查詢結果分析
來源資料
頁籤選單縮合
題名 | Development of a Dual-Probe Detection System for Positron Emission Radiotracer Detection=雙探頭正子輻射偵測器之研製以應用於正子放射製劑之偵測 |
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作 者 | 高潘福; 黃嘉彥; 王吉祥; 曾凱元; | 書刊名 | 長庚醫學 |
卷期 | 21:2 1998.06[民87.06] |
頁次 | 頁139-145 |
分類號 | 414.93 |
關鍵詞 | 雙探頭正子輻射偵測器; 正子放射製劑; Dual-probe detection system; Positron emission radiotracer; |
語文 | 英文(English) |
中文摘要 | 背景:正子放射製劑在生化及藥理學研究方面是極為有用的工具,但受限於正子 斷層掃描(positron emission tomography, PET)的昂貴,無法普遍的被應用。本研究之目的 在於發展製作一部簡易且經濟實用的雙探頭正子輻射偵測器(dual probe positron emitter detector system, DPDS),以用來測量正子放射製劑在人體或動物體內之放射強度。 方法:此DPDS儀器是根據coincidence線路,同時偵測到正子與電子撞擊產生互毀效 應(annihilation reaction)後所產生的兩個511 KeV光子(photons),而測量體內的放射性強 度。儀器是由兩個相面對的碘化鈉(sodium iodide, Nal)結晶體分別接上光電倍增管 (photomultiplier tube, PMT)後形成兩根放射線偵測探頭(probe)。各個光電位口增管後方 再接到前置放大器(preamplifier)及線性擴大器(linear amplifier)。隨後訊號經過單頻分析 器(single channel analyzer,SCA)來鑑別γ-ray量,只有能量為511 KeV的訊號才會被傳 輸到初級coincidence判讀器,此時兩偵測探頭所同時收集到的訊號才被認定為有意義的訊 號。這時所認為有意義的訊號中包括有「真實訊號」(true count)及來自兩個或多個互毀反 應所產生的不同光子來源,而被同時偵測到的「隨意訊號」(random count),此時一側訊號 經過計時延緩器(gate and delay generator)後再與另一側探頭的訊號同時輸入次級coincidence 判讀器,而被視為「隨意訊號」,再予以校正才是有用的「真實訊號」。整部DPDS計數器 之控制及所得資料之紀錄均經透過一Visual Basic軟體所撰寫的程式,由一部486個人電腦 執行。本研究並測試其穩定性、敏感度、線性實驗及計數之幾何效率(geometric counting efficiency)等特性。 結果:本研究成功的完成了DPDS之設計製作,並且測試結果良好。DPDS之敏感度及 線性實驗能正確的偵測到100μCi.以下的放射活性;穩定性方面則可以穩定的連續收錄2小 時以上的訊號;在幾何計數效率(geometric counting efficiency)方面,射源偏離中央線2公 分時其計數值差異小於5%。 結論:DPDS儀器可以成功的應用於正子放射活性的偵測,未來將有助於正子放射製劑 應用在臨床及基礎醫學研究,譬如腦神經受體及惡性腫瘤葡萄糖代謝等方面之人體或動物研 究。 |
英文摘要 | Background: Positron emission radiotracers are very useful in biochemical and pharmacological research. The purpose of this work was to develop and build a simple and inexpensive dual-probe detector system (DPDS) for detecting the activity of positron emmission radiotracers. Materials and Methods: The design of the DPDS was based on the coincident detection of two 511 KeV annihilation gamma-rays, which determined the positron activity in the body. A pair of sodium iodide (NaI) scintillators coupled to a photomultiplier tube (PMT) were positioned face-to- face as in a dual-probe system. The signals from each probe were then sent to a preamplifier, a linear amplifier, a single channel analyzer (SCA), and the primary and secondary coincidence units, respectively, to determine the number of total coincidence events and random events. Validation of basic characteristics, including stability, sensitivity, linearity and geometric counting efficiency, were tested. Results: The sensitivity and linearity of the DPDS worked well in detecting radioactivity within 100μCi. The DPDS was very stable in continuous counting for more than 2 hours. The geometric counting efficiency changed less than 5% when the source was placed 2 cm from the central coincidence line. Conclusion: This DPDS is a promising tool for positron emission radiotracer detection. It may be helpful in future in both clinical and basic biomedical research, such as neuroreceptor occupancy or glucose metabolic studies. Eventually, we will be able to use the DPDS in the human or animal body for evaluating position emission radiotracer metabolism and distribution. |
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