Skip to main content
Learn More About Proton Therapy
Learn More About Proton Therapy

About Mevion

Mevion Medical Systems exists to deliver on the promise of proton therapy for cancer centers, clinicians and patients worldwide. We invented compact proton therapy and are continuing to transform the industry and patient care with the MEVION S250 Series™.

As a testament to the proven results delivered by our systems, we have more systems installed and treating patients than any other compact proton therapy manufacturer.

Powerful Medicine. Smart Business.

The MEVION S250 Series integrates our patented technology at the very forefront of proton therapy to deliver exceptional beam quality, industry-leading uptime, reduced system size and complexity, higher reliability and throughput, and lower capital and operating costs. Because of these advantages, more NCI-Designated Cancer Centers choose Mevion than any other proton therapy system provider.

The Mevion advantage is clear:

  • Superior clinical performance
  • Highly efficient design
  • Lower cost and rapid deployment
  • Proven profitability

Leadership Team

  • Joseph K. Jachinowski

    President, Chief Executive Officer, Director

    Joseph K. Jachinowski

    President, Chief Executive Officer, Director

    With more than thirty years of experience in the field of oncology, Joe brings an unmatched depth of expertise and experience to our company. He has served as Mevion’s chief executive officer and member of the board of directors since 2009 and president since 2012. Since joining the company, Joe has overseen the development of industry-leading technologies and our growth into a leading global provider of proton therapy systems.

    Joe cofounded IMPAC Medical Systems and served as its president and chief executive officer from 1990 through the company’s initial public offering and sale to Elekta in 2005. After the sale, Joe was an executive vice president of Elekta for four years running global R&D and North American commercial operations. Joe began his career at Varian Medical Systems, Inc., where he led the team that developed linear accelerators from 1983 to 1990.

    He holds a Bachelor of Science from Ohio University and Master of Science from Washington State University.

  • Donald B. Melson

    Vice President, Chief Financial Officer

    Donald B. Melson

    Vice President, Chief Financial Officer

    Donald is an experienced financial leader who joined Mevion in 2013 as chief financial officer. Prior to joining our team, Donald served as vice president and corporate controller for Analogic Corporation, a leading manufacturer of healthcare and security imaging systems. He previously held a similar position at Millipore Corporation, a life sciences tools and technologies company, and held a senior finance role at W.R. Grace & Company.

    He holds a Bachelor of Arts from Brown University an M.B.A. from Columbia University.

  • Patricia A. Davis, Esq

    Vice President, General Counsel, Secretary

    Patricia A. Davis, Esq

    Vice President, General Counsel, Secretary

    Patricia is a licensed patent attorney and seasoned law practitioner with more than twenty years of experience, a majority of those spent serving as in-house counsel for public medical device companies. Before joining Mevion, she was senior vice president, general counsel, and secretary of Cynosure. She served in a similar position at Palomar Medical Technologies when it was acquired by Cynosure. Patricia has also held roles as senior patent counsel at Boston Scientific Corporation and legal associate at Fish & Richardson, P.C.

    She received a Bachelor of Science in Electrical Engineering from Northeastern University and a Juris Doctorate from Suffolk University Law School.