ONKOCET Ltd. has exhibited the devices from its portfolio on the MEDTEC UK exhibition in Birmingham, April 2011 through our partner Medical & Partners.
1.1 Overview
Electric Control System is composed of upper control computer, operation box, manual remote control box, timers, UPS, motion controller, drivers, motors, increment encoders, logic circuits limit switches, monitoring system, and intercommunication system. The main functions of the Electric Control System is: to control X, Y, and Z axis movement and localization of the treatment bed; to position and rotate the source carrier and the collimator carrier; to open, close, load and unload the cobalt sources; to import treatment data, to display the state of the equipment in the process of treatment, and to monitor the equipment and the patients. In order to ensure the security of the patients and the operators, the system is also equipped with safety interlocking and audible-visual alarm.
The operation of the treatment is accomplished on the console on which there is upper control computer, operation box, intercommunication system and monitoring system. The operation section of the console is composed of operation box, and manual remote control box. Using the upper control computer to monitor and control the running state of the equipment; operating the buttons on the operation box to control the operation, pause and emergency stop of SGS; using the indicator lights on the operation box to be aware of the running status of the system. In addition, the buzzing alarm on the operation box can be activated to remind the operators when there is something wrong with the system. The manual remote control box is used when the axis of SGS need respective movement. The monitoring system and the intercommunication system are installed in the treatment room and the control room. The operators can observe the whole treatment process and communicate with the patients through the monitor and microphone of the console.
The electrical source is supplied by Electric Supply and online UPS. When there is something wrong with the Electric Supply, UPS will be able to make the equipment run properly for more than 30 minutes to make sure that the treatment will not be broken off when power is suddenly failed.
The actuators of source carrier and collimator carrier include the drivers, servo motors, incremental encoders, etc. The position detection and localization among source carrier and collimator carrier is accomplished by the incremental encoders. The opening and closing of radiation source is displayed by the status indicator lamp. In addition, the rotating speed and rotating range which is used by the upper control computer to control the 6K8 motion controller is determined by the treatment planning. During the treatment, the maximum rotating speed of source carrier and collimator carrier is 1rpm.
The x movement and z movement of the treatment bed is achieved by the decelerated motion device which is driven by the stepping motor. The y movement is achieved by the decelerated motion device which is driven by servo motor. The position of all the movements is fed back to the 6K8 controller through the encoders, which can ensure the positioning accuracy of the treatment bed. Moreover, the three axes on the treatment bed have zero switch and positive-negative motion limit switches which can ensure the safety operation of the treatment bed and the determination of the axis’ zero position. The barrier of the source storage is driven by servo motor, while the handspike and the source box lock is driven by stepping motor. The position verification is achieved by proximity switch.
The diagram of Electric Control System is as following:
The control of radiation dose of SGS-I is composed of two independent timers. These two timers use redundancy association and can stop the radiation process independently. When SGS is started to radiate, one timer is timing ascendingly and the other is timing descendingly. Timers will be displayed in the Remaining Time and Elapsed Time on the control board. The value of timers is initialized by the upper control computer. When one of the timers goes out of order (the count value of the two timers has more than five seconds difference or one of the timers powers down), the treatment will be terminated with alarm tone and the failure will be shown on the upper control computer. When the radiation is stopped accidentally, the value of the current timers will be saved individually on the timers and the upper control computer for later examination.