摘要
目的探讨在保证影像质量前提下的头颈部256层CT最优低剂量节省模式。方法应用组织等效头颈部模型置于Philips Brilliance256层CT机以标准模式(400mAs)和低剂量节省模式进行分别扫描,其中低剂量节省模式包括自动管电流选择(ACS)、螺旋剂量节省(Helical Dose Saving)、X-Y平面动态电流调节(D-DOM)、Z轴动态电流调节技术(Z-DOM)等进行组合,测量、记录模型蝶鞍、下颌骨和胸骨柄各部位CT值、CT值噪声标准差(SD),分别行方差分析。结果共有8种组合模式可降低辐射剂量。即:①ACS;②ACS+Helical;③ACS+(D-DOM);④ACS+(Z-DOM);⑤ACS+Helical+(D-DOM);⑥ACS+(D-DOM)+(Z-DOM);⑦ACS+Helical+(Z-DOM);⑧ACS+Helical+(D-DOM)+(Z-DOM)。与标准剂量CTDI26.5mGy,DLP1276.8mGy*cm相比,CT不同剂量节省方式扫描时,在保证图像质量的同时,辐射剂量可节省11.21%～68.12%。采用最优剂量节省模式ACS+Helical+(D-DOM)+(Z-DOM),CTDI从26mGy降低到11.8mGy,DLP从1134.6mGy*cm降低到504.9mGy*cm。蝶鞍、下颌骨和胸骨柄水平相同部位软组织和骨骼的CT值在各组间差异均无统计学意义(P≥0.05)。蝶鞍、下颌骨水平骨骼结构测量的SD值有统计学差别(P<0.01),而胸骨柄水平骨骼SD值和蝶鞍、下颌骨、胸骨柄水平相同部位软组织SD值间差异均无统计学意义(P>0.05)。结论在头颈部螺旋CT扫描中,恰当运用螺旋CT剂量节省模式,辐射剂量可大大降低。
Objective To investigate the optimal low dose 256-slice CT scan mode of the head and neck on the promise to ensure image quality. Methods A head and neck phantom equivalent to human tissue was scaned by Philips Brilliance 256 slice-CT at standard dose（400 mAs）and low dose saving mode scanning, the low-dose saving mode includes automatic current selection （ACS）, helical dose saving, dynamic angular dose modulation （D-DOM）, Z-axis dose modulation （Z- DOM）, and the combination of the above mode. The CT value and the noise standard deviation （SD） of which in site of the phantom were recorded, and variance analysis was used to dertermine the variane between different dosage saving mode. Results There was only eight kinds of dose saving modes which could reduce the radiation doseage, that is ACS, ACS＋ Helical, ACS＋ （INDOM）, ACS＋ （Z-DOM）, ACS＋ Helical＋ （D-DOM）, ACS＋ （D-DOM） ＋ （Z-DOM）, ACS＋ Helical＋ （Z-DOM）, and ACS＋ Helical＋ （D-DOM） ＋ （Z-DOM）. Compared with the radiation dosage （CTDI 26.5 mGy, DLP 1276.8 of mGy ＊cm） using standard protol, the dosage saving ranged to 11.21%-68.12% when used different dosage saving mode ensuring the quality of image. Used the optimal dosage saving mode ACS＋ Helical ＋ （D-DOM）＋ （Z- DOM）, the CTDI could decreased from 26mGy to 11.8 mGy, and DLP could decreased from 1134.6 mGy＋ cm to 504.9 mGy ＊ cm. There was no statistical difference in CT value between the groups in soft and bone tissue in any sites of the phantom （all P value≥0.05）. There was statistical difference in SD value between the groups in bone tissue in sites of the sella turcica and mandible of the phantom （all P value〈0.01）. There was no statistical difference in SD value between the groups in bone tissue in site of sternum handle and in soft in any sites of the phantom （all P value≥0.05）. Conclusion With proper use of radation dosage saving mode, the radiation dose can be greatly reduced on the spiral CT scan of the head and neck.
出处
《医学影像学杂志》
2013年第3期481-485,共5页
Journal of Medical Imaging
