《ct的質(zhì)量控制》ppt課件 (2)-文庫吧
2025-01-04 02:00 本頁面
【正文】 be no more than +/7 應在 +/7 之內(nèi) ? Uniformity depends on scanner 均一性取決于掃描儀 ? Noise depends on technique used for scan 噪聲取決于所使用的掃描技術 ? Data should be charted so trends can be seen 應將有關數(shù)據(jù)作圖以觀察趨勢變化 8642024681 2 / 2 5 / 2 0 0 1 2 / 1 3 / 2 0 0 2 4 / 4 / 2 0 0 2 5 / 2 4 / 2 0 0 2 7 / 1 3 / 2 0 0 2 9 / 1 / 2 0 0 2 1 0 / 2 1 / 2 0 0 2CT Number Accuracy CT值精度 ? Check accuracy and constancy of known materials 檢查已知物質(zhì)的精度和穩(wěn)定性 CT Numbers CT值 ? Air 空氣 1000 970 ? Polyethylene 聚乙烯 107 87 ? Water 水 7 7 ? Acrylic 丙烯酸 110 130 You need to verify which material is in the phantom. If in doubt, check with the manufacturer. 需確認模體中是何種物質(zhì)，如有疑問，與制造商溝通。 Resolution 分辨率 ? Resolution Test Object 受試目標分辨率 Commercial Phantoms 商業(yè)模體 ? Variety of phantoms available 可選的模體很多 ? Accreditation program in the . requires use of phantom designed by American College of Radiology (ACR) which measures more than QC Phantoms from manufacturers 在美國，認證過程中需使用放射協(xié)會設計的模體，而不僅僅是制造商提供的質(zhì)控模體 Costly 昂貴 Doesn‘t work with manufacturer?s software 不能與制造商提供的軟件一起使用 Requires annual physicist evaluation 每年需要評估 Monitor Display amp。 Film Printing 監(jiān)視器顯示和底片打印 ? Monitor should be adjusted to have a proper gray scale 監(jiān)視器應進行調(diào)節(jié)，以便獲得適當?shù)幕叶? ? Printed films should match monitor display 底片的打印應與監(jiān)視器顯示狀態(tài)相匹配 ? Printers and monitors must function in DICOM format 打印機和監(jiān)視器應在 DICOM格式狀態(tài)下工作 ? SMPTE Test Pattern used for image quality evaluation of both monitors and printers 對于打印機和監(jiān)視器，應用 SMPTE圖形進行影像質(zhì)量的監(jiān)測 SMPTE Test Pattern Accuracy of Table Location 掃描床的定位精度 ? Accuracy of Positioning Lights and Table Motion should be within + 2 mm 定位光與掃描床位移之間的精度應在 + 2 mm之內(nèi) ? Return of table to the same location is especially important for interventional studies 掃描床的歸位對于干涉分析特別重要 Protocol for Table Localization 掃描床定位步驟 ? Set slice width to thinnest available 將層厚設至最小值 ? Position radioopaque wire on table and align with positioning lights 將線定位于掃描床并與定位光對齊 ? Scan – wire should appear in image 掃描 —線應出現(xiàn)在影像中 ? Move table out to extreme and reposition to same location using numerical indicators 將掃描床移出頂端，使用數(shù)字指示重新將它定位 ? Scan – wire should appear in image 掃描 —線應出現(xiàn)在影像中 Frequency of Testing 測試頻度 ? Test frequency is not as well defined as for some other imaging methods 測試頻度與其它的影像測試方法定義不同 ? Physicist should determine test frequency based on 其定義基于 ? Manufacturers remendations 制造商的建議 ? Experience with scanner 對掃描儀的工作經(jīng)驗 Frequency Testing Remendations 測試頻度建議 ? Dose Evaluation 劑量評估 ? Annually 每年 ? Following major service 大修后 ? Clinical Technique Evaluation 臨床技術評估 ? Annually 每年 ? When a new technique is developed 開發(fā)新技術時 ? Water Evaluation 水測試 ? Weekly 每周 Frequency Testing Remendations 測試頻度建議 ? Monitor amp。 Film Printer Evaluation 監(jiān)視器和打印機評估 ? Monthly 每月 ? Table Motion and Alignment Lights 床位移和光定位 ? Quarterly 每季 ? Weekly if used for therapy planning 對于治療方案，可每周進行 ? Full Physics Evaluation 全部評估 ? Annually 每年 ? Following major service 大修后 Essential QC Activities 基本質(zhì)控 ? Determine doses from scanner 確定掃描劑量 ? Working with physician colleagues determine appropriate imaging protocols 與臨床人員協(xié)調(diào)確定適當?shù)墓ぷ鞣桨? ? Insure that water has a appropriate CT number 確定水測試時獲得適當?shù)?CT值 ? Accurate 精度 ? No artifacts 無偽影 ? Uniform 均一 ? Appropriate noise 噪聲適當 Essential QC Activities 基本質(zhì)控 ? Insure that the monitors and film printers work correctly 確認監(jiān)視器和底片打印機工作正常 ? Insure that positioning lights and table motion are correct 確
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