A novel system for patient ventilation and dosing of hyperpolarized ^{3}He for magnetic resonance imaging of human lungs

A versatile ventilator for controlling a patient’s breath cycle and dosing 3He gas has been designed and constructed. It is compatible with a medical magnetic resonance imaging scanner and can be incorporated into routine human lungs imaging procedure that employs hyperpolarized noble gas as a contrast agent. The system adapts to the patient’s lung volume and their breath cycle rhythm, providing maximum achievable comfort during the medical examination. Good quality magnetic resonance lung images of healthy volunteers were obtained. The system has the capability of recycling the exhaled gas to recover the expensive 3He isotope, and can be also adapted to human lung imaging with hyperpolarized 129Xe

Evanescent wave mirror for cold atoms - a quasi-resonant case

The measurements of the inelastic photon scattering in the optical dipole mirror created by a quasi-resonant evanescent wave are presented. The momentum transfer between an evanescent wave and cold atoms accompanying the atom reflection are discussed for a single and double evanescent wave configurations. The latter configuration allows 10-fold reduction of the systematic errors in the measurements. A simple theoretical description is provided to account for any saturation parameter in the interaction of an atom and evanescent field. A large number of photons scattered from a quasi-resonant evanescent wave makes this method a promising tool for investigations of surface related phenomena

Hyperpolarized ^{3}He gas production by metastability exchange optical pumping for magnetic resonance imaging

A portable ^{3}He gas polarizer based on metastability exchange optical pumping is described. It produces 75 ml of highly polarized ^{3}He gas at the pressure of 100 mbar, by implementing a non-magnetic peristaltic compressor, which transfers the ^{3}He gas from the low-pressure optical pumping cell to the storage cell. About 30% polarization at 1 mbar is achieved in the optical pumping cell in a single run, and 20 compression cycles are needed to reach the final pressure in the storage cell. After adding a buffer gas up to the atmospheric pressure, the mixture is used in magnetic resonance imaging (MRI) experiments. Preliminary images of phantoms and of the rat lungs in vivo confirm the usefulness of the ^{3}He gas polarizer in MRI applications

Magnetic resonance imaging at low magnetic field using hyperpolarized ^{3}He gas

A low magnetic field magnetic resonance imaging system for small animal lung imaging using hyperpolarized ^{3}He gas is presented. The hyperpolarized ^{3}He gas at 1 mbar pressure and 30% polarization is obtained by the metastability exchange optical pumping technique. The magnetic resonance imaging unit is based on a permanent magnet of open geometry, built from a new generation Nd-B-Fe magnetic material. It produces the magnetic field of 88 mT with homogeneity better than 50 ppm in the 10 cm diameter sphere, after application of passive shimming. The magnetic field gradients of 30 mT/m are generated by a set of biplanar, actively shielded gradient coils. The first ^{1}H images of various biological objects, as well as ^{3}He images of the rat lung in vivo obtained in the described system are shown. In terms of sensitivity and resolution, the technique is superior to conventional ^{1}H magnetic resonance imaging, and offers great possibilities in early diagnosis of lung diseases