Objective:To explore the sensitivity of intensity-modulated radiotherapy(IMRT)designed respectively by overlapping method and gradient optimization method on fixed field of whole brain and whole spinal cord of pediatric patients to positioning error.Methods:A retrospective study analyzed 10 pediatric patients who underwent radiotherapy on whole brain and whole spinal cord at The First Affiliated Hospital of Guangzhou Medical University during December 1,2022 and January 1,2024.Overlapping method and gradient optimization method were respectively adopted to design IMRT plan for whole brain and whole spinal cord.The length of the merged region of the field was set as 10 cm.The positioning errors of±1 mm,±3 mm and±5 mm on head-foot direction that occurred in spinal cord segmentation and other isocenter field were simulated,and the flux optimization did not be conducted,and the dose distribution was recalculated.The exposure doses of D2%,D98%,V30Gy,homogeneity index(HI),conformity index(CI)and organ at risk(OAR)of target regions in the merged region of field were recorded and compared,thus the robustness of the two optimization methods were assessed.Results:The IMRT plan of whole brain and whole spinal cord that were designed respectively by overlapping method and gradient optimization method can meet the clinical requirements under the condition that did not introduced positioning error.With the increasing of positioning error,the changes of cold and hot spots(ΔD2%,ΔD98%and ΔV30 Gy)of doses in the merged region of field were more and more significant.In the merged region of field,theΔD2%,ΔD98%and ΔV30 Gy of the overlapping method were respectively 13.98%±3.29%,-17.26%±3.44%and-44.06%±9.17%,and those of the gradient optimization method were respectively 6.0%±0.75%,-6.31%±0.81%and-37.37%±4.3%when positioning error was 5 mm.The differences of them between the overlapping method and the gradient optimization method were statistically significant(t=-10.889,15.928,2.808,P<0.05).Conclusion:With increase of positioning error in the merged region of field of IMRT plan for whole brain and whole spinal cord,the gradient optimization method can effectively relieve the changes of the cold and hot spots in the merged region of field,and its each indicator was less than that of the overlapping method.Therefore,it can effectively improve the plan's robustness.

Objective:To compare four postmastectomy radiotherapy plans with different arc angles for left-sided breast cancer prepared using deep inspiration breath hold (DIBH) technique, in order to explore the feasibility of selecting optimal arc angles based on the parameters of patients′ anatomical structures.Methods:A total of 51 patients who underwent postmastectomy radiotherapy for left-sided breast cancer using DIBH at the Second Affiliated Hospital of Guangxi Medical University and the First Affiliated Hospital of Guangzhou Medical University were selected. Among these, 40 patients selected using simple random sampling were treated with four radiotherapy plans with different arc angles, labeled as SV120, SV100, SV80, and SV60, while the remaining 11 patients were treated with only the SV60 plans. The dose parameters of the target volumes (TVs) and organs at risk (the heart, lungs, and contralateral breast), as well as the beam-on times of individual arcs, in these plans were compared. The parameters of the anatomical structures (i.e., the heart, lung, and breast) of the 51 patients, including PHeart, PLungl, and PBreast, were extracted. Taking these parameters as independent variables and the quality of the SV60 plans as the dependent variable, fitting was conducted using P(SV60)—a multivariate logistic regression model—based on a training set (45 patients) and a testing set (six patients). The classification threshold of the plans was set at 0.5. Results:As the arc angle increased, the plans exhibited improved modulation capabilities for TVs and the left lung. However, the V5 of the right lung and the average beam-on time of a single arc also increased. The SV120 plans demonstrated significantly better V107% of planning target volume (PTV; 6.84%), homogeneity index (HI; 0.13), conformity index (CI; 0.81), and mean dose to the left lung (1 330.97 cGy) compared to the other three types of plans, with statistically significant differences ( W = 0-99, P < 0.001). The SV60 plans displayed lower mean doses to the contralateral breast (198.97 cGy) and the heart (440.35 cGy) and lower V5 of the right lung (0.27%) than the other three types of plans, with significant differences in V5 of the right lung and the mean dose to the contralateral breast ( W = 0-157, P < 0.001). In contrast, no significant difference was observed in these parameters (except for V5 of the right lung) among the other three types of plans. The four types of plans exhibited average beam-on times of individual arcs of 22.0, 19.1, 16.1, and 14.4 s, respectively, with statistically significant differences ( χ2= 93.0, P < 0.001). A multivariate logistic regression model revealed that PLungl, PHeart, and PBreast were negatively correlated with the quality of the SV60 plans ( t = -64.84, -28.20, -24.45, P<0.001). This model yielded an accuracy of 93.33% and a precision of 92.86% in the training set, while its accuracy and precision reached 100% in the testing set. Conclusions:For patients treated with postmastectomy radiotherapy for left-sided breast cancer using DIBH, it is feasible to select appropriate arc angles based on patients’ anatomical structures.

