Lee Junghoon, Labat Christian, Jain Ameet K, Fichtinger Gabor, Prince Jerry L
Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA.
Proc IEEE Int Symp Biomed Imaging. 2009 Jun 28:1047-1050. doi: 10.1109/ISBI.2009.5193235.
X-ray fluoroscopy is widely used for intra-operative dosimetry in prostate brachytherapy. Three-dimensional locations of the implanted radioactive seeds can be calculated from multiple X-ray images upon resolving the correspondence of seeds. This is usually modeled as an assignment problem that is NP-hard. We propose an algorithm that allows us to derive an equivalent problem of reduced dimensionality based on practical observation that the optimal solution has almost zero cost if the C-arm pose is known. The reduced problem is efficiently solved by linear programming in polynomial time. Additionally, our method solves the hidden seeds problem. Simulation results demonstrate that the implanted seeds can be localized with a matching rate of ≥ 98.8 % and reconstruction error of ≤ 0.37 mm using three images with hidden seeds in a few seconds when the pose of the C-arm is known.
X射线荧光透视法在前列腺近距离放射治疗的术中剂量测定中被广泛应用。在解决植入放射性种子的对应关系后，可从多个X射线图像计算出植入种子的三维位置。这通常被建模为一个NP难的分配问题。我们提出了一种算法，基于实际观察结果，即如果已知C形臂的姿态，最优解的成本几乎为零，从而使我们能够推导出一个降维的等效问题。通过线性规划可在多项式时间内有效地解决降维问题。此外，我们的方法还解决了隐藏种子问题。模拟结果表明，当已知C形臂的姿态时，使用包含隐藏种子的三张图像，在几秒钟内即可定位植入的种子，匹配率≥98.8%，重建误差≤0.37毫米。
