Paul Scherrer Institute (PSI) in Switzerland, houses the world’s first compact scanning gantry for the irradiation of deep-seated tumors using proton beam PBS technology. Under the leadership of Damien Charles Weber, MD, professor of radiation oncology at the University of Bern and Zürich and Head of the Center for Proton Therapy, CPT research focuses on the optimization of treatment delivery and the development of innovative treatment concepts. In this Q&A, Professor Weber offers his insight and experience regarding the field of proton therapy.
Q: What attracted you to the field of proton therapy?
A: In the 1990s, we were using 3D conformal radiation therapy (CRT) to treat most common cancers. We used proton therapy to treat only the very rarest cancers, such as chordoma tumors and other skull-based cancers. Consequently, proton therapy required substantial expertise and knowledge, which I found both very challenging and exciting. I was fascinated by the level of precision protons offered in treating some of the most challenging cancers.
Q: What triggered your research interest in proton therapy?
A: I’ve always been drawn to physics, and how it can be applied to radiation oncology to deliver more effective treatments. Proton therapy was appealing to me because I could see how much it could benefit my neuro oncology research: It allowed me to treat brain tumors in ways never contemplated before particle therapy. Also, proton therapy research has enabled me to combine two fields of research that are often separated: proton and photon therapy. I think this double focus of my research is a great asset because it allows me to research the benefits of particle and non-particle therapies, such as IMRT and volumetric modulated arc therapy, so that patients can receive optimal treatment depending on their clinical situation.
Q: Are there any personal experiences that might have influenced your interest?
A: My involvement in my institution at that time attempts to establish a proton therapy center in the mid-1990’s greatly influenced my interest in proton therapy. I was a young resident at the time and in the wake of the project, I began a fellowship sponsored by Massachusetts General Hospital in proton beam therapy located at the Harvard Laboratory Cyclotron and Northeast Proton Therapy Center in Boston. This fellowship gave me so much insight and experience into proton therapy that I was deeply impressed. I found the physics of particle therapy fascinating. While on fellowship, I was also involved with a radiosurgery program that used proton therapy, and I was amazed by how the two technologies could be used to treat schwannomas or other small targets. Proton therapy to me was – and still is – on the cutting-edge of science in radiation oncology.
Q: What makes your approach to proton therapy research unique?
A: November 23, 1996 – almost 20 years ago – PSI treated its first patient using pencil beam scanning (PBS). Many in the radiotherapy community thought we were headed in the wrong direction because they believed that it was too complicated to use PBS to deliver proton therapy and that passive delivery was more efficient. In fact, these beliefs were so widespread that in 1996 we were the only center offering PBS in Europe. By 2010, we were one of only two centers. However, the benefits of proton therapy with PBS are now so widely embraced that by 2020, all new proton centers in Europe will either be PBS centers or have PBS capacity.
The Center for Proton Therapy at PSI will have 3 gantries by 2017, when we commission our third gantry. In addition, our center is unique because we offer the most advanced ways of delivering PBS proton therapy. For instance, we are looking into line-scanning or contour scanning. By building up the optimal dose distribution, we can precisely tailor the dose to the shape of the tumor in three-dimensions. We are also devising repainting technology for better motion mitigation for optimizing proton delivery.
Q: What makes proton therapy research exciting today?
A: I think there are three aspects that make proton therapy research very interesting. First, motion management presents exciting challenges because the tumor and beam are dynamic, and we are beginning to make significant headway in solving these problems. Also, proton therapy is becoming more accessible as we discover new ways to make this therapy available to patients in need. Finally, research focusing on making proton therapy more affordable presents exciting opportunities to greatly improve health worldwide.