Department of Radiation Oncology, University of California San Diego, La Jolla, CA 92093, USA.
Phys Med Biol. 2010 May 7;55(9):2505-22. doi: 10.1088/0031-9155/55/9/006. Epub 2010 Apr 14.
Algorithms for direct tumor tracking in rotational cone-beam projections and for reconstruction of phase-binned 3D tumor trajectories were developed. The feasibility of the algorithm was demonstrated on a digital phantom, a physical phantom and two patients. Tracking results were obtained by comparing reference templates generated from 4DCT to rotational cone-beam projections. The 95th percentile absolute errors (e(95)) in phantom tracking results did not exceed 1.7 mm in either imager dimension, while e(95) in the patients was 3.3 mm or less. Accurate phase-binned trajectories were reconstructed in each case, with 3D maximum errors of no more than 1.0 mm in the phantoms and 2.0 mm in the patients. This work shows the feasibility of a direct tumor tracking technique for rotational images, and demonstrates that an accurate 3D tumor trajectory can be reconstructed from relatively less accurate tracking results. The ability to reconstruct the tumor's average trajectory from a 3D cone-beam CT scan on the day of treatment could allow for better patient setup and quality assurance, while direct tumor tracking in rotational projections could be clinically useful for rotational therapy such as volumetric modulated arc therapy (VMAT).
开发了用于旋转锥束投影中直接肿瘤跟踪和相位-bin 三维肿瘤轨迹重建的算法。该算法的可行性已在数字体模、物理体模和两名患者上得到验证。通过将从 4DCT 生成的参考模板与旋转锥束投影进行比较，获得了跟踪结果。在体模跟踪结果中，95%的绝对误差（e(95)）在两个成像维度上均不超过 1.7 毫米，而在患者中 e(95)则不超过 3.3 毫米。在每种情况下都准确地重建了相位-bin 轨迹，在体模中 3D 最大误差不超过 1.0 毫米，在患者中不超过 2.0 毫米。这项工作表明了旋转图像中直接肿瘤跟踪技术的可行性，并证明了可以从相对不太准确的跟踪结果中重建出精确的三维肿瘤轨迹。在治疗当天，从三维锥形束 CT 扫描中重建肿瘤的平均轨迹的能力可以实现更好的患者摆位和质量保证，而在旋转投影中的直接肿瘤跟踪对于旋转治疗（如容积调制弧形治疗（VMAT））可能具有临床意义。
