Purpose: This study investigated the use of synthetic computed tomography (CT) images derived from cone beam CT (CBCT) scans to analyze dose changes in breast cancer patients undergoing treatment and to evaluate the optimal timing for implementing adaptive radiotherapy. Methods: A retrospective analysis was conducted on five breast cancer patients treated with tomotherapy-based volumetric-modulated arc therapy at Yongin Severance Hospital. Each patient received 15 fractions, with doses of 320 centigray (cGy) to the high-dose planning target volume (PTV) and 267 cGy to the low-dose PTV. Planning CT images were acquired using the Aquilion scanner, andCBCT images were captured with the VersaHD linear accelerator’s on-board imager. These imageswere registered in RayStation using a hybrid deformable image registration method to generate synthetic CT images. Dose distributions were reanalyzed using the synthetic CT images, and dose-volume histogram parameters, including the dose to 95% of the volume (D95 ) and mean dose (Dmean ) for the PTV, as well as D95 , Dmean , the percentage of the volume receiving at least 5 Gy (V5 ) and 10 Gy (V10 )for organs-at-risk (OARs), were extracted using MATLAB to assess dose changes during treatment. Results: For the original plans, the mean D95 for PTV high across all patients was 287.13±31.32cGy, while for PTV low, it was 245.53±6.21 cGy. In contrast, the adaptive plans yielded a mean D95of 298.17±12.37 cGy for PTV High and 247.25±4.23 cGy for PTV low. The ART Plan may lead to increased dose exposure in certain structures, such as the spinal cord, while providing targeted improvements in reducing radiation exposure in specific OARs (e.g., contralateral breast and esophagus). Conclusions Synthetic CT images generated from CBCT scans provide a fast and efficient means of quantifying dose changes, supporting precise patient care through interfractional evaluation.Future studies will aim to apply this method to other organs and larger patient cohorts.

Purpose: This study investigated the use of synthetic computed tomography (CT) images derived from cone beam CT (CBCT) scans to analyze dose changes in breast cancer patients undergoing treatment and to evaluate the optimal timing for implementing adaptive radiotherapy. Methods: A retrospective analysis was conducted on five breast cancer patients treated with tomotherapy-based volumetric-modulated arc therapy at Yongin Severance Hospital. Each patient received 15 fractions, with doses of 320 centigray (cGy) to the high-dose planning target volume (PTV) and 267 cGy to the low-dose PTV. Planning CT images were acquired using the Aquilion scanner, andCBCT images were captured with the VersaHD linear accelerator’s on-board imager. These imageswere registered in RayStation using a hybrid deformable image registration method to generate synthetic CT images. Dose distributions were reanalyzed using the synthetic CT images, and dose-volume histogram parameters, including the dose to 95% of the volume (D95 ) and mean dose (Dmean ) for the PTV, as well as D95 , Dmean , the percentage of the volume receiving at least 5 Gy (V5 ) and 10 Gy (V10 )for organs-at-risk (OARs), were extracted using MATLAB to assess dose changes during treatment. Results: For the original plans, the mean D95 for PTV high across all patients was 287.13±31.32cGy, while for PTV low, it was 245.53±6.21 cGy. In contrast, the adaptive plans yielded a mean D95of 298.17±12.37 cGy for PTV High and 247.25±4.23 cGy for PTV low. The ART Plan may lead to increased dose exposure in certain structures, such as the spinal cord, while providing targeted improvements in reducing radiation exposure in specific OARs (e.g., contralateral breast and esophagus). Conclusions Synthetic CT images generated from CBCT scans provide a fast and efficient means of quantifying dose changes, supporting precise patient care through interfractional evaluation.Future studies will aim to apply this method to other organs and larger patient cohorts.

