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Zhou J, Li S, Ye C, Shen K, Li A, Chen G, Li X, Bai S, Wang W, Zhong R. Analysis of local setup errors of sub-regions in cone-beam CT-guided post-mastectomy radiation therapy. J Radiat Res 2021; 61:457-463. [PMID: 32100830 PMCID: PMC7299271 DOI: 10.1093/jrr/rraa007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/27/2019] [Indexed: 02/05/2023]
Abstract
The purpose of the study was to quantify local setup errors and evaluate the planning target volume (PTV) margins for sub-regions in cone-beam computed tomography (CBCT)-guided post-mastectomy radiation therapy (PMRT). The local setup errors of 20 patients undergoing CBCT-guided PMRT were analysed retrospectively. Image registration between CBCT and planning CT was performed using four sub-regions of interest (ROIs): the supraclavicular area (SROI), ipsilateral chest wall region (CROI), ipsilateral chest wall plus supraclavicular region (SROI + CROI) and vertebral region (TROI). Bland–Altman analysis, correlation, local setup errors and PTV margins among these ROIs were evaluated. There was no significant consistency or correlation for registration results between the TROI and the CROI or SROI regions on any translational axis. When using the SROI + CROI as the ROI, the systematic error (Σ) and random error (σ) of the local setup errors for the CROI region were 1.81, 1.19 and 1.76 mm and 1.84, 2.64 and 3.00 mm along the medial–lateral (ML), superior–inferior (SI) and anterior–posterior (AP) directions, respectively. The PTV margins for the CROI region were 5.80, 4.82 and 6.50 mm. The Σ and σ of the local setup errors for the SROI region were 1.29, 1.15 and 0.77 mm and 1.96, 2.65 and 2.2 mm, respectively, and the PTV margins were 4.59, 4.73 and 3.47 mm. Large setup errors and local setup errors occur in PMRT. The vertebral body should not be a position surrogate for the supraclavicular region or chest wall. To compensate for the local setup errors, different PTV margins are required, even with CBCT guidance.
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Affiliation(s)
- Jidan Zhou
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Shuai Li
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Chengwei Ye
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Konglong Shen
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - An Li
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Gang Chen
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Xiaoyu Li
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Sen Bai
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
| | - Weifeng Wang
- Department of Radiotherapy, Jingzhou Central Hospital, the Second Clinical Medical College, Yangtze University, Jingzhou 434020, P.R. China
| | - Renming Zhong
- Department of Radiotherapy, Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
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