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A technique for continuous production of solutions containing hyperpolarized (129)Xe is explored for MRI applications. The method is based on hollow fiber membranes which inhibit the formation of foams and bubbles. A systematic analysis of various carrier agents for hyperpolarized (129)Xe has been carried out, which are applicable as contrast agents for in vivo MRI. The image quality of different hyperpolarized Xe solutions is compared and MRI results obtained in a clinical as well as in a nonclinical MRI setting are provided. Moreover, we demonstrate the application of (129)Xe contrast agents produced with our dissolution method for lung MRI by imaging hyperpolarized (129)Xe that has been both dissolved in and outgassed from a carrier liquid in a lung phantom, illustrating its potential for the measurement of lung perfusion and ventilation.

Aim: To assess the potential mutagenic effect of static magnetic fields of 1.5 T and 7 T, gradient fields and high frequency magnetic fields., Method: We used the Salmonella mutagenicity test (Ames test), which detects mutations in a gene of a histidine-requiring (his-) strain to produce a histidine-independent (his+) strain, Exposure to a static magnetic field of 1.5 T and 7.2 T, in a bipolar magnetic gradient and additionally in a high frequency field took place with and without known genotoxic chemicals., Results: No differences in the number of revertants between the bacterial strains of exposed and control cells could be detected and the exposure with known genotoxic chemicals showed no significant difference in mutagenicity., Conclusion: In conclusion our data do not provide evidence that exposure to a static magnetic field exerts effects on the mutagenicity in our standard tester strains and whether the exposure took place in a diagnostic 1.5 T MR scanner which is used in the clinical routine or at 7.2 T which is a much stronger field made no difference. Also an exposure in a gradient field or in a high frequency field did not show any alteration in the number of revertants.

NMR imaging with protons is becoming a more and more versatile tool for material research. Two different approaches are presented to obtain spatial resolution in elastomers and solids. The first, magic-sandwich-echo-imaging, belongs to the group of multiple-pulse techniques which are applied to overcome the strong dipolar couplings in solids. A driver for fast gradient pulses was constructed, and the technique was used to measure one-dimensional projections and spatially resolved spectra of rigid polymers. The second approach uses surface coils. In this way large objects can be investigated from the surface at optimum signal to noise. The drawback of the inhomogeneous B1 field resulting in signal attenuation across the image can be overcome by imaging an NMR parameter like the relaxation time T2. This was applied to image a phantom of different polyurethane foams. Furthermore spin-echo images of signal intensity maps around conducting wires are presented for the analysis of current distributions.