J Cancer 2018; 9(20):3683-3689. doi:10.7150/jca.27220 This issue Cite

Research Paper

How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?

Zhikai Liu*, Xia Liu*, Fuquan Zhang, Ke Hu

Department of Radiation Oncology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
* These authors contributed equally to this work

Citation:
Liu Z, Liu X, Zhang F, Hu K. How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?. J Cancer 2018; 9(20):3683-3689. doi:10.7150/jca.27220. https://www.jcancer.org/v09p3683.htm
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Abstract

Background and purpose: Image guided radiotherapy (IGRT) without 6 degree of freedom couch can only correct the translational setup errors of pelvic radiotherapy. But errors introduced by rotation and deformation of CTV can't be adjusted in most of IGRT systems. This article is to evaluate these errors and to provide recommendations on the margin needed in the era of IGRT.

Material and methods: 218 patients who received pelvic radiotherapy in PUMC Hospital from 2012 to 2014 were included. A simulation CT and a CBCT were acquired for every patient. 3D and 6D registrations of CT and CBCT were applied. 9 bony landmarks were marked and distances of each landmark between CT and CBCT were measured in three directions.

Results: Without image guidance, movements of landmarks in the directions of LR, AP and SI were 0.4 ± 2.5 mm, 1.3 ± 3.8 mm and 1.5 ± 5.0 mm respectively, with 3D-registration, movements were 0.0 ± 1.5 mm, 0.7± 2.8 mm and 0.6± 3.2 mm, and with 6D-registration, movements were 0.0 ± 0.5 mm, 0.2 ± 1.0 mm and 0.2 ± 1.1 mm in each direction.

Conclusions: IGRT could reduce setup errors. IGRT with 6D treatment couches could further reduce setup errors compared to 3D couches. For centers without IGRT, we suggest CTV-PTV margins of 6 mm, 9 mm and 12 mm in LR, AP and SI directions respectively, margins of 3 mm, 6.5 mm and 7 mm for the use of daily IGRT with 3D couch and 2 mm, 3 mm and 3 mm for 6D couch.

Keywords: Pelvic lymph nodes, irradiation, image guided radiotherapy (IGRT)


Citation styles

APA
Liu, Z., Liu, X., Zhang, F., Hu, K. (2018). How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?. Journal of Cancer, 9(20), 3683-3689. https://doi.org/10.7150/jca.27220.

ACS
Liu, Z.; Liu, X.; Zhang, F.; Hu, K. How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?. J. Cancer 2018, 9 (20), 3683-3689. DOI: 10.7150/jca.27220.

NLM
Liu Z, Liu X, Zhang F, Hu K. How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?. J Cancer 2018; 9(20):3683-3689. doi:10.7150/jca.27220. https://www.jcancer.org/v09p3683.htm

CSE
Liu Z, Liu X, Zhang F, Hu K. 2018. How much margin do we need for pelvic lymph nodes irradiation in the era of IGRT?. J Cancer. 9(20):3683-3689.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). See http://ivyspring.com/terms for full terms and conditions.
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