• The chest was struck or thumped and the resulting sound analyzed to identify the presence of fluid in the lungs, implying tuberculosis or pneumonia.
• The abdomen and breasts were palpated to detect cancerous lumps.
Currently biomedical technology extends and enhances the senses of the physician and thus dramatically increases the ability of the physician to diagnose disease.
Considering that the primary sense used by physicians in diagnosis was sight, it is understandable that optics and imaging have played a critical role in improving health care. Over the past 100 years, optics and imaging have allowed the clinician to see the previously unseen. For example, observation of bacteria and microbial parasites led to the development of antibiotics, and direct imaging of skeleton and organs with x ray aided in observing and setting bone fractures and diagnosing traumatic injuries to other organs. For example, laser-based flow cytometers provide detailed quantification of critical blood cell types, which is one of the primary tools for diagnosing and monitoring the treatment of AIDS patients.6
In addition to allowing the physician to see what could not be seen unaided, state-of-the-art optical technologies increase the sensitivity and specificity of measurements far beyond the physician’s sense of taste, smell, hearing, and touch.7 Photonics plays a major role in many modern molecular diagnostic instruments. Optical technologies now provide precise measurements of blood serum chemistry for maintaining safe glucose levels in patients with diabetes, replacing urine taste tests.8 Kidney function tests rely on accurate optical measurements of the glomerular filtration rate (GFR) rather than smelling a patient’s urine. Lung diseases such as emphysema, lung cancer, and tuberculosis are detected using computed tomography (CT) and chest x ray imaging. In addition, these imaging modalities provide more complete diagnosis of potential tumors detected by palpation.
During the 20th century, improvements in medical technology have doubled the life expectancy9 of individuals in high-income countries, changing the primary causes of death for a typical individual. One hundred years ago, infectious diseases often killed most individuals before the age of 50, whereas today the typical individual in a high-income country lives until the age of 80. Optics and photonics have been essential technologies leading to this dramatic increase in life expectancy. For example, the microscope was the key technology allowing discoveries in microbiology
6 Hazenberg, M.D., S.A. Otto, B.H. van Benthem, M.T. Roos, R.A. Coutinho, J.M. Lange, D. Hamann, M. Prins, and F. Miedema. 2003. Persistent immune activation in HIV-1 infection is associated with progression to AIDS. AIDS 17(13):1881-1888.
7 Bynum, W.F., and Roy Porter, eds. 1933. Medicine and the Five Senses. Cambridge, Mass.: Cambridge University Press.
9 See, for example, the CIA’s World Factbook, available at https://www.cia.gov/library/publications/the-world-factbook/. Accessed December 1, 2011.