Dosimetric

剂量测定
  • 文章类型: Journal Article
    UNASSIGNED: Radiotherapy is one of the most important treatments for high-grade glioma (HGG), but the best way to delineate the target areas for radiotherapy remains controversial, so our aim was to compare the dosimetric differences in radiation treatment plans generated based on the European Organization for Research and Treatment of Cancer (EORTC) and National Research Group (NRG) consensus to provide evidence for optimal target delineation for HGG.
    UNASSIGNED: We prospectively enrolled 13 patients with a confirmed HGG from our hospital and assessed dosimetric differences in radiotherapy treatment plans generated according to the EORTC and NRG-2019 guidelines. For each patient, two treatment plans were generated. Dosimetric parameters were compared by dose-volume histograms for each plan.
    UNASSIGNED: The median volume for planning target volume (PTV) of EORTC plans, PTV1 of NRG-2019 plans, and PTV2 of NRG-2019 plans were 336.6 cm3 (range, 161.1-511.5 cm3), 365.3 cm3 (range, 123.4-535.0 cm3), and 263.2 cm3 (range, 116.8-497.7 cm3), respectively. Both treatment plans were found to have similar efficiency and evaluated as acceptable for patient treatment. Both treatment plans showed well conformal index and homogeneity index and were not statistically significantly different (P = 0.397 and P = 0.427, respectively). There was no significant difference in the volume percent of brain irradiated to 30, 46, and 60 Gy according to different target delineations (P = 0.397, P = 0.590, and P = 0.739, respectively). These two plans also showed no significant differences in the doses to the brain stem, optic chiasm, left and right optic nerves, left and right lens, left and right eyes, pituitary, and left and right temporal lobes (P = 0.858, P = 0.858, P = 0.701 and P = 0.794, P = 0.701 and P = 0.427, P = 0.489 and P = 0.898, P = 0.626, and P = 0.942 and P = 0.161, respectively).
    UNASSIGNED: The NRG-2019 project did not increase the dose of organs at risk (OARs) radiation. This is a significant finding that further lays the groundwork for the application of the NRG-2019 consensus in the treatment of patients with HGGs.
    UNASSIGNED: The effect of radiotherapy target area and glial fibrillary acidic protein (GFAP) on the prognosis of high-grade glioma and its mechanism, number ChiCTR2100046667. Registered 26 May 2021.
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  • 文章类型: Journal Article
    目的:通过综合措施预测局部晚期宫颈癌(LACC)患者的临床反应,包括临床和近距离放射治疗参数以及几种机器学习(ML)方法。
    方法:近距离放射治疗的特征,如插入方法,源度量,剂量测定,和临床措施用于建模。四种不同的机器学习方法,包括LASSO,里奇,支持向量机(SVM),和随机森林(RF),单独或组合应用于模型开发的提取度量。使用接收器工作特性曲线的曲线下面积(AUC)评估模型性能,灵敏度,特异性,和准确性。我们的结果与通过简单逻辑回归开发的参考模型进行了比较,该模型应用于先前论文确定的三个不同的临床特征。
    结果:纳入了111例LACC患者。根据这些特征获得了9个数据集,并建立了36个预测模型。就AUC而言,使用RF开发的模型应用于剂量测定,物理,和总BT会话特征被发现是最具预测性的[AUC;0.82(0.95置信区间(CI);0.79-0.93),灵敏度;0.79,特异性;0.76,准确性;0.77]。AUC(0.95CI),灵敏度,特异性,参考模型的准确性为0.56(0.52。..0.68),分别为0.51、0.51和0.48。大多数RF模型的性能明显优于参考模型(Bonferroni校正p值<0.0014)。
    结论:可以使用从治疗参数中提取的剂量学和物理参数来预测近距离放射治疗反应。机器学习算法,包括随机森林,可以在这种预测建模中发挥关键作用。
    OBJECTIVE: To predict clinical response in locally advanced cervical cancer (LACC) patients by a combination of measures, including clinical and brachytherapy parameters and several machine learning (ML) approaches.
    METHODS: Brachytherapy features such as insertion approaches, source metrics, dosimetric, and clinical measures were used for modeling. Four different ML approaches, including LASSO, Ridge, support vector machine (SVM), and Random Forest (RF), were applied to extracted measures for model development alone or in combination. Model performance was evaluated using the area under the curve (AUC) of receiver operating characteristics curve, sensitivity, specificity, and accuracy. Our results were compared with a reference model developed by simple logistic regression applied to three distinct clinical features identified by previous papers.
    RESULTS: One hundred eleven LACC patients were included. Nine data sets were obtained based on the features, and 36 predictive models were built. In terms of AUC, the model developed using RF applied to dosimetric, physical, and total BT sessions features were found as the most predictive [AUC; 0.82 (0.95 confidence interval (CI); 0.79 -0.93), sensitivity; 0.79, specificity; 0.76, and accuracy; 0.77]. The AUC (0.95 CI), sensitivity, specificity, and accuracy for the reference model were found as 0.56 (0.52 ...0.68), 0.51, 0.51, and 0.48, respectively. Most RF models had significantly better performance than the reference model (Bonferroni corrected p-value < 0.0014).
    CONCLUSIONS: Brachytherapy response can be predicted using dosimetric and physical parameters extracted from treatment parameters. Machine learning algorithms, including Random Forest, could play a critical role in such predictive modeling.
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  • 文章类型: Journal Article
    BACKGROUND: Adaptive radiotherapy is being used in few institutions in patients with head and neck cancer having bulky disease using periodic computed tomography imaging accounting for volumetric changes in tumor volume and/or weight loss. Limited data are available on ART in the postoperative setting. We aim to identify parameters that would predict the need for ART in patients with head and neck cancer and whether ART should be applied in postoperative setting.
    METHODS: Twenty patients with stage III-IV head and neck cancer were prospectively accrued. A computed tomography simulation was done prior to treatment and repeated at weeks 3 and 6 of concurrent intensity-modulated radiotherapy and chemotherapy. The final plan was coregistered with the subsequent computed tomography images, and dosimetric/volumetric changes at weeks 1 (baseline), 3, and 6 were quantified in high-risk clinical target volumes, low-risk clinical target volumes , right parotid , left parotid , and spinal cord . An event to trigger ART was defined as spinal cord maximum dose >45 Gy, parotid mean dose >26 Gy, and clinical target volume coverage <95%.
    RESULTS: Comparing the 2 groups, the proportion of patients with at least 1 event triggering ART was higher in bulky disease than in postoperative group: 72.7% versus 18.2% (P = .03) overall; 54.6% versus 1.8% (P = .064) at week 3; and 63.6% versus 18.2% (P = .081) at week 6. In the bulky disease group, 8 of 11 patients had events at week 3 and/or 6 as follows: overdose in spinal cord (n = 2), right parotid (n = 3), left parotid (n = 5), coverage < 95% seen in low-risk clinical target volumes (n = 3), and high-risk clinical target volumes (n = 5). In the postoperative group, 2 of 11 patients had events: spinal cord (n = 1) and low-risk clinical target volume (n = 1).
    CONCLUSIONS: Our study confirmed the need for ART in patients with head and neck cancer having bulky disease due to target under dosing and/or spinal cord/parotids overdosing in weeks 3 and 6. In contrast, the benefit of ART in postoperative patients is less clear.
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