最佳kVp与体模表面剂量和体模厚度关系的实验研究

目的在保持一定的X射线图像信噪比的前提下,探讨管电压（kVp）与体模表面剂量和体模厚度的关系.方法应用自制人体模型模拟X射线数字减影血管造影,在特定的X射线影像增强器表面剂量下,采用不同的kVp和毫安秒组合曝光,采集相关数据并绘制成体模表面剂量-kVp曲线、体模厚度-kVp曲线以及体模厚度和kVp的关系式.结果体模表面剂量-kVp曲线提示,kVp越大,体模表面剂量越低,但斜率渐趋于零;体模厚度-kVp曲线提示,体模越厚,所需kVp越大;体模厚度和kVp的关系式为：kVp=64＋0.89D（D为体模厚度,cm）.结论随着kVp的不断增高会导致体模表面剂量的逐渐降低,理想的kVp值与体模的厚度直接相关.

The experimental study of the optimized kVp and it's relationships with the surface dose of phantom and the phantom thickness

Objective To investigate the relationships of X-ray tube voltage (kVp) with surface dose of the phantom and phantom-thickness on the basis of the particular signal to noise ratio of X-ray images. Methods X-ray digital subtraction angiography was simulated using a phantom made of acrylic acids. Under the particular surface dose of X-ray image intensifier, the curve of the surface doses of phantom surface-kVp and the curve of the phantom thickness-kVp were acquired with different exposure combinations of kVp and mAs. Results According to the curve of the surface dose of phantom-kVp, it suggestsd that the gradual increase in kVp corresponded to the gradually decreased surface dose of phantom, with the slope tending to zero. However, the gradual increased phantom thickness corresponded to the gradually increased kVp on the basis of the curve of the phantom thickness-kVp, with the presentation of kVp=64+0.89D (phantom thickness, cm) between the phantom thickness and kVp. Conclusion The graduall increased in kVp might result in the gradual decrease in surface dose of phantom, the optimized kVp relating directly to the phantom thickness.;