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Die tumorosteolytische Destruktion des Sakrums, verursacht durch Metastasen, kann zu einer signifikanten Instabilitat des hinteren Beckenrings fuhren. Die Folge sind Schmerzen, Immobilitat und konsekutiv ein Verlust an Lebensqualitat. Das Portfolio an operativen Moglichkeiten ist begrenzt. Vorgestellt wird eine neue 3D-navigiert-assistierte Technik der perkutanen Defektaugmentation des Beckenrings mit Hilfe eines expandierbaren und zementaugmentierten Cage als Stand-alone-Variante und in Kombination mit einer Osteosynthese.

Destruction of the sacrum due to metastatic tumors may lead to a significant instability of the posterior pelvic ring. This often causes pain, immobility, and subsequently a loss of quality of life. The surgical treatment options are limited. A new technique is presented using a cement augmented expandable cage placed percutaneously using 3D fluoroscopy-based navigation with or without an additional osteosynthesis.

The metastable decomposition of sputtered, mass-selected, cluster ions is investigated under ultrahigh-vacuum conditions. Highly excited $\mathrm{Al}_{n}^{}{}_{}{}^{+}$ and $\mathrm{Cu}_{n}^{}{}_{}{}^{+}$ cluster ions are found to decompose mainly by evaporation of single neutral atoms, whereas for $\mathrm{Si}_{n}^{}{}_{}{}^{+}$ clusters, fission is also observed. The decay rates of $\mathrm{Cu}_{n}^{}{}_{}{}^{+}$ clusters are in agreement with calculations presented by Klots. Some consequences of our results for the interpretation of cluster-ion mass spectra produced by other experimental methods are discussed.

The topography induced by 7 keV particle bombardment of Si substrates has been measured dynamically as a function of particle fluence with a B11 source coupled into a scanning electron microscope. Distinctive differences are observed according to particle species used (Ar, Kr or O) and flux incidence angle to the surface. Strategies for morphology development minimization are discussed and the relevance of the study to sputter profiling and lithographic etching outlined.

High depth resolution Rutherford backscattering-channelling has been employed to assess the depth of damage and the increase in total damage with increasing ion fluence over the range 1014-1016 ions cm−2 for 5 keV A+ implants into Si conducted under low flux density and UHV conditions. It is shown that damage-depth estimates for zero fluence conditions are similar to theoretical predictions and that the increasing damaged (amorphised layer) depth with increasing fluence is the result of continuing damage accumulation deeper in the Si.

Mass separated metal and silicon cluster ion beams M+,− n are produced by sputtering and undergo fragmenting and/or neutralizing collisions at different kinetic energies (100-1800 eV) in Ar and SF6. Fragment patterns induced by rare gas collisions open a way to determine ionization potentials and electron affinities of clusters. These values are compared to known experimental and theoretical data. For negatively charged clusters the absorption in gas targets is mainly due to neutralization, the cross sections varying with cluster material, number of atoms and collision partner from 10 A2 to about 50 A2.

A variety of metal cluster ions is produced by sputtering under UHV conditions. Mass selected beams of these species undergo collision induced fragmentation (CIF) in rare gas and oxygen gas targets under single collision conditions, the fragments being analyzed in a time-of-flight reflectron. The striking similarity between fragmentation rates, the abundances in mass spectra, and unimolecular decay rates suggest that such measurements directly reveal the cluster ion stabilities.

Our own (1,2) and other earlier studies (3,4) of the development of surface topography during ion bombardment of Si suggested that different observations by different investigators could possibly be ascribed to surface contamination and residual vacuum condition effects. We therefore decided to conduct studies of the topography developed on Si under relatively high vacuum conditions. Cleaved segments of (100) oriented Si wafers were bombarded to fluences of about 5 x 10 cm with approximately 5 keV Ar ions, without beam aperturing, at a base pressure of about 10 torr. Bombardment was at normal incidence to the surface. The ion beam flux density profile was non uniform so that ion fluence decayed quite rapidly towards the periphery of the bombarded area. Following bombardment any morphological changes to the Si surface were examined by Scanning Electron microscopy.