Analysis of components of variance determining probability of setup errors in CBCT‐guided stereotactic radiotherapy of lung tumors

Cuijpers, J.P.; Dahele, Max; Jonker, Marianne A.; Kraan, B.; Senan, Suresh; Slotman, Ben J.; Verbakel, Wilko F.A.R.

doi:10.1002/mp.12074

Cited by 7 publications

(4 citation statements)

References 20 publications

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“…The setup errors have always being a vexing problem during radiotherapy [18][19][20][21] . It plays an important role in the delineation and definition of PTV [21][22][23][24] or ITV 25 , and therefore affects radiation effect [25][26][27][28] and toxicity 29,30 of the patients. A precise fixing device is beneficial to reduce the setup errors, improve radiation precision and efficacy.…”

Section: Discussionmentioning

confidence: 99%

Compare of Interfractional Setup Reproducibility Between Vacuum-Lock Bag and Thermoplastic Mask in Radiotherapy for Breast Cancer

Song

Jin

Chen

et al. 2021

Technol Cancer Res Treat

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Background: This study aimed to analyze the difference of setup reproducibility between Vacuum-lock bag and Thermoplastic mask in the radiotherapy for breast cancer. Methods: A total of 100 invasive breast carcinoma patients were collected, among whom 50 patients were immobilized with Vacuum-lock bag (VB group), and the other 50 patients were immobilized with Thermoplastic mask (TM group). Set up reproducibility in different axes and comfort levels between two groups at three treatment progress points during the radiation therapy were collected and analyzed. Results: The linear regression model showed that fixed device was an independent factor of radiotherapy setup error (SE). Further subgroup analysis based on different axes showed that the SE caused by the fixed device was obvious in all directions. The comfort level in the VB group was significantly larger than that in the TM group at the beginning of treatment, reduced as the treatment progress going on, and finally disappeared within three weeks. Conclusions: Thermoplastic mask could significantly reduce positioning errors in the radiotherapy of breast cancer. Although more discomfort was found in the TM group, it could be eliminated as the treatment progresses.

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Section: Discussionmentioning

confidence: 99%

Compare of Interfractional Setup Reproducibility Between Vacuum-Lock Bag and Thermoplastic Mask in Radiotherapy for Breast Cancer

Song

Jin

Chen

et al. 2021

Technol Cancer Res Treat

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“…In the past, image-guided radiotherapy based on CBCTs was primarily performed by matching implanted markers (6), a rigid 3-6-degrees-offreedom carina or bony match (7,8) or a rigid soft-tissue match. The latter may be achieved automatically or by aligning the center of mass and orientation of the small peripheral targets (9)(10)(11)(12). Motion at distinct points, e.g., implanted markers or center of masses of target volumes, were traditionally used for PTV margin calculation under simplifying assumptions (13).…”

Section: Introductionmentioning

confidence: 99%

Machine-learning-based prediction of the effectiveness of the delivered dose by exhale-gated radiotherapy for locally advanced lung cancer: The additional value of geometric over dosimetric parameters alone

Guberina¹,

Pöttgen²,

Santiago³

et al. 2023

Front. Oncol.

