診斷X射線空氣比釋動能的絕對測量研究
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本文選題:空氣比釋動能 切入點:自由空氣電離室 出處:《成都理工大學(xué)》2013年碩士論文 論文類型:學(xué)位論文
【摘要】:x射線診斷學(xué)和放射治療學(xué)等電離輻射醫(yī)學(xué)應(yīng)用蓬勃發(fā)展并不斷廣泛普及,在多種疾病和臨床診斷的現(xiàn)代醫(yī)學(xué)是不可或缺的,接受醫(yī)療照射的人員不斷增加,醫(yī)學(xué)診斷x射線的廣泛使用使之成為公眾照射劑量的最大的人工電離輻射來源,約占了人工輻射源照射的99%。常規(guī)診斷X射線管電壓范圍從(40-150)kV,射線輻射設(shè)備和計量器具至今沒有形成完整的溯源體系。為統(tǒng)一x射線劑量量值,保證x射線工作計量器具的準(zhǔn)確一致和正確使用,確保人身的安全,必須實現(xiàn)X射線劑量的量值溯源,保證x射線設(shè)備的質(zhì)量控制。 論文依托中國計量科學(xué)研究院電離輻射所和中國測試技術(shù)研究院共同申請的國家科技支撐計劃課題《醫(yī)用X診斷設(shè)備計量標(biāo)準(zhǔn)及溯源體系研究》,在現(xiàn)有的中能X射線(60~250)kV空氣比釋動能基準(zhǔn)和低能X射線(10~50)kV空氣比釋動能基準(zhǔn)和基準(zhǔn)裝置基礎(chǔ)上,進行了診斷X射線(40~150)kV空氣比釋動能絕對測量研究,并復(fù)現(xiàn)了空氣比釋動能的量值,為規(guī)范診斷水平空氣比釋動能的量值傳遞提供支持。 在國內(nèi)計量單位內(nèi)首次搭建了介入式管電壓測量系統(tǒng),實現(xiàn)工業(yè)X射線管電壓的精確測量,并與非介入式管電壓測量儀器相互比較,為解決非介入式管電壓溯源提供保障;論文初步完成了使用高能量分辨率的能譜儀測量診斷x射線束的能譜測量及分析,使用能譜終點法實現(xiàn)對X射線管電壓進行了嘗試性的測量。論文對x射線參考輻射束規(guī)范的快速建立方法進行研究,在他人的基礎(chǔ)上,提出了快速獲得半值層和調(diào)整輻射質(zhì)的數(shù)值處理方法,建立了國際電工委員會推薦的診斷X射線參考輻射束規(guī)范——RQR和RQA系列輻射質(zhì)規(guī)范;通過實驗方法研究,對X射線光管的固有過濾等效鋁進行了測量。X射線過濾束的能譜可以應(yīng)用于確定過濾X射線輻射質(zhì)、X射線機的管電壓、自由空氣電離室修正因子、空氣比釋動能到劑量當(dāng)量的轉(zhuǎn)換系數(shù)等,這對于國際比對、量值傳遞和儀器儀表的檢定與校準(zhǔn)有著非常重要的推廣價值。文章初步實現(xiàn)對X射線過濾束的能譜測量及分析。 論文對自由空氣電離室的原理和國際上主要國家的基準(zhǔn)電離室研究狀況進行了調(diào)研,在此基礎(chǔ)上,設(shè)計了實驗,實驗和計算出復(fù)現(xiàn)量值所需要的修正因子,實現(xiàn)了自由空氣電離室空氣減弱修正系數(shù)、復(fù)合損失修正系數(shù)、電場畸變修正系數(shù)、通過室壁的輻射穿透修正系數(shù)、光闌邊緣穿透修正、極性修正的測量。最后復(fù)現(xiàn)了診斷水平X射線的空氣比釋動能,并合理評估了測量結(jié)果的不確定度。在建立的IEC推薦的輻射質(zhì)下,實現(xiàn)了空氣比釋動能的量值復(fù)現(xiàn),其不確定度為0.28%(k=1)。
[Abstract]:The application of ionizing radiation medicine, such as x-ray diagnostics and radiotherapy, has flourished and has been widely spread. Modern medicine is indispensable in a wide range of diseases and clinical diagnostics, and the number of people receiving medical radiation is increasing, The widespread use of medical diagnostic x-rays makes them the largest source of artificial ionizing radiation for public exposure, The conventional diagnostic X-ray tube voltage ranges from 40 to 150 kV, and no complete traceability system has been formed for radiation equipment and measuring instruments. To ensure the accurate, consistent and correct use of x-ray working measuring instruments and to ensure the safety of human beings, it is necessary to trace the value of X-ray dose to the source and ensure the quality control of X-ray equipment. The thesis relies on the National Science and Technology support Program Project "Research on Measurement Standards and traceability system of Medical X Diagnostic equipment", which is jointly applied by the Institute of Ionizing radiation of the China Institute of Metrology and the China Institute of Test Technology. On the basis of X ray 60,250kV air specific kinetic energy reference and low energy X ray 1050kV air specific release kinetic energy reference and reference device, In this paper, the absolute measurement of the air specific release kinetic energy of the diagnostic X-ray is studied, and the value of the air specific release kinetic energy is recounted, which provides the support for the standard diagnosis of the horizontal air specific release kinetic energy transfer. The interventional tube voltage measurement system has been set up in the domestic measurement unit for the first time to realize the accurate measurement of the industrial X-ray tube voltage and to compare with the non-interventional tube voltage measurement instrument to provide the guarantee for solving the non-interventional tube voltage traceability. In this paper, the energy spectrum measurement and analysis of diagnostic x-ray beam using high energy resolution energy spectrometer are preliminarily completed. In this paper, the method of rapid establishment of X-ray reference beam specification is studied, based on others, the X-ray tube voltage is measured by using the energy spectrum end point method. In this paper, a numerical treatment method for quickly obtaining half-value layer and adjusting radiation quality is proposed, and the diagnostic X-ray reference beam specification, RQR and RQA series radiative quality code, recommended by the International Electrotechnical Commission, is established. The energy spectrum of X ray filter beam can be used to determine the tube voltage of X ray radiator and the correction factor of free air ionization chamber. The conversion coefficient from air specific release kinetic energy to dose equivalent is very important for international comparison, quantity transfer and verification and calibration of instruments and instruments. The energy spectrum measurement and analysis of X ray filter beams are preliminarily realized in this paper. In this paper, the principle of free air ionization chamber and the research status of reference ionization chamber in major countries are investigated. On this basis, experiments are designed, and the correction factors needed to calculate the reappearance value are designed. The correction coefficients of air attenuation, compound loss and electric field distortion in the free air ionization chamber are realized. The correction coefficients of radiation penetration of the wall of the chamber and the edge of the diaphragm are corrected. The measurement of polarity correction. Finally, the air specific release kinetic energy of diagnostic level X ray is reappeared, and the uncertainty of the measurement result is reasonably evaluated. Under the radiation quality recommended by IEC, the value of air specific release kinetic energy is restated. The uncertainty is 0.28%.
【學(xué)位授予單位】:成都理工大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2013
【分類號】:R144
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