小儿 CT 自动管电流调制和管电压选择：辐射剂量和图像质量的体模研究。

OBJECTIVES

The aim of this study was to investigate the effects of a modern automatic tube current modulation (ATCM) and automatic tube voltage selection (ATVS) system on radiation dose and image quality in pediatric head, and torso computed tomography (CT) examinations for various clinical indications.

MATERIALS AND METHODS

Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old child were used. Standard head, thorax, and abdomen/pelvis acquisitions were performed with (1) fixed tube current, (2) ATCM, and (3) ATVS. Acquisitions were performed at various radiation dose levels to generate images at different levels of quality. Reference volume CT dose index (CTDIvol), reference image noise, and reference contrast-to-noise ratios were determined. The potential dose reductions with ATCM and ATVS were assessed.

RESULTS

The percent reduction of CTDIvol with ATCM ranged from 8% to 24% for head, 16% to 39% for thorax, and 25% to 41% for abdomen/pelvis. The percent reduction of CTDIvol with ATVS varied on the clinical indication. In CT angiography, ATVS resulted to the highest dose reduction, which was up to 70% for head, 77% for thorax, and 34% for abdomen/pelvis. In noncontrast examinations, ATVS increased dose by up to 21% for head, whereas reduced dose by up to 34% for thorax and 48% for abdomen/pelvis.

CONCLUSIONS

In pediatric CT, the use of ATCM significantly reduces radiation dose and maintains image noise. The additional use of ATVS reduces further the radiation dose for thorax and abdomen/pelvis, and maintains contrast-to-noise ratio for the specified clinical diagnostic task.

目的

本研究旨在探讨一种现代自动管电流调制（ATCM）和自动管电压选择（ATVS）系统对各种临床适应证下儿科头部和胸部计算机断层扫描（CT）检查的辐射剂量和图像质量的影响。

材料与方法

使用 4 个代表新生儿、1 岁、5 岁和 10 岁儿童的平均个体的物理人体模型。对标准头部、胸部和腹部/骨盆进行采集，分别采用（1）固定管电流、（2）ATCM 和（3）ATVS。在不同的辐射剂量水平下进行采集，以生成不同质量水平的图像。确定参考容积 CT 剂量指数（CTDIvol）、参考图像噪声和参考对比噪声比。评估 ATCM 和 ATVS 的潜在剂量降低。

结果

ATCM 的 CTDIvol 降低百分比范围为头部 8%至 24%，胸部 16%至 39%，腹部/骨盆 25%至 41%。ATVS 的 CTDIvol 降低百分比因临床适应证而异。在 CT 血管造影中，ATVS 导致最高剂量降低，头部最高可达 70%，胸部可达 77%，腹部/骨盆可达 34%。在非对比检查中，ATVS 使头部的剂量增加最高可达 21%，而胸部的剂量减少最高可达 34%，腹部/骨盆的剂量减少最高可达 48%。