380:
images, and with a greater ability to vary the thickness of the cross-section being examined. This was achieved through the introduction of more complex, multidirectional devices that can move in more than one plane and perform more effective blurring. However, despite the increasing sophistication of focal plane tomography, it remained ineffective at producing images of soft tissues. With the increasing power and availability of computers in the 1960s, research began into practical computational techniques for creating tomographic images, leading to the development of computed tomography (CT).
298:, which acquired the rights to manufacture it. Pfizer subsequently introduced their version of the machine, called the "200FS" (with "FS" denoting Fast Scan). The 200FS generated images in a 256×256 matrix, offering much better image definition compared to the EMI-Scanner's 80×80. It took approximately 20 seconds to acquire a single image slice, making full-body scans feasible, although patients still had to hold their breath during this process – a key distinction from the EMI scanner, which could not perform body scans due to its five-minute acquisition time for a single slice.
291:, DDS, at Georgetown University. This revolutionary machine was equipped with 30 photomultiplier tubes as detectors and was capable of completing a scan in just nine translate/rotate cycles, significantly faster than the EMI-Scanner. To operate the servo-mechanisms and handle image acquisition and processing, the ACTA scanner used a DEC PDP11/34 minicomputer.
20:
28:
46:. In the early 1900s an Italian radiologist named Alessandro Vallebona invented tomography (named "stratigrafia") which used radiographic film to see a single slice of the body. It was not widely used until the 1930s, when Dr Bernard George Ziedses des Plantes developed a practical method for implementing the technique, known as
325:
CT may use continuous rotation of the gantry, and can acquire a data set in a few seconds with a spiral technique where the patient is moved in continuously while the machine basically acquires a single spiraling slice, so that all areas of interest are covered quickly. This data can be processed and
301:
The workflow for the ACTA and 200FS machines involved the operator acquiring a series of slices and then processing the images. These images were printed onto films and the raw data were archived onto magnetic tape. This archival step was necessary because the computer lacked the storage capacity for
189:
and the development of transverse axial scanning led CT to gradually supplant as the preferred modality of obtaining tomographic images. In terms of mathematics, the method is based upon the use of the Radon
Transform. But as Cormack remembered later, he had to find the solution himself since it was
379:
appears sharper, while the images of the other points annihilate as noise. This is only marginally effective, as blurring occurs in only the "x" plane. This method of acquiring tomographic images using only mechanical techniques advanced through the mid-twentieth century, steadily producing sharper
61:
apparatus for investigating selected areas of interior objects obscured by dense material". The advent of sophisticated computers in the late 1960s and early 1970s made the development of the first practical computed tomography scanners possible. The first clinical CT scan was performed in a London
309:
computer played a pivotal role in the operation of the ACTA and 200FS scanners. It controlled the gantry, managed the scanning process, and processed raw data into the final images. Remarkably, this computer functioned with a mere 64 KB of memory and a 5 MB hard disk, which held both the operating
250:
tank with a pre-shaped rubber "head-cap" at the front, which enclosed the patient's head. The water-tank was used to reduce the dynamic range of the radiation reaching the detectors (between scanning outside the head compared with scanning through the bone of the skull). The images were relatively
198:
CT technology has vastly improved. Improvements in speed, slice count, and image quality have been the major focus primarily for cardiac imaging. Scanners now produce images much faster and with higher resolution enabling doctors to diagnose patients more accurately and perform medical procedures
122:
fruit by detecting dehydrated portions. In 1961, he built a prototype in which an X-ray source and a mechanically coupled detector rotated around the object to be imaged. By reconstructing the image, this instrument could get an X-ray picture of a nail surrounded by a circle of other nails, which
318:
Portable CT scanners can be brought to the patient's bedside and do a scan without getting the patient out of bed. Some portable scanners are limited by their bore size and therefore mainly used for head scans. They do not have image viewing capabilities directly on the scanner. The portable CT
334:
In 2021, the FDA approved
Siemens' photon-counting scanner. The scanner counts individual x-ray photons that pass through a patient and discriminates their energy, increasing the detail supplied to the reader. The technique also reduces the amount of x-rays needed for a scan.
