(F) The number of cycles of a periodic process per unit time. Frequency and wavelength are inversely related. The higher the frequency the smaller the wavelength. The frequency of for example ultrasound is expressed in units of hertz (Hz), where 1 Hz = 1 cycle per second.
Usual frequencies in medical imaging are e.g., for ultrasound in the range of 1-20 MHz, for x-rays above 3x10¹⁶ Hz and for gamma rays less than 10²⁰ Hz.

GE Healthcare is the result of the merger between GE Medical and Amersham Health in Nov. 2004, after GE acquired Amersham Health for 9.5 billion in Oct. 2003. Jeffrey R. Immelt, Chairman of the Board and Chief Executive of General Electric, said, 'Amersham's diagnostic pharmaceutical and life sciences business will add new, high growth platforms to GE Medical's diagnostic imaging, services and health care information technology businesses'. GE Healthcare, a UK company, is a unit of General Electric (NYSE: GE). GE Healthcare is a global leader in medical imaging, diagnostic imaging agents, interventional procedures, health care services, and information technology. For more than 100 years, health care providers have relied on GE Medical Systems, now GE Healthcare, for high quality medical technology and productivity solutions. GE Healthcare, headquartered now at the formerly seat of Amersham Healthcare in Great Britain, operates facilities around the world. Global Operations include organizations on the Americas, Europe, and Asia, including India, Japan, Korea China, Thailand and Vietnam.

Granulocyte scintigraphy is a medical imaging test to visualize infections and inflammatory processes. The used monoclonal granulocyte antibodies are radioactive marked with for example 99mTc, 67Ga-citrate or with 111In-oxine.

See also Inflammation Scintigraphy.

The France-based Guerbet Group is highly specialized in contrast media for medical imaging. Its strategic goal is to be a key player in this market. Guerbet Group produces products for x-ray imaging, MRI, ultrasound imaging and imaging through radioactive tracers.

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As a full-line supplier of medical imaging equipment in Japan, Hitachi Medical Corporation (HMC) founded HMSA 1989 to provide a direct link to the U.S. marketplace. HMSA is responsible for the sales, marketing and service of all Hitachi Open MRI, PET/CT, Ultrasound, and Computed Tomography products in the United States.

In December 2019 Japan's Fujifilm announced the acquisition of Hitachi's diagnostic imaging business for 179 billion yen ($1.63 billion). This includes Hitachi’s CT, MRI, X-ray, and ultrasound imaging operations, also its electronic health record business. Fujifilm expects the deal to close in July 2020 subject to regulatory clearances.