Our experience

The origin of our solutions in proton therapy

The services of Trees with Character are built on the founder's 20+ years (since 2000) of experience in proton therapy.

Where and what


  • Formal training as a medical radiation physicist at University of Wales
  • 10 years at the Paul Scherrer Institut (Center for Proton Therapy, Switzerland)
  • 5 years as a project manager of the Amsterdam Proton Therapy Center (Netherlands)
  • Independent proton therapy consultant since 2016


  • Treatment of 1800+ patients with proton therapy
  • Responsible for realisation of new ocular treatment room
  • Project leader to realise entirely new proton therapy center
  • Responsible for procurement of proton therapy equipment (European public tender)
  • Developing exploitation model and business case for proton therapy center
  • Building an extensive network in proton therapy

See also our Publications and our Cases.

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Our clients

Projects and proton therapy

For the following clients we have provided services in proton therapy.

Workshops & Speaking

Workshop Proton Therapy.

A hands-on approach

When considering proton therapy, but not yet ready to commit (and could use a simple client-specific business case).


In the workshop proton therapy a wide range of relevant aspects and conditions are covered, ending with a simple but useful and client-specific business case.

Following a first meeting to learn about the client’s particular thinking and its situation a client-specific workshop will be prepared. Typical topics to be included:

  • Why proton therapy, and why not
  • Brief overview of history of proton therapy
  • The lessons learned and the lessons apparently too hard to learn
  • Patient selection and referral
  • Costs and revenues, risks and financing
  • Let’s make a business case!


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Let’s talk proton therapy!

Asking questions is for free.

When you want to learn about proton therapy first hand, from the why to the how, from the benefits to the risks.

Speaker engagements

Should you consider proton therapy for your patients? What does it involve? How to identify the patients who benefit from it most? Why are so many centers struggling? Where is proton therapy heading? The list of possible topics is practically endless.

The founder of Trees with Character, Jorn Verweij, has given countless presentations on many different topics, for audiences ranging from hospital administrators, investors, clinicians and medical physicists to interested laymen.

Jorn Verweij can draw from a wide range of experiences in proton therapy, from treating patients to dealing with vendors, banks, and healthcare authorities.

Above all, Jorn Verweij can draw from enthusiasm for doing proton therapy the right way, offering all of the benefits and minimise the risks involved.


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Other services

Proton Therapy Consultancy for Initiatives.

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Independent Risk Assessment for Initiatives and Investors

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Vendor selection and procurement

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more services >

You can learn more about what we do by reading our cases.

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‘Procuring proton therapy equipment.’

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‘A Business Case for a Proton Therapy Initiative.’

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‘Project managing a proton therapy center.’

more Cases >
Patient selection and patient referral are pivotal.

Many proton therapy centers struggle because of an unrealistic projection of the number of patients that will be treated. In the past, and even in the present, the number of patients projected to be treated was simply the number that was required to make the business case look good. Today we know that the most successful centers treat, on average, no more than 300 patients per treatment room. But to achieve even this number takes great effort. There is the challenge of identifying the patients who will benefit from proton therapy, and there is the challenge of getting these people referred to the center.

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Don’t buy equipment, identify the right vendor.

Initiatives who want to provide proton therapy treatments — often hospital organisations — are confronted with very complex and very capital intensive equipment they have never procured before. A proton therapy project is perceived as a major risk, and rightly so. Too many centers have failed or are failing. The risk lies not with the equipment, however. All vendors build reliable machinery delivering identical protons. Not all vendors, however, provide the same expertise and solutions. Initiatives should not focus on technology, but on identifying the vendor who is best able to meet their particular challenges.

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You can start to minimise risk in proton therapy today.

A decision is a conclusion reached after careful consideration. If you have to think about something it means this something is not transparent. If you take a decision when something is not transparent risk increases. This risk is minimised by unambiguous aims and access to expertise. What is it that you need to achieve? Who is the expert that will help you achieve it? Trees with Character helps with both.

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Proton therapy technology is the least of your worries.

Cyclotrons and synchrotrons alike are built to last for decades — as is shown by the early proton therapy centers who became operational in the previous millennium. To this day, however, the complexity of the equipment often is an initiative’s biggest concern and many resources are spent on trying to understand it. Meanwhile none of the proton therapy centers who failed failed because of the technology. There are other, much more relevant issues and challenges to be considered.

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Independent consultancy made the difference for us.

Proton therapy vendors have a lot of expertise. They also need to sell their equipment and associated services and may not point out which of an initiative’s assumptions are unrealistic. Some consultants possess great expertise — as well as an agreement with a vendor. Independent consultancy can make a difference. Independent consultancy means that the only interest to consider is your interest. Trees with Character will help you to make the right choices.

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Proton Therapy’s biggest problem is lack of transparency.

Initiatives don’t share their overall aims, vendors focus on technology. Everybody is blind to the other side’s needs and capabilities. Without transparency everything is a risk. Everybody is looking for safety and control. Many resources are spent on inspections, on meetings, on the contract. But there is another way.

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