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Optimizing bolus application in postmastectomy radiotherapy: A dosimetric study on the impact of frequency and reoptimization
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Z. Shan   , F. Zhou |
| Department of Radiotherapy, Luohu People’s Hospital, Shenzhen, 518000, China , fszl2025@163.com |
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Abstract: (6 Views) |
Background: This study assessed the dosimetric implications of a reduced-frequency bolus regimen combined with treatment plan reoptimization in post-mastectomy radiotherapy (PMRT), with the goal of optimizing target coverage and organ-at-risk (OAR) dose sparing. Materials and Methods: Eighteen post-mastectomy patients scheduled for radiotherapy were enrolled. CT simulation was performed without bolus. A baseline plan (Plan(all)) was created using a virtual bolus to meet clinical objectives. Two derivative plans were generated from Plan(all): Plan (nobolus)- direct bolus removal without re-optimization and Plan(nobolus-new)- re-optimized after bolus removal to enhance target coverage. Three hybrid 25-fraction plans were generated by combining fractions of Plan(all) and Plan (nobolus): Plan(20bolus) (20 fractions Plan(all)+5 fractions Plan(nobolus)), Plan(18bolus)(18+7), and Plan(13bolus)(13+12). Similarly, three additional hybrid plans were constructed by combining Plan(all) with Plan(nobolus-new): Plan(20bolus-new), Plan(18bolus-new) and Plan(13bolus-new). Dosimetric parameters were compared across all plans. Results: Compared with Plan(nobolus), Plan(nobolus-new) offered improved target coverage, reduced high-dose volumes within the target, and enhanced dose homogeneity, albeit at the expense of elevated doses to the lungs, heart, and skin. Notably, Plan(13bolus-new) achieved comparable skin dose (body2mm/D10cc: 50.19±1.33 Gy vs 50.19±0.46 Gy, P>0.05) and high-dose target volume (PTV/D2%: 52.95±0.25 Gy vs 52.99±0.20 Gy, P>0.05) relative to the Plan(20bolus), while yielding statistically superior target coverage (PTV/V95%p: 96.59±1.86% vs 97.36 ±1.53%, P<0.05). Conclusion: A reduction in bolus application frequency compromises target coverage yet attenuates skin dose. A strategy combining reduced bolus frequency with plan reoptimization represents a feasible approach to minimize bolus use while preserving both target coverage and skin dose parameters. |
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| Keywords: Post-radical mastectomy radiotherapy, bolus, plan design, plan dosimetry. |
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Full-Text [PDF 774 kb]
(2 Downloads)
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Type of Study: Original Research |
Subject:
Radiation Biology
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