scholarly journals Evaluation of tissue computed tomography number changes and dosimetric shifts after conventional whole-breast irradiation in patients undergoing breast-conserving surgery

Tumor Biology ◽  
2018 ◽  
Vol 40 (8) ◽  
pp. 101042831879188
Author(s):  
Joo Hwan Lee ◽  
Dong Soo Lee ◽  
So Hyun Park ◽  
Young Kyu Lee ◽  
Jeong Soo Kim ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Computed Tomography ◽  
Soft Tissue ◽  
Breast Conserving Surgery ◽  
Ct Scans ◽  
Whole Breast Irradiation ◽  
Breast Irradiation ◽  
Breast Cancer Patients ◽  
Ct Number ◽  
Electron Boost

The aim of this study was to assess tissue computed tomography (CT) number changes and corresponding dosimetric shifts in repeatedly performed simulation CT (re-sim CT) scans after conventionally fractionated irradiation in breast cancer patients. A total of 28 breast cancer patients who underwent breast-conserving surgery were enrolled in this study. All the patients had received 50.4 Gy of conventional whole-breast irradiation (WBI) and underwent re-sim CT scans for tumor bed boost. For evaluation of dosimetric shifts between initial and re-sim CT scans, electron boost plans in the same field size with the same monitor unit with source-to-skin distance of 100 cm were conducted. Dosimetric parameters (V105%, V103%, V100%, V98%, V95%, V90%: Vx% indicates volumes which receive X% of prescribed doses) between initial and re-sim CT scans were compared. The CT number data (CTmean, CTmax, CTmin) of the original and irradiated CT (re-sim CT) scans from each representative structure (lung, rib bone, soft tissue, muscle, etc.) were examined and recruited. CT numbers showed highly variable changes. Soft tissue CTmean and muscle CTmax/CTmin showed statistically and significantly increased values in the CT (re-sim CT) compared to the original CT scans. Rib bone CTmean/CTmin showed statistically and significantly decreased values in the re-sim CT compared to the original CT scans. Other CT number values showed no statistically significant changes. Among the dosimetric parameters, only V105% (p = 0.015, mean = 3.07 cc versus 1.63 cc) and V103% (p = 0.017, mean = 13.8 cc versus 11.9 cc) exhibited statistically increased values in the re-sim CT compared to the original CT scans. CT number changes after conventional WBI were different according to tissue component. For electron boost plans, the implementation of a re-sim CT might be helpfully considered because significant dosimetric factor changes were observed especially in the high-dose areas (hot spots: V105% and V103%).

scholarly journals A comparative study on hypofractionated whole-breast irradiation with sequential or simultaneous integrated boost on different positions after breast-conserving surgery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ting Yu ◽  
Yankang Li ◽  
Tao Sun ◽  
Min Xu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Breast Conserving Surgery ◽  
Simultaneous Integrated Boost ◽  
Whole Breast Irradiation ◽  
Breast Irradiation ◽  
Breast Cancer Patients ◽  
Sequential Boost ◽  
Integrated Boost ◽  
Hypofractionated Whole Breast Irradiation

AbstractThis study explored the dosimetric difference between hypofractionated whole-breast irradiation (HFWBI) with sequential boost (SEB) and simultaneous integrated boost (SIB) based on supine and prone positions to identify the superior boost mode and superior position. Thirty breast cancer patients eligible for HFWBI after breast-conserving surgery were enrolled. All patients underwent 3DCT simulation scanning in both supine and prone positions. For the SEB-HFWBI plan, the dose prescribed for the planning target volume (PTV) of whole breast (WB) was 2.67 Gy per fraction with a total of 15 fractions, followed by a sequential boost of 3.2 Gy per fraction to the PTV of tumor bed (TB) in 3 fractions. For the SIB-HFWBI plan, the dose prescribed for the PTV of WB was 2.67 Gy per fraction with a total of 15 fractions, with a simultaneously integrated boost of 3.2 Gy per fraction to the PTV of TB with a total of 15 fractions. Regardless of the position, for the PTV of TB, the conformal index (CI) in the SIB-HFWBI plans was greater than those in the SEB-HFWBI plans (T = − 8.114, − 8.114; both P < 0.05). The CI for the PTV of WB increased significantly in the prone position relative to the supine position in both two plans(Z = − 3.340, − 3.501; all P < 0.05). The study suggested that prone SIB-HFWBI might be more suitable for postoperative radiotherapy after breast-conserving surgery for early-stage breast cancer patients.

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