The Principal System Physicist will be part of the Product Engineering group, a multi-disciplinary team of radiotherapy use experts. This team will work with the design engineers and outside clinicians to define, develop, and validate the clinical performance of new RefleXion’s unique Biology Guided Radiation therapy product. The successful candidate will need a strong background in computational radiation physics, radiation therapy, diagnostic imaging, commissioning radiation therapy systems, and clinical workflow.

Principal System Physicist shall have a deep understanding of the state of the art in several of the underlying theory and technologies that constitute the Reflexion BgRT system such as particle physics, Monte Carlo modeling, dynamic system behavior, PET/CT imaging, radiation beam generation, collimation systems, treatment planning systems, dose calculation and optimization method.  

Principal System Physicist will lead projects resolving issues crossing multidisciplinary boundaries, frequently solving problems that have never been solved before, and will participate in early prototyping of many of the solutions as part of these projects and standardizing the process for scalability.


  • Lead projects to develop and/or refine beam modeling and commissioning procedures for Reflexion’s Biology-guided Radiation Therapy platform and Treatment Planning System.
  • Work with a team of radiation physicists, software and algorithm engineers to define the measurement and analysis methodologies for radiation beam characteristics, performance metrics, and evaluate the procedures at the factory and utilize them in commissioning on-site installations.
  • Drive projects to standardize the beam modeling and commissioning procedures and transfer knowledge to others in R&D and Operations to scale with the business, as Reflexion’s platform and Treatment Planning software evolve in functionality and capabilities.
  • Provide guidance to the product development teams to ensure that RefleXion’s products meet their clinical performance goals.
  • Collaborate with clinical partners and KOL’s in the industry to develop protocols and criteria for acceptance and clinical utilization of Reflexion systems
  • Publish system evaluation and clinical performance papers in collaboration with clinical partners, KOL’s, and internal R&D partners.
  • Develop protocols and conduct formal testing to validate the clinical safety and efficacy of the product.
  • Support Regulatory (FDA, CE, …) documentation and applications
  • Collaborate with other organizations within the company as needed i.e., regulatory, product education. training, sales and marketing
  • Keep the organization’s vision and values at the forefront of decision making and actions
  • Perform other duties as required to support the company's overall strategy and goals
  • Other duties as assigned


  • Master’s of Science or PhD degree in Physics or Engineering and relevant clinical/research work experience.
  • Strong background in computational radiation physics, radiation therapy, diagnostic imaging,  radiation therapy systems,  and clinical workflow.
  • Demonstrated understanding of the state of the art in several of the underlying theory and technologies that constitute the Reflexion BgRT system: particle physics, Monte Carlo modeling, dynamic system behavior, PET/CT imaging, radiation beam generation, collimation systems, treatment planning systems, dose calculation and optimization method.
  • Experience in commissioning state-of-the-art radiation therapy systems for clinical use, and demonstrated ability to meet performance requirements for clinical use.
  • Clinical experience in radiation therapy or radiosurgery in a cancer center with strong research focus, and a track record of introduction of novel radiation therapy technologies is highly desirable.
  • Demonstrated success working as part of a cross-functional product development team and lead cross-functional projects to move successful products from concept through launch.
  • Hands-on experience with QA methodologies, commercially available tools, devices, and software for radiation therapy and medical imaging.
  • Familiarity with current medical physics guidance reports including AAPM, ICRU, IAEA
  • Excellent communicator with strong written and oral presentation skills.
  • Excellent teamwork skills
  • Use of Microsoft office tools for documentation and data analysis
  • Ability to program in Matlab or equivalent language for simulation and data analysis is highly desirable
  • Must be a self-starter and work with minimal supervision.
  • Experience with design control process & deliverables is highly desirable
  • Proven experience in a fast paced, high transaction environment
  • A passion for creating robust and reliable products

Company Benefits and Perks – What you will love about us!

All positions at RefleXion are eligible to receive the same benefits, listed here. We also want to highlight the following perks that add to our collaborative and team-work company culture.  As we continue to grow as a company, we strive to have these benefits and perks grow with us – we are so excited for what is in store! 

