Digital radiography (DR) denotes a motif of X-rayimaging in which radiologists use digital X-ray radars instead of theconventional photographic film (Bertolini et al. 2618).Since one obtains an image by using digital X-rays, the amount ofX-rays reaching are greatly reduced thus, clear visibility. Adigital radiography embraces the economic and convenient storage ofimages thus, it is a form of PAC (picture archiving andcommunications systems). PACS refer to medical imaging innovations ortechnology that offers economic storage of, and expedient access to,images from manifold modalities. In this regards, instead of usingX-ray films, digital radiography utilizes digital image capturesensor, which eliminates costly film dispensation procedures as wellas enhance the overall display of an image. In fact, the developmentof digital radiography has transformed the radiological imagingprocesses and success greatly. Today, digital radiography is amainstay across numerous hospitals as well as radiology practices.The introduction of wireless DR and increased innovation in thefield, which has decreased imaging prices, have enhanced efficiencyand enriched workflow in the radiology practices greatly. Thediscourse pursues to provide significant timelines on the evolutionof digital radiography as well as provides imperative changes thathave taken place in the evolution of digital radiography.
Evolution of digital radiography
Modern digital radiography owes much to thediscovery of x-rays in 1895 by Wihelm Rontgen (Hrabaket al. 1189). Scientists found x-rays stemming from Crooke tubes, theexperimental tubes invented in 1875 to research cathode rays. Duringthe 1980s, scientists such as Johann Hittorf and William Crookesdiscovered that photographic plates positioned close to Crooke tubesbecame flawed by shadows (Hrabak et al. 1189). However, thescientists did not research this phenomenon and it is not until 1877when Ivan Pulyui started to investigate the properties of dischargetubes. Both Pulyui and Rontgen published x-ray photographs, but isFernando Sanford who generated and detected X-rays in 1891. In 1894,Nikola Tesla began comprehensive observations of X-rays and designeda special x-ray bulb. Tesla’s invention in today’s used asbraking radiation. Flower asserts that Tesla generated the firstx-rays in America and also acquired the images of a human body thathe named shadowgraphs (19). Imperative refinements in X-rays allowedscientists to discard cassettes and integrate PACS in the developmentof digital radiography. After the detection of x-rays came thedevelopment of fluoroscopy, which is used in digital imaging tointensify images. In this regards, digital radiography developedthrough the integration of x-rays and computer technology. Forexample, predominant digital radiography sensors such asphotostimulable store the image data generated by the immersion ofoccasion x-rays as a supressed image.
In the past 25 years, DR has played apredominant role in radiology practices as it has slowly replacedconventional forms of radiography, specifically, the screen-filmradiography. Technological innovations have provided people with thenecessary resources and skills to develop efficient and qualityradiographs while using quality equipment. DR allows theimplementation of a complete digital image archiving andcommunication structure where images are kept by electronic meansthus, they are obtainable anywhere and anytime. In this regards, itis essential to understand the major timelines in the evolution ofdigital radiography.
Evolution of DR in 1970s and 1980s
Nelson, Zekas, and Reese assert thatAlbert Jutras started the concepts of digital imaging in Canada inthe 1950s (484). However, Nelson et al. also contend that theearliest forms of PACS were developed in the late 1970s and early1980s by the military to send images or pictures between VeteranAdministration Hospitals (485). The US government supported andencouraged the development of early forms of PACS. Bertolini et al.assert that the development of digital radiography commenced with thedescription and introduction of Experimental Digital SubtractionAngiography in 1980 (2618). The subtraction angiography became thefirst digital imaging systems to be used in a clinical setting whenthey launched in 1980. CCD slot-scan system was the first generalradiography to use digital imaging where it used cassette-basedstorage phosphor plates in 1980. In this regards, the computedradiography were the first digital radiography systems in the worldand used storage phosphor plates, existent equipment, requiredcassettes, and special cassette readers as the CCD slot-scan systemreveals. Flower reveals that these radiographs also used computerworkstation and a printer to work (9). In addition Fuji MedicalSystems of Japan was the first company to introduce digitalradiography systems in the US, which used a cassette reader, aphosphor storage plate, and a laser printer.
