Novel Gadolinium-Free Ultrasmall Nanostructured Positive Contrast for Magnetic Resonance Angiography and Imaging.

Nanostructured contrast agents are promising alternatives to Gd3+-based chelates in magnetic resonance (MR) imaging techniques. A novel ultrasmall paramagnetic nanoparticle (UPN) was strategically designed to maximize the number of exposed paramagnetic sites and r1 while minimizing r2, by decorating 3 nm titanium dioxide nanoparticles with suitable amounts of iron oxide. Its relaxometric parameters are comparable to those of gadoteric acid (GA) in agar phantoms, and the r2/r1 ratio of 1.38 at 3 T is close to the ideal unitary value. The strong and prolonged contrast enhancement of UPN before renal excretion was confirmed by T1-weighted MR images of Wistar rats after intravenous bolus injection. Those results associated with good biocompatibility indicate its high potential as an alternative blood-pool contrast agent to the GA gold standard for MR angiography, especially for patients with severe renal impairment.

Highly efficient method for production of radioactive silver seed cores for brachytherapy.

A simple and highly efficient (shorter reaction time and almost no rework) method for production of iodine based radioactive silver seed cores for brachytherapy is described. The method allows almost quantitative deposition of iodine-131 on dozens of silver substrates at once, with even distribution of activity per core and insignificant amounts of liquid and solid radioactive wastes, allowing the fabrication of cheaper radioactive iodine seeds for brachytherapy.