Abstract: In an integrated asthma analysis and therapy determination method, a patient is administered hyperpolarized gas and an magnetic resonance (MR) scan is conducted to obtain a first MR image set, and the patient is then administered an allergen provoker and is again administered hyperpolarized gas and another MR scan is conducted, to obtain a second MR image set. This is followed by administering asthma therapeutics and again administering hyperpolarized gas to the subject, and another MR scan is conducted to obtain a third image data set. The first, second and third image data sets are compared among each other in order to determine the effect of the allergen provoker and the effect of the asthma therapeutics, in order to determine an appropriate medication dosage for the subject.

Abstract: A magnet assembly for a magnetic resonance imaging apparatus, has a magnet with a patient receptacle therein, the magnet producing a basic magnetic field having a homogeneity volume within the patient receptacle. Auxiliary components in the form of coils or ferromagnetic elements are disposed relative to the magnet to selectively spatially displace the homogeneity volume, either by selectively activating current flowing through the respective coils, or by selective positioning of the ferromagnetic elements.

Abstract: A voltage source provides an input signal to a drive circuit for a power semiconductor. A protective circuit is connected between the drain and the source of the power semiconductor and is activated when excess current is present. The protective circuit provides an output signal that is received by a control circuit to limit the voltage at the gate of the power semiconductor. The control circuit is connected between the gate and the source. A controllable resistance including an enhancement MOSFET and an external capacitor in which the enhancement MOSFET has a gate, a source and an internal capacitance between the gate and the source is connected in parallel to the external capacitance. The controllable resistance carries the input signal from the voltage source to the power semiconductor. The controllable resistance is switched to high impedance when the protective circuit is activated and switched to low impedance when the protective circuit is deactivated.