Tian Zhen, Yuan Kehong, Bai Yanling
Faculty of Graduate School at Shenzhen and Department of Biomedical Engineering, Tsinghua University, China.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:3541-4. doi: 10.1109/IEMBS.2009.5332419.
Four-dimensional computed tomography(4D CT) is significant in radiotherapy treatment planning for thorax and upper abdomen to take their motion induced by respiration into consideration, but its high radiation dose becomes a major concern and impedes its wide application. To solve the problem, we propose an image interpolation approach to get 4D CT simulation images. We simulate 4D CT images at arbitrary intermediate phases by B-Spline deformable model with cosine interpolation of the deformation field, which is obtained by deformable registration of two CT images at end-exhale and end-inhale phases. The mean of absolute differences computed between actual 4D CT images and simulation ones is used to evaluate the accuracy of simulation. Our experiment results show that both linear interpolation and cosine interpolation with proper parameters perform well and the latter performs a little better than the former in general.
四维计算机断层扫描（4D CT）在胸部和上腹部放疗治疗计划中具有重要意义，因为它考虑了呼吸引起的运动，但其高辐射剂量成为一个主要问题并阻碍了其广泛应用。为了解决这个问题，我们提出了一种图像插值方法来获取4D CT模拟图像。我们通过B样条可变形模型对呼气末和吸气末两个CT图像进行可变形配准获得变形场，并用余弦插值法在任意中间相位模拟4D CT图像。通过计算实际4D CT图像与模拟图像之间的绝对差均值来评估模拟的准确性。我们的实验结果表明，线性插值和参数合适的余弦插值都表现良好，总体上后者比前者表现稍好。
