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Objective: To evaluate breath-hold stability and constancy for a voluntary breath-hold (VBH) technique in a retrospective analysis. Methods: Movie loop sequences of electronic portal image data from multiple breath holds in a cohort of 19 patients were used to assess within and between breath-hold stability. In vivo dosimetry data based on electronic portal imaging (EPI) were analysed for 31 VBH patients plus a cohort of free-breathing (FB) patients to provide a reference. A phantom experiment simulated the impact on dose of FB, breath hold and unplanned release of breath hold. Results: 165/174 (93%) movie loop data sets had no detectable displacement. For the remaining 12, median displacement = 1.5 mm and maximum displacement = 3 mm (one patient on one fraction). In vivo dosimetry data analysis showed a median dose difference measured to planned of -0.2% (VBH) and -0.1% (FB). Dose distribution evaluation (γ) pass rates were 84% (VBH) and 91% (FB) including the lung region; 93% and 96% with a lung override. Unplanned release of phantom breath-hold position changed median dose by =1% and degraded γ pass rates to 79-62%. Failing regions were mostly in the periphery of the treated volume. Conclusion: The data confirmed that multiple VBHs using visual monitoring are stable; in vivo dose verification via EPI was within expected and acceptable levels. Advances in knowledge: These data provide further reassurance that VBH is a safe technique for cardiac sparing breast radiotherapy and support its rapid, widespread implementation. [ABSTRACT FROM AUTHOR]

Purpose To compare mean heart and left anterior descending coronary artery (LAD) doses (NTD mean ) and positional reproducibility in larger-breasted women receiving left breast radiotherapy using supine voluntary deep-inspiratory breath-hold (VBH) and free-breathing prone techniques. Materials and methods Following surgery for early breast cancer, patients with estimated breast volumes >750 cm 3 underwent planning-CT scans in supine VBH and free-breathing prone positions. Radiotherapy treatment plans were prepared, and mean heart and LAD doses were calculated. Patients were randomised to receive one technique for fractions 1–7, before switching techniques for fractions 8–15 (40 Gy/15 fractions total). Daily electronic portal imaging and alternate-day cone-beam CT (CBCT) imaging were performed. The primary endpoint was the difference in mean LAD NTD mean between techniques. Population systematic ( Σ ) and random errors ( σ ) were estimated. Within-patient comparisons between techniques used Wilcoxon signed-rank tests. Results 34 patients were recruited, with complete dosimetric data available for 28. Mean heart and LAD NTD mean doses for VBH and prone treatments respectively were 0.4 and 0.7 ( p < 0.001) and 2.9 and 7.8 ( p < 0.001). Clip-based CBCT errors for VBH and prone respectively were ⩽3.0 mm and ⩽6.5 mm ( Σ ) and ⩽3.5 mm and ⩽5.4 mm ( σ ). Conclusions In larger-breasted women, supine VBH provided superior cardiac sparing and reproducibility than a free-breathing prone position. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to investigate the effect of body habitus on supraclavicular (SC) dose-volume histogram (DVH) parameters among breast cancer patients according to 3 different techniques. Three SC irradiation plans were generated for 24 postoperative breast cancer patients: (1) direct antero-posterior field only (1fieldP), with dose prescribed to a 3-cm depth; (2) 3-cm depth plan (3cmP) using an antero-posterior field plus a posterior boost with the dose prescription defined to 3 cm; and (3) optimized plan (OptP) similar to 3cmP, with dose prescribed depending on the anatomy. The OptP plans had the least variation in DVH parameters with body habitus; 3cmP plans were the most varied. Conformity index among normal weight patients were 0.73, 0.78, and 0.87 (p = 0.02) and 0.61, 0.6, and 0.82 among overweight-obese patients for 1fieldP, 3cmP, and OptP, respectively (p < 0.001). V 95% of the planning target volume among normal weight patients were 72.63%, 78.03%, and 87.18% for 1fieldP, 3cmP, and OptP, respectively (p = 0.02). The corresponding values among overweight-obese patients were 60.5%, 59.62%, and 81.62%, respectively (p = 0.001). Fixed depth dose prescriptions caused greater SC under dose than plans optimized according to patient's anatomy. [ABSTRACT FROM AUTHOR]