With permission and input from the Founder, Dr. Donald Goer, and the Principal Owner, Mr. Kevin Landis of Intraop Medical Corporation.
This is another cover page story—a continuation of the previous one, “Andrey Mishin: Designing Tomorrow’s Systems, One Electron Beam at a Time.” We offered Dr. Mishin to publish another cover page article about him, but he said he would rather shift the focus to his mentors and describe the history of an intraoperative radiation therapy system called Mobetron, which was born in the early nineties of the previous century at Schonberg Research Corporation (SRC), the first Andrey’s project upon relocation to the United States. Andrey asked for permission and proposed that the founder of Intraop, Dr. Donald Goer, and Mr. Kevin Landis, the current majority owner of the Intraop company, contribute by describing this fantastic machine, sharing treatment cases, and sharing memories; they agreed.
The Mobetron machine can be operated and treat patients without external shielding and is installed in the standard Operating Room (OR) during actual surgery. That was the fundamental idea of this innovative concept for Intra Operative Radiation Therapy (IORT). This publication honors the founder, Dr. Don Goer, and commemorates the late Russell Schonberg, a well-known pioneer and inventor in the particle accelerator community, whose company was the place where many concepts were born and nurtured, reduced to practice, such as Cyberknife for Accuray and Mobetron for Intraop, for example.
The Mobetron was an exciting innovation, representing the world’s first “self-shielded” linac radiation therapy system, as far as we are concerned. The concept of self-shielded machines was explored further, and another remarkable self-shielded machine, ZAP-X, has recently been developed and introduced by Dr. John Adler’s company, ZAP. Incidentally, John and Russell worked together on the Cyberknife concept in its early days. It is fascinating to see how great inventors unite and create.
This history offers a chance to cherish the memory of Andrey’s mentors and his first employer in the United States: a visionary, a sponsor, and a colleague during the six years Dr. Mishin spent at SRC (1993–1998). After helping Russ sell his company assets to AS&E, Andrey became AS&E Vice President and General Manager of the newly formed High Energy Systems Division in Santa Clara, California, based on this acquisition. Russell continued to consult and communicate with Andrey, remaining actively involved for about six to eight years after the acquisition, while also focusing on the business of his new company, which he founded during that period, nearly until his passing. On 22 January 2010, the world lost a truly remarkable person. His obituary highlights his many life accomplishments, recognizing him as one of the pioneers and leading innovators of high-energy linear accelerators.
Perhaps Russell’s strongest suit was this: “As a CEO, he assembled teams of unique, creative people to develop new and exciting ideas. He took the same approach with his family…” Andrey recalls that people loved Russ, just as employees and students had loved his previous mentor, Dr. Igor Shchedrin (who passed on 1 July 2017, in Moscow, Russia). Both “giants” treated their employees as part of their families, which was deeply appreciated and inspired undivided loyalty in return. Andrey feels very blessed to have had these two people in his life as mentors in his early career. Their legacy continues, and Dr. Mishin is proud to carry it forward, leading his own linac school and guiding the High Energy Sources (HES) group at Varex Imaging Corporation.
Dr. Mishin has always praised his mentors, expressing deep respect and gratitude for their wisdom and guidance. He believes that cherishing the memory of one’s mentors and showing appreciation for guidance from more senior colleagues are fundamental qualities for any professional, from the earliest phases of growth to full maturity as an expert. Andrey often quotes Sir Isaac Newton: “If I have seen further, it is by standing on the shoulders of giants.” First, it was Dr. Igor Shchedrin, then Mr. Russell Schonberg – the “giants”, the mentors who shaped Andrey. Mr. Russell Schonberg mentored Dr. Andrey Mishin in the USA, following Dr. Igor Shchedrin, Head of the Small Accelerator Laboratory at Moscow Engineering Physics Institute, who was Andrey’s first mentor in Russia. Many other senior colleagues contributed to Andrey’s growth in both business and science & technology, but these first two “giants” laid the most important foundation for his development.
Now, we return to the history of Mobetron. When Andrey relocated to the USA, Russell was working alongside Dr. Donald Goer, President of SRC at the time and future founder of Intraop Medical Corporation. From that point, Mobetron was produced by Intraop Medical Corporation for intraoperative radiation therapy and later adapted for the treatment of skin cancer. Using high electron beam radiation doses applied in an extremely short interval—now referred to as FLASH Radiation Therapy—this approach holds the potential to be a breakthrough of the century.
Andrey was interviewed in August 1992 and joined SRC in February 1993. He began working on the Mobetron project immediately upon his relocation to Silicon Valley. Russell was already well known in particle accelerator circles for his portable X-band linear accelerator system, MINAC. (“X-Band” is a professional term describing an operational microwave frequency around 9.3 GHz, which largely defines the size of a linac; at this higher frequency, compared with the commonly used 3 GHz or “S-Band,” it was possible to create smaller, portable linacs.) Indeed, SRC had created the original MINAC linear accelerators before Dr. Mishin joined, and with his participation, the existing machines were improved and new designs developed.
