Making a very precise scan of a tumor, plus irradiating it in a targeted way, from within the body. All in one treatment session. That’s theranostics. This therapy method is a huge step forward in the personalized treatment of people with cancer. We catch up with Arthur Braat, UMC Utrecht’s brand new theranostics professor.
Theranostics is a combination of the English words ‘therapy’ (treatment) and ‘diagnostics’ (determining a disease). In other words: diagnosis and treatment take place at the same time.
Theranostics is developing rapidly within cancer care. The approach is already being used for various forms of cancer. The method is now most successful in prostate cancer, neuroendocrine tumors and thyroid cancer.
Arthur Braat has been appointed professor of ‘Theranostics: diagnostics and therapy in nuclear medicine’ as of 1 November 2026. He and his team focus on the further development of this innovative treatment method.
In theranostics, radioactive atoms are linked to, for example, a protein, which helps to transport the ‘package’ through the body. The patient is injected with the drug through an IV.
The first package with a radioactive atom that passes through the IV is intended to light up the tumor during a PET or SPECT scan. This allows doctors to see exactly where and how big the tumor is. In a second package, the same protein is used, but linked to a radioactive atom that is more powerful, irradiating the tumor locally, i.e. from the inside.
Theranostics allows doctors to closely monitor how (quickly) the drug spreads through the body, after which the irradiating substance can do its job in a more targeted way. This also helps to better tailor the treatment and dose to the individual patient in advance: doctors then only add the lightening substance to the molecule at first and make a scan, before also using the more powerful atom.
“Making a scan before treatment is the way for us to select the right patient for the right treatment. We also check whether the drug binds to all of the patient’s tumors, so that we can be sure that we are treating everything and not missing any tumors. You can see this as a kind of ‘test procedure’. Only then do we add the irradiating atom to the agent.”
According to Arthur, his work is not just about fighting tumors: “The biggest challenge in oncology remains to make a treatment as effective as possible, without negatively affecting the quality of life of patients and with as few side effects as possible.”
For example, with theranostics, the surrounding tissue is less damaged. And because it is easier to make it possible to see in advance where a medicine will end up, overtreatment and side effects can be prevented.
“By personalizing treatments for our patients in this way, patients not only benefit from the therapy, but they can also continue to live their daily lives in the best possible way during and after treatment,” says Arthur.
Theranostics is now most successful in prostate cancer, neuroendocrine tumors and thyroid cancer. “This is because we have to find a specific ‘property’ for each tumor, a kind of antenna (receptor – ed.), to which the package with the radioactive atoms can bind,” Arthur explains.
Arthur and his colleagues then make special proteins for this receptor. They bind to the ‘antenna’ but not to healthy cells.
“That balance is very important to us. So, we have not yet found the right protein for many other tumors, but that is only a matter of time. Together with researchers from UMC Utrecht, the Princess Máxima Center and the Netherlands Cancer Institute-Antonie van Leeuwenhoek Hospital (NKI-AVL), we are identifying more and more tumor properties, in the hope of being able to make a new generation of theranostics for each tumor.”
Arthur’s research focuses on brain tumors, neuroendocrine cancer and other rare tumors, among other things. His chair also distinguishes itself by innovative nuclear treatments for children with cancer.
“Theranostics in adults is successful, but we also need to show this development in pediatric tumors, in collaboration with the Princess Máxima Center for pediatric oncology,” says Arthur. “Together with Professor Max van Noesel , we have a team within the Princess Máxima Center that is specifically committed to the development of theranostics within pediatric oncology.”
Arthur and his team are also discovering more and more applications in other forms of cancer. For example, together with associate professor Alex Poot, he is researching how theranostics can help with ovarian cancer. “As soon as a woman with ovarian cancer has metastases, they are difficult to find and the treatments have a very big impact on the patient. We want to change that.”
In addition, together with Alex Poot and assistant professor Berend van der Wildt, Arthur is developing a new platform for the latest generation of theranostics. “The atom Astatine-211 is a very powerful irradiator that easily binds to molecules of, for example, proteins, without us having to adjust the chemical structure first. That will make many new applications for theranostics possible.”
This development is accompanied by the current construction of a state-of-the-art laboratory. In this new lab, Astatine-211 is processed into a drug, as the only hospital in Europe. Here, UMC Utrecht can start the effectiveness of these new drugs as soon as possible.
With the new generation of theranostics for rare tumors, Arthur and his colleagues from the Department of Endocrine Oncology (Endocrine Cancer Center) want to be able to treat patients as quickly as possible. The Endocrine Cancer Center is part of the joint European accreditation of UMC Utrecht and NKI-AVL for rare neuroendocrine tumors (ENETS Center of Excellence)
“Unfortunately, rare tumors are always at the back of the line, but we can change that,” says Arthur.
Arthur studied Medicine in Utrecht and then specialized in nuclear medicine. Since 2017, he has been working as a nuclear medicine physician at UMC Utrecht and the Princess Máxima Center for pediatric oncology.
From 2023, he has also worked at the NKI-AVL in Amsterdam. His professorship strengthens the ties between UMC Utrecht, NKI-AVL and the Princess Máxima Center all the more, because he will also remain active for these centers.
Together, UMC Utrecht, NKI-AVL and the Princess Máxima Center have the knowledge and facilities for the entire process: from the development and production of new radioactive medicines to imaging, clinical studies and application in adults and children. The three centers complement each other perfectly.
“My ambition is to form a joint platform for the development of theranostics, from the development of the drug to the first application in patients,” says Arthur about the collaboration. “Together, we can become the best in the world. I want to pursue that vision in the coming years.”
For Arthur, patient care and science are strongly linked: “My daily work in the treatment room and my research go hand in hand.”
Because he treats patients himself, he sees firsthand which questions remain unanswered. “When I come across relevant clinical questions during my daily practice, I can translate them into my research.” This also allows him to bring new knowledge and therapies to his patients more quickly.
According to Arthur, the ultimate goal of theranostics is easy to summarize: “It’s about the right treatment for the right patient, at the right time.”
How does he think theranostics will be doing in, say, 20 years? “Theranostics is only in its infancy now, but several of these therapies will by then have changed our work immensely because we can see much better in advance which treatment will suit a patient. In this way, the therapy will have less impact on the patient, so that they will be able to continue with their daily activities. Also if they have rarer types of cancer.”
In this video Arthur explains how theranostics works (in Dutch).
