Oncosia Scientific GmbH has received a Forschungszulage grant under Germany's Forschungszulagengesetz (FZulG) for its work on quantitative SPECT/CT reconstruction and multi-time-point dosimetry for actinium-225 (²²⁵Ac).
²²⁵Ac dosimetry raises problems that conventional methods do not solve. Administered activities are low, producing low count statistics; the imaging signal comes from decay-chain daughters such as ²²¹Fr and ²¹³Bi rather than from the parent nuclide; and daughters can redistribute within tissue after recoil. The same challenges apply to other alpha-emitters entering early-phase development, including ²¹²Pb. For sponsors preparing IND and CTA submissions, accurate quantification is required across the full measurement chain — from activity calibration through imaging to absorbed dose calculation — not only at the dosimetry step.
Oncosia is using the grant to extend its existing trial-dosimetry portfolio with a validated end-to-end workflow for targeted alpha therapies, aimed at supporting sponsors running First-in-Human and early-phase trials. The work covers phantom-validated system modelling, a Monte Carlo model of the ²²⁵Ac daughter emission spectrum, a reconstruction algorithm for low-count multi-energy data, and a kinetic model separating parent and daughter contributions, built for 21 CFR Part 11 compliance. The resulting workflow is intended to support site setup and qualification for sponsors running ²²⁵Ac and related alpha-emitter trials and ensuring scientific rigorous reporting for the dosimetry endpoint.
The project is certified as research and development under Germany's Forschungszulagengesetz (FZulG) by the Bescheinigungsstelle Forschungszulage (BSFZ).
"Conventional imaging and dosimetry methods may not transfer to ²²⁵Ac. The photons we image come from daughter nuclides, not the parent, and that changes what we need to correct for and what we can claim about where the dose was delivered. This project strengthens Oncosia's position as an expert provider for sponsors, de-risking the technical and regulatory questions they face, with a validated, compliant workflow end-to-end."
Nico Schürrle — CEO, Oncosia Scientific GmbH
Oncosia Scientific GmbH is a German-based specialist in dosimetry for nuclear medicine — providing patient-specific dosimetry services and software solutions for radioligand therapy, SIRT, and radiopharmaceutical trials. As authorised distributor of PLANET® Dose by DOSIsoft and of Radnostix calibration and reference products, Oncosia Scientific serves nuclear medicine departments, clinical trial sponsors, and CROs requiring expert-led dosimetry and the measurement infrastructure to support it. www.oncosia.de