Objective:To compare four postmastectomy radiotherapy plans with different arc angles for left-sided breast cancer prepared using deep inspiration breath hold (DIBH) technique, in order to explore the feasibility of selecting optimal arc angles based on the parameters of patients′ anatomical structures.Methods:A total of 51 patients who underwent postmastectomy radiotherapy for left-sided breast cancer using DIBH at the Second Affiliated Hospital of Guangxi Medical University and the First Affiliated Hospital of Guangzhou Medical University were selected. Among these, 40 patients selected using simple random sampling were treated with four radiotherapy plans with different arc angles, labeled as SV120, SV100, SV80, and SV60, while the remaining 11 patients were treated with only the SV60 plans. The dose parameters of the target volumes (TVs) and organs at risk (the heart, lungs, and contralateral breast), as well as the beam-on times of individual arcs, in these plans were compared. The parameters of the anatomical structures (i.e., the heart, lung, and breast) of the 51 patients, including PHeart, PLungl, and PBreast, were extracted. Taking these parameters as independent variables and the quality of the SV60 plans as the dependent variable, fitting was conducted using P(SV60)—a multivariate logistic regression model—based on a training set (45 patients) and a testing set (six patients). The classification threshold of the plans was set at 0.5. Results:As the arc angle increased, the plans exhibited improved modulation capabilities for TVs and the left lung. However, the V5 of the right lung and the average beam-on time of a single arc also increased. The SV120 plans demonstrated significantly better V107% of planning target volume (PTV; 6.84%), homogeneity index (HI; 0.13), conformity index (CI; 0.81), and mean dose to the left lung (1 330.97 cGy) compared to the other three types of plans, with statistically significant differences ( W = 0-99, P < 0.001). The SV60 plans displayed lower mean doses to the contralateral breast (198.97 cGy) and the heart (440.35 cGy) and lower V5 of the right lung (0.27%) than the other three types of plans, with significant differences in V5 of the right lung and the mean dose to the contralateral breast ( W = 0-157, P < 0.001). In contrast, no significant difference was observed in these parameters (except for V5 of the right lung) among the other three types of plans. The four types of plans exhibited average beam-on times of individual arcs of 22.0, 19.1, 16.1, and 14.4 s, respectively, with statistically significant differences ( χ2= 93.0, P < 0.001). A multivariate logistic regression model revealed that PLungl, PHeart, and PBreast were negatively correlated with the quality of the SV60 plans ( t = -64.84, -28.20, -24.45, P<0.001). This model yielded an accuracy of 93.33% and a precision of 92.86% in the training set, while its accuracy and precision reached 100% in the testing set. Conclusions:For patients treated with postmastectomy radiotherapy for left-sided breast cancer using DIBH, it is feasible to select appropriate arc angles based on patients’ anatomical structures.

