We develop radiation detectors and dosimetric methods across two connected tracks — medical imaging and dosimetry — with a deliberate bias toward architectures that don't yet exist.

Detector performance is bounded less by scintillator materials than by the topology of the detector and the readout scheme wrapped around it. Most commercial systems converge on a small number of well-understood configurations, which makes their trade-offs predictable and their limits hard to move. Our work starts from the opposite premise: that unconventional geometries, coupling schemes, and readout topologies remain underexplored, and that the meaningful gains are there rather than in incremental refinement of established designs.

The two tracks share their physics, their electronics, and their people. Concepts and methods cross between them routinely, and that exchange is a large part of why a small group can work across this range.

How we work

Our development chain runs from concept to characterized hardware within a single institution. Monte Carlo simulation in Geant4 and optical photon transport modeling let us evaluate a candidate architecture and quantify its expected performance before any material is committed. Promising concepts move into analogue and digital front-end design in our electronics development laboratory, then to characterization under controlled irradiation using multichannel data acquisition for systematic performance evaluation. Because the loop is short and entirely in-house, we can afford to test ideas that would be uneconomic to outsource.

We carry several concepts at once, at different stages of maturity. Some are refined toward prototypes and IP protection; others are evaluated, understood, and set aside in favor of something better. That turnover is the method, not a failure of it.

Medical imaging

Our imaging work targets positron emission tomography, where the persistent design tension is between spatial resolution, depth-of-interaction capability, and the number of readout channels a system can afford. We pursue two architectural approaches to that problem in parallel.

Virtual voxels in segmented scintillator arrays. A segmented crystal array with light sharing at the entrance face and a dynamic-range-optimized SiPM readout at the opposite end. Rather than treating each crystal as the smallest addressable unit, the light-sharing and readout scheme together resolve interaction position within the array volume — a virtual voxelization that decouples spatial sampling from physical segmentation. Recent work in this line includes a single-ended multiplexed configuration with 4-to-1 crystal-to-pixel coupling that maintains depth-of-interaction capability across the full scintillator matrix, including the edge crystals where conventional light-sharing schemes degrade. The architecture is the subject of an international patent application.

Monolithic detectors with improved light collection. A monolithic scintillator concept combining a new approach to light collection with a matched reconstruction methodology for both planar and depth-of-interaction position determination. Monolithic crystals offer intrinsically continuous position sampling and excellent depth behavior, but their performance stands or falls on how light is collected and how the resulting distribution is interpreted, so we develop both halves together. This work is covered by a separate international patent application.

Elements of both approaches appear applicable to computed tomography. We have not yet investigated that application, and intend to pursue it as a future research direction.

Dosimetry

Our dosimetry track centers on a single detector platform rather than a family of separate instruments. The detector achieves a flat energy response for both ambient dose equivalent, H*(10), and personal dose equivalent, Hp(10), down to 15 keV — a region where conventional instruments typically over- or under-respond substantially. It has been type tested in our own laboratories.

Because the response is governed by intrinsic and geometric parameters that can be adjusted without redesigning the detector, the same platform addresses application domains that would normally require different instruments:

Personal and area dosimetry for occupational and environmental monitoring, including networked instrumentation for continuous measurement.

Airborne radiological mapping, with the detector integrated onto unmanned aerial platforms for radiological survey of terrain and sites. Airborne deployment imposes its own constraints — mass, power, vibration, and the relationship between flight geometry and the resulting dose map — which shape the configuration of the detector.

Radiobiological research support. With the radiobiology group at IMROH, we provide dosimetric characterization and controlled delivery for cell and animal irradiation studies, where accurate dose to the biological target is a precondition for interpreting the biological result.

Collaboration

We work with partners across the Croatian research, clinical, and industrial landscape, including the Department of Physics at the Faculty of Science and the Faculty of Electrical Engineering and Computing, both University of Zagreb; University Hospital Centre Sestre milosrdnice; and R&D companies. These collaborations bring complementary expertise in physics, electronics, and signal processing, and ground our work in clinical practice and real application requirements.

We are actively building international partnerships in detector technologies, medical imaging, radiation protection, and digital signal processing, and are particularly interested in collaborations where an unconventional detector concept meets a problem that standard instrumentation handles badly. Our laboratories are available to external users through joint projects and collaborative arrangements.

Intellectual property and publications

Foreground results from our imaging detector work are protected through international patent applications filed under the Patent Cooperation Treaty. Some technical detail is therefore not publicly available ahead of publication of those applications. Results we are able to share appear on our publications page, and we are open to discussing licensing and joint development with industry partners under appropriate confidentiality arrangements.