The definition of imaging is the visual representation of an object. Medical imaging is a broad term that encompasses various imaging modalities and techniques used in the field of medicine to visualize and study the body's anatomy and physiology. It includes both diagnostic and non-diagnostic imaging procedures, where diagnostic imaging specifically refers to the subset of medical imaging techniques that are primarily focused on diagnosing diseases or conditions. Medical imaging techniques are employed to obtain images or visual representations of the internal organs, tissues, and structures, aiding in the diagnosis, treatment, and monitoring of medical conditions.
The field of medical imaging has significantly evolved since the discovery of X-rays by Konrad Roentgen in 1896. Initially, radiological imaging involved focusing X-rays on the body and capturing the images on a single piece of film within a specialized cassette. Subsequent advancements introduced the use of fluorescent screens and special glasses for real-time visualization of X-ray images.
A significant breakthrough came with the application of contrast agents, enhancing image contrast and improving organ visualization. In the 1950s, nuclear medicine studies utilizing gamma cameras demonstrated the uptake of low-level radioactive chemicals in organs, enabling the observation of biological processes in vivo. Currently, positron emission tomography (PET) and single photon emission computed tomography (SPECT) technologies play pivotal roles in clinical research and the diagnosis of biochemical and physiological processes. Additionally, the advent of the x-ray image intensifier in 1955 facilitated the capture and display of x-ray movies.
In the 1960s, diagnostic imaging incorporated the principles of sonar, using ultrasonic waves generated by a quartz crystal. These waves, reflecting at the interfaces between different tissues, were received by ultrasound machines and translated into images through computer algorithms and reconstruction software. Ultrasound (ultrasonography) has become an indispensable diagnostic tool across various medical specialties, with immense potential for further advancements such as targeted contrast imaging, real-time 3D or 4D ultrasound, and molecular imaging. The first use of ultrasound contrast agents (USCA) dates back to 1968.
Digital imaging techniques were introduced in the 1970s, revolutionizing conventional fluoroscopic image intensifiers. Godfrey Hounsfield's pioneering work led to the development of the first computed tomography (CT) scanner. Digital images are now electronic snapshots represented as grids of dots or pixels. X-ray CT brought about a breakthrough in medical imaging by providing cross-sectional images of the human body with high contrast between different types of soft tissue. These advancements were made possible by analog-to-digital converters and computers. The introduction of multislice spiral CT technology dramatically expanded the clinical applications of CT scans.
The first magnetic resonance imaging (MRI) devices were tested on clinical patients in 1980. With technological improvements, such as higher field strength, more open MRI magnets, faster gradient systems, and novel data-acquisition techniques, MRI has emerged as a real-time interactive imaging modality capable of providing detailed structural and functional information of the body.
Today, imaging in medicine offers a wide range of modalities, including:

These imaging modalities have become integral components of modern healthcare. With the rapid advancement of digital imaging, efficient management has become important, leading to the expansion of radiology information systems (RIS) and the adoption of Picture Archiving and Communication Systems (PACS) for digital image archiving. In telemedicine, real-time transmission of all medical image modalities from MRI to X-ray, CT and ultrasound has become the standard. The field of medical imaging continues to evolve, promising further innovations and advancements in the future, ultimately contributing to improved patient care and diagnostics.

See also History of Ultrasound Contrast Agents, and History of Ultrasound.

From Medison Co.,Ltd.;
'PC-based Digital B/W Ultrasound System
Your First Digital Ultrasound
SONOACE 5500, the world's most affordable digital B/W ultrasound, is designed for those who use ultrasound system first-time. It offers you clearer digital images, user convenience, reducing price burden. Enjoy the benefits of SONOAV|CE 5500 with best price.'

From Siemens Medical Systems;
The ACUSON Aspen™ ultrasound system resulted from a unique convergence of select ACUSON Sequoia™ ultrasound system technologies and other ACUSON innovations to form an entirely new imaging platform. Its new digital system architecture provides complete digital control of the ultrasound echoes from the transducer through the captured digital examination.

Specifications for this system will be available soon.

From ALOKA Co., Ltd.;
'A Platform for Digital, Pure-Beam Imaging The high-performance, ALOKA ProSound SSD-3500 utilizes advanced ProSound technologies including:
Fully digital beam former A wide dynamic range, 12-bit A/D converter Multi beam processing.
The SSD-3500 also helps you achieve more efficient examinations. Its ergonomic, user-friendly design enables you to customize the system according to your specific application needs.'

Environmental protection in ultrasound imaging involves adopting practices and technologies that minimize the environmental impact associated with the use of ultrasound equipment and disposables.

Here are some key considerations:

By focusing on energy efficiency, digitalization, waste management, equipment lifespan, and education, healthcare facilities can make significant strides towards reducing their carbon footprint and the environmental impact of ultrasound imaging practices.

See also Ultrasound System Performance, Equipment Preparation, Ultrasound Accessories and Supplies and Sonographer.