en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background:</span></span></span></span></span></span> <span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:black"><span style="language:en-GB">To compare the dosimetry of Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) techniques for breast cancer patients with 1-2 sentinel lymph node metastases. </span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-GB">Materials and Methods: </span></span></span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:black"><span style="language:en-GB">A total of 90 breast cancer patients (left:33, right:57) receiving post-operative radiotherapy were retrospectively included. IMRT and VMAT treatment plans were designed for each patient with same prescriptions and dose-volume constraints. Key dose-volume histogram (DVH) metrics in target volumes and organs-at-risks (OARs) were analyzed and compared in groups. </span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-GB">Results: </span></span></span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:black"><span style="language:en-GB">Compared with IMRT, VMAT showed superior target coverage and dose conformity, particularly for planning target volume (PTV) and axillary levels 1-2 lymph nodes in both left- and right-sided cancers. For left-sided cases, VMAT significantly reduced mean dose (Dmean) to the heart and left coronary artery (p<0.001), with a 33% decrease in V40% for left coronary artery. For right-sided cases, VMAT showed a modest Dmean increase to these structures due to dose spillage, though all values remained within clinical constraints. Compared with IMRT, VMAT demonstrated superior dose sparing for the ipsilateral lung and humeral head. While both techniques achieved comparable dose coverage for axillary level 3 lymph nodes (p > 0.05), VMAT required significantly fewer monitor units (MU) (p < 0.001). </span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-GB">Conclusion: </span></span></span></span></span></span><span lang="en-GB" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:black"><span style="language:en-GB">The dosimetric analysis demonstrates VMAT&#39;s superiority over IMRT in breast cancer patients with 1-2 sentinel lymph node metastases, offering improved target coverage, enhanced organ sparing, and greater delivery efficiency.</span></span></span></span></span></span></span></span></span></span></div> Breast Cancer, Sentinel Irradiation, Lymph Node Metastasis, Dosimetry, Radiotherapy. 301 307 http://ijrr.com/browse.php?a_code=A-10-1-1494&slc_lang=en&sid=1 K. Yao 7900319475328460033367 7900319475328460033367 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China M. Wang 7900319475328460033368 7900319475328460033368 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China C. Shi 7900319475328460033369 7900319475328460033369 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China H. Wu 7900319475328460033370 7900319475328460033370 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China J. Liu 7900319475328460033371 7900319475328460033371 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China H. Yue 7900319475328460033372 7900319475328460033372 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China R. Wang ruoxi.wang@pku.edu.cn 7900319475328460033373 7900319475328460033373 Yes Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China Y. Du yidu_rt@163.com 7900319475328460033374 7900319475328460033374 No Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China