The X-Ray's Continuing Journey
As this cartoon illustrates, X-Rays have come a long way from
simply photographing bones. Today, many aspects of the
medical world are dependent upon the X-Ray's invention.
Copyright Radiology Centennial Inc.92
The first of these breakthroughs was the invention of CAT, or CT, scanning. Invented in 1972 by British engineer Godfrey Hounsfiel and South African physicist Allan Cormack, the CAT scan is essentially an X-Ray tube that is passed in circles around the patient, who is lying in a large tube. Thousands of pictures are taken from many different angles and from this a 3-D image is created.95 The first scanner took hours to collect an image and several days to complete the analysis; today, it takes only 350 milliseconds to complete four images and less than a second to create the model. The CAT scan is primarily used to diagnose head trauma, osteoporosis, and cancer.96
A similarly technique, the MRI, had its beginnings in 1946 when two scientists, Felix Bloch and Edward Purcell, independently discovered the phenomenon of magnetic resonance. Between 1950 and 1970, nuclear magnetic resonance was primarily used for chemical and physical magnetic resonance. However, in 1977 Raymond Damadian demonstrated the use of MRI on the entire body.97 The MRI works similarly to the CAT scan, taking cross-sectional images of the body based on hydrogen atoms and their spin. MRIs have taken the place of most CAT scans and have also found a place in drug development and in developing cooling units for both NASA and the US government.98
Several other imaging techniques evolved from the X-Ray, such as is PET (positron emission tomography), SPECT, and the ultrasound. PET is based on radioactive isotopes in the human body and is used primarily for the brain research in curing epilepsy, cancer, Parkinson's, and Alzheimer's disease.99 SPECT, which is also based on radioactive isotopes, is crucial in diagnosing bone cancer and problems with blood flow to the brain, heart, and liver.100 The ultrasound, based on sound waves, is currently used in hospitals everywhere and plays an important part in mammography, fetal care, and the heart.101
Progress in the realm of the X-Ray continue today. Treatments are becoming minimally evasive thanks to standardized safety precautions.102 Even X-Ray film may soon be replaced by X-Ray absorbing nylon, which would allow the images to be easily manipulated and transferred to a computer disk for storage.103 X-ray machines have also become used in the non-medical setting as security devices. Airports, governmental buildings, and public sites are now equipped with machines to check for weapons, bombs, and other items that could endanger national safety. X-Rays continue to play an important role in American, as well as worldwide, society over a century after its invention.