In his “previous life”, Andrey had also worked on X-Band linear accelerators under Dr. Igor Shchedrin’s guidance and defended his Ph.D. thesis on a portable 1 MeV X-Band linear accelerator in 1992. This shared history—and some “strange forces” of the universe—brought Russell and Andrey together to work on Mobetron and numerous other projects. The new 4–12 MeV energy-regulated electron beam linac that Andrey designed, based on Russell’s MINAC, became the foundation of the Mobetron system. It allowed a self-shielded design for this unique machine, which could be installed in an operating room at any hospital and used safely without external shielding.
It happened that Don lost his mother in her battle with inoperable cancer. He then decided to create a system that could treat locally advanced tumors with electron beams during an open surgery. Russell was the CEO and the founder of his Schonberg Radiation Corporation (SRC, later renamed Schonberg Research Corporation), and he agreed to help. At that time, Don held the position of SRC President. Together, they initiated the project, and SRC applied for and received a Department of Health (DOH) government grant to develop Mobetron.
Dr. Andrey Mishin, while working with a group of talented individuals employed by SRC or acting as consultants, designed the 12 MeV X-Band linac suitable for this Mobetron system, which was his first major assignment. A novel two-section linear accelerator, with a radio frequency feed operating with a powerful X-Band magnetron (a unique microwave generator at that time, designed at California Tube Laboratories in Watsonville, CA), permitted energy regulation across a broad range of electron beam energies, and therefore a range of electron penetration depths in human tissues. The Accelerator Beam Centerline (ABC) with a unique low-energy buncher—the front part of the linear accelerator, which forms electrons into bunches and was invented by Andrey earlier in his career—along with a patented innovative RF circuit (patent transferred to Intraop), were part of a linac based on the standard SRC X-Band linac system design.
Dr. Don Goer recalls: “Mobetron (Serial #1) was delivered to UCSF in November 1997, and the first patient was treated in December. The case involved a head and neck cancer patient. Dr. Mike Kaplan was the surgeon, and Dr. Mack Roach—who would later succeed Dr. Ted Phillips as Chair of UCSF’s Department of Radiation Oncology—was the radiation oncologist. One particularly vivid memory from this period involved Dr. David Jablons, a thoracic surgeon conducting a Phase II trial using IORT for mesothelioma. Traditionally, mesothelioma treatment involved removing the entire lung. Dr. Jablons was exploring whether it was possible to spare the lung by combining tumor resection with IORT. It offered a much better quality of life for the patient. During one surgery, he called me over to the patient on the table and showed me a beating heart in his hand—he had just repaired an area where the tumor had invaded the pericardium. That extraordinary moment has stayed with me for nearly three decades.”
Here is another amazing story by Don:
“In February 1998, I received a call from Dr. Daphne Haas-Kogan, a pediatric radiation oncologist at UCSF. She wanted to treat a five-year-old girl with a second recurrence of melanoma behind her ear,” Dr. Don Goer said.
“Unless this patient receives IORT,” she told Don, “She has no chance of survival. I reminded her that our initial use of the Mobetron prohibited treating patients under 18,” Don said.
Her response was direct and unwavering: “Don’t tell me I can’t do it. Tell me what I need to do to make it happen.”
“I gave her the name and phone number of the FDA official responsible for our early studies. She contacted him directly and convinced him to grant permission for the treatment. Not long after, I received an angry phone call from that same FDA officer warning me never to bypass protocol like that again,” said Dr. Goer.
Naturally, Don went to UCSF to observe the treatment. Before the procedure, he visited the radiation oncology department, where her colleagues were debating the value of using such a resource-intensive treatment for what they considered a hopeless case. Daphne pushed back firmly: “No. We can save this child.” That was the first time Don met Daphne.
In the scrub room, Don watched her calmly coach a resident through the treatment plan—what energy to use, what applicator size, and what follow-up therapy would be appropriate. It was a masterclass in clinical leadership and mentorship.
In the OR, the small child was lying on the surgical table—so small she didn’t even fill half of it. Dr. Mike Kaplan performed the surgery, and the Mobetron delivered treatment without incident. It was a powerful moment for all involved.
Years later, Don asked Daphne about that patient. She told him the girl had grown into a healthy, vibrant 15-year-old teenager living in the Sacramento area. The skill and commitment of the clinical team at UCSF had clearly saved her life, but Don took pride in knowing that Mobetron had played a role in her survival.
In 1998, SRC assets were sold to American Science and Engineering, Inc. (AS&E), an East-Coast public company focused on security screening. Russell and Don’s vision for Mobetron had created a foundation that persisted even through corporate transitions. Andrey was employed as a Vice President and General Manager of the High Energy Systems Division (HESD), a successor to SRC. The company was headquartered in Billerica, Massachusetts, and focused on linacs for security screening of dense objects—cargo, buildings, and other high-density targets—with domestic and overseas governments as primary customers.