686:
Franco
Bistolfi, Alessandro Vallebona 1899-1987. Ricordo di un grande radiologo e del suo contributo allo sviluppo delle scienze radiologiche (PDF), in Fisica in Medicina, n. 2, 2005, pp. 115-123. URL consulted on 9 may 2016 (archived from original url on 4 march 2016)
241:
The first production X-ray CT machine (in fact called the "EMI-Scanner") was limited to making tomographic sections of the brain, but acquired the image data in about 4 minutes (scanning two adjacent slices), and the computation time (using a
134:
with
Hounsfield. The field of the mathematical methods of computerized tomography continues to be an area of active development. An overview on the history of CT as well as the mathematical methods and their developments has been written by
286:
The first computed tomography (CT) system capable of producing images of any part of the human body without the need for a cumbersome "water tank" was the
Automatic Computerized Transverse Axial (ACTA) scanner, designed by Dr.
117:
conceived an idea for "scanning a head through a transmitted beam of X-rays, and being able to reconstruct the radiodensity patterns of a plane through the head" after watching an automated apparatus built to reject
50:. It relies on mechanical movement of the X-ray beam source and capture film in unison to ensure that the plane of interest remains in focus with objects falling outside of the plane being examined blurring out.
302:
more than one study at a time. In busy hospitals, CT operators found themselves constantly engaged in this labor-intensive process. Maintaining the machine's functionality was also a significant undertaking.
518:
406:
Radon J (1917). "Uber die
Bestimmung von Funktionen durch ihre Integralwerte Langs Gewisser Mannigfaltigkeiten" [On the determination of functions from their integrals along certain manifolds].
371:, representing a single slice of the body on radiographic film. This method was proposed by the Italian radiologist Alessandro Vallebona in the early 1900s. The idea is based on simple principles of
234:
The original 1971 prototype took 160 parallel readings through 180 angles, each 1° apart, with each scan taking a little over 5 minutes. The images from these scans took 2.5 hours to be processed by
130:
In
October 1963, Oldendorf received a U.S. patent for a "radiant energy apparatus for investigating selected areas of interior objects obscured by dense material," for which he shared the 1975
964:
Oldendorf WH. Isolated flying spot detection of radiodensity discontinuities – displaying the internal structural pattern of a complex object. Ire Trans Biomed
Electron. 1961 Jan;BME-8:68–72.
375:: moving synchronously and in opposite directions the X-ray tube and the film, which are connected together by a rod whose pivot point is the focus; the image created by the points on the
322:
In 2008 Siemens introduced a new generation of scanner that was able to take an image in less than 1 second, fast enough to produce clear images of beating hearts and coronary arteries.
653:
Vallebona A. Una modalitĂ di tecnica per la dissociazione radiografica delle ombre applicata allo studio del cranio
Comunicazione al IX Congresso Italiano di Radiologia, Turin, May 1930
310:
program and the acquired raw data. The hard disk itself comprised two 12" platters, one of which was internal and fixed, while the other was housed in a removable round cartridge.
1051:
Townsed CM Jr, Beauchamp RD, Evers BM et al. (2008). Sabiston
Textbook of Radiology: The Biological Basis of Modern Radiological Practice, ed 22. Saunders. pp. 104–112.
998:
F. Natterer and F. WĂĽbbeling "Mathematical Methods in Image Reconstruction (Monographs on Mathematical Modeling and Computation)", Society for Industrial (2001),
824:
Bulletin International de l'Académie Polonaise des Sciences et des Lettres. Classe des Sciences Mathématiques et Naturelles. Série A, Sciences Mathématiques
688:
238:
on a large computer. The scanner employed a pencil X-ray beam aimed at a single photomultiplier detector, and operated on the Translate/Rotate principle.
472:
275:
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258:. As a tribute to the impact of this system on medical imaging the Mayo Clinic has an EMI scanner on display in the Radiology Department.
82:, who showed mathematically that a function could be reconstructed from an infinite set of its projections. In 1937, Polish mathematician
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displayed in any plane. This results in a big reduction in x-ray exposure. Siemens and Toshiba are the leaders in this technology.