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PurposeThis study aimed to assess interfraction stability of the delivered dose distribution by exhale-gated volumetric modulated arc therapy (VMAT) or intensity-modulated arc therapy (IMAT) for lung cancer and to determine dominant prognostic dosimetric and geometric factors.MethodsClinical target volume (CTVPlan) from the planning CT was deformed to the exhale-gated daily CBCT scans to determine CTVi, treated by the respective dose fraction. The equivalent uniform dose of the CTVi was determined by the power law (gEUDi) and cell survival model (EUDiSF) as effectiveness measure for the delivered dose distribution. The following prognostic factors were analyzed: (I) minimum dose within the CTVi (Dmin_i), (II) Hausdorff distance (HDDi) between CTVi and CTVPlan, (III) doses and deformations at the point in CTVPlan at which the global minimum dose over all fractions per patient occurs (PDmin_global_i), and (IV) deformations at the point over all CTVi margins per patient with the largest Hausdorff distance (HDPworst). Prognostic value and generalizability of the prognostic factors were examined using cross-validated random forest or multilayer perceptron neural network (MLP) classifiers. Dose accumulation was performed using back deformation of the dose distribution from CTVi to CTVPlan.ResultsAltogether, 218 dose fractions (10 patients) were evaluated. There was a significant interpatient heterogeneity between the distributions of the normalized gEUDi values (p<0.0001, Kruskal–Wallis tests). Accumulated gEUD over all fractions per patient was 1.004–1.023 times of the prescribed dose. Accumulation led to tolerance of ~20% of fractions with gEUDi<93% of the prescribed dose. Normalized Dmin >60% was associated with predicted gEUD values above 95%. Dmin had the highest importance for predicting the gEUD over all analyzed prognostic parameters by out-of-bag loss reduction using the random forest procedure. Cross-validated random forest classifier based on Dmin as the sole input had the largest Pearson correlation coefficient (R=0.897) in comparison to classifiers using additional input variables. The neural network performed better than the random forest classifier, and the gEUD values predicted by the MLP classifier with Dmin as the sole input were correlated with the gEUD values characterized by R=0.933 (95% CI, 0.913–0.948). The performance of the full MLP model with all geometric input parameters was slightly better (R=0.952) than that based on Dmin (p=0.0034, Z-test).ConclusionAccumulated dose distributions over the treatment series were robust against interfraction CTV deformations using exhale gating and online image guidance. Dmin was the most important parameter for gEUD prediction for a single fraction. All other parameters did not lead to a markedly improved generalizable prediction. Dosimetric information, especially location and value of Dmin within the CTVi, are vital information for image-guided radiation treatment.

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“…Radiotherapy setup errors include errors caused by the treatment system that cannot be reduced or eliminated and errors caused by changes in setup and anatomical position (respiratory motion, tumour size, etc.) during treatment ( 2 ). Research on breast cancer radiotherapy mainly focuses on radiotherapy technology, curative effects, and dosimetry, while research on the psychological aspects of patients undergoing radiotherapy is limited.…”

Section: Introductionmentioning

confidence: 99%

Psychosomatic symptoms affect radiotherapy setup errors in early breast cancer patients

He¹,

Gao²,

Pang³

et al. 2021

Chinese Journal of Cancer Research

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Objective To examine the trajectory of psychosomatic symptoms and to explore the impact of psychosomatic symptoms on setup error in patients undergoing breast cancer radiotherapy. Methods A total of 102 patients with early breast cancer who received initial radiotherapy were consecutively recruited. The M.D. Anderson Symptom Inventory (MDASI) and three different anxiety scales, i.e., the Self-Rating Anxiety Scale (SAS), State-Trait Anxiety Inventory (STAI), and Anxiety Sensitivity Index (ASI), were used in this study. The radiotherapy setup errors were measured in millimetres by comparing the real-time isocratic verification film during radiotherapy with the digitally reconstructed radiograph (DRR). Patients completed the assessment at three time points: before the initial radiotherapy (T1), before the middle radiotherapy (T2), and before the last radiotherapy (T3). Results The SAS and STAI-State scores of breast cancer patients at T1 were significantly higher than those at T2 and T3 (F=24.44, P<0.001; F=30.25, P<0.001). The core symptoms of MDASI were positively correlated with anxiety severity. The setup errors of patients with high SAS scores were greater than those of patients with low anxiety levels at T1 (Z=−2.01, P=0.044). We also found that higher SAS scores were associated with a higher risk of radiotherapy setup errors at T1 (B=0.458, P<0.05). Conclusions This study seeks to identify treatment-related psychosomatic symptoms and mitigate their impact on patients and treatment. Patients with early breast cancer experienced the highest level of anxiety before the initial radiotherapy, and then, anxiety levels declined. Patients with high somatic symptoms of anxiety may have a higher risk of radiotherapy setup errors.

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Analysis of components of variance determining probability of setup errors in CBCT‐guided stereotactic radiotherapy of lung tumors

Abstract: Our findings show that it is essential to account for measurement and system inaccuracies when obtaining data for validating PTV margins from online CBCT image guidance.

Cited by 7 publications

References 20 publications

Compare of Interfractional Setup Reproducibility Between Vacuum-Lock Bag and Thermoplastic Mask in Radiotherapy for Breast Cancer

Compare of Interfractional Setup Reproducibility Between Vacuum-Lock Bag and Thermoplastic Mask in Radiotherapy for Breast Cancer

Machine-learning-based prediction of the effectiveness of the delivered dose by exhale-gated radiotherapy for locally advanced lung cancer: The additional value of geometric over dosimetric parameters alone

Psychosomatic symptoms affect radiotherapy setup errors in early breast cancer patients

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