Szczykutowicz Timothy P, Bour Robert K, Rubert Nicholas, Wendt Gary, Pozniak Myron, Ranallo Frank N
University of Wisconsin Madison.
J Appl Clin Med Phys. 2015 Jul 8;16(4):228–243. doi: 10.1120/jacmp.v16i4.5412.
This article explains a method for creating CT protocols for a wide range of patient body sizes and clinical indications, using detailed tube current information from a small set of commonly used protocols. Analytical expressions were created relating CT technical acquisition parameters which can be used to create new CT protocols on a given scanner or customize protocols from one scanner to another. Plots of mA as a function of patient size for specific anatomical regions were generated and used to identify the tube output needs for patients as a function of size for a single master protocol. Tube output data were obtained from the DICOM header of clinical images from our PACS and patient size was measured from CT localizer radiographs under IRB approval. This master protocol was then used to create 11 additional master protocols. The 12 master protocols were further combined to create 39 single and multiphase clinical protocols. Radiologist acceptance rate of exams scanned using the clinical protocols was monitored for 12,857 patients to analyze the effectiveness of the presented protocol management methods using a two-tailed Fisher's exact test. A single routine adult abdominal protocol was used as the master protocol to create 11 additional master abdominal protocols of varying dose and beam energy. Situations in which the maximum tube current would have been exceeded are presented, and the trade-offs between increasing the effective tube output via 1) decreasing pitch, 2) increasing the scan time, or 3) increasing the kV are discussed. Out of 12 master protocols customized across three different scanners, only one had a statistically significant acceptance rate that differed from the scanner it was customized from. The difference, however, was only 1% and was judged to be negligible. All other master protocols differed in acceptance rate insignificantly between scanners. The methodology described in this paper allows a small set of master protocols to be adapted among different clinical indications on a single scanner and among different CT scanners.
本文介绍了一种利用少量常用协议中的详细管电流信息，为各种患者体型和临床适应症创建CT协议的方法。创建了与CT技术采集参数相关的解析表达式，这些表达式可用于在给定的扫描仪上创建新的CT协议，或在不同扫描仪之间定制协议。生成了特定解剖区域的毫安（mA）与患者体型的关系图，并用于确定单个主协议中患者体型与管输出需求之间的函数关系。管输出数据从我们PACS中临床图像的DICOM头文件中获取，患者体型在获得机构审查委员会（IRB）批准的情况下从CT定位X光片中测量。然后使用这个主协议创建了另外11个主协议。这12个主协议进一步组合，创建了39个单期和多期临床协议。对12857例患者使用临床协议扫描的检查的放射科医生接受率进行监测，使用双尾Fisher精确检验分析所提出的协议管理方法的有效性。使用单个常规成人腹部协议作为主协议，创建了另外11个不同剂量和束能量的主腹部协议。文中呈现了可能超过最大管电流的情况，并讨论了通过1）降低螺距、2）增加扫描时间或3）增加千伏（kV）来提高有效管输出之间的权衡。在跨三种不同扫描仪定制的12个主协议中，只有一个在统计学上具有显著不同于其定制来源扫描仪的接受率。然而，差异仅为1%，被认为可以忽略不计。所有其他主协议在不同扫描仪之间的接受率差异不显著。本文所述方法允许在单个扫描仪上的不同临床适应症之间以及不同CT扫描仪之间调整少量主协议。
