165 k microcooler operating with a sorption compressor and a micromachined cold stage

This paper presents the fabrication of a microcooler consisting of small stainless steel sorption compressor cells, micromachined silicon check valves, and a micromachined cold stage that incorporates glass-tube heat exchangers. The design, fabrication and experiments on the different elements are described. Two compressor cells were thermally cycled to investigate the dynamic behaviour. The cold stage could reach a stable temperature of 169 K with a cooling power of about 200 mW

Lanthanide-Loaded Liposomes for Multimodality Imaging and Therapy

Many advanced molecular imaging agents are currently being investigated preclinically. Especially, liposomes, have proven to be very promising carrier systems for diagnostic agents for use in single-photon emission computed tomography (SPECT) or magnetic resonance imaging (MRI), as well as for therapeutic agents to treat diseases such as cancer. In this study, nanosized liposomes were designed and labeled with the radionuclides, holmium-166 (both a beta- and gamma-emitter and also highly paramagnetic) or technetium-99m, and coloaded with paramagnetic gadolinium allowing multimodality SPECT and MR imaging and radionuclide therapy with one single agent. Methods: Diethylenetriaminepentaacetic acid bisoctadecylamide (an amphiphilic molecule with a chelating group suitable for labeling with radionuclides) and gadoliniumacetylacetonate (GdAcAc) (a small lipophilic paramagnetic molecule) were incorporated in liposomes. The liposomes were characterized by measuring their mean size and size distribution, gadolinium content, and radiochemical stability after incubation in human serum at 37°C. The MRI properties (in vitro) were determined by use of relaxivity measurements at 1.5 and 3.0 Tesla in order to evaluate their potency as imaging agents. Results: The liposomes were successfully labeled with holmium-166, resulting in a high labeling efficiency (95% ± 1%) and radiochemical stability (> 98% after 48 hours of incubation), and coloaded with GdAcAc. Labeling of liposomes with technetium-99m was somewhat less efficient (85% ± 2%), although their radiochemical stability was sufficient (95% ± 1% after 6 hours of incubation). MRI measurements showed that the incorporation of GdAcAc had a strong effect on the MRI relaxivity. Conclusions: The synthesized liposomes allow for multimodality imaging and therapy, which makes these new agents highly attractive for future applicationsRadiation, Radionuclides and ReactorsApplied Science

Clinical effects of transcatheter hepatic arterial embolization with holmium-166 poly(l-lactic acid) microspheres in healthy pigs

Purpose The aim of this study is to evaluate the toxicity of holmium-166 poly(l-lactic acid) microspheres administered into the hepatic artery in pigs. Methods Healthy pigs (20–30 kg) were injected into the hepatic artery with holmium-165-loaded microspheres (165HoMS; n?=?5) or with holmium-166-loaded microspheres (166HoMS; n?=?13). The microspheres’ biodistribution was assessed by single-photon emission computed tomography and/or MRI. The animals were monitored clinically, biochemically, and (166HoMS group only) hematologically over a period of 1 month (165HoMS group) or over 1 or 2 months (166HoMS group). Finally, a pathological examination was undertaken. Results After microsphere administration, some animals exhibited a slightly diminished level of consciousness and a dip in appetite, both of which were transient. Four lethal adverse events occurred in the 166HoMS group due either to incorrect administration or comorbidity: inadvertent delivery of microspheres into the gastric wall (n?=?2), preexisting gastric ulceration (n?=?1), and endocarditis (n?=?1). AST levels were transitorily elevated post-166HoMS administration. In the other blood parameters, no abnormalities were observed. Nuclear scans were acquired from all animals from the 166HoMS group, and MRI scans were performed if available. In pigs from the 166HoMS group, atrophy of one or more liver lobes was frequently observed. The actual radioactivity distribution was assessed through ex vivo 166mHo measurements. Conclusion It can be concluded that the toxicity profile of HoMS is low. In pigs, hepatic arterial embolization with 166HoMS in amounts corresponding with liver-absorbed doses of over 100 Gy, if correctly administered, is not associated with clinically relevant side effects. This result offers a good perspective for upcoming patient trialsDepartment of Radiation, Radionuclides and ReactorsApplied Science

Clinical effects of transcatheter hepatic arterial embolization with holmium-166 poly(l-lactic acid) microspheres in healthy pigs

Purpose The aim of this study is to evaluate the toxicity of holmium-166 poly(l-lactic acid) microspheres administered into the hepatic artery in pigs. Methods Healthy pigs (20–30 kg) were injected into the hepatic artery with holmium-165-loaded microspheres (165HoMS; n?=?5) or with holmium-166-loaded microspheres (166HoMS; n?=?13). The microspheres’ biodistribution was assessed by single-photon emission computed tomography and/or MRI. The animals were monitored clinically, biochemically, and (166HoMS group only) hematologically over a period of 1 month (165HoMS group) or over 1 or 2 months (166HoMS group). Finally, a pathological examination was undertaken. Results After microsphere administration, some animals exhibited a slightly diminished level of consciousness and a dip in appetite, both of which were transient. Four lethal adverse events occurred in the 166HoMS group due either to incorrect administration or comorbidity: inadvertent delivery of microspheres into the gastric wall (n?=?2), preexisting gastric ulceration (n?=?1), and endocarditis (n?=?1). AST levels were transitorily elevated post-166HoMS administration. In the other blood parameters, no abnormalities were observed. Nuclear scans were acquired from all animals from the 166HoMS group, and MRI scans were performed if available. In pigs from the 166HoMS group, atrophy of one or more liver lobes was frequently observed. The actual radioactivity distribution was assessed through ex vivo 166mHo measurements. Conclusion It can be concluded that the toxicity profile of HoMS is low. In pigs, hepatic arterial embolization with 166HoMS in amounts corresponding with liver-absorbed doses of over 100 Gy, if correctly administered, is not associated with clinically relevant side effects. This result offers a good perspective for upcoming patient trialsDepartment of Radiation, Radionuclides and ReactorsApplied Science