For the record: the origin of the rapid serial sheet-film changer.

The early development of angiography and angiocardiography, and especially the equipment for the rapid automatic serialization of X-ray exposures, was chronologically described in detail by Dr. Wendell Scott in his Carmen Lecture delivered to the Radiological Society of North America (RSNA) in December 1950 [1]. Radiologic publications of the 1940s were saturated with articles describing homemade, and a few commercial, rapid filming devices, all of which were cassette or roll-film changers. None of these units satisfied the ultimate needs for the developing art of rapid serial angiography. Up to the time of Scott’s lecture, no mention had been made of instruments transporting only sheet film. In January 1951 , my preceptor, Dr. Paul Perry, then chairman of the Department of Radiology at Robert Packer Hospital and Guthrie Clinic in Sayre, PA, granted me 4 months’ leave from the terminal portion of my residency to visit major centers of radiology in the United States. Two weeks of this experience during January 1 951 was spent at the University of Michigan in Ann Arbor. Most of that visit was spent with Dr. Melvin Figley, reviewing his experiences with the roll-film changer he had developed along with Drs. Thompson and Hodges [2]. During an interval return to Sayre, I discussed the state of the art of serial angiography with Dr. Perry, who agreed to the use of departmental research funds to proceed with the development of a unit designed to more closely satisfy the optimal requirements of a rapid serial changer. Mr. Harold Reynolds, Chief Developmental Engineer at Ingersoll Rand Company in Athens, PA, was invited to participate in this project. He quickly recognized the inherent limitations of transporting the mass of relatively heavy cassettes in the cassette changer units, and the film handling and processing problems of the large roll-film units. His suggestion was to move the lightest mass possible, namely the sheet film. After many discussions of the problem and some innovative suggestions by me, on February 7, 1 951, Reynolds completed drawings of the prototype unit we had envisioned. This instrument was fabricated by Reynolds, a superb machinist, in his home workshop. The unit was completed in the summer of 1951 and put into clinical use at the Robert Packer Hospital. A description of the sheet-film changer (named the Serialograph) was not published until early 1953 [3]. Later that year, it was shown as a scientific exhibit at the 39th annual meeting of the RSNA in Chicago. At that meeting, the instrument was reviewed by interested representatives from most of the American manufacturers and, in addition, in great detail by engineers from the Elema-Schonander Company of Solna, Sweden. The Elema-Schonander representatives drew our attention to the fact that they had developed a sheetfilm unit in 1952 based on strikingly similar design principles. Thirty years later, in 1983, I reviewed the Swedish contributions with the help of Mr. L. Stolpe, then president of Elema-Schonander in Elk Grove, IL. Mr. Stolpe obtained information and documents from Mr. Georg Fredzell, the previous long-term director of research and