Human Centrifuge
This is the first civilian human centrifuge in the United States. It was built at the Mayo Clinic under the direction of Dr. Earl Wood to study the effects of high gravitational (G) forces on the human body. The research began during World War II, much of it under military secrecy, and included test subjects such as Charles Lindbergh. Many historians believe this work contributed to the development of safer, more effective military aircraft and gave the Allies an important advantage during the war.
The centrifuge itself was a remarkable example of ingenuity. Dr. Wood and his team built it from steel pipe, recycled 40-ton flywheels salvaged from an old brewery, and even a used automobile engine. In the early years, there was no shortage of volunteers because the researchers often served as their own test subjects.
Dynamic Spatial Reconstructor (DSR)
The Dynamic Spatial Reconstructor (DSR) was one of the most ambitious medical imaging projects ever undertaken. Developed at the Mayo Clinic during the 1970s and early 1980s under the direction of Dr. Earl Wood, it was the world’s first high-speed, multi-source, three-dimensional CT scanner capable of producing detailed images of moving organs such as the beating heart and expanding lungs.
Conventional CT scanners of the era could produce excellent images of stationary anatomy but struggled with constantly moving organs. The DSR solved this problem by using 14 synchronized x-ray sources and 14 detectors arranged around the patient, capturing an entire three-dimensional volume in a fraction of a second. This made it possible to observe complete cardiac cycles and blood flow in ways that had never before been possible.
Although originally conceived as a non-invasive tool for the early detection of heart disease and lung cancer, the DSR ultimately became even more valuable as a research instrument. The data it produced established benchmarks for cardiac imaging and helped validate many of the non-invasive imaging technologies that followed.
The machine itself was extraordinary. The scanner’s gantry measured approximately 15 feet in diameter, 20½ feet long, and weighed nearly 17 tons. It incorporated 14 x-ray tubes, 14 rotating television cameras (later upgraded to CCD cameras), multiple video disc recorders, and sophisticated electronics and reconstruction software that pushed the limits of computing technology at the time.
Despite its groundbreaking capabilities, the DSR was too large, complex, and expensive to become a practical clinical instrument. Advances in conventional CT technology eventually achieved many of the same diagnostic goals at a fraction of the cost, and the Mayo Clinic ultimately decommissioned and scrapped the one-of-a-kind machine. Its influence, however, lives on in modern high-speed medical imaging, which owes much to the pioneering work accomplished by the DSR.
Medical Sciences Building
At first glance, this Medical Sciences Building from the 1950s looks unremarkable, but its design reflects the practical needs of a world-class research facility.
The interior walls are constructed from removable wooden panels, each a few feet in size and secured with screws. Instead of tearing into walls whenever a laboratory needed to be reconfigured, technicians could simply remove a panel to install new wiring, plumbing, tubing, or equipment. It was a remarkably flexible design that allowed the building to evolve as research needs changed.
The laboratories were equally well thought out. Much of the plumbing for laboratory sinks was made from Pyrex glass to withstand the corrosive chemicals used in research. Beneath the basement floors, an underground creek flows through the site.
This building also has a personal connection for me. Its elevator served as the prototype for the working elevator model that I built years later. Click here to see it.
Surplus
I bought all sorts of surplus equipment from the Mayo Clinic warehouse, including an old EEG machine. It was a massive piece of equipment built from stainless steel and vacuum tubes—perfect for transforming into Control 3. When I paid the attendant five dollars, he smiled and said, “The casters have to be worth that much alone!”
More than forty years later, I discovered there may be much more to this machine than I ever imagined.
Mayo Clinic established its electroencephalography (EEG) program in 1935 with a custom-built system, laying the foundation for what became a dedicated medical department by the late 1940s. Around that same time, Grass Instruments introduced the Grass Model III, the world’s first commercially available eight-channel EEG console. Although designed in 1939, wartime production delays meant it was not manufactured until 1949.
That same year, Mayo Clinic engineers developed a sophisticated electrode selector specifically for the Grass Model III. The design became widely adopted and remained in use until digital EEG systems eventually replaced it decades later. Dr. C. W. Mayo reportedly used this system during more than fifty lengthy surgical procedures.
The machine I purchased is a Grass Model III. Based on its age and serial number, it is believed to be one of the units used during this pioneering period that helped establish EEG as a practical medical technology. Because the original serial number plate is still intact, Mayo Clinic is researching its historical records to determine whether this is the very machine used by Dr. Mayo himself.