However, many forms of computed radiography were deemed slow thus,major developments occurred in 1990s to full digital radiographs.Digital radiographs use cassetteless systems unlike computedradiographs, which use cassette plates. In addition digitalradiography uses smooth panel sensor or charge-coupled devicecommonly referred as CCD hard wired to a computer. The development ofDigital subtraction angiography in 1977 and amorphous selenium-basedimage plates in 1987 saw the clinical application of digitalradiography. In fact, the development of Digital subtractionangiography in 1977 allowed many companies to start large-scaledevelopment of digital sensors across the world.
Evolution of DR in 1990s
As asserted, the development of DR started in thelate 1970s, but large-scale and successful implementation of thesystems started in the 1990s with the development of CCD(charge-coupled device) slot scan in 1990 (Korner et al. 678).The year also saw the establishment of effective PACS and theconjunction between digital imaging and these systems enhanced thedevelopment of effective digital radiography. CCD slot scan usedlarge FOV (Field of View) X-ray phosphors and optical lensassemblies, which focused on the X-ray, induced light output ontoCCD’s photodetector arrays. Korner et al. assert that CCDsrevolutionized digital imaging as well as allowed the development ofother digital detectors and radiographs (679). According to Flower,the CCD slot scan was the first digital radiography system in termsof imaging and storage since earlier forms of radiography such assubtraction angiography used X-ray films but recorded them digitallyusing cassettes (11). In 1994, selenium drum DR were developedfollowed by amorphous silicon-cesium iodide, which used smooth panesensors in 1995 (Nelson et al. 490 Lança and Silva 11). Inaddition, Nelson et al. assert that Gadolinium-based sensors weredeveloped in 1997 and 2001 and their use has continued ever since(491). These sensors use semiconductor materials to convert rays intosignals and together with CCDs use dynamic information of an imageensuing attainment to present the image instantly without furtherinteraction.
In 2001, technologists developed dynamic flat panel sensorsfluoroscopy and active matrix whose use continues to date (Bertoliniet al. 2620). In fact, dynamic flat panelsensors and wireless DR systems developed in 2009 both using flatpanels remain the latest innovation in the field of digitalradiography. Wireless DR is non-assimilated sensors that obtainradiographs in similar ways to computed radiography. However,wireless DR uses digital imaging and wireless LAN communicationsbetween a sensor and a workstation console. In this regards, awireless DR relays performed radiographs in real time. Today, thedigital radiography sector is witnessing major advances especially inthe direct digital radiography. Although the growth of digitalradiography remains slow, its steady uptake in major medical settingmeans low costs and more efficiency. As suggested earlier, DR ensureseffective uptake of workflow and clinical improvements of up to 50%hence, hospitals will continue to use digital radiography in themainstream radiology.
The development of digital radiography has revolutionized theradiology field, improved workflow, and provided many patients withcomfortable experiences. The evolution of the systems from the late1970s have ensured increased efficiency and capture ofhigh-resolution images as well as the capacity to review theperformed images in real time. In fact, the revolution of digitalradiography has ensured great enhancements in patient care. Asdemonstrated, DR has experienced major timelines each with adifferent development of a digital sensor. In this regards, thediscourse has depicted the major timelines in the field of radiologyespecially in the development of digital radiography and itsconnection to PACS.
Bertolini, Marco, et al. "A comparison of digital radiographysystems in terms of effective detective quantum efficiency." Medicalphysics 39.5 (2012): 2617-2627.
Flower, Maggie A., ed. Webb`s physics of medical imaging.CRC Press, 2012.
Hrabak, Maja, et al. "Nikola Tesla and the Discovery of X-rays1."Radiographics 28.4 (2008): 1189-1192. Print.
Korner, Markus, et al. "Advances in Digital Radiography:Physical Principles and System Overview 1." Radiographics 27.3(2007): 675-686. Print.
Lança, Luís, and Augusto Silva. "Digital radiographydetectors: a technical overview." Digital imagingsystems for plain radiography. Springer New York, 2013. 9-19.Print.
Nelson, Nathan C., Lisa J. Zekas, and David J. Reese. "DigitalRadiography for the Equine Practitioner: Basic Principles and RecentAdvances." Veterinary Clinics of North America: EquinePractice 28.3 (2012): 483-495. Print.