Comparison of difference registration landmarks for image - guided radiotherapy for lung cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To investigate the impact of anatomical landmarks on registration in image?guided radiotherapy (IGRT) for central and peripheral lung cancer. Methods Twenty?five patients with central or peripheral lung cancer for IGRT were enrolled in this study. Kilo?voltage cone?beam CT ( kV?CBCT) scanning was acquired before irradiotion. Tumor coverage on CBCT was assessed using gross tumor volume (GTV), clinical target volume (CTV), and planning target volume (PTV) contours according to tumor alignment, carina registration, and spine registration, respectively. The grading analysiswas based on visual tumor assessment as followsgrade 0, tumor within GTV;grade 1, tumor outside GTV but inside CTV;grade 2, tumor outside CTV but inside PTV;and grade 3, tumor outside PTV. Results Totally 177 sets of kV?CBCT of 25 patients was collected. According to the registration landmarks of the tumor, carina and spine for central lung cancer, the percentages were 57?55%, 53?77% and 16?04% in grade 0, 39?62%, 45?28%and 58?49% in grade 1, and 1?89%, 0?94% and 25?47% in grade 2, respectively. For peripheral lung cancer, the percentages were 47?89%, 14?08% and 2?82% in grade 0, 43?66%, 29?58% and 45?07% in grade 1, and 8?45%, 40?85% and 35?21% in grade 2, respectively. Conclusions For central lung cancer,the tumor was recommended as the best registration landmark, and the carina was recommended as well, while the spine was not recommended. For peripheral lung cancer, the tumor was recommended as the best registration landmark, while the spine and the carina were not recommended.