Purpose: This study investigated the use of synthetic computed tomography (CT) images derived from cone beam CT (CBCT) scans to analyze dose changes in breast cancer patients undergoing treatment and to evaluate the optimal timing for implementing adaptive radiotherapy. Methods: A retrospective analysis was conducted on five breast cancer patients treated with tomotherapy-based volumetric-modulated arc therapy at Yongin Severance Hospital. Each patient received 15 fractions, with doses of 320 centigray (cGy) to the high-dose planning target volume (PTV) and 267 cGy to the low-dose PTV. Planning CT images were acquired using the Aquilion scanner, andCBCT images were captured with the VersaHD linear accelerator’s on-board imager. These imageswere registered in RayStation using a hybrid deformable image registration method to generate synthetic CT images. Dose distributions were reanalyzed using the synthetic CT images, and dose-volume histogram parameters, including the dose to 95% of the volume (D95 ) and mean dose (Dmean ) for the PTV, as well as D95 , Dmean , the percentage of the volume receiving at least 5 Gy (V5 ) and 10 Gy (V10 )for organs-at-risk (OARs), were extracted using MATLAB to assess dose changes during treatment. Results: For the original plans, the mean D95 for PTV high across all patients was 287.13±31.32cGy, while for PTV low, it was 245.53±6.21 cGy. In contrast, the adaptive plans yielded a mean D95of 298.17±12.37 cGy for PTV High and 247.25±4.23 cGy for PTV low. The ART Plan may lead to increased dose exposure in certain structures, such as the spinal cord, while providing targeted improvements in reducing radiation exposure in specific OARs (e.g., contralateral breast and esophagus). Conclusions Synthetic CT images generated from CBCT scans provide a fast and efficient means of quantifying dose changes, supporting precise patient care through interfractional evaluation.Future studies will aim to apply this method to other organs and larger patient cohorts.

Capsular contracture (CC) is a concerning issue for individuals undergoing postmastectomy radiation therapy (PMRT) with implant-based breast reconstruction. This study investigated whether the extent of CC and implant migration differs based on implant placement and the reconstruction stage. Insertion plane and stage of breast implants were investigated, and the presence and severe cases of CC and implant migration were analyzed. Among 195 participants, 83 were in the pre-pectoral group, and 112 were in the sub-pectoral group. Two-staged surgery was performed on 116 patients, while 79 underwent direct-to-implant (DTI).Notably, The occurrence of CC (prepectoral, 17 [20.48%] and subpectoral, 42 [37.50%];p = 0.011), CC severity (prepectoral, 4 [4.82%] and subpectoral, 17 [15.17%]; p = 0.021), and implant upward migration (prepectoral, 15 [18.07%] and subpectoral, 38 [33.92%]; p = 0.014) significantly varied between the two groups. The incidence of CC was more common in the DTI group (odds ratio [OR], 2.283; 95% confidence interval [CI], 1.164–4.478). Furthermore, subpectoral placement was an independent risk factor for occurrence (OR, 2.989; 95% CI, 1.476–6.054) and severity of CC (OR, 38.552; 95% CI, 1.855–801.186) and upward implant migration (OR, 2.531; 95% CI, 1.263–5.071). Our findings suggest that pre-pectoral reconstruction and the two-stage operation benefit patients who may undergo PMRT. These approaches can help reduce the incidence of CC and abnormal implant migration following radiation, leading to improved aesthetic outcomes and greater patient satisfaction.

Capsular contracture (CC) is a concerning issue for individuals undergoing postmastectomy radiation therapy (PMRT) with implant-based breast reconstruction. This study investigated whether the extent of CC and implant migration differs based on implant placement and the reconstruction stage. Insertion plane and stage of breast implants were investigated, and the presence and severe cases of CC and implant migration were analyzed. Among 195 participants, 83 were in the pre-pectoral group, and 112 were in the sub-pectoral group. Two-staged surgery was performed on 116 patients, while 79 underwent direct-to-implant (DTI).Notably, The occurrence of CC (prepectoral, 17 [20.48%] and subpectoral, 42 [37.50%];p = 0.011), CC severity (prepectoral, 4 [4.82%] and subpectoral, 17 [15.17%]; p = 0.021), and implant upward migration (prepectoral, 15 [18.07%] and subpectoral, 38 [33.92%]; p = 0.014) significantly varied between the two groups. The incidence of CC was more common in the DTI group (odds ratio [OR], 2.283; 95% confidence interval [CI], 1.164–4.478). Furthermore, subpectoral placement was an independent risk factor for occurrence (OR, 2.989; 95% CI, 1.476–6.054) and severity of CC (OR, 38.552; 95% CI, 1.855–801.186) and upward implant migration (OR, 2.531; 95% CI, 1.263–5.071). Our findings suggest that pre-pectoral reconstruction and the two-stage operation benefit patients who may undergo PMRT. These approaches can help reduce the incidence of CC and abnormal implant migration following radiation, leading to improved aesthetic outcomes and greater patient satisfaction.