200 More Therapies a Year. Without Expanding Decay Tanks.

As radioligand therapy (RLT) continues to grow, hospitals face an increasingly familiar challenge: how to accommodate more patients when their existing radioactive wastewater infrastructure is already operating at full capacity.

How University Hospital Freiburg unlocked additional radioligand therapy capacity by filtering urine from just one patient room.

Expanding conventional decay tank capacity is often easier said than done. In existing hospital buildings, space for additional tanks is frequently unavailable, while ageing installations, piping and technical infrastructure can make extensions technically complex, costly or even impractical.

Moreover, expanding decay tank infrastructure often involves substantial construction work or significant changes to the use of existing hospital spaces. Such modifications may require new building permits, amendments to operational permits or additional regulatory approvals, adding further complexity, costs and delays.

University Hospital Freiburg faced precisely this situation. Its existing decay tanks were operating at maximum capacity, leaving little room for further growth in patient numbers. Expanding the tank infrastructure was not feasible, while replacing the ageing installation was equally unattractive, particularly with a new hospital building envisaged in the longer term, potentially still a decade away.

Yet the demand for nuclear medicine therapies continues to grow today. Waiting for a future hospital building was simply not an option.

“The solution was not to expand or replace the existing decay tanks, but to make better use of the capacity already available.”

By installing a Zereau Urine FilterBOX in one strategically selected patient room, the hospital has created sufficient additional wastewater management capacity to accommodate 200 more patients per year, particularly those receiving Lutetium-177 therapy.

The bottleneck: high-dose iodine therapy

University Hospital Freiburg operates an established nuclear medicine department with dedicated decay tanks for collecting and storing radioactive wastewater. However, these tanks had reached their maximum operational capacity, limiting opportunities to expand the hospital’s treatment programme.

The main constraint was the radioactivity entering the tanks from patients receiving Iodine-131 therapy. In one of the two-bed patient rooms patients receive activities of up to 7.4 GBq of I-131 during weekend treatments. These patients typically remain hospitalised for three nights before discharge.

During their stay, a substantial amount (80-90%) of the administered activity is excreted, mostly through urine. Traditionally, this activity would enter the hospital’s decay tanks, where it must remain until radioactive decay allows the wastewater to be discharged below release limits.

Because I-131 has a physical half-life of approximately eight days and the most stringent release limits, these high-activity wastewater streams effectively occupying tank capacity that could otherwise support additional, other treatments.

A targeted intervention with a major impact

Rather than redesigning the hospital’s wastewater infrastructure, Freiburg installed the first Zereau Urine FilterBOX connected to the existing decay-tank system.

The FilterBOX captures radioactive substances directly from patient urine, before being discharged to the tanks. The treated water continues into the existing wastewater infrastructure, while the captured radioactivity remains concentrated in replaceable filters. The blackwater, with low radioactivity concentrations, is directed straight into the decay tanks.

The compact installation required no structural modifications to the building and could be integrated into the existing wastewater infrastructure without the need for construction work or changes to the use of hospital spaces. By avoiding these interventions, the hospital also avoided the possibly associated building and operational permitting procedures.

By positioning the system in the room accommodating the highest-activity iodine patients, the hospital removes a major source of radioactivity from its wastewater stream. This targeted intervention means that the existing tanks accumulate less activity and can reach their permitted discharge conditions sooner.

The result: faster tank turnover, more available capacity and the opportunity to treat more patients without expanding the existing decay-tank infrastructure.

200 additional patients per year

The impact on the hospital’s treatment capacity is substantial. By reducing the radioactive load from high-dose I-131 patients, University Hospital Freiburg has been able to expand its annual nuclear medicine treatment capacity from approximately 700 to 900 patients.

That represents an increase of almost 30%, with the additional capacity particularly benefiting the hospital’s growing Lu-177 radioligand therapy programme.

Filtration when needed. Bypass when not.

An important feature of the Freiburg installation is its operational flexibility.

During the week, the same patient room is also used for other nuclear medicine patients. For these patients, urine filtration is not always necessary.

The Urine FilterBOX therefore includes a bypass function, allowing the toilet to operate as a conventional toilet connected directly to the existing decay tanks.

Hospital staff can choose whether to activate filtration, depending on the treatment being administered and the available capacity in the decay tanks.

This gives the hospital direct control over how its wastewater infrastructure is used. Filtration is applied where it delivers the greatest benefit, rather than being required for every patient.

It is a practical example of capacity management at source, combining conventional decay storage with selective filtration.

Making better use of existing infrastructure

The Freiburg installation demonstrates that expanding radioligand therapy capacity does not necessarily require larger decay tanks, additional storage rooms or extensive construction work.

For hospitals facing spatial constraints, ageing infrastructure or complex building and permitting requirements, source-based filtration offers an alternative approach to increasing treatment capacity.

Sometimes, the most effective intervention is also the most targeted.

By identifying the patient group responsible for the greatest radioactive load and capturing that activity before it enters the wastewater system, hospitals can significantly improve the performance of their existing infrastructure.

And because the FilterBOX works alongside the existing decay tanks, hospitals retain the flexibility to combine filtration and conventional decay storage according to their operational needs.

“At University Hospital Freiburg, filtering urine from one patient room has helped create capacity for 200 additional patients every year.”

A relatively small intervention, requiring no structural modifications, with a significant impact on patient access to treatment.

“Grow your therapy capacity. Not your decay tanks.”

Discover how Zereau’s Urine FilterBOX can help hospitals expand radioligand therapy programmes by making better use of their existing wastewater infrastructure.