Chest radiograph - Abnormalities. 1  A pulmonary nodule is a discrete opacity in the lung which may be caused by... 2  Neoplasm: benign or malignant. 3  Granuloma: tuberculosis. 4  Infection: roundish pneumonia. 5  Vascular: infarct, varix, granulomatosis with polyangiitis, rheumatoid arthritis.
Helium is used for purposes that require some of its unique properties: its low density, low solubility, and high thermal conductivity. 7,000 tons, or 22%, of the total helium used involves the cooling of superconducting magnets in medical magnetic resonance imaging (MRI) scanners.
Helium is a colorless and odorless gas in its natural state. It gives off a blue neon color when burned. When an electric current runs through it, helium is a pale peach to orange color. Helium is nonreactive and lighter than air, which makes it ideal for use in weather or decorative balloons. Helium is used to keep satellite instruments, spacecraft and MRI machines cool. After hydrogen, helium is the second-most abundant gas in the universe. It is present in all stars and has no known biological role. Helium is nontoxic and used by deep-sea divers at a rate of 80 percent helium and 20 percent oxygen.