Jain A, Deguet A, Iordachita I, Chintalapani G, Blevins J, Le Y, Armour E, Burdette C, Song D, Fichtinger G
Johns Hopkins University, USA.
Med Image Comput Comput Assist Interv. 2007;10(Pt 2):9-17. doi: 10.1007/978-3-540-75759-7_2.
Intra-operative guidance in Transrectal Ultrasound (TRUS) guided prostate brachytherapy requires localization of inserted radioactive seeds relative to the prostate. Seeds were reconstructed using a typical C-arm, and exported to a commercial brachytherapy system for dosimetry analysis. Technical obstacles for 3D reconstruction on a non-isocentric C-arm included pose-dependent C-arm calibration; distortion correction; pose estimation of C-arm images; seed reconstruction; and C-arm to TRUS registration. In precision-machined hard phantoms with 40-100 seeds, we correctly reconstructed 99.8% seeds with a mean 3D accuracy of 0.68 mm. In soft tissue phantoms with 45-87 seeds and clinically realistic 15 degrees C-arm motion, we correctly reconstructed 100% seeds with an accuracy of 1.3 mm. The reconstructed 3D seed positions were then registered to the prostate segmented from TRUS. In a Phase-1 clinical trial, so far on 4 patients with 66-84 seeds, we achieved intra-operative monitoring of seed distribution and dosimetry. We optimized the 100% prescribed iso-dose contour by inserting an average of 3.75 additional seeds, making intra-operative dosimetry possible on a typical C-arm, at negligible additional cost to the existing clinical installation.
经直肠超声（TRUS）引导下前列腺近距离放射治疗的术中引导需要确定插入的放射性粒子相对于前列腺的位置。使用典型的C型臂对粒子进行重建，并将其导出到商业近距离放射治疗系统进行剂量分析。在非等中心C型臂上进行三维重建的技术障碍包括与姿势相关的C型臂校准；畸变校正；C型臂图像的姿势估计；粒子重建；以及C型臂与TRUS配准。在植入40 - 100个粒子的精密加工硬模体中，我们正确重建了99.8%的粒子，平均三维精度为0.68毫米。在植入45 - 87个粒子且C型臂有15度临床实际运动的软组织模体中，我们正确重建了100%的粒子，精度为1.3毫米。然后将重建的三维粒子位置与从TRUS分割出的前列腺进行配准。在一项一期临床试验中，到目前为止对4例植入66 - 84个粒子的患者，我们实现了术中对粒子分布和剂量的监测。我们通过平均额外插入3.75个粒子优化了100%规定的等剂量轮廓，使得在典型的C型臂上进行术中剂量测定成为可能，而对现有临床设备的额外成本可忽略不计。
