Application of Linear Accelerator on Boarding Kilovolt Fan Beam CT and Megavolt Cone Beam CT System on Set-up Errors During Radiation Treatment
10.3971/j.issn.1000-8578.2023.23.0288
- VernacularTitle:直线加速器机载千伏级扇形束CT和兆伏级锥形束CT系统在放疗摆位误差中的应用
- Author:
Yong ZHOU
1
;
Zeying JIANG
;
Baofeng SU
;
Jianfeng ZHOU
;
Qian WANG
;
Anting WANG
;
Jingxian LIU
;
Yan XUE
;
Huiyi FENG
;
Xiaoliang WU
;
Mingxing XIAO
;
Wenyong TAN
Author Information
1. Department of Oncology, Shenzhen Hospital of Southern Medical University, Shenzhen 518101, China
- Publication Type:Research Article
- Keywords:
On-board image system;
Set-up error;
Image-guided radiation therapy
- From:
Cancer Research on Prevention and Treatment
2023;50(11):1097-1102
- CountryChina
- Language:Chinese
-
Abstract:
Objective To quantify the setup errors for the different anatomical sites of patients who received intensity-modulated radiotherapy (IMRT) with linear accelerator on-board kilovolt fan beam CT(kV-FBCT) as non-isocenter IGRT and megavolt cone beam CT (MV-CBCT) as isocenter IGRT. Methods A retrospective analysis was performedon 70 patients who underwent radiotherapy, kV-FBCT, and/or MV-CBCT scans after each routine setup prior to IMRT. The average displacement (M), systematic error (Σ), and random error (б) at different treatment sites in the left-right, anterior-posterior, and cranial-caudal directions were calculated according to the individual displacements. The formula 2.5Σ+0.7б was used to estimate the PTV margin in respective direction. For each single patient, the root mean square in three directions was used as 3D displacement. Results A total of 1130 displacements were recorded in the 70 patients. The PTV margin was estimated to be 1.9-3.1 mm in head and neck cancer, 2.8-5.1 mm in thoracic cancer, 4.6-5.1 mm in breast cancer, 3.0-5.5 mm in upper abdominal cancer, and 3.5-6.8 mm in pelvic tumor. For the 3D mean displacements, the head and neck, thoracic, breast, upper abdominal, and pelvic cancer were 2.4±1.0, 4.0±1.6, 4.1±2.0, 4.6±2.1, and 4.6±2.1 mm, respectively. The average 3D displacement obtained by kV-FBCT and MV-CBCT were 4.1 and 3.4 mm, respectively (P=0.212). Conclusion The quantitative setup-error data can be obtained using linear accelerator on-board FBCT, and the non-isocenter IGRT induced set-up error cannot be negligible.
