For the first time Radboud university medical center has treated a patient with liver metastases by using holmium radio-embolization. With this technique, radioactive holmium microspheres are injected via a catheter into the liver artery. These microspheres then become stuck in the small blood vessels of tumors. As a result the tumor is irradiated from close proximity.Patients with metastases in the liver or liver cancer can benefit from this form of internal irradiation, known as radio-embolization of the liver. With this technique, radioactive microspheres are injected with a catheter into the liver artery, after which they become stuck in the capillaries of the tumors. The microspheres then emit radiation with the goal of damaging the tumor as much as possible with minimal damage to normal tissue. This palliative (non-curative) form of therapy has been used for several years at Radboud university medical center, but with yttrium microspheres. For the first time, a patient has now been treated with holmium microspheres at Radboud university medical center. The most important difference between holmium and yttrium is the visibility of holmium on MRI, which yttrium lacks. This provides physicians with more information on the distribution of the microspheres in the liver, even during the procedure.
To the clinic
Radboud university medical center is the third medical center in the Netherlands that can offer this treatment with holmium spheres. Frank Nijsen, medical biologist at the department of Radiology and Nuclear Medicine at Radboud university medical center, is pleased with this innovation. More than a year ago he left UMC Utrecht – where he developed the therapy and founded the spin-off Quirem Medical to bring the therapy to the clinic – and joined Radboud university medical center. He wants to use the opportunities at Radboud university medical center to further improve the therapy.
Nijsen: “Radboud university medical center has the MITeC, the Medical Innovation and Technology expert Center. This is a collection of innovative surgical facilities; for example, MRI is available in the OR itself. This is important because now we can make MRI images during surgery. This enables us to immediately confirm where the spheres are located and in what concentrations, and to adjust the therapy during the procedure if necessary. For the standard procedure, we do not yet use MRI, but we have submitted a research proposal to optimize radio-embolization with MRI.”
Nuclear medicine physician Marcel Janssen, who performed the first procedure with interventional radiologist Mark Arntz and colleagues: “Several weeks before the actual treatment of the patient we already insert a catheter. Afterwards, we determine at what location in the liver artery we can best inject the spheres, we close any ‘leaks’ and we simulate the therapy by injecting soluble protein spheres and observing how they spread. Based on these insights, we decide whether the patient qualifies for the treatment. If all looks well, the patient will be treated 1 or 2 weeks afterwards.”
Because real-time MRI imaging is not yet available, adjusting and fine tuning the therapy in individual patients is not yet possible. “We have demonstrated the efficacy of the therapy in previous studies,” says Nijsen. “By using MRI imaging while administering the microspheres, we hypothesize that we can direct the holmium spheres towards the tumor more effectively. We expect this will yield better outcomes, perhaps even with lower dosages. Over the next few years at the MITeC, we will investigate whether this is possible.”
Quirem Medical, a spin-off of UMC Utrecht, supplies the radioactive micospheres, which are prepared for use by Radboud Translational Medicine. For each treatment, approximately 30 million spheres are used with a diameter of approximately 30 micron. A micron is 0.001 millimeter.