Objective:To explore the sensitivity of intensity-modulated radiotherapy(IMRT)designed respectively by overlapping method and gradient optimization method on fixed field of whole brain and whole spinal cord of pediatric patients to positioning error.Methods:A retrospective study analyzed 10 pediatric patients who underwent radiotherapy on whole brain and whole spinal cord at The First Affiliated Hospital of Guangzhou Medical University during December 1,2022 and January 1,2024.Overlapping method and gradient optimization method were respectively adopted to design IMRT plan for whole brain and whole spinal cord.The length of the merged region of the field was set as 10 cm.The positioning errors of±1 mm,±3 mm and±5 mm on head-foot direction that occurred in spinal cord segmentation and other isocenter field were simulated,and the flux optimization did not be conducted,and the dose distribution was recalculated.The exposure doses of D2%,D98%,V30Gy,homogeneity index(HI),conformity index(CI)and organ at risk(OAR)of target regions in the merged region of field were recorded and compared,thus the robustness of the two optimization methods were assessed.Results:The IMRT plan of whole brain and whole spinal cord that were designed respectively by overlapping method and gradient optimization method can meet the clinical requirements under the condition that did not introduced positioning error.With the increasing of positioning error,the changes of cold and hot spots(ΔD2%,ΔD98%and ΔV30 Gy)of doses in the merged region of field were more and more significant.In the merged region of field,theΔD2%,ΔD98%and ΔV30 Gy of the overlapping method were respectively 13.98%±3.29%,-17.26%±3.44%and-44.06%±9.17%,and those of the gradient optimization method were respectively 6.0%±0.75%,-6.31%±0.81%and-37.37%±4.3%when positioning error was 5 mm.The differences of them between the overlapping method and the gradient optimization method were statistically significant(t=-10.889,15.928,2.808,P<0.05).Conclusion:With increase of positioning error in the merged region of field of IMRT plan for whole brain and whole spinal cord,the gradient optimization method can effectively relieve the changes of the cold and hot spots in the merged region of field,and its each indicator was less than that of the overlapping method.Therefore,it can effectively improve the plan's robustness.

Objective:To propose an automatic planning approach for Eclipse15.6 planning system based on Eclipse scripting application programming interface (ESAPI) and evaluate its clinical application.Methods:20 patients with nasopharyngeal carcinoma and 20 cases of rectal cancer were selected in the clinical planning. The developed automatic planning script SmartPlan and RapidPlan were used for automatic planning and dosimetric parameters were compared with manual planning. The differences were compared between two groups by using Wilcoxon signed rank test. Results:The dosimetric results of automatic and manual plans could meet clinical requirements. There was no significant difference in target coverage in nasopharyngeal carcinoma planning between two groups ( P>0.05), and automatic plans were superior to manual plans in organs at risk sparing ( P<0.05). Except for the homogeneity index of PTV and the maximum dose of bowel in rectal cancer plans, the other dosimetric parameters of the automatic plans were better than those of the manual plans (all P<0.05). Conclusions:Compared with the manual plans, the automatic plans have the same or similar target coverage, similar or better protection of organs at risk, and more convenient implementation. The developed SmartPlan based on ESAPI has clinical feasibility and effectiveness.

Objective:To compare the dosimetric parameters and plan complexity between newly-delicated HyperArc (HA) and conventional volumetric-modulated arc therapy (VMAT) in the treatment of brain metastases.Methods:For 26 patients with brain metastases, HA, conventional coplanar (Cop) and non-coplanar (Non-cop) VMAT plans with a prescription dose of 9 Gy 3fx or 6 Gy 5fx were generated. The dosimetric parameters for planning target volume (PTV), RTOG conformity index (RTOG CI), Paddick CI, homogeneity index (HI), gradient index (GI), maximum dose (D max) of brainstem and dose-volume parameters of brain-PTV(V 2Gy-V 26Gy) were statisticaly compared among these three approaches. In addition, the monitor unit (MU) and the plan complexity parameters (including MCSv and AlPO) were statistically compared. Results:To prevent missed targets during treatment, all plans were established with RTOG CI of greater than 1.1. For Paddick CI, HA provided significantly higher conformity (0.89±0.019) than Non-cop (0.87±0.036, P=0.001) and Cop (0.88±0.017, P=0.003) VMAT. For GI, the fastest dose fall-off was noted in HA (3.35±0.64), followed by conventional Non-cop VMAT of (3.70±0.80), and conventional Cop VMAT of (4.90±1.85)(all P<0.05). For the brainstem sparing, HA plan performed better than Non-cop plan[(604.14±531.61) cGy vs.(682.75±558.22) cGy, P<0.05)]. For normal brain tissue sparing, HA approach showed significant reduction than conventional Cop and Non-cop VMAT (both P<0.05). For MU, HA approach (2 872.60 ± 566.93) was significantly lower than those of Non-cop VMAT (3 771.28 ± 1 022.38, P<0.05) and Cop VMAT (4 494.08 ± 1 323.09, P<0.05). In terms of plan complexity, the MCSv of Cop plan was the lowest, indicating that the complexity was the highest ( P<0.05). The AlPO of HA was significantly higher than that of Non-cop VMAT ( P<0.05), suggesting that the complexity of HA plan was lower ( P<0.05). Conclusion:For the treatment of brain metastases, HA provides better conformity, more rapid dose fall-off, better sparing of brainstem and normal brain tissues and less plan complexity compared with conventional VMAT.

