Ion Beams in Biology and Medicine: IBIBAM   History

The series of workshops "Heavy Charged Particles in Biology and Medicine" (HCPBM) later renamed in "Ion Beams in Biology and Medicines" (IBIBAM) started in 1982 when Professor Cornelius Tobias from the Lawrence Berkeley Laboratory was visiting GSI for a few weeks.

Because of Tobias special interest in modelling, the 1^st workshop had the special topic: Models on Energy Deposition of Ionizing Radiation and the Biological Response. Approximately 30 scientists participated in the workshop held at GSI on June, 27-29. Speakers included A.M. Kellerer, C.A. Tobias, W. Pohlit, H. Paretzke, S. Curtis, D. Harder, H.P. Leenhouts and others. The spirit of this workshop was to present overviews in a sufficient time followed by an intense discussion. Although it was not expected at this first meeting to find one commonly accepted model, the workshop clarified position and stimulated future discussion.

After 4 years September 23-25, 1987 one year before the completion of the SIS the 3^rd workshop was held at GSI and more than 100 scientists participated. The program became more detailed; the physics of track structure was of greater interest and covered by M.N. Varma, L. Toburen, W. Schimmerling, and J. Kiefer. Chemistry and DNA damages became a new topic presented by H.A. Wright, A. Chatterjee, J. La Verne, J. Hüttermann, R.Roots, I.Kaneko. New aspects were also chromosomal aberrations induced by heavy ions (C. Geard, T.C. Yang, and G. Kraft) and the large influence of LET on other parameters like inactivation and repair (E.A. Blakely, G. Illiakis). New was also the report on space biology by R.J.M. Fry, S. Nachtwey, H. Bücker, J. Ainsworth. Cancer Therapy and status reports were the topic of the last day including reports on the pion- (G.B. Goodman), proton- (J. Munzenrider) and heavy ion-trials (J. Castro).

After a larger break filled with construction of a radiobiology area at new SIS the commissioning of the prototype of a high energy raster scan system the 4th workshop was held again at GSI September 23-25, 1991. At that time the first accelerator dedicated for therapy started at Loma Linda. Himac at Chiba, Japan was under construction and a proton beam line for therapy was installed at Villigen, Switzerland. This was a great and exciting time and the workshop provided an excellent basis for exchange and discussions. But our main goal to start a therapy program at the new facility was not accepted from GSI's scientific director. At the end of the workshop in a closing remark he stated very emotionally "that there will be never, never, never patients at GSI."

The situation at GSI had changed completely at the 5^th workshop held August 23-25 1995. Because of a change in the GSI directorship 1993 a carbon therapy project was started with high priority in April 1993 and with the very ambitious goal to treat the first patient within less than 4 years although a completely new strategy was planed: The project should be based on an active beam delivery using 3D scan techniques and an advanced biology based treatment planning. In addition, PET methods should be used to control the beam inside the patients. Meanwhile, the therapy units at Chiba and Loma Linda were in operation and Villigen was close to start. In Italy and Austria the initiatives TERA and MedAustron were started for the promotion of heavy ion therapy and the workshop at GSI was a market place for the exchange of ideas and mutual help. This was clearly reflected in the program where not only the new GSI project was discussed in extenso but also sessions on treatment planning, instrumentation complemented the clinical reports and the therapy status reports.

Because of the good public relation results at GSI the 6^th workshop was decided to be at Baveno, Italy to promote the new Italian TERA project for heavy ion therapy. The Baveno meeting was extreme dense in the program but also in the discussions: A history overview talk by L. Skarsgard was followed by a great radiobiology program with sessions on DNA damage and repair, chromosome aberrations, mutation, cell and tissue radiobiology and RBE. Triggered by the indented use of the novel technology of beam scanning, the question of the clinical RBE’s, even local RBE’s for each pixel became a central topic: It was very clear that only a deeper theoretical understanding would allow to follow the RBE dependence from physical and biological variables in a treatment field. Consequently a session was dedicated to compare the different theoretical approaches: Dual radiation theory (A.M. Kellerer), Local effect model (M. Scholz), Amorphous track structure model (R. Katz) and more or less microdosimetric approaches (A. Campa & A.Ottolenghi). The problems of treatment planning and dosimetry for raster and spot scanning were another extended topic including the problems of quality assurance in particle therapy. There, the new in vivo PET monitoring of the carbon beam in a patient was the highlight (W. Enghardt) followed by the summary of the clinical proton and ion data and the status reports of the existing and upcoming projects.

The 7^th workshop September 28-30 2000 at GSI Darmstadt was a very special one and focused on one topic only: the integration of RBE into clinical treatment planning. The questions were: are there different RBE values for different biological endpoints, like inactivation, mutation, chromosome aberration, late effects. What are the reference data for treatment planning? How to integrate RBE into treatment planning? How could we produce clinical RBE´s and which of the different models yields the best results? Because these were urgent questions, the time structure of the workshop was organized in overview talks only and amble time for discussions, this means 4 speaker in a two hour session and nearly half of the time for discussion. As a result it turned out that there are general approaches to assign an RBE dependence from depth (Berkeley, Chiba) which are sufficient for passive beam preparations. At Chiba the important step from in vivo RBE values to in vitro data was achieved over the clinical neutron experience. For scanned beams, the Local Effect Model LEM as already used in the daily routine at GSI produced a pointwise RBE field. At this workshop also the idea of a contest for RBE was discussed for the first time: For a well defined, high LET experiment with cells, the various modellers should predict the outcome of cell survival. (This contest was much later performed but did not really clear the situation). The RBE discussion was followed at the last day by status reports and clinical data. These intense days were complemented by a beautiful concert with works from Vivaldi, Mendelson-Bartholdy, Flotow & Offenbach for violin and piano. This was one of the most fruitful workshops and supported by the Heraeus foundation.

