/2015/09/17/1508702112.abstract publication online
Silke Paradowski | Technische Universität Darmstadt
Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering