In imaging's infancy (around 1900), all that existed was the X-ray. In fact, it was the only form of medical imaging available for decades. Ultrasoundâimaging by bouncing sound waves off the object under examinationâcame along in the '60s.
Computer-assisted tomography scanningâ which uses X-rays to image cross-sections of tissue and computers to reconstruct them into readable formâwas patented in 1975. Magnetic resonance imaging (formerly nuclear magnetic resonance, until the "nuclear" was dropped because it sounded scary) arrived in the early '80s. It uses powerful magnets to reorient certain atoms in the body and then capture the data produced when they pop back to their normal positions.
From there, the exponential growth and declining cost of computer power, combined with the development of miniaturized devices, have given radiologists a stunning array of tools.
With technological developments came economic opportunism, and over the past two decades, free-standing imaging centers have become commonplace.