September 26-28 2002 the 8^th workshop was organized at Baden near Vienna by the Austrian Hadrontherapy project in collaboration with the newly formed European Network for Light Ion Therapy initiative: Enlight. This combination with the workshop gave the Enlight group a lot of useful information and a platform for discussions. Baden was definitely one of the finest locations we had for the workshops and provided accordingly an excellent working atmosphere. In this meeting basic science like physics and biology were compressed to one day but medical physic with three session covered treatment planning, dose prescription, patient positioning and fixation. Epidemiology, patient recruitment specific for high LET radiation and the criteria for their selection preceded the session on clinical data and the status reports. Two Enlight sessions on the ”reporting of Hadrontherapy" and "the standard radiation quality to which the hadrontherapy should be compared” completed the program.

At the Baden meeting it was decided to have the 9^th workshop after a short break of one year only October 2-5 2003 at Lyon again together with the Enlight working meeting. The workshop was clearly structured in: radiobiology, physics and space research, treatment planning, a round table on “recording and reporting Hadrontherapy“, a very strange session where the discussion leaders used most of the allocated time to present their own results far from the topic. The scientific part was ended with presentations on accelerator and gantry developments and as new topic socioeconomic studies very presented. Then status reports and clinical data were presented followed by the 3^rd Enlight coordination meeting.

The 10^th workshop was held June 15-19, 2005 at Oropa (Biella) Italy together with the 4^th Enlight meeting. On the occasion of the anniversary, this meeting started with a summary of the 9 meetings of the last 20 years given by G. Kraft and a show of selected photos of the participants of these meetings. In the scientific part the radiobiology has clearly shifted to molecular biology, including signalling, genetic instability and as a novel and rapidly evolving field, the formation of foci at the location of particle traversals through the cell nucleus (G.Taucher-Scholz). For the first time it was possible to see the local effects of tracks inside a cell nucleus and to follow the processing of the induced damage by using differently labelled antibodies. Another highlight of this meeting was F. Cucinottas review on radiation effects in space. In the more therapy related sessions again treatment planning and the integration of the proper RBE were central as well as epidemiology and clinical data for carbon therapy. Meanwhile two projects at Heidelberg and Pavia had started to work and were reported in some detail. But the major part of clinical information came from NIRS Chiba presented by H. Tusjii. The last half day took an Enlight internal discussion.

The 11^th workshop now called IBIBAM meeting at Heidelberg September 26-29, 2007 was held together with many German and Swiss societies on radiation protection, nuclear physics and medical physics. At Heidelberg the Heidelberg Ion Therapy HIT was under construction. Although HIT was still far from patient treatment, the technical layout was in a status that the principles of a modern therapy facility for both protons and carbon ions were visible. In addition the radiation protection people could inspect the care taken for shielding and other safety devices. Accordingly the workshop started with a sessions “Radiation safety“ and “particle physics“ where legal aspect for such facilities and the personal working there were presented. Also the different layouts of particle therapy centers were compared and computer codes for nuclear fragmentation, especially the neutron production were presented. The biology session focussed on molecular aspect and in the following dosimetry sessions on the beam monitoring inside the patient via PET techniques. But also new detectors for particle radiation were discussed. The session “Radiobiology 2“ was less molecular but close to the following session on treatment planning. New at this meeting were the large number of participants close to 200 and a new topic: the treatment of moving organs with a scanned beam, an area that still deserves intense research and development (C. Bert). A session on “Dream Beams” reported on the research for smaller accelerators: the laser driven acceleration (S. Kraft) and the dielectric wall accelerators (K. Blasche). Both techniques have a some potential but are many years away from clinical applications. Clinical results and status reports ended the meeting where new reports on the Pavia, Marburg and Kiel projects were presented; the two later ones were just started.

The 12^th workshop was integrated in a larger conference: Heavy ions in therapy and space, held at Cologne July 6-10 2009 as a joint meeting of the 1^st ESA and the 20^th NASA Space Radiation Health investigators workshop and the 5^th International workshop on Space Radiation Research. The number of the participants and the many presentation made parallel sessions necessary where the therapy related topics were separated from the Space research. So at one side the medical physics paralleled the space radiation sessions but also the molecular biology which was one complete day of damage processing after heavy ion exposure was in parallel to the status reports of accelerators, facilities and clinical data. Cancer and dosimetry were also at the same time. Only at the very end at Friday morning the effects on the central nervous system was a non parallel session of interest for both communities. But in between the conference provided a great chance to discuss problems that are common to space research and therapy like the induction of cancer and late effects. All together it was a great meeting in the center of the city of Cologne.

Speakers at the IBIBAM-Workshops