Objective:To help clinicians simplify the post-processing operations of structures by developing rapid processing software for target area and organs at risk structures based on ESAPI.Methods:SmartStructure script software was developed based on ESAPI, verified and evaluated in clinical work. 10 cases of rectal cancer receiving neoadjuvant radiotherapy, 10 breast cancer treated with postoperative radiotherapy, 10 cervical cancer receiving postoperative radiotherapy, 10 nasopharyngeal carcinoma receiving radical radiotherapy and 10 lung stereotactic body radiotherapy (SBRT) were selected, and different types of tumors had different post-processing operations of structures. In each case, three methods were used for post-processing of structures. In the control group (manual group), normal manual processing was employed. In the experimental group 1(SmaStru-N group), scripts without templates were utilized. In the experimental group 2(SmaStru-P group). scripts combined with templates were adopted. The processing time of the three methods was compared. Clinicians scored the scripting software from multiple aspects and compared the feeling scores of scripting software and manual operation.Results:All three methods can be normally applied in clinical settings. The error rate in the manual group was 7.0%, 3.0% in the SmaStru-N group 0% in the SmaStru-P group, respectively. Compared with the manual method, SmaStru-N shortened the processing time of target area and organs at risk by 60.9% and 93.3% for SmaStru-P. In addition, SmartStructure was superior to manual method in terms of using feeling scores. Clinicians gave lower score for the" applicability" and" simplicity" , and higher score on the" accuracy" and" efficiency" .Conclusions:Compared with conventional manual structure processing method, SmartStructure software can rapidly and accurately process all structures of the target area and organs at risk, and its advantages become more obvious with the increasing number of structures that need to be processed. SmartStructure software can meet clinical requirements, reduce the error rate, elevate processing speed, improve the working efficiency of clinicians, providing basis for the development of adaptive radiotherapy.

Objective To screen the optimal dose of Tangtong Formula in vitro. Methods RSC96 Schwann Cells were cultivate by DMEM mediums which contains different concentrations of glucose (5–125 mmol/L). The prevention effects of Tangtong Formula at different concentrations (0.25, 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, 5.0 mg/mL) on the proliferation of RSC96 Schwann Cells induced by high glucose were detected. After the RSC96 Schwann Cells were cultivated in 100 mmol/L and 125 mmol/L high glucose mediums for 72 h, the apoptosis of RSC96 Schwann Cells was detected by flow cytometry Annexin V/PI, and the apoptosis rate was calculate; the proliferation situation of RSC96 Schwann cells in different times was detected by CCK-8 method. Results RSC96 Schwann cells were in apoptosis after being intervened by 100 mmol/L and 125 mmol/L high glucose mediums. The apoptosis rates were respectively(7.46±0.96)％ and(16.53±1.01)％, with statistical significance compared with control group (P<0.01). Different concentrations of Tangtong Formula could alleviate the inhibitory effect of high glucose on the proliferation of RSC96 Schwann cells, and the threshold concentration of Tangtong Formula in 24 h was 0.25 mg/mL. The concentrations of Tangtong Formula in 0.5 mg/mL, 1.0 mg/mL, and 1.5 mg/mL could inhibit the apoptosis of RSC96 Schwann cells induced by high glucos, compared with 125 mmol/L high glucose group, the apoptosis rate of RSC96 Schwann cells decreased significantly (P<0.05, P<0.01). Conclusion Among three different doses, when the dose of Tangtong Formula is in 1.5 mg/mL, the effects on inhibiting apoptosis are the best.