Efforts to attack tumors with a wide variety of particles – protons and various ions, for example – has a long history. The benefit is these particles typically damage only the target tissue and not surrounding tissue. Unfortunately, these beams come from bulky particle accelerators, which make the treatment cost prohibitive for many patients.
An article posted on the Oak Ridge National Laboratory website today (Titan Targets Tumors) details research being conducted at German research laboratory Helmholtz-Zentrum Dresden-Rossendorf (HZDR) that is seeking to replace particle accelerators with high-powered lasers. The electromagnetic fields of the laser can accelerate ions in a very short time, thus effectively reducing the distance needed to accelerate the ions to therapeutic energies from several meters to a few micrometers.
Simulation is a critical step in the work and the HZDR researchers, led by Michael Bussman, are using the GPU-accelerated Titan Supercomputer at Oak Ridge Leadership Computing Facility to run the complex simulations. “I need to simulate a huge volume of atoms over a very long time scale,” according Bussmann, quoted in the article. “The only way to do this comes through supercomputing, because the large volume needs a lot of memory, and the long time scales mean I need a lot of computational power, and that is where the GPUs come into play.”
Titan uses traditional CPUs along with high-speed GPUs, or graphics processing units, to accelerate simulations. Bussmann’s team does all of its calculations on Titan’s GPUs at a rate 10–100 times faster than what is possible on CPU-only machines. “We no longer think of simulations in terms of CPU hours but rather frames per second,” Bussmann said, describing the effect this speed-up has had on the team’s research.
Article excerpt: “When using lasers to treat tumors, researchers must work within extremely small parameters. Typically, a team must aim a laser pulse at a target about the same size as the laser’s focus—no more than several micrometers long. Researchers then suspend a thin foil material; next, they use the laser to excite electrons connected to its atoms and drive the electrons away from the atoms. In the end, the strong separation of negatively charged electrons and now positively charged atoms, or ions, creates the forces that accelerate an ion beam toward the tumor.”
As shown here: Proton density after laser impact on a spherical solid density target: irradiated by an ultra-short, high intensity laser (not in picture) the intense electro-magnetic field rips electrons apart from their ions and creates a plasma. By varying the target geometry and laser properties, scientists could find optimal regimes to accelerate high quality, directed ion beams that are currently studied in accompanying experiments. Image Credits: Axel Huebl, HZDR, David Pugmire, ORNL).
Here are links to the full article written by Eric Gedenk; a Bussmann presentation on the topic; and a related NVIDIA blog:
Article (Titan Target Tumors): https://www.olcf.ornl.gov/2016/01/26/titan-targets-tumors/
Bussmann presentation: http://on-demand.gputechconf.com/gtc/2015/presentation/S5193-Axel-Huebl-Michael-Bussman.pdf
NVIDIA blog: http://on-demand.gputechconf.com/gtc/2015/presentation/S5193-Axel-Huebl-Michael-Bussman.pdf