Loading
Advanced Radiotherapy Techniques / Radiation Dose and Imaging / Advanced X-ray and Ct Imaging · Journal article
Precision Radiation Oncology · August 12, 2026
Early or partial results. Treat as a signal, not a conclusion.
This retrospective dosimetric study of 10 breast cancer patients used deep learning–synthesized CT images to compare the robustness of physical versus virtual bolus methods under interfraction anatomical variations. Virtual bolus showed statistically superior robustness for target dose coverage (Vpd, P<0.05) but with minimal absolute difference (−0.8% vs −1.5%), while physical bolus performed better for conformity; the clinical significance of these marginal differences remains unclear.
Retrospective dosimetric comparison study. Ten patients with skin-involved breast cancer treated with VMAT; treatment setting not specified. Intervention: Virtual bolus optimization (plan vb). Compared with: Physical bolus during simulation (plan pb). n = 10.
Virtual bolus method demonstrated statistically superior robustness for Vpd (P<0.05) with mean Vpd deviation of −0.8% versus −1.5% for physical bolus Initial planning showed no statistically significant differences between methods in target coverage or organ-at-risk sparing Physical bolus method showed better robustness for conformity index (CI)
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
Although virtual bolus showed statistically superior robustness for target coverage, the absolute magnitude of improvement is small (0.7 percentage points). This finding requires validation in larger prospective cohorts and clinical outcome data before recommending preferential adoption of virtual bolus strategies in routine practice.
Small retrospective study (n=10) using synthetic CT to evaluate robustness of bolus strategies; demonstrates feasibility of the RegGAN approach but provides limited clinical evidence with marginal absolute differences and no hard clinical outcomes.
As stated by the source record.
Quoted from the source exactly as published.
Although virtual bolus showed statistically superior robustness for target coverage, the absolute magnitude of improvement is small (0.7 percentage points). This finding requires validation in larger prospective cohorts and clinical outcome data before recommending preferential adoption of virtual bolus strategies in routine practice.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
Abstract Background Volumetric modulated arc therapy (VMAT) for breast cancer with skin involvement requires a bolus to ensure adequate surface dose. Although both physical and virtual bolus methods are clinically established, their dosimetric robustness against interfraction anatomical variations remains underexplored. This study utilized deep learning–based synthetic CT (sCT) to evaluate the robustness of these two strategies. Methods Ten patients with skin‐involved breast cancer treated with VMAT were retrospectively analyzed. Two plans were generated for each patient: plan pb (physical bolus during simulation) and plan vb (virtual bolus optimization). To evaluate robustness, pretreatment cone beam CT images from fractions 1, 6, and 11 were converted to sCT using a registration‐based generative adversarial network (RegGAN). Dose distributions were recalculated on these sCT to quantify deviations in the conformity index (CI), homogeneity index (HI), and volume percentage of the prescribed dose ( V pd). Results Initial planning showed no statistically significant differences between the two methods in target coverage or organs at risk sparing. In the robustness analysis performed on sCT, the virtual bolus method (plan vb ) demonstrated statistically superior robustness for Vpd ( P < 0.05), although the absolute magnitude of improvement was small (mean Vpd deviation: –0.8% vs –1.5%). The physical bolus method (plan pb ) showed better robustness for CI. Conclusions Using a RegGAN‐based evaluation framework, this study demonstrates that although both bolus strategies are dosimetrically comparable, the virtual bolus method provides marginally improved robustness in target dose coverage against daily anatomical variations.
Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.