In the 1966 movie Fantastic Voyage (starring Stephen Boyd and Raquel Welch), a crew including two doctors boards a submarine which is miniaturized using new technology and injected into a scientist’s body on a mission to remove a life-threatening blood clot.
We are closer to doing this than you might think. Virtual endoscopy lets physicians fly through the body using three-dimensional computed tomography (CT). Conventional endoscopy (minimally invasive surgery) is being enhanced with surgical robotics and high resolution video. Swallow Given Imaging’s PillCam, and doctors can examine your gastro-intestinal tract.
19th century physicians were thwarted even when they tried to peer inside the living eye--an open window. Hermann Helmholtz knew that others were illuminating the eye from one side and trying to catch a reflection from the other side. Instead, Helmholtz positioned himself as close to the line of the incident light as possible, and was able to catch just enough of the light bouncing back to the source to see the retina through a lens. His invention, the ophthalmoscope, was an immediate hit.
Wilhelm Roentgen’s discovery of x-rays was more disruptive. Roentgen placed some coins in an opaque, wooden box and produced an x-ray photograph showing the coins. When news of Roentgen's discovery spread, people feared they would need lead-lined underwear. (They would never get past today’s airport security with that, however.) Suddenly, it was possible to see through solid objects.
The first medical x-rays required long exposures and physicians were ignorant of the dangers. Thomas Edison’s assistant Clarence Dally died from overexposure and Edison terminated his x-ray research. Ironically, Michael Pupin used one of Edison’s inventions, a fluorescent screen, to dramatically reduce exposure times. An x-ray photograph that had required one hour could now be taken in a few seconds.
Conventional x-rays were good for examining bones but not soft tissues. An Austrian mathematician, Johann Radon, developed a way to calculate 3D images from a series of imaginary pencil beams. Radon's scheme offered a way, at least on paper, of visualizing soft tissues.
The British company EMI made a fortune producing the Beatles’ records and, therefore, it's said that the group contributed to the development of CT scanners. That’s a bit of a stretch. EMI engineer Godfrey Hounsfield came up with the idea of producing 3D x-rays of the head while relaxing in the country. EMI turned down Hounsfield’s request for funding, but when he obtained funding from a government agency he was allowed to conduct the research at EMI’s facilities. Unfamiliar with Radon’s technique (now known as “back projection”), Hounsfield used brute force math, and managed to secure orders for three CT scanners.
When Nuclear Magnetic Resonance imaging was introduced a few years later, some feared that “NMR” meant “No More Roentgen.” NMR had its own public relations problem—use of the word “nuclear”—and is now known as Magnetic Resonance Imaging (MRI). While MRI doesn’t use x-rays, scans can take an hour or longer. CT is much faster.
Before Roentgen, the inside of the living body was so tantalizingly close—and yet so inaccessible. Now, by combining computed tomography with stereotactic radiosurgery it’s possible to not only look inside the body from the outside, but to perform totally non-invasive procedures. Which is good thing, because that way there’s less risk of getting trapped inside the body as almost happened to the crew of the fictional submarine in the movie Fantastic Voyage.
Next time: Human Electricity
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