982:
F. Natterer, "The Mathematics of Computerized Tomography (Classics in Applied Mathematics)", Society for Industrial Mathematics,
66:. The first commercial installation of a CT scanner, an EMI-Scanner Mark I took place at the Mayo Clinic in the U.S. in 1973.
722:
Oldendorf WH (1978). "The quest for an image of brain: a brief historical and technical review of brain imaging techniques".
319:
scanner does not replace the fixed CT suite. An example of this type of machine is the Siemens Healthineers SOMATOM On.site.
123:
made it impossible to X-ray from any single angle. In his landmark 1961 paper, he described the basic concept later used by
664:"Alessandro Papa tsrm, Ospedale Maggiore della CaritĂ di Novara, Dipartimento di Radiologia Diagnostica ed Interventistica"
1216:
1181:
223:
Central Research Laboratories using X-rays. Hounsfield conceived his idea in 1967. The first EMI-Scanner was installed in
973:
Herman, G. T., Fundamentals of computerized tomography: Image reconstruction from projection, 2nd edition, Springer, 2009
1064:, in: 75 Years of Radon Transform, S. Gindikin and P. Michor, eds., International Press Incorporated (1994), pp. 32–35,
689:
https://web.archive.org/web/20160304211917/http://www.fisicamedica.it/aifm/periodico/2005/2005_2_Fisica_in_Medicina.pdf
86:
developed a method to find an approximate solution to a large system of linear algebraic equations. This, along with
701:
429:
Radon J (1 December 1986). "On the determination of functions from their integral values along certain manifolds".
889:
Cormack AM (1964). "Representation of a Function by its Line Integrals, with Some Radiological Applications. II".
74:
The mathematical theory behind computed tomographic reconstruction dates back to 1917 with the invention of the
224:
854:
Cormack AM (1963). "Representation of a Function by its Line Integrals, with Some Radiological Applications".
182:
155:
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231:, England, and the first patient brain-scan was done on 1 October 1971. It was publicly announced in 1972.
368:
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Georgetown University's prototype of the ACTA scanner caught the attention of the pharmaceutical giant
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minicomputer) was about 7 minutes per picture. This scanner required the use of a water-filled
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A historic EMI-Scanner Mark I, alongside the minicomputer used to process the CT image data
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1120:"The Nobel Prize in Physiology or Medicine 1979 Allan M. Cormack, Godfrey N. Hounsfield"
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established guidelines for diagnosis of a common abdominal pathologies, including
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255:
822:
Kaczmarz S (1937). "Angenäherte Auflösung von Systemen linearer Gleichungen".
360:
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as the image reconstruction mechanism in his first commercial CT scanner.
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498:"Dr. Alessandro Vallebona - The Evolution of Medical Imaging Technology"
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used a method similar to the Radon transform to reconstruct a map of
42:(CT) dates back to at least 1917 with the mathematical theory of the
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Deuflhard, P.; Dössel, O.; Louis, A. K.; Zachow, S. (5 March 2009).
19:
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low resolution, being composed of a matrix of only 80 Ă— 80 pixels.
27:
840:
Kaczmarz S., "Approximate solution of system of linear equations.
90:'s theoretical and experimental work, laid the foundation for the
26:
18:
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808:
Hornich H., Translated by Parks PC. A Tribute to Johann Radon.
1039:"Past and future directions in x-ray computed tomography (CT)"
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only in 1972 that he learned of the work of Radon, by chance.
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The first commercially viable CT scanner was invented by Sir
545:"TomografĂa lineal: nacimiento, gloria y ocaso de un mĂ©todo"
473:"Half A Century In CT: How Computed Tomography Has Evolved"
127:
to develop the mathematics behind computerized tomography.
1084:
Beckmann EC (January 2006). "CT scanning the early days".
347:
for imaging of the brain, as well as most applications of
477:
The International Society for Computed Tomography (ISCT)
270:independently invented a similar process, and both
1037:Natterer, Frank; Ritman, Erik (22 November 2002).
