[915425]
A cbct manufactured by yoshida dental and terarecon was installed in late 2007. During a scan, the machine struck a patient in 2008. The machine was damaged and knocked out of mechanical calibration. There is no proximity interlock on the machine to shut it down in the event it should strike a patient while scanning a patient. The documentation for the machine does not describe a size limitation to be concerned about. There is a mass limitation of. 187 kg. This presumably is all that the positioning motors can handle. The damage to the machine was not apparent until several chiropractors used the machine to take cervical scans. The scan data was unreadable and not diagnostic. The company scheduled a repair visit after an engineer came to the office to evaluate the problem. Two technicians came out the following month to calibrate the machine. Dr decided to stay and determine why the machine failed after two months use and to determine what the issues with the machine were. When the technicians disassembled the covers to calibrate the machine it was easy to see that this machine was made with such inferior materials that it could not and would not be calibrated. The techs went about the calibration, reassembled the machine, and were preparing to leave. Dr who is an ex-engineer, asked them how they checked calibration. They had no way. The techs then scanned the spine of dr. Martin at his request and found that the machine was far out of calibration. They rescheduled a return visit on the next day and returned again to calibrate the machine. Calibration consists of aligning a flat panel detector to exact center of the x-ray beam using two jigs which are able to determine the center of the beam coming from the tube. The position must be exact to within a 3 thousands of an inch tolerance in the x, y, z axis. The adjustment screws are remote from the panel and are connected to the flat panel by very weak and flimsy sheet metal. Once the flat panel detector is exactly aligned, the covers must be re-installed. This is where dr informed the technicians that they would not be able to re-install the covers without pre-loading the fragile sheet metal and causing the machine to go out of mechanical calibration. A baseline calibration scan was done, with the covers off, of dr. Martin's spine showing a very good scan. There were several attempts to reassemble the machine each attempt threw the machine out of calibration as proven by another cervical spine scan. The technicians left after their failed attempts to calibrate the machine. On that date, they informed me that they had been in many offices re-calibrating the equipment, and that on the next day, they were going to an office for the tenth time to re-calibrate the machine in that office. I was amazed that they had no objective way to test calibration of a machine after they had completed the procedure. They were prepared to leave my office with the machine far out of calibration after they had gone through the procedure they had been taught by management. Management has repeatedly denied that there are any other users with mechanical calibration problems. I know of two other users who have problems the same as mine. Another three drs claim, he has filed a report to the fda, and one dr will probably be filing a report.
Patient Sequence No: 1, Text Type: D, B5