Abstract：Objective To evaluate the quantitative effect on tumor and important organs in patients with non-small cell lung cancer
(NSCLC) caused by daily set-up error measured by Kilo-voltage cone beam CT (CBCT) in intensity modulated radiotherapy
(IMRT). Methods A total of 60 patients with NSCLC who received IMRT from April 2019 to January 2020 were randomly selected.
A total of 588 CBCT image acquisitions were analyzed. CBCT scan and positioning error verification was taken for each patient
prior the first treatment and subsequent one time per week, so as to obtain the positioning errors of the patient’s actual and planned
isocenter positions in the directions of left-right (X-axis), superior-inferior (Y-axis), and front-back (Z-axis), the positioning errors
and distribution patterns were statistically analyzed. The positioning errors of 40 patients were selected and input into the Eclipse
planning system to simulate the dose distribution of the planned and actual irradiation when the bed was not moved and named
Plansum. Finally, Plansum was compared with the original planned dose Planapproved to obtain the dosimetry parameters and volume
change parameters of the target area and organs at risk, and to study the impact of positioning errors on the planned dose distribution
of radiotherapy for NSCLC. Results A total of 588 image-guided positioning verification data of 60 patients with NSCLC were
analyzed. The set-up errors of left-right (X-axis), superior-inferior (Y-axis) and front-back (Z-axis) directions were (1.8±1.5),
(2.5±1.9), and (2.2±1.5) mm respectively. In the Plansum, V5, V20, V30, V40 and Dmean of the lung tissue were 101.2%, 101.2%,
103.3%, 102.9% and 101.5% of Planapproved respectively; V10, V20, V30, V40 and Dmean of the heart were 102.1%, 102.6%, 107%, 112.1%
and 105.1% of Planapproved respectively; the planned target volume D95, Dmean of the target area were 94.9% and 95.7% of Planapproved
respectively, and PGTV D95 and Dmean were 95.5% and 96.2% of Planapproved respectively. The difference was statistically significant
(P<0.01). Conclusion In order to maintain the dosimetry index in the radiotherapy plan and improve the tumor gain ratio, CBCT
should be used as far as possible to correct the set-up error of radiotherapy for NSCLC.
张利，倪千喜，余功奕. 基于KV-CBCT影像引导下非小细胞肺癌调强放疗的摆位误差分析[J]. 中国医疗设备, 2022, 37(7): 59-63.
ZHANG Li, NI Qianxi, YU Gongyi. Analysis of Set-up Error in Intensity-Modulated Radiotherapy for Non-Small Cell Lung
Cancer Guided by Kilo-Voltage Cone Beam CT Image. China Medical Devices, 2022, 37(7): 59-63.
