1968 to 1993
While I was with the 3M Medical Imaging Group, I traveled to San Francisco, California, to the Dunn Camera Company. This trip took place in about 1979 or 1980. I was there (as a 3M technical service representative) to help get our Special 3M Camera Film approved by the Dunn Camera people for use in their camera systems which were used extensively in the Medical Imaging business. The Dunn camera was one of many camera's on the market that produced pictures of studies done on X-ray machines, CAT. scanners (Computerized Axial Tomography), MRI's (Magnetic Resonance Imaging), Ultrasound, and other diagnostic devices. These "pictures" were really like the normal "radiograph" or X-ray films that every one is used to seeing. The Radiologist would place them on a view box to look at just like a chest X-ray film. The films were single sided emulsion type films. In other words, the film had photo emulsion on only one side of the poly-ester base material.
The "Camera" was really nothing more than a Video tube, placed in the bottom of a light tight box, facing up, with a camera style "shutter" near the top of the box. The very top of the box had a special access where a light tight film cassette could be placed. When the cassette was in place, a dark slide was removed from the side of the cassette that would be facing the video tube, with the shutter separating the tube and cassette. When a picture was to be imaged, the shutter would be opened for a measured amount of time, exposing the film. When the exposure was completed, the dark slide was replaced, the cassette was removed and taken to a dark room where the film was developed in the same manner as a normal X-ray film. You were in effect taking a picture of the information on the Video tube.
While I was working with the personnel at Dunn, I picked up a document that had been written by Robert (Bob) Dunn, owner of Dunn Camera. He had presented this "paper" at a meeting or symposium. The paper said that through the whole imaging chain, the video tube concept was in effect the "bottle neck" of the whole system. He felt that if any place needed a "break through" it had to be at this point. He reasoned (I think correctly) that it was at this point we could go no further in producing a "sharper" image. This was because we were limited by the number of "lines" that could be produced on a video tube. If you were to look very close at the image on your home TV set, you can see the image lines (525 lines U.S. and 625 lines for Europe). That's as sharp as you can get with this kind of system. Later systems forced the image up to 1024 lines and better. I brought this document back to 3M and copied it to everyone in the office including our Vice President. Some one evidently took my comments about the letter seriously, and I personally think that this was the start of what turned out to be the 3M Medical Laser Imager.
My boss came to me about 2 or 3 weeks after I had passed the above mentioned document around, and asked me to come up with a document or paper on "How to build a Laser Printer" (we called it a printer until later on in the project) . They were asking me because I was the only one in the Technical Service Group that had previous experience with X-ray and related equipment design. They felt that I would know what would be required of a piece of equipment in an X-ray environment. He gave me just 3 days to come up with a document that could be used to instruct a manufacturer on what would be needed to build a machine. It was from this document that the 3M Laser Imager would be conceived and built, with some modifications of course.
In my document, I instructed that the device should be "modular" in concept so that parts could easily be replaced with out disturbing any other part of the machine, or fogging film. I suggested that the unit should have separate light tight Receive and Supply magazines for the film. They had to be inserted and removed with out exposing the film. The film "pick up" and transport mechanism had to handle the film without placing "artifacts" on the film. It had to be easy to access in the event of a film jam some where in the transport area. I also suggested that in order to save space, the "print" portion of the system should employ a rotating "drum" which would provide the surface on which the Laser Beam exposure would take place. This was brought about by running the film over a rotating drum and exposing the film with the Laser Beam at the exact tangent of the roller. From the drum the film would than be transported into a waiting receive cassette or on into an attached film processor. The other alternative was a flat plate that the film would rest on while moving through the imaging area. This would have taken up to much space. I suggested that the unit should be built on a "vertical" concept to further save space, as space always seems to be at premium in a Hospital environment. This suggestion was not accepted (3 years later Kodak used this concept in their design). The Imager that was built followed the design of a paper Copying machine (horizontal), which allowed the film to follow a straight line during the transport and printing. It turned out to be a good alternative.
I had conceived the idea of attaching a film processor to the Laser Imager in order to speed up the system. I drew up a model "Docking Unit" (DU) to attach the Laser Imager to the film processor. By the way I was the one who coined the use of the name "Docking Unit" for this system. At that time it sounded a lot like "Space" program terminology that was being used at that time. The DU concept allowed the operator to choose either the Receive Magazine or the Film Processor by throwing a switch mounted on the Laser Imager. I talk more about the DU in my article on "Other Products".
One of our scientists was tasked to do the investigation into imaging with a Laser Diode onto a sheet of film. After quite some time and a lot of hard work, he came up with the Worlds 1st Medical image that had been produced by a Laser Diode. It was an image of a hand! The resulting image was spectacular!! The resolution was (for a 1st try) far and above the best that could be produced by a Video style camera. We were on the way! Several other scientist's worked on the method of sweeping the Laser beam so an image as large as 14" x 17" (35 x 43 CM) could be produced. There was no technology in the world at that time that could be used for a film this size, using laser technology. We searched the globe to find a company that would have the capability and had the necessary Optics "know how" to do it. We had in fact done it with a smaller film when we produced the image of a hand. We finally found one company in Japan that said they would try. Minolta Camera Company! They not only tried but succeeded in a little over 6 months. Their effort was nothing short of fantastic. I have nothing but the greatest respect for them. 3M in conjunction with other electronic companies invented the "brains" and memory systems for the 3M Laser Imager. I was not so involved with this part of the system but more with the invention, improvement and operation of the electronic and mechanical transport portion of the Laser Imager.
In 1984, 3M introduced and installed the Worlds 1st Medical Laser Imager in a Hospital in St. Paul, Minnesota (under test). I can and do claim that I was the Worlds 1st Laser Imager Service Engineer. I installed and serviced the Imager and I helped to make many changes on later devices over the first years of production. Other personnel were added to the staff in just a few short months to bring this great device into the market place. I helped to develop the service and instruction manuals, and in the process set up many specifications for adjustment and operation of the 3M Medical Laser Imager.
Today there have been several models of the 3M Laser Imager introduced into the market place. The first was the P831, followed by the P952, and others.
To this day I don't think any other Imager on the market can compete with the 3M Laser Imager.
Something to note: Because of difficulties in the business world, 3M "spun" the Medical Imaging Systems Division off into a company called Imation. As of 1998, Imation sold the Medical Imaging Systems Division off to Kodak due to some legal settlements made between the two companies. The worlds leading Laser Imaging system is now owned by Kodak, who in the "old" days was our chief competitor in the Laser Imaging field.
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Last updated on 15 January 2006