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
Scientists propose synestia, a new type of planetary object
23.05.2017 | University of California - Davis
Turmoil in sluggish electrons’ existence
23.05.2017 | Max-Planck-Institut für Quantenoptik
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering
23.05.2017 | Life Sciences