Swanick Cameron W, Castle Katherine O, Rechner Laura A, Rauch Gaiane M, Jhingran Anuja, Eifel Patricia J, Klopp Ann H
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX.
Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX.
Brachytherapy. 2015 May-Jun;14(3):385-9. doi: 10.1016/j.brachy.2014.12.005. Epub 2015 Jan 22.
We prospectively tested five variations in vaginal gauze packing in an effort to improve contrast between the packing, cervix, and applicator for MRI-based intracavitary brachytherapy planning.
Five patients enrolled on a prospective study from May 2013 to October 2013 received MRI-based intracavitary brachytherapy for cervical cancer with variations of impregnated gauze packing. Substances tested included antibiotic cream alone, antibiotic cream mixed with ultrasound gel, conjugated estrogens cream mixed with ultrasound gel, ultrasound gel alone, and gadolinium. Images from the T2-weighted pelvic MRI were used to obtain signal intensity measurements at points within the packing, cervix, and applicator. Signal intensity values were normalized using the signal-to-noise ratio and compared using an unpaired t-test.
Ultrasound gel-impregnated gauze allowed for the greatest contrast between the packing and the cervix with a difference in mean normalized signal intensity of 38.2 (p < 0.01). Conjugated estrogens cream mixed with ultrasound gel and gadolinium also provided contrast when compared with cervix, with differences in mean normalized signal intensity of 25.3 and -16.2, respectively (p < 0.01 for both). For all variations but gadolinium, the normalized mean signal intensity of the packing was found to be significantly different from the applicator, with the ultrasound gel again demonstrating the greatest contrast with a difference of 42.5 (p < 0.01).
Gauze impregnated with ultrasound gel, conjugated estrogens cream mixed with ultrasound gel, and gadolinium allowed for a significant difference in MRI signal intensity between the packing and the cervix. With respect to both the cervix and the applicator, ultrasoundgel-impregnated gauze provided the best contrast overall.
我们前瞻性地测试了阴道纱布填塞的五种变体，以提高基于MRI的腔内近距离放射治疗计划中填塞物、宫颈和施源器之间的对比度。
2013年5月至2013年10月参加一项前瞻性研究的5例患者接受了基于MRI的宫颈癌腔内近距离放射治疗，采用了不同的浸渍纱布填塞方法。测试的物质包括单独的抗生素乳膏、与超声凝胶混合的抗生素乳膏、与超声凝胶混合的共轭雌激素乳膏、单独的超声凝胶和钆。使用T2加权盆腔MRI图像在填塞物、宫颈和施源器内的点处获取信号强度测量值。信号强度值使用信噪比进行归一化，并使用非配对t检验进行比较。
超声凝胶浸渍纱布在填塞物和宫颈之间产生了最大的对比度，平均归一化信号强度差异为38.2（p<0.01）。与宫颈相比，与超声凝胶混合的共轭雌激素乳膏和钆也提供了对比度，平均归一化信号强度差异分别为25.3和-16.2（两者p<0.01）。对于除钆以外的所有变体，发现填塞物的归一化平均信号强度与施源器有显著差异，超声凝胶再次显示出最大的对比度，差异为42.5（p<0.01）。
超声凝胶浸渍纱布、与超声凝胶混合的共轭雌激素乳膏和钆使填塞物和宫颈之间的MRI信号强度有显著差异。就宫颈和施源器而言，超声凝胶浸渍纱布总体上提供了最佳的对比度。
