Outstanding biophysics publication: One of the most important articles in six decades
A publication by researchers of the GSI Helmholtz Center for Heavy Ion Research in Darmstadt and the German Cancer Research Center (DKFZ) in Heidelberg is included in the 25 most important articles of the 60-year history of the scientific journal "Physics in Medicine and Biology". The publication dating from the year 2000 was fundamental for the three-dimensional treatment planning in tumor therapy with ion beams based on of the so-called raster scan method.The article was published again in an anniversary edition on the occasion of the 60th birthday of the journal.
The tumor therapy with ion beams is a particularly effective and gentle method. Ion beams penetrate the body and unfold their maximal effect in the tumor tissue, where they are stopped. They can be aimed at the tumor tissue point-by-point with millimeter accuracy using the raster scan method developed by GSI, so that the surrounding healthy tissues are spared. Up to 40,000 raster points in a three-dimensional space can be precisely targeted.
The publication describes the computer programming for treatment planning, which is used for the application of the raster scan method. "The raster scan method for carbon ions was an absolute novelty in radiation therapy back then, and the same is true for the necessary treatment planning. The software is a standard in this field until today," says Dr. Michael Krämer, scientist in the GSI biophysics department and the first author of the publication.
The GSI treatment planning created the basis for radiation therapy adapted to the shape of the tumor by using ion beams with variable intensity and energy and high spatial resolution. "It was innovative to integrate physical and radiobiological modeling, as well as three-dimensional optimization, in the software, and to take into account the relative biological effectiveness of the ions at the same time. This technique or comparable ones are in use in all new facilities for therapy with proton or ion beams today," explains Krämer. The publication was quoted several hundred times until now, representing a measure for its scientific impact. The software TRiP (Treatment planning for particles) is still in use today, not only for carbon ions but also for other particles such as protons, and helium and oxygen ions. Additionally it is used for the treatment planning of of tumors in the lung or liver, which can move during treatment due to breathing ( so-called 4D radiation therapy).
The field of 4D radiation therapy shows a large development potential for future innovative treatment techniques. Furthermore, it is planned to expand the treatment planning software to be used for risk assessment of the radiation hazards in outer space, for example in space flight missions. In the future the research on these topics shall be deepened in the biophysical research both at GSI and also at the planned international accelerator FAIR.
An article on the likewise relevant radiobiological aspects of the tumor therapy with ion beams was published in the same issue of the journal in the year 2000. The two subjects were published separately, although scientifically they belong together. The goal already then: as a first publication the paper about treatment planning aimed to serve as a reference for future research.
The international journal "Physics in Medicine and Biology" issued by IOP Publishing has been published since 1956. It covers publications on physics in relation to medicine and biology, among them e.g. radiation therapy, biomedical imaging, and radiation protection. The editorial office and the international editorial board of the journal selected the publication out of the total number of more than 10,000 publications.