  • The opportunity to work with a passionate, driven team in a pre-IPO start-up environment
  • Competitive compensation and stock option package
  • Three (3) weeks PTO to start
  • Medical (both HMO and PPO options), Dental and Vision
  • Health Savings Account (HSA), Flexible Spending Account (FSA), Dependent Care Flexible Spending Account (DCFSA)
  • Employee Assistance Program (EAP)
  • 401K
  • Employer paid Life Insurance
  • RefleXion Benefit Hub – for company exclusive discounts and deals on a variety of sites and items
  • Free daily on-site lunches
  • Kitchens filled with a variety of healthy and delicious snacks and drinks – including espresso and soda machines!
  • Company culture building events such as Coffee Chats with the Executives, Friday Afternoon Ice Cream Socials and monthly Book Club
  • On-site mobile car wash services weekly
  • Electric car charging stations on site



Apply for this Job

* Required


U.S. Equal Opportunity Employment Information (Completion is voluntary)

Individuals seeking employment at RefleXion Medical are considered without regards to race, color, religion, national origin, age, sex, marital status, ancestry, physical or mental disability, veteran status, gender identity, or sexual orientation. You are being given the opportunity to provide the following information in order to help us comply with federal and state Equal Employment Opportunity/Affirmative Action record keeping, reporting, and other legal requirements.

Completion of the form is entirely voluntary. Whatever your decision, it will not be considered in the hiring process or thereafter. Any information that you do provide will be recorded and maintained in a confidential file.

Race & Ethnicity Definitions

If you believe you belong to any of the categories of protected veterans listed below, please indicate by making the appropriate selection. As a government contractor subject to Vietnam Era Veterans Readjustment Assistance Act (VEVRAA), we request this information in order to measure the effectiveness of the outreach and positive recruitment efforts we undertake pursuant to VEVRAA. Classification of protected categories is as follows:

A "disabled veteran" is one of the following: a veteran of the U.S. military, ground, naval or air service who is entitled to compensation (or who but for the receipt of military retired pay would be entitled to compensation) under laws administered by the Secretary of Veterans Affairs; or a person who was discharged or released from active duty because of a service-connected disability.

A "recently separated veteran" means any veteran during the three-year period beginning on the date of such veteran's discharge or release from active duty in the U.S. military, ground, naval, or air service.

An "active duty wartime or campaign badge veteran" means a veteran who served on active duty in the U.S. military, ground, naval or air service during a war, or in a campaign or expedition for which a campaign badge has been authorized under the laws administered by the Department of Defense.

An "Armed forces service medal veteran" means a veteran who, while serving on active duty in the U.S. military, ground, naval or air service, participated in a United States military operation for which an Armed Forces service medal was awarded pursuant to Executive Order 12985.

Form CC-305

OMB Control Number 1250-0005

Expires 05/31/2023

Voluntary Self-Identification of Disability

Why are you being asked to complete this form?

We are a federal contractor or subcontractor required by law to provide equal employment opportunity to qualified people with disabilities. We are also required to measure our progress toward having at least 7% of our workforce be individuals with disabilities. To do this, we must ask applicants and employees if they have a disability or have ever had a disability. Because a person may become disabled at any time, we ask all of our employees to update their information at least every five years.

Identifying yourself as an individual with a disability is voluntary, and we hope that you will choose to do so. Your answer will be maintained confidentially and not be seen by selecting officials or anyone else involved in making personnel decisions. Completing the form will not negatively impact you in any way, regardless of whether you have self-identified in the past. For more information about this form or the equal employment obligations of federal contractors under Section 503 of the Rehabilitation Act, visit the U.S. Department of Labor’s Office of Federal Contract Compliance Programs (OFCCP) website at

How do you know if you have a disability?

You are considered to have a disability if you have a physical or mental impairment or medical condition that substantially limits a major life activity, or if you have a history or record of such an impairment or medical condition.

Disabilities include, but are not limited to:

  • Autism
  • Autoimmune disorder, for example, lupus, fibromyalgia, rheumatoid arthritis, or HIV/AIDS
  • Blind or low vision
  • Cancer
  • Cardiovascular or heart disease
  • Celiac disease
  • Cerebral palsy
  • Deaf or hard of hearing
  • Depression or anxiety
  • Diabetes
  • Epilepsy
  • Gastrointestinal disorders, for example, Crohn's Disease, or irritable bowel syndrome
  • Intellectual disability
  • Missing limbs or partially missing limbs
  • Nervous system condition for example, migraine headaches, Parkinson’s disease, or Multiple sclerosis (MS)
  • Psychiatric condition, for example, bipolar disorder, schizophrenia, PTSD, or major depression

1Section 503 of the Rehabilitation Act of 1973, as amended. For more information about this form or the equal employment obligations of Federal contractors, visit the U.S. Department of Labor's Office of Federal Contract Compliance Programs (OFCCP) website at

PUBLIC BURDEN STATEMENT: According to the Paperwork Reduction Act of 1995 no persons are required to respond to a collection of information unless such collection displays a valid OMB control number. This survey should take about 5 minutes to complete.