The Realization Of Gamma Knife Dosimeter Which Is Based On Man-machine Interface

"Gamma Knife" is called "knife", but in fact it is no real scalpel, it is a device filled with quasi-hemispherical straight helmet, 201 beams of 60 high-dose cobalt ion ray can be fired in the helmet --- gamma rays.Through CT and MRI of the modern imaging technology ,it can accurately locate a particular area, we call it "target." It is extremely accurate positioning, the error is usually less than 0.5 mm; each dose of gamma-ray has a great gradient, there is almost no damage to the organization. But the 201 rays come together from different locations can be lethal to destroy the target tissue. Its functions just like a scalpel because of its name.There are advantages just like no trauma, no anesthesia, no surgery, no bleeding and no infection and so on. The lesion can not be completely removed if the dose of Gamma Knife is too less, then it's not effective, if the does is too more it may endanger the patient's life. Therefore the dose of Gamma Knife is closely related to patient's health, the detection of gamma knife dose is of great significance.The equipments of Gamma Knife are increasing at home and abroad in recent years, due to its marginal changes in the distribution curve of the dose of radiation field is very steep, the direction of the beam which is formed by the the focus is incident and so on, so Therefore the focus of Department for Gamma Knife dose rate of measured dose parameters, required dosimeter probe diameter (sensitive area) which is less than 2mm, directional, sensitive and reliable, therefore radiation measuring instruments are usually not suitable for measurement of gamma knife. The hospital which has a Gamma Knife, is mainly helped by knife manufacturers in debugging when measured gamma knife dose parameters (or Gamma Knife Hospital has hired national experts in the measurement) input treatment planning system for the treatment of the use of the vast majority of hospitals in the use of Gamma Knife in the future, no ability to measure the basic dosimetric parameters, which is obviously not scientific, but also affect the effectiveness of therapy.First of all, this design feature is the fast, accurate display of the current dose of gamma knife, using man-machine interface makes the design more humane and intelligent. Design seeks to make fast response, high accuracy, and attractive interface to achieve the demand of the market.Gamma dosimeter mainly focused on three aspects:①the measurement principle of Gamma-ray output and implementation approach;②Detector research and work options;③data acquisition hardware and software systems.First, this study has determined the overall structure and system requirements in the literature and on the basis of market research. After the radiation dose by different detectors in-depth comparative analysis of diagnostic test based on the technology development trends and characteristics of Gamma-ray radiation field is determined to made of high purity silicon PIN-type silicon photodiode as a semiconductor radiation detection device, it is high sensitivity, small size, fast response, without pressure, then we have a detailed theoretical analysis and experimental study on the performance of the detector, Focuses on the energy response and compensation to meet the design requirements,choose the best work .And we use 0.6cc of graphite ionization chamber as the scale of the detector of the dosimeter,as mainly using the high energy response characteristics of the ionization chamber.The dosimeter of Gamma Knife has two channels, one channel is connected to semiconductor detector, another channel is connected 0.6CC graphite ionization chamber. Except for the measurement of the ono absorbed dose of the Gamma Knife and X knife, but also can be used for the test of radiotherapy equipment by Legal Metrology department, and hospital's routine monitoring of radiation absorbed dose.Intelligent, personalized and intuitive is the theme objectives of this study. Human-computer interface designed to make use of the gamma knife dose meter is not only more simple in appearance, aesthetics, but also the use of the convenience of operation can be more intuitive. The dosimeter of Gamma Knife can visually display the current dose of gamma knife, and its man-machine interface design, makes the operation more humanity and intelligence.With the semiconductor probe as a radiation detector, the radiation signals into weak current, pre-level integration of weak signals, time to measure voltage, this voltage is proportional to the dose value. Board with MCU as the core, in its external expansion of the ADC, display module, printer, keyboard, etc., with data processing, display, storage, printing, set the alarm value, correction factor setting, measurement and alarm time setting functions.Gamma knife dosimeter which is based on Man-machine interface has three parts which are the main detector front-end circuit (pre-integration, amplification and post-grade A / D conversion circuit), MCU control circuit, and the man-machine interface. Main achieved front-end detector circuit will convert the digital signal radiation intensity. MCU control circuit is the core of the instrument, play a role in receiving and sending information. Man-machine interface is a device and the link between the transmission of information, it makes the operation more intuitive and user friendly.The instrument is mainly used for Gamma Knife Dose "γradiation head stereotactic radiosurgery radiation sources" (also called gamma knife) and the focus of the absorbed dose measurements in the small area (less than 18×18mm). It is the Gamma Knife treatment based on routine monitoring and "γradiation treatment of head and stereotactic radiosurgery radiation source verification regulations" necessary to conduct periodic testing of equipment.