Shimonobo Toshiaki, Funama Yoshinori, Utsunomiya Daisuke, Nakaura Takeshi, Oda Seitaro, Kiguchi Masao, Masuda Takanori, Sakabe Daisuke, Yamashita Yasuyuki, Awai Kazuo
Department of Radiology, Kumamoto University Hospital, Kumamoto, Japan.
Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Phys Med. 2016 Jan;32(1):197-201. doi: 10.1016/j.ejmp.2015.12.005. Epub 2015 Dec 28.
We used pediatric and adult anthropomorphic phantoms to compare the radiation dose of low- and standard tube voltage chest and abdominal non-contrast-enhanced computed tomography (CT) scans. We also discuss the optimal low tube voltage for non-contrast-enhanced CT.
Using a female adult- and three differently-sized pediatric anthropomorphic phantoms we acquired chest and abdominal non-contrast-enhanced scans on a 320-multidetector CT volume scanner. The tube voltage was set at 80-, 100-, and 120 kVp. The tube current was automatically assigned on the CT scanner in response to the set image noise level. On each phantom and at each tube voltage we measured the surface and center dose using high-sensitivity metal-oxide-semiconductor field-effect transistor detectors.
The mean surface dose of chest and abdominal CT scans in 5-year olds was 4.4 and 5.3 mGy at 80 kVp, 4.5 and 5.4 mGy at 100 kV, and 4.0 and 5.0 mGy at 120 kVp, respectively. These values were similar in our 3-pediatric phantoms (p > 0.05). The mean surface dose in the adult phantom increased from 14.7 to 19.4 mGy for chest- and from 18.7 to 24.8 mGy for abdominal CT as the tube voltage decreased from 120 to 80 kVp (p < 0.01).
Compared to adults, the surface and center dose for pediatric patients is almost the same despite a decrease in the tube voltage and the low tube voltage technique can be used for non-contrast-enhanced chest- and abdominal scanning.
我们使用儿童和成人人体模型比较低管电压和标准管电压下胸部和腹部非增强计算机断层扫描（CT）的辐射剂量。我们还讨论了非增强CT的最佳低管电压。
我们使用一个成年女性人体模型和三个不同尺寸的儿童人体模型，在一台320排CT容积扫描仪上进行胸部和腹部非增强扫描。管电压设置为80、100和120 kVp。CT扫描仪根据设定的图像噪声水平自动分配管电流。在每个模型的每个管电压下，我们使用高灵敏度金属氧化物半导体场效应晶体管探测器测量表面剂量和中心剂量。
5岁儿童胸部和腹部CT扫描的平均表面剂量在80 kVp时分别为4.4和5.3 mGy，在100 kV时分别为4.5和5.4 mGy，在120 kVp时分别为4.0和5.0 mGy。在我们的三个儿童模型中，这些值相似（p>0.05）。随着管电压从120 kVp降至80 kVp，成人模型中胸部CT的平均表面剂量从14.7 mGy增加到19.4 mGy，腹部CT从18.7 mGy增加到24.8 mGy（p<0.01）。
与成人相比，尽管管电压降低，但儿童患者的表面剂量和中心剂量几乎相同，低管电压技术可用于非增强胸部和腹部扫描。
