| 郑君惠,梁长虹,罗维.高场磁共振射频能量吸收率SAR的研究[J].中国医学影像技术,2008,24(9):1469~1472 |
| 高场磁共振射频能量吸收率SAR的研究 |
| Study on the specific absorption rate of high field MR |
| 投稿时间：2008-03-21 修订日期：2008-06-25 |
| DOI： |
| 中文关键词: 射频能量吸收率 体重 |
| 英文关键词:Specific absorption rate Weight |
| 基金项目: |
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| 中文摘要: |
| 目的 通过对SAR影响参数研究,计算10秒SAR,指导MR扫描顺利进行。方法 采用GE公司HD 3T扫描仪,头颅8通道线圈,扫描序列为T2-FSE,改变体重、TR、层数等参数对水模进行扫描,观察SAR的改变。结果 SAR与体重和TR有关,而与扫描的层数无关,SAR是RF、B0、体重和TR的函数。根据体重与10秒SAR的关系曲线,通过MATLAB,进行一个曲线拟合,得出10 s SAR与体重的关系方程式:SAR=((-5.96E-09)X4-(2.08E-06)X3+0.0005681X2-0.04531X+1.638)*Peak_SAR. 结论 SAR是RF脉冲序列、 B0、体重和TR的函数,我们所得到的MATLAB 4次方程式,只要输入病人体重和Peak_SAR就能直接得到10 s SAR,就可以估计扫描是否暂停,以及暂停时间。 |
| 英文摘要: |
| Objective To acquire the SAR value/10 seconds by evaluation of the parameters that affect the SAR value, and to estimate whether the SAR is safe or not by this value for determination of the scan-pause and pause-duration. Methods 3 Tesla MR System and 8-channel head coil were applied, and T2-FSE (fast spin echo) sequence was selected in this study. The variation of SAR values when using different weight of phantom, different TR, and different slice number was evaluated. Results SAR value was correlated with weight and TR, but not with slice number. SAR value was a function of RF, B0, weight and TR. The equation of SAR value /10 seconds and weight was acquired after MATLAB fitting of SAR value /10 seconds-weight curve:10 s SAR=((-5.96E-09)X4-(2.08E-06)X3+0.0005681X2-0.04531X+1.638)*Peak_SAR. Conclusion SAR value was a function of RF, B0, weight and TR. We could acquire the SAR value /10 seconds directly by substituting the patient weight and the Peak_SAR to the MATLAB equation. So we can determine whether to stop the scan or not and the pause duration. |
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