Correlation between the setting of gating window width and setup accuracy in left breast cancer radiotherapy based on deep inspiration breath hold.

Personalized precision irradiation of patients with left-sided breast cancer is possible by examining the setup errors of 3- and 4-mm gated window widths for those treated with deep inspiration breath-hold (DIBH) treatment. An observational study was performed via a retrospective analysis of 250 cone-beam computed tomography (CBCT) images of 60 left-breast cancer patients who underwent whole-breast radiotherapy with the DIBH technique between January 2021 and 2022 at our hospital. Among them, 30 patients had a gated window width of 3 mm, while the remaining 30 had a gated window width of 4 mm; both groups received radiotherapy using DIBH technology. All patients underwent CBCT scans once a week, and the setup errors in the left-right (x-axis), inferior-superior (y-axis), and anterior-posterior (z-axis) directions were recorded. The clinical-to-planning target volume (CTV-PTV) margins of the two gating windows were calculated using established methods. The setup error in the Y direction was 1.69 ± 1.33 mm for the 3-mm - wide gated window and 2.42 ± 3.02 mm for the 4-mm - wide gated window. The two groups had statistically significant differences in the overall mean setup error (Dif 0.7, 95% CI 0.15-1.31, t = 2.48, p= 0.014). The Z-direction setup error was 2.32 ± 2.12 mm for the 3-mm - wide gated window and 3.15 ± 3.34 mm for the 4-mm - wide gated window. The overall mean setup error was statistically significant between the two groups (Dif 0.8, 95% CI 0.13-1.53, t= 2.34, p = 0.020). There was no significant difference in the X-direction setup error (p > 0.05). Therefore, the CTV-PTV margin values for a 3-mm gated window width in the X, Y, and Z directions are 5.51, 5.15, and 7.28 mm, respectively; those for a 4-mm gated window width in the X, Y, and Z directions are 5.52, 8.16, and 10.21 mm, respectively. The setup errors of the 3-mm - wide gating window are smaller than those of the 4-mm - wide gating window in the three dimensions. Therefore, when the patient's respiratory gating window width is reduced, the margin values of CTV-PTV can be reduced to increase the distance between the PTV and the organs at risk (OARs), which ensures adequate space for the dose to decrease, resulting in lower dose exposure to the OARs (heart, lungs, etc.), thus sparing the OARs from further damage. However, some patients with poor pulmonary function or unstable breathing amplitudes must be treated with a slightly larger gating window. Therefore, this study lays a theoretical basis for personalized precision radiotherapy, which can save time and reduce manpower in the delivery of clinical treatment to a certain extent. Another potential benefit of this work is to bring awareness to the potential implications of a slightly larger gating window during treatment without considering the resulting dosimetric impact.

Outcome and long-term efficacy of four facio-cervical fields conformal radiotherapy for nasopharyngeal carcinoma.

PURPOSE: To evaluate the outcomes of 255 patients with nasopharyngeal carcinoma (NPC) treated with four facio-cervical fields conformal radiotherapy (4F-CRT). RESULTS: In one patient's 3 different RT treatment modalities, the 4F-CRT techniques resulted in sharper of the dose-volume histograms (DVHs) for primary gross tumor volume (PGTVnx) and planning target volume (PTVnx), similar to the intensity modulated radiation therapy (IMRT). The median follow-up duration was 43 months. Locoregional relapse and distant metastases as the first treatment failure events occurred in 32 (32/255, 12.5%) and 20 (30/255, 11.8%) patients, respectively. The 3-year and 5-year local control, disease-free survival, and overall survival rates were 83.3%, 82%, 83.8%, and 76.1%, 73.2%, 76.3% respectively. Univariate analysis displayed that clinical stage, T-stage, N-stage, and tumor response were related to prognosis. Multivariate analysis indicated that age, T-stage, N-stage, and combined chemotherapy were independent prognosticators. The incidence of grade 1-2 acute mucositis and leukocytopenia were 93.7% and 91.0%, respectively, with no cases of grade 4 toxicity detected. MATERIALS AND METHODS: From November 2007 to December 2011, 255 patients with histologically diagnosed, non-metastatic NPC were enrolled into this study and received 4F-CRT. Magnetic resonance imaging scans of the nasopharynx were performed on every patient. All patients received definitive radiotherapy with 6 MV X-rays using conventional fractions at 2 Gy daily, 5 fractions per week, and 231 patients with stage IIb-IV received concurrent chemotherapy and cisplatin-based adjuvant chemotherapy. The accumulated survival was calculated according to the Kaplan-Meier method; the log-rank test was used to compare survival differences. Multivariate analysis was performed using Cox's proportional hazard model. CONCLUSIONS: Compared with the conventional treatment plans, the 4F-CRT plan delivered more dose to cover the tumor volume and reduces the doses of the normal tissues including the parotid gland, TMJs and so on. The long-term efficacy of 4F-CRT is satisfactory and its toxicities are tolerable.

Effect of a Siraitia grosvenori extract containing mogrosides on the cellular immune system of type 1 diabetes mellitus mice.

The purpose of this study was to observe the islet changes of pancreas in insulin-dependent diabetes mellitus (IDDM) mice in comparison to normal mice after application of an extract from Siraitia grosvenori fruits containing mogrosides, in particular, mogroside V. We hypothesized that mogroside extract (MG) attenuates the severity of alloxan-induced IDDM by effects on the immune system. Our data show that IDDM mice exhibited significant injury to pancreatic islets cells, which were atrophic. In addition, alloxan induced a notable increase in the expression of CD8+ lymphocytes to form a dramatic decrease in CD4+/CD8+ ratio (while CD4+ was unchanged). MG, administered to normal and experimental diabetic mice for 4 wk, effectively attenuated the early clinical symptoms, biochemical abnormalities, and pathological damages in pancreatic islets. Furthermore, at low dose, MG regulated the immune imbalance observed in alloxan-induced IDDM mice by up-regulating the CD4+ T-lymphocyte subsets and CD4/CD8 ratio, and altering the intracellular cytokine profiles. The expression of the pro-inflammatory Th1 cytokines: IFN-gamma, TNF-alpha in splenic lymphocytes was altered toward a beneficial Th2 pattern. MG therapy had no effect on normal mice, except that low dosage MG could up-regulate the IL-4 expression levels. The results revealed that MG exhibited antidiabetic effects presumably due to the presence of mogrosides.