702:"Bernard George Ziedses des Plantes, MD 1902-1993"
278:for their contributions to the development of CT.
62:hospital in 1971 using a scanner invented by Sir
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254:In the U.S., the first installation was at the
185:until the late 1970s, when the availability of
1143:"FDA Clears 'Major Advancement' in CT Imaging"
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543:Buzzi, A. E.; Suárez, M. V. (2013-01-01).
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395:
1178:A History of the Radiological Sciences
1062:My Connection with the Radon Transform
926:"Strip Integration in Radio Astronomy"
7:
431:IEEE Transactions on Medical Imaging
770:"Obituary – Sir Godfrey Hounsfield"
619:Vallebona, A. (November 1947). "".
236:algebraic reconstruction techniques
519:"VALLEBONA, Alessandro - Treccani"
92:algebraic reconstruction technique
14:
1017:"More Mathematics into Medicine!"
23:Hounsfield's prototype CT scanner
16:History of CT scanning technology
1086:The British Journal of Radiology
586:Annali Di Radiologia Diagnostica
549:Revista Argentina de RadiologĂa
343:CT replaced the more invasive
57:received a U.S. patent for a "
1:
1182:American Roentgen Ray Society
668:alessandropapa.altervista.org
359:Before computed tomography,
274:and Cormack shared the 1979
768:Richmond, Caroline (2004).
409:Ber. Saechsische Akad. Wiss
339:Largely replaced techniques
1243:
1222:History of medical imaging
1141:Ingram, Ian (2021-09-30).
584:Vallebona, A. (1948). "".
382:
78:by Austrian mathematician
1227:X-ray computed tomography
1171:"Conventional Tomography"
810:IEEE Trans. Med. Imaging.
39:X-ray computed tomography
786:10.1136/bmj.329.7467.687
443:10.1109/TMI.1986.4307775
363:images could be made by
225:Atkinson Morley Hospital
199:with greater precision.
276:Nobel Prize in Medicine
156:small bowel obstruction
94:, which was adapted by
700:Valk, J. (June 1994).
369:focal plane tomography
355:Focal plane tomography
349:focal plane tomography
183:radiologic diagnostics
179:focal plane tomography
48:focal plane tomography
32:
24:
1024:Zuse Institute Berlin
924:Bracewell RN (1956).
383:Further information:
345:pneumoencephalography
181:remained a pillar of
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1217:History of computing
1147:www.medpagetoday.com
1098:10.1259/bjr/29444122
736:10.1212/wnl.28.6.517
621:La Radiologia Medica
260:Allan McLeod Cormack
125:Allan McLeod Cormack
88:Allan McLeod Cormack
55:William H. Oldendorf
942:1956AuJPh...9..198B
903:1964JAP....35.2908C
868:1963JAP....34.2722C
562:10.7811/rarv77n3a10
373:projective geometry
194:Commercial scanners
139:and Erik Ritman.
103:Ronald N. Bracewell
70:Mathematical theory
209:Godfrey Hounsfield
172:apple peel atresia
164:acute pancreatitis
152:acute appendicitis
96:Godfrey Hounsfield
64:Godfrey Hounsfield
33:
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1060:Allen M.Cormack:
911:10.1063/1.1713127
897:(10): 2908–2913.
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244:Data General Nova
115:William Oldendorf
53:In October 1963,
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525:(in Italian)
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479:. 2016-10-07
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844:1993; 57-9.
627:(11): 601.
377:focal plane
365:radiography
361:tomographic
256:Mayo Clinic
120:frostbitten
109:. In 1959,
37:history of
1211:Categories
1195:11 January
1152:2021-10-01
673:2023-11-24
529:2023-11-24
504:2023-11-24
483:2023-11-24
390:References
272:Hounsfield
724:Neurology
706:radiology
633:0033-8362
598:0003-4673
571:0048-7619
229:Wimbledon
142:In 1968,
101:In 1956,
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830:: 355–7.
752:42007208
641:18933293
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523:Treccani
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1197:2014
1128:2013
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1066:ISBN
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