Background Recent advances in nanotechnology have offered new hope for cancer detection, prevention, and treatment. Nanomedicine, a term for the application of nanotechnology in medical and health fields, uses nanoparticles for several applications such as imaging, diagnostic, targeted cancer therapy, drug and gene delivery, tissue engineering, and theranostics. Results Here, we overview the current state-of-the-art of radiolabeled nanoparticles for molecular imaging and radionuclide therapy. Nanostructured radiopharmaceuticals of technetium-99m, copper-64, lutetium-177, and radium-223 are discussed within the scope of this review article. Conclusion Nanoradiopharmaceuticals may lead to better development of theranostics inspired by ingenious delivery and imaging systems. Cancer nano-theranostics have the potential to lead the way to more specific and individualized cancer treatment. Graphical abstract

Hydroxyapatite and titanium dioxide are widely used materials in a broad spectrum of branches. Due to their appropriate properties such as a large specific surface area, radiation stability or relatively low toxicity, they could be potentially used as nanocarriers for medicinal radionuclides for diagnostics and therapy. Two radiolabelling strategies of both nanomaterials were carried out by 99mTc for diagnostic purposes and by 223Ra for therapeutic purposes. The first one was the radionuclide sorption on ready-made nanoparticles and the second one was direct radionuclide incorporation into the structure of the nanoparticles. Achieved labelling yields were higher than 94% in all cases. Afterwards, in vitro stability tests were carried out in several solutions: physiological saline, bovine blood plasma, bovine blood serum, 1% and 5% human albumin solutions. In vitro stability studies were performed as short-term (59 h for 223Ra and 31 h for 99mTc) and long-term experiments (five half-lives of 223Ra, approx. 55 days). Both radiolabelled nanoparticles with 99mTc have shown similar released activities (about 20%) in all solutions. The best results were obtained for 223Ra radiolabelled titanium dioxide nanoparticles, where overall released activities were under 6% for 59 h study in all matrices and under 3% for 55 days in a long-term perspective.

Sorption kinetics of radium on hydroxyapatite and titanium dioxide nanomaterials were studied. The main aim of the current study was to determine the rate-controlling process and the corresponding kinetic model, due to the application of studied nanomaterials as α-emitters’ carriers, and to assess the sorption properties of both materials from the radiopharmaceutical point of view by time regulated sorption experiments on the nanoparticles. Radium-223 was investigated as radionuclide used in targeted alpha particle therapy as an in vivo generator. It was found that the controlling process of the 223Ra sorption kinetics was the diffusion in a reacted layer. Therefore, parameters like particle size, their specific surface area, contact time and temperature played important role. Moreover, the composition of liquid phase, such as pH, the concentration of 223Ra, ionic strength, the presence of complexation ligands, etc., had to be considered. Experiments were conducted under free air conditions and at pH 8 for hydroxyapatite and pH 6 for titanium dioxide in Britton–Robinson buffer. Initial 223Ra concentration was in the range from 10−11 to 10−12 mol/L. It was found that sorption kinetics was very fast (more than 90% in the first hour) in the case of both nanomaterials, so they can be directly used for efficient radium sorption.

Nanoparticles of various materials were proposed as carriers of nuclides in targeted alpha particle therapy to at least partially eliminate the nuclear recoil effect causing the unwanted release of radioactive progeny originating in nuclear decay series of so-called in vivo generators. Here, we report on the study of 211Pb and 211Bi recoils release from the 223Ra surface-labelled TiO2 nanoparticles in the concentration range of 0.01–1 mg/mL using two phase separation methods different in their kinetics in order to test the ability of progeny resorption. We have found significant differences between the centrifugation and the dialysis used for labelled NPs separation as well as that the release of 211Pb and 211Bi from the nanoparticles also depends on the NPs dispersion concentration. These findings support our previously proposed recoils-retaining mechanism of the progeny by their resorption on the NPs surface. At the 24 h time-point, the highest overall released progeny fractions were observed using centrifugation (4.0% and 13.5% for 211Pb and 211Bi, respectively) at 0.01 mg/mL TiO2 concentration. The lowest overall released fractions at the 24 h time-point (1.5% and 2.5% for 211Pb and 211Bi respectively) were observed using dialysis at 1 mg/mL TiO2 concentration. Our findings also indicate that the in vitro stability tests of such radionuclide systems designed to retain recoil-progeny may end up with biased results and particular care needs to be given to in vitro stability test experimental setup to mimic in vivo dynamic conditions. On the other hand, controlled and well-defined progeny release may enhance the alpha-emitter radiation therapy of some tumours.

The interest for ZrP this material is based on its physicochemical properties which makes this material a perspective candidate for applications in nuclear medicine. In this study ZrP was prepared and completely characterized using various analytical methods. Finally, the study of radiometals sorption mechanism on a surface of ZrP and the surface characterization of ZrP were done. In conclusion, ZrP appears as promising for next studies with various purposes like drug delivery system or ion-exchanger for separations of medical radionuclides such as 225Ac and 213Bi.

In this study suitability of α-ZrP nanoparticles as a 223Ra and 225Ac carriers for TAT was investigated. The yields of radiolabelling were higher than 98% in both cases. Subsequently, in vitro stability studies were carried out in various biological matrices during 48 h period. Measurements of released radioactivity showed the highest stability in saline. Released activity of 223Ra, 225Ac and their daughter radionuclides was around 0.5%. On the other hand, the lowest stability was shown in plasma and serum. Released activity for 223Ra, 225Ac and their progeny atoms was from 15 to 32%.

No abstract