ESTRO meets Asia 2024 - Abstract Book

S385

RTT – Treatment planning, OAR and target definitions

ESTRO meets Asia 2024

References:

1. Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

2. M.Heinrich Seegenschmiedt, Thomas Olschewski, Felicitas Guntrum, Radiotherapy optimization in early-stage dupuytren’s contracture: First results of a randomized clinical study, International Journal of Radiation Oncology*Biology*Physics, Volume 49, Issue 3, 2001, Pages 785-798, ISSN 0360-3016, https://doi.org/10.1016/S0360-3016(00)00745-8. 3. Paige Solie, Bryan Stump, Cortney Cashner, Nishele Lenards, Ashley Hunzeker, Sabrina Zeiler, A case study of radiotherapy treatment for Dupuytren's contracture and Ledderhose disease, Medical Dosimetry, Volume 48, Issue 3, 2023, Pages 149-153, ISSN 0958-3947, https://doi.org/10.1016/j.meddos.2023.03.001.

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Digital Poster

A Promising individualized Clinical Target Volume Delineation in Eccentric Nasopharyngeal Carcinoma

Yunrui Song 1,2 , Yuwei Wang 1 , Jiangdong Sui 1 , Mengqi Yang 1 , Xinhao Yu 1 , Mengze Li 1 , Bin Long 1 , Xiaolei Shu 1 , Xin Zhang 1 , Feng Wang 1 , Chengchen Wang 1 , Mengyu Hu 1 , Ying Wang 1 1 Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China. 2 College of Medicine, Chongqing University, Chongqing, China

Purpose/Objective:

Clinical target volume(CTV) delineation is a major focus in the field of radiotherapy for nasopharyngeal carcinoma(NPC) and there is no uniform delineation standard in each center.We aim to compare the dosimetric parameters of planning target volumes (PTVs) and organs at risk (OARs) of two CTV delineation(individualized CTV and conventional CTV) ， and to compare the dosimetric parameters of different radiotherapy techniques [tomotherapy (TOMO), volume-modulated arc therapy (VMAT), and intensity-modulated radiation therapy (IMRT)] for eccentric NPC.

Material/Methods:

This is a retrospective study that plans to include 90 patients with eccentric NPC and each treatment plan was replanned based on individualized CTV.For individualized CTV, the contralateral CTV1 was defined as a subclinical disease consisting of 5mm margin surrounding GTVnx(not include entire nasopharynx mucosa).The CTV2 was defined as potentially involved regions consisting of 5mm margin surrounding CTV1, and contralateral CTV2 only included the pharyngeal recess.To evaluate the superiority of individualized CTV on target volume, conformity index(CI),homogeneity index(HI),dosimetric parameters of PTV and OAR,and to compare dosimetric parameters of PTV and OAR among IMRT,VMAT and TOMO for eccentric NPC.The dosimetric parameters of the PTV and OAR were assessed and compared using the paired-samples t-test.The Friedman M test was applied to assess significant differences among the three radiotherapy techniques.

Results: