Novel Radiosotopes for Diagnostics and Therapy

Theranostics is a powerful technique that combines diagnostic and therapy in medicine, for cancer treatments in particular. It combines one radioactive drug to identify (diagnose) and a second radioactive drug to deliver therapy to treat, for example, a tumour. 

With the Bern cyclotron, we tackle the scientific and technological challenges of producing suitable quantities of high-purity Sc-43 and Sc-44, which, in combination with Sc-47, are appealing candidates for theranostics in nuclear medicine. Our group develops novel techniques based on solid targets. In particular, a specific target "coin" was conceived and realised to bombard material in form of powder compressed in 6-mm diameter pellets. Another aspect of this challenge is the measurement of the production cross-section, which is being measured with high precision. Beyond Scandium, other radioisotopes are investigated (Ga-68, Cu-61, Cu-64, Tb-155, V-48, Er-165, Tm-165). 

The group was awarded the IBA award 2020 for the publication on the production of Sc-44 with the Bern cyclotron (see "Selected publications" below). This work was performed in collaboration with the Paul Scherrer Institute (PSI).

 

The coin

The "coin" consists of two halves of high-purity aluminium kept together by permanent SmCo magnets. An O-ring is inserted to avoid radioactive degassing during the irradiation. The coin is filled with powder material compressed into a pellet (e.g. 6-mm diameter, 500-um thickness, ~30 mg CaO for Sc and ~100 mg Zn for Ga production). The coin is closed in an inert Ar atmosphere. The thickness of the front side of the coin can be varied to allow for different entry energies to optimise the purity and quantity of the produced radioisotopes. This is done on the basis of their cross sections.

Photo of an open coin. The pallet is positioned in the centre, and the magnets, on the outer radius, close the coin. The one Swiss Franc coin is used as a size reference.

 

The Solid Target Station

The Bern cyclotron is equipped with an IBA NIRTA Solid Target Station with a pneumatic target transfer system by TEMA Sinergie (Italy). It foresees two delivery pathways: to the hot-cell in the radio-pharmacy and to the BTL research bunker.

The solid target station with the pneumatic transfer system.

 

Hyperloop

To load the solid target station without opening and accessing the cyclotron bunker, we developed a mechanical automatic system named HyperLoop. This device allows to drastically reduce both the waiting time and the radiation exposure of the personnel.

Hyperloop, the mechanical system to load the coins from the service area to the cyclotron without access to the bunker.

 

Selected publications

N. P. van der Muelen, R. Hasler, Z/ Talip, P. V. Grundler, C. Favaretto, C. A. Umbricht, C. Müller, G. Dellepiane, T. S. Carzaniga, S. Braccini, Developments toward the Implementation of Sc-44 Production at a Medical Cyclotron, Molecules 2020, 25(20), 4706; https://doi.org/10.3390/molecules25204706

S. Braccini, C. Belver-Aguilar, T.S. Carzaniga, G. Dellepiane, P.D. Häffner, P. Scampoli, Novel Irradiation Methods for Theranostic Radioisotope Production with Solid Targets at the Bern Medical Cyclotron, Proceedings of the International Conference on Cyclotrons and their Applications (CYC), Cape Town, South Africa, 22–27 September 2019; https://doi.org/10.18429/JACoW-Cyclotrons2019-TUA02