Research And Design Of Three Dimensional Conformal Quality Analyzer Based On Optical Fiber Sensor

Radiotherapy has become one of the main methods for the treatment of cancer at present.There is no treatment is perfect,and radiotherapy also have side effects.The side effects of radiotherapy are receiving more and more attention to people because of radiotherapy not only kills cancer cells,but also damages the irradiated normal tissues.In order to eliminate the side effects of radiotherapy on the human body as far as possible,precise radiotherapy technology is rapidly developing last few years.Its main theoretical basis is to plan the output dose as much as possible into the lesion area and make the normal tissue receives a very small dose.Besides,the quality of radiotherapy accelerators also affects the accuracy and effectiveness in the radiotherapy process.Therefore,regular monitoring and maintenance work of the accelerator quality is also an effective measure to ensure that lessly side effects of radiotherapy and safe radiotherapy procedures.Based on the above situation,a fiber sensing quality inspection system that can be used as a evaluation method of three-dimensional conformal precision radiotherapy program and quality testing method of accelerator at the same time is proposed.The quality assurance(QA)instrument is mainly composed of an optical fiber X-ray sensor filled with the rare earth luminescent material,the signal detection system,and the signal processing system.The optical fiber X-ray sensor can convert X-rays into visible light and transmit the optical signal to the signal detection system which convert light signals to electrical signals.And a computer will calculate the strength of signal which represents the intensity of radiation.The multiple fiber optic X-ray sensors in this QA instrument are insert three-dimensional solid water with stereoscopic distribution.According to radiotherapy requirements,three dimensional conformal therapy can be evaluated by simulating the lesion area using three dimensional solid water and some fiber X ray probes or all fiber X ray probes are used for routine accelerator quality monitoring.In order to ensure achievement of the above-mentioned functions with the QA system,a selective experiment of rare earth luminescent materials with an optical fiber X-ray sensor to selected rare-earth luminescent materials suitable for the QA instrument has been made.Three different photoelectric signal acquisition systems were selected and tested to comparetheir advantages and disadvantages.The fiber probes of the QA system were tested at different temperatures,water depths and encapsulation modes.Two tests were conducted at the national quality inspection institutions,and second generations of prototypes solved many problems exposed by the first prototype.For make a larger test system with more units,we put forward a new type of 3D conformal fiber sensor system based on CCD technology,and carried out some preliminary experiments.