Fully-automated radiosynthesizers are continuing to be developed to meet the growing need for the reliable production of positron emission tomography (PET) tracers made under current good manufacturing practice (cGMP) guidelines. There is a current trend towards supporting “kit-like” disposable cassettes that come preconfigured for particular tracers, thus eliminating the need for cleaning protocols between syntheses and enabling quick transitions to synthesizing other tracers. Though ideal for production, these systems are often limited for the development of novel tracers due to pressure, temperature, and chemical compatibility considerations. This study demonstrates the versatile use of the ELIXYS fully-automated radiosynthesizer to adapt and produce eight different 18F-labeled PET tracers of varying complexity. Methods Three reactor syntheses of D-[18F]FAC, L-[18F]FMAU, and D-[18F]FEAU along with the one reactor syntheses of D-[18F]FEAU, [18F]FDG, [18F]FLT, [18F]Fallypride, [18F]FHBG, and [18F]SFB were all produced using ELIXYS without the need for any hardware modifications or reconfiguration. Synthesis protocols were adapted, and slightly modified from literature, but not fully optimized. Furthermore, [18F]FLT, [18F]FDG, and [18F]Fallypride were produced sequentially on the same day and used for preclinical imaging of A431 tumor-bearing SCID mice and wild-type BALB/c mice, respectively. To assess future translation to the clinical setting, several batches of tracers were subjected to a full set of quality control tests. Results All tracers were produced with radiochemical yields comparable to those in literature. [18F]FLT, [18F]FDG, and [18F]Fallypride were successfully used to image the mice with results consistent with literature. All tracers subjected to clinical quality control tests passed. Conclusion The ELIXYS radiosynthesizer facilitates rapid tracer development and is capable of producing multiple 18F-labeled PET tracers suitable for clinical applications using the same hardware setup.

The temperature dependence of morphology of InAs islands on Si grown through Stranski–Krastanow mode is investigated by atomic force microscopy. Formation of islands in the range of 15–50 nm is observed for depositions at various temperatures for the same monolayer coverage. Growth temperatures between 400 and 425 °C are found to yield dense ensembles of islands with uniform dimensional distributions. Found to exhibit long-term stability, these islands undergo morphological transformation when annealed at temperatures above 700 °C. Ostwald ripening occurs in these islands through an enhanced surface diffusion mechanism at high annealing temperatures. The results of annealing experiments indicate surface diffusion being the dominant mechanism responsible for morphological changes in these island structures rather than the heterointerface diffusion.

Three dimensional islands of InAs have been grown on Si (100) by using molecular-beam epitaxy to obtain nanometer-scale quantum dots. Morphological examination by atomic force microscopy revealed the formation of islands with narrow size distributions and high densities. For an approximate coverage of 1.2 monolayers of lnAs beyond the growth mode transition, our observations of a rapid evolution of island morphology are explained in terms of strain relaxing mechanisms in the early stages of InAs/Si heteroepitaxy.