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Comparison Study of the Biological and Physical Optimization for Cervical Carcinoma

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Z Feng

Z Feng1, C Tao2 , J Zhu2 , G Yu1 , S Qin1 , Y Yin2 , D Li1* , (1) Shandong Normal University, Jinan, Shandong, (2) Shandong Cancer Hospital and Institute, Jinan, Shandong


SU-F-T-257 (Sunday, July 31, 2016) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: In this study, IMRT optimization based on biological related models were applied in the clinic for cervical carcinoma cases and the results were compared with the traditional physical optimization.

Methods: Twenty patients of advanced stage cervical carcinoma were selected in this study. The treatment plan was generated on each patient using both biological and physical optimized model respectively. Additionally, the biological optimization was based on two basic models for bladder and rectum: Poisson (adjustable parameters: alpha/beta, gamma, D50 ) and Lyman-Kutcher-Burman (adjustable parameters: m, n, D50). And then each optimized biological plan was compared with the corresponding physical plan. During this comparison, all biological and physical parameters, such as NTCP,TCP, target coverage and homogeneous index(HI), were evaluated by paired T-test to verify IMRT plans quality.

Results: The NTCP values by biological optimization were lower than the values from corresponding physical optimization. For the bladder and rectum, the detail of NTCP values are 0.144 and 0.178 with p=0.028 for bladder, and 0.108 and 0.186 with p= 7.97E-5 for rectum respectively. The mean dose and V40 of bladder and rectum were comparable, and there was no significant difference between these two optimizations. For PTV, both optimized models achieved similar target coverage and homogeneous index (For example, D98=53.4 Gy and 54.6 Gy from biological optimization and physical optimization respectively with p=2.94E-9), and there were no significant differences in the tumor control probability(TCP) values.

Conclusion: IMRT optimization based on biological model did not decrease the plan quality, and could spare bladder and rectum with lower NTCP value much more compared with traditional physical optimization for cervical carcinoma. Our initial experiment demonstrated that the biological optimization could be a potential alternative method to the traditional physical one.

Funding Support, Disclosures, and Conflict of Interest: We want to thank Dr. Lei Xing and Dr. Yong Yang in the Stanford University School of Medicine for this work. This work was jointly supported by NSFC (61471226), Natural Science Foundation for Distinguished Young Scholars of Shandong Province (JQ201516), and China Postdoctoral Science Foundation (2015T80739, 2014M551949).

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