Lok Edwin, San Pyay, White Victoria, Liang Olivia, Widick Page C, Reddy Sindhu Pisati, Wong Eric T
Brain Tumor Center & Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Department of Radiation Oncology, US Oncology/Signature Healthcare of Brockton, Brockton, Massachusetts.
Adv Radiat Oncol. 2021 May 17;6(4):100716. doi: 10.1016/j.adro.2021.100716. eCollection 2021 Jul-Aug.
Since the inception of tumor treating fields (TTFields) therapy as a Food and Drug Administration-approved treatment with known clinical efficacy against recurrent and newly diagnosed glioblastoma, various in silico modeling studies have been performed in an effort to better understand the distribution of applied electric fields throughout the human body for various malignancies or metastases.
Postacquisition attenuation-corrected positron emission tomography-computed tomography image data sets from 2 patients with ovarian carcinoma were used to fully segment various intrapelvic and intra-abdominal gross anatomic structures. A 3-dimensional finite element mesh model was generated and then solved for the distribution of applied electric fields, rate of energy deposition, and current density at the clinical target volumes (CTVs) and other intrapelvic and intra-abdominal structures. Electric field-volume histograms, specific absorption rate-volume histograms, and current density-volume histograms were generated, by which plan quality metrics were derived from and used to evaluate relative differences in field coverage between models under various conditions.
TTFields therapy distribution throughout the pelvis and abdomen was largely heterogeneous, where specifically the field intensity at the CTV was heavily influenced by surrounding anatomic structures as well as its shape and location. The electric conductivity of the CTV had a direct effect on the field strength within itself, as did the position of the arrays on the surface of the pelvis and/or abdomen.
The combined use of electric field-volume histograms, specific absorption rate-volume histograms, current density-volume histograms, and plan quality metrics enables a personalized method to dosimetrically evaluate patients receiving TTFields therapy for ovarian carcinoma when certain patient- and tumor-specific factors are integrated with the treatment plan.
自肿瘤治疗电场（TTFields）疗法作为一种经美国食品药品监督管理局批准、对复发性和新诊断的胶质母细胞瘤具有已知临床疗效的治疗方法问世以来，已经进行了各种计算机模拟研究，以更好地了解在各种恶性肿瘤或转移瘤情况下施加的电场在整个人体内的分布情况。
使用来自2例卵巢癌患者的采集后经衰减校正的正电子发射断层扫描-计算机断层扫描图像数据集，对盆腔内和腹腔内的各种大体解剖结构进行完整分割。生成三维有限元网格模型，然后求解临床靶区（CTV）以及其他盆腔内和腹腔内结构处施加的电场分布、能量沉积速率和电流密度。生成电场-体积直方图、比吸收率-体积直方图和电流密度-体积直方图，并由此得出计划质量指标，用于评估不同条件下模型之间的场覆盖相对差异。
TTFields疗法在整个骨盆和腹部的分布在很大程度上是不均匀的，具体而言，CTV处的场强受到周围解剖结构及其形状和位置的严重影响。CTV的电导率对其内部的场强有直接影响，骨盆和/或腹部表面阵列的位置也有同样的影响。
当将某些患者和肿瘤特异性因素与治疗计划相结合时，电场-体积直方图、比吸收率-体积直方图、电流密度-体积直方图和计划质量指标的联合使用能够提供一种个性化方法，用于对接受TTFields疗法治疗卵巢癌的患者进行剂量学评估。
