Abstract：
X-ray micro-computed tomography (CT) produces three-dimensional images of samples on a micrometer scale. This technique has several advantages, such as its nondestructive character and low measurement time, compared with other techniques. However, when applied to biological samples of soft tissue, the low attenuation and low effective contrast between structures pose difficulties in creating appropriate images for morphological studies. Diffusible iodine-based contrast-enhanced CT (DICE-CT), which uses iodine solutions to enhance contrast, is a viable alternative for addressing the aforementioned challenges. Given the variety of biological samples, an appropriate methodology must be adapted depending on the dimensions and morphological characteristics of the investigated object. A specimen that has not been morphologically studied by micro-CT and is of high sanitary importance is the adult Aedes aegypti mosquito. This study investigated the stage of iodine staining in the treatment of the A. aegypti mosquito to determine the most suitable staining time for the morphological study of this mosquito in adulthood. After determining the appropriate staining time, we discuss the potential of applying DICE-CT and methodology to mosquito studies. Seven A. aegypti females were treated using fixation steps with Bouin\'s solution, dehydration in a graded ethanol series, staining with iodine solution (1%), and washing in absolute ethanol. Only the staining step was different between samples. Each mosquito spent a varying amount of time (6-72 h) in the iodine solution (1%). For comparison, one of the mosquitoes was not stained. After treatment, the samples were scanned using the Bruker SkyScan 1172 micro-CT scanner. The reconstructed volumes and histograms were compared to determine the most suitable time. In addition, a quantitative analysis was performed based on a comparison of the attenuation profiles of the mosquito brains. Thereafter, the most suitable treatment process was selected, and two other samples were scanned after applying the selected process. Although fewer than 18 h was insufficient for an effective increase in attenuation and effective contrast, surpassing 24 h proved unnecessary and resulted in saturating the gray tones visualized through the histograms, leading to information loss. Therefore, a time of approximately 24 h was the most suitable staining time for studying adult A. aegypti. It was possible to isolate the organs of the digestive and reproductive systems of the mosquito stained for 24 h. Thus, micro-CT was confirmed to be an excellent technique in studies of individual structures of adult A. aegypti mosquitoes.
摘要：
X射线显微计算机断层扫描(CT)在微米尺度上产生样品的三维图像。这种技术有几个优点，如其无损特性和低测量时间，与其他技术相比。然而,当应用于软组织的生物样本时，结构之间的低衰减和低有效对比度在创建用于形态学研究的适当图像方面存在困难。基于扩散碘的对比增强CT（DICE-CT），使用碘溶液来增强对比度，是解决上述挑战的可行替代方案。鉴于生物样本的多样性，必须根据所研究对象的尺寸和形态特征来调整适当的方法。尚未通过micro-CT进行形态学研究并且具有高度卫生重要性的标本是成年埃及伊蚊。本研究调查了治疗埃及伊蚊的碘染色阶段，以确定该蚊子成年期形态学研究的最合适染色时间。确定合适的染色时间后，我们讨论了将DICE-CT和方法应用于蚊子研究的潜力。用Bouin's溶液固定步骤治疗7只埃及伊蚊,在分级乙醇系列中脱水，用碘溶液（1％）染色，在无水乙醇中洗涤。样品之间仅染色步骤不同。每个蚊子在碘溶液（1％）中花费不同的时间（6-72小时）。为了比较，其中一只蚊子没有染色。治疗后,使用BrukerSkyScan1172微型CT扫描仪扫描样本。比较重建的体积和直方图以确定最合适的时间。此外,根据对蚊子大脑衰减曲线的比较，进行了定量分析。此后,选择最合适的处理工艺，和其他两个样品在应用选定的过程后进行扫描。虽然少于18小时不足以有效增加衰减和有效对比度，超过24小时被证明是不必要的，并导致通过直方图可视化的灰色色调饱和，导致信息丢失。因此,大约24小时的时间是研究成年埃及伊蚊的最合适染色时间。可以将蚊子的消化系统和生殖系统的器官分离24小时。因此，Micro-CT被证实是研究成年埃及伊蚊个体结构的一项优秀技术。