The California Division, which Dr. Mishin managed, built linacs for security screening, provided some assistance to Intraop (which took a life of its own), and mostly focused on completion of the CyberKnife design and technology, selling about 20 linac systems to Accuray. Then the assets of HESD were sold to Accuray in 2005, and Andrey moved to the East Coast, continuing as AS&E Vice President and Technical Fellow, building linacs for security while overseeing projects completely unrelated to radiation therapy machines. In 2008, he was asked by AS&E CEO Anthony Fabiano to spearhead the development of the Russian and Ukrainian markets for AS&E screening systems, moving even further away from Mobetron’s legacy.
By strange destiny, in 2013, Andrey was approached by Dr. John Powers, CEO of Intraop at that time, to build another, shorter accelerator beam centerline for the renewed design of the Mobetron that exists today. Andrey was running his own business then, having founded Radmedex LLC, which produced a new prototype. The prototype was delivered and tested by Intraop in January 2014, and they were impressed with its performance. At that time, Kevin and his Firsthand Capital Management took over ownership and management of Intraop. Andrey’s LLC produced five production units before his businesses were acquired by Varian Medical Corporation to help establish Varex Imaging Corporation, a new public company based on a spin-off of Varian’s component division, headquartered in Salt Lake City, Utah.
In any case, Andrey returned to working with Intraop Mobetron linac design, nearly 20 years after the project was first launched. He reflected: “What were the chances? Now, I believe there was something very special that connected me to Intraop’s Mobetron – it is perhaps a memory of Russell and his schooling. At Varex, we produced nearly 40 ABCs for Mobetron. The linac for Mobetron is part of Russell’s legacy. I understand from medical professionals that it is a great tool for saving lives, and the technical concept is superb.”
The Mobetron concept began to develop and spread among hospitals, and Don kindly shared his recollection of the next steps and the success of the concept: “The Serial Number 2 Mobetron went to University Hospitals of Cleveland. They treated several hundred patients successfully and published several papers about the success of their treatments. They used their Mobetron to treat a variety of tumors, including colorectal cancer, pancreatic cancer, and soft-tissue sarcomas. I remember one patient with a soft-tissue sarcoma of the leg. Instead of amputating his leg, the University Hospital of Cleveland was able to use IORT plus external beam radiation to preserve his leg with complete functionality. UNC also purchased a Mobetron, and they became one of IntraOp Medical’s training centers. Their Chief of Surgical Oncology, Ben Calvo, was very helpful in training a Mobetron user in Colombia because he spoke fluent Spanish, having been born in Bolivia. The Mobetron at Methodist Hospital of Indianapolis was used almost exclusively for locally advanced and recurrent head and neck cancer. The Mobetron was also purchased by Mayo Clinic-Scottsdale, where they treated several disease sites, including colorectal cancer, esophageal cancer, pancreatic cancer, and breast cancer. The James Cancer Center at The Ohio State University purchased a Mobetron and Don became good friends with John Grecula, a radiation oncologist, who was very gracious in providing his expertise to help train Chinese users. Massachusetts General Hospital (MGH) has a Mobetron and has become the leader in the use of IORT with unresectable pancreatic cancer. Historically, this disease killed 50% of patients in the first year, and almost everyone else by year three. Combining modern neoadjuvant chemotherapy and pre-operative external beam chemoradiation therapy with surgery and IORT, MGH has achieved 5-year survivals approaching 50%.”
Andrey described the story as “an impressive story of this concept saving lives”. He noted that “the public rarely hears about these inventors, the creators of such advanced concepts and systems, and the doctors who are putting the systems to work. These are the true heroes operating away from the limelight, usually, so I thought I would share this with many”.
He recalled hearing some of these stories repeatedly among professionals and said, “It brings tears to my eyes every time I hear about cases of saving people, especially very sick children whose chances of survival were close to nothing and who now have their lives back. They have the greatest gift of the Universe – many years in front of them to live, to be a part of humanity, to contribute, and to enjoy.”
Andrey expressed his gratitude to those involved in the development, stating, “I want to thank all who were involved in this development, with many special thanks to Dr. Don Goer, as the initiator of the concept and founder of Intraop, the late Russ Schonberg for supporting this tremendous effort and turning the IORT self-shielded concept into a working Mobetron system that saves lives, and Kevin Landis, who continues this battle and strives to drive Intraop to commercial success.”
He also acknowledged the medical professionals using the system, saying, “The medical doctors who are performing miracles using this system have my deep respect and appreciation. It is a great honor for me to have been involved and to have contributed to the development of Mobetron”.
Andrey concluded by noting the ongoing impact of the system: “The system continues to be used in the ORs, and it happens that this design is also excellent for FLASH radiotherapy, treating skin cancer, for example. Legacy lives!”
