Fakhraei Sharareh, Ehler Eric, Sterling David, Chinsoo Cho L, Alaei Parham
Department of Radiation Oncology, University of Minnesota, Minneapolis, MN, 55455, USA.
Department of Radiation Oncology, University of Minnesota, Minneapolis, MN, 55455, USA.
Phys Med. 2023 Dec;116:103167. doi: 10.1016/j.ejmp.2023.103167. Epub 2023 Nov 15.
We present a patient-specific model to estimate tumor location in the thorax during radiation therapy using chest surface displacement as the surrogate signal.
Two types of data are used for model construction: Four-dimensional computed tomography (4D-CT) images of the patient and the displacement of two points on the patient's skin on the thoracic area. Principal component analysis is used to fit the correspondence model. This model incorporates the recorded surrogate signals during radiation delivery as input and delivers the 3D trajectory of the tumor as output. We evaluated the accuracy of the proposed model on a respiratory phantom and five lung cancer patients.
For the respiratory phantom, the location of the center of the sphere during treatment was calculated in three directions: Left-Right (LR), Anterior-Posterior (AP) and, Superior-Inferior (SI). The error of localization was less than 1 mm in the LR and AP directions and less than 2 mm in the SI direction. The location of the tumor center for two of the patients, and the location of the apex of the diaphragm for the other three, was calculated in three directions. For all patients, the localization error in the LR and AP directions was less than 1.1 mm for two fractions and the maximum localization error in the SI direction was 6.4 mm.
This work presents a feasibility study of utilizing surface displacement data to locate the tumor in the thorax during radiation treatment. Future work will validate the model on a larger patient population.
我们提出一种针对患者的模型，以利用胸部表面位移作为替代信号来估计放射治疗期间胸部肿瘤的位置。
使用两种类型的数据进行模型构建：患者的四维计算机断层扫描（4D-CT）图像以及患者胸部区域皮肤上两点的位移。主成分分析用于拟合对应模型。该模型将放射治疗期间记录的替代信号作为输入，并输出肿瘤的三维轨迹。我们在呼吸体模和五名肺癌患者身上评估了所提出模型的准确性。
对于呼吸体模，在三个方向上计算了治疗期间球体中心的位置：左右（LR）、前后（AP）和上下（SI）。在LR和AP方向上的定位误差小于1毫米，在SI方向上小于2毫米。计算了两名患者肿瘤中心的位置以及另外三名患者膈肌顶点的位置，均在三个方向上进行。对于所有患者，在LR和AP方向上两个分次的定位误差均小于1.1毫米，在SI方向上的最大定位误差为6.4毫米。
这项工作展示了利用表面位移数据在放射治疗期间定位胸部肿瘤的可行性研究。未来的工作将在更大的患者群体中验证该模型。
