質子與人體元素的作用截面之分析與應用

Analysis and application of the Cross Section of proton induced reaction in human body element

鄭安(Cheng, An)

指導教授 ： 蔡惠予

國立清華大學/原子科學院/核子工程與科學研究所/碩士(2020年)

摘要

在質子治療的過程中，質子射程的準確度十分重要，目前常見的質子射程的間接驗證方式有以瞬發加馬成像，以偵測質子誘發瞬發加馬輻射回推質子射程；或是正子斷層掃描，即以正子釋出核種的活度進行質子射程的回推。除了實驗之外，也會以蒙地卡羅程式進行模擬來確認質子誘發瞬發加馬輻射與質子誘發正子釋出核種的產量來確定實驗，但各個蒙地卡羅程式所使用的內建作用截面資料庫都不相同，就會造成模擬的結果也不同。本研究目的為建立一個由實驗的作用截面所構成的作用截面資料庫，並可以將這些作用截面資料應用於計算質子誘發瞬發加馬輻射與質子誘發正子釋出核種的產量。
實驗的作用截面資料是以EXFOR資料庫中所記載的為主，質子誘發瞬發加馬輻射會根據其產生機制與參考文獻所使用的參數進行搜索，搜尋完後會針對其產生不同能量的瞬發加馬輻射進行整理；質子誘發正子釋出核種會依照其產物進行搜索，搜尋完後會針對其產生不同正子釋出核種的反應進行整理，也會根據不同的組織進行巨觀截面的換算，最後會將這些資料建立作用截面資料庫，資料庫內包含質子誘發瞬發加馬輻射與質子誘發正子釋出核種的作用截面資料，以及轉換為巨觀截面的檔案。
本研究所建立之作用截面資料庫建立完成後，會將這些作用截面資料進行產量的換算，換算的結果會先根據參考文獻進行驗證，最後再帶入實驗的應用。驗證結果顯示以運算的方式可以良好的重現以蒙地卡羅程式模擬的產量，以及本研究所使用之實驗作用截面可以一定程度的與其他參考文獻之所作的產量結果相符合。最後再將其帶入人體組織材料推定射程，其所得到之結果也可以與參考文獻相符。證明本研究所建立之作用截面資料庫與產量運算的方法可以應用於產量的運算中。

關鍵字

質子治療 ； 正子斷層掃描 ； 瞬發加馬輻射 ； 微觀截面 ； 巨觀截面

並列摘要

The accuracy of the proton range is essential in the process of proton therapy. The technology of indirect proton range verification now includes prompt gamma imaging, which detects the proton-induced prompt gamma-ray, and the positron emission tomography, which estimated the range from the activity of the positron emission. Except for the experiments, Monte Carlo simulations are also used to simulation the yields of proton-induced prompt gamma-ray and proton-induced positron emitter in order to ensure the result of the experiment. But the built-in cross section data library used by each Monte Carlo Simulation code is different, and it will make the simulation results different. The purpose of this research is to establish the cross section data library composed of experimental action cross-sections, and this cross section data library can be used to calculate the yield of proton-induced prompt gamma-ray and proton-induced positron emission.
The experimental cross section data in the cross section data library is mainly based on the records in the EXFOR online data library. proton-induced prompt gamma-ray will be searched according to its mechanism and the searching quantity used in other references. After searching, the data will be arranged by different energies. Proton-induced positron emitter will be searched according to the products of the mother nuclide. After searching, they will be sorted out for their reactions to produce different positron emitter. macroscopic cross section conversion will also be performed according to various organizations. Finally, these data will be built into a cross section data library, which contains the cross-section data of the proton-induced prompt gamma-ray and the proton-induced positron emitter, as well as the files of the macro cross-section converting.
After building the cross section data library, we will take the data from the library to calculate the yield. The calculated yield will be verified by the reference and brought into the application of the human organ simulation. The verification results show that the yield, which is simulated by the Monte Carlo simulation code can be reproduced well by calculated yield. Finally, the data from the Cross Section data library is brought into the human organ material to estimate the range, and the results obtained can also be consistent with the reference. It is proved that the method of yield calculation and the data of the cross section data library which by this research can be applied to the calculation of yield of proton induced-prompt gamma-ray and proton induced-positron emitter.

並列關鍵字

proton therapy ； positron emission tomography ； PET ； prompt gamma ； cross section ； macroscopic cross section

參考文獻

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