Radiology Then and Now
Reproduced with permission from a Lecture in the Advances in Digital Imaging Symposium, University of Malaya 8th April 2004

By Assoc Prof Dr Y Faridah, MRad and Assoc Prof Dr B J J Abdullah FRCR
Department of Radiology, University of Malaya, Kuala Lumpur, Malaysia

Discuss this topic at the Radiology Malaysia Forum

Enter the Digital World
Computers and the digital world have impacted the science of Radiology bringing it to what it is today. The advancement of artificial intelligence this past 25 years has created an explosion of diagnostic imaging technique. Techniques have now been developed for digital rather than photographic recording of conventional radiographs. In the early days, a head x-ray would require up to 11 minutes of exposure time. Now digital radiographic images are made in milliseconds while reducing the radiation dose to as little as 2% of what was used for the 11 minutes head examination 100 years ago.

Armed with the ability to acquire cross-section images, researchers explore the possibility of acquiring volumetric data. This gave birth to spiral CT scanners in which volume datasets rather than axial slices are acquired. With powerful computers and complex reconstruction programmes, radiologists are able to select structures they wish to visualize from these datasets. Subsequent 2-Dimensional and 3-Dimensional display of these structures could be achieved. 3D imaging improves planning for surgical treatment.

The resolution achievable by the different imaging methods may be classified as spatial, contrast or temporal. Spatial resolution is the ability of a system to resolved anatomic detail. Contrast resolution is the ability of the system to differentiate different tissue especially to distinguished normal from pathological tissue. Temporal resolution is the ability of the modality to reflect either changing physiological events such as cardiac motion or disease remission or progression as a function of time (5). Each imaging modality has its strength and weaknesses much to the frustration of hospital administrators. No single method will solve all diagnostic problems and the fusion of knowledge gleaned from different modalities would serve our patients best.

Another aspect of digitalization is the development of more sophisticated management and information system. With great imaging power comes increasing volume of data and increasing cost. Photographic film has served as the reception, storage and display medium for x-ray images for a decade. It was cheap, readily available and thus was chosen to provide a permanent record of investigation. However, with the current expansion in the variety of digitally acquired image and the increasing capacity of digital storage systems, the possibility of dispensing with photographic film has arisen. Film-less imaging can lead to important savings in disposable resources and staff time and improves the efficiency of the department (14). It is estimated that by the end of this decade well over half of all medical centres’ radiology department will be completely or nearly completely digital (15).

Storage of digital images is undertaken by a picture archiving and communication system (PACS).

Workflow in a Radiology Department without PACS

Limited Storage, Missing Films, Labour Intensive

Workflow in an ideal Radiology Department with PACS

Conclusion

Radiology has developed at a tremendous pace and this progress in imaging has contributed immensely to the advancement of medicine. While the evolution will continue, the radiology community is left grappling with the ever-increasing sophistication of these current modalities while discarding obsolete examinations. Judging from the last 100 years, the future of Radiology is certainly bright.

References:

1. Grigg ERW. The trail of the invisible light. Illinois: Thomas, 1965.

2. Thomas AMK, Sherwood I, Wells PNT. The invisible light: 100 years of medical radiology. Oxford:Blackwell Science Ltd., 1995.

3. Aldrich I. Rontgen and the discovery of x-rays. In: Aldrich JE, Lentle BC, editors. A new kind of ray: The radiological sciences in Canada 1895-1995. Montreal: The Canadian association of Radiologists, 1995, p. 5.

4. Thomas AMK. One hundred years of medical radiology. Radiological history. http://www.rhhct.org.uk/history.html

5. Lentle B. Radiology: A brief history. http://www.promed-associates.com/RadioHistBL.pdf

6. Evens RG. Rontgen retrospective one hundred years of revolutionary technology. JAMA 1995; 274(11): 912-916.

7. Curry TS, Dowdey JE, Murry RC. Flouroscopic Imaging. In: Christensen’s Physics of diagnostic radiology 4th Ed. Philadelphia: Lea & Febiger 1990; p. 165-174.

8. Bakal CW. Advances in imaging technology and the growth of vascular and interventional radiology: A brief history. J Vasc Interv Radiol 2003; 14: 855-860.

9. Hinkle J. CT Scanning. Am J Nurs 1999; 99(6): 24AA, 24DD, 24FF.

10. The Editors. Looking back on the millennium in Medicine. N Eng J Med 2000; 342(1): 42-49.

11. Hounsfield GN. Computed Medical Imaging. Nobel lecture 1979.

http://www.nobel.se/medicine/laureates/1979/hounsfield-lecture

12. Gore J. Out of the shadows-MRI and the Nobel Prize. N Eng J Med 2003; 349(24): 2290-2292.

13. Slowiczek F, Peters PM. The Discovery of Radioactivity: The Dawn of the Nuclear Age. http://www.accessexcellence.org

14. Meire HB, Darzi A, Lee N. ABC of medical computing: Digital Imaging. BMJ 1995; 311(7014): 1218-1221

15. Gamsu G, Perez E. Picture Archiving and Communication Systems (PACS). Journal of Thoracic Imaging 2003; 18(3): 165-168.

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