en Radiation Biology Radiation Biology مطالعه موردي Case Report <div style="text-align: justify;">Background: To investigate a method for standardizing intensity modulated radiation therapy (IMRT) optimization for nasopharyngeal carcinoma (NPC), in order to reduce the influence of subjective factors. Materials and Methods: This study is based on example IMRT plans for NPC, which were randomly divided into data acquisition and data verification groups. Organs at risk (OARs) were analyzed for various sub-organs. The data acquisition group was used for statistical evaluations of the mean value of the normalized mean doses of sub-organs. The data validation group was used to validate the findings. Results: Significant negative correlations were observed between the normalized mean doses of sub-organs for each OAR and the shortest distance between sub-organs and the target region surface. For each OAR, there was no statistically significant difference in the normalized mean doses of sub-organs between the data acquisition and verification groups (p > 0.05). Conclusion: The influence of subjective factors can be reduced by using the normalized mean doses of sub-organs for each OAR as the evaluation parameter for standardizing. This method is relatively simple; a majority of radiotherapy centers can apply the model for standardizing IMRT planning optimization based on the existing planning system.</div> IMRT, planning optimization, standardize. 177 181 http://ijrr.com/browse.php?a_code=A-10-1-771&slc_lang=en&sid=1 H. Pang haowenpang@foxmail.com 7900319475328460012751 7900319475328460012751 Yes Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China S. Lin 7900319475328460012752 7900319475328460012752 No Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China B. Yang 7900319475328460012753 7900319475328460012753 No Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China J. Wu 7900319475328460012754 7900319475328460012754 No Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China X. Sun 7900319475328460012755 7900319475328460012755 No Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China