Objective To investigate the clinical value of sarcopenia in predicting the efficacy of bronchial artery chemoembolization(BACE)in patients with lung cancer.Methods The clinical data of 160 patients with lung cancer,who received BACE treatment at the Lishui Municipal Central Hospital of China from December 2012 to August 2021,were retrospectively analyzed.Using CT images to measure and calculate the skeletal muscle index(SMI)at the 4th thoracic vertebra(T4)level,patients with T4-SMI below the gender specific quartile were classified in sarcopenia group(n=40),and patients with T4-SMI above the threshold were classified in non-sarcopenia group(n=120).Kaplan-Meier method was used to compare the differences in progression-free survival(PFS)and overall survival(OS)between the two groups after BACE treatment,and Cox regression analysis was used to determine the risk factors affecting prognosis.Results In the non-sarcopenia group and the sarcopenia group,the median PFS was 5.6 months and 3.0 months respectively(x2=5.141,P=0.023),and the postoperative 14-month PFS rates were 16.7％and 5.0％respectively.There was no statistically significant difference in OS between the two groups(P＞0.05).Cox multivariate analysis showed that sarcopenia(HR=1.557,95％CI=1.083-2.238,P=0.017)was an independent risk factor for postoperative PFS after BACE.Conclusion Sarcopenia is an independent risk factor affecting the efficacy of BACE in patients with lung cancer,and sarcopenia can be used as a predictive indicator for the postoperative efficacy of BACE.

Objective:To compare the effects of different appointment regimens on the daily waiting time, fixedness of treatment time and lateness rate of radiotherapy patients.Methods:Medical records of 5488 radiotherapy from 332 patients on the same linear accelerator in West China Hospital of Sichuan University from March to June 2022 were selected. Based on the radiotherapy information integration platform of MOSAIQ, all patients were randomly assigned to the morning class, afternoon class and evening class. Traditional manual appointment regimen was adopted for the morning class, 30 min appointment regimen for the afternoon class, and 15 min appointment regimen for the evening class, respectively. The differences in patient waiting time for treatment, fixedness of treatment time, and lateness rate under different appointment regimens were compared. The fixedness of treatment time and waiting time was determined by one-way ANOVA, and the 2×3 Chi-square test was adopted for the lateness rate. Results:The waiting time in the 15 min appointment, the 30 min appointment and manual appointment groups were (27.08 ± 17.21), (34.57± 19.12) and (41.50 ±20.94) min, respectively. There was statistical significance among three appointment regimens ( F=254.97, P<0.001). The waiting time was the shortest in the 15 min appointment group, followed by the 30 min appointment group, and the manual appointment group (all P<0.001 for two-group comparison). The fixedness of treatment time in the 15 min appointment, the 30 min appointment and the manual appointment groups were (15.60±7.87), (18.69±8.94) and (24.30±15.10) min, respectively. There was statistical significance among three groups ( F=25.23, P<0.001). Among them, the fixedness of treatment time in the 15 min appointment group was the highest, followed by the 30 min appointment group, and the manual appointment group (all P<0.001). The lateness rates in the 15 min appointment, the 30 min appointment and the manual appointment groups were 5.7%, 6.2% and 9.6%, respectively. The lateness rate in the manual appointment group was higher than those in the 15 min appointment and the 30 min appointment groups ( χ2=19.24、14.90, both P<0.001), but there was no statistical significance in the lateness rate between the 15 min appointment and 30min appointment groups ( χ2=0.39, P=0.535). Conclusion:In the clinical practice of conventional intensity-modulated radiotherapy technology carried out by conventional linear accelerator, the 15 min appointment regimen can shorten the waiting time for radiotherapy and improve the fixedness of daily radiotherapy time, which is worthy of clinical promotion.

Objective:To compare the effects of different appointment regimens on the daily waiting time, fixedness of treatment time and lateness rate of radiotherapy patients.Methods:Medical records of 5488 radiotherapy from 332 patients on the same linear accelerator in West China Hospital of Sichuan University from March to June 2022 were selected. Based on the radiotherapy information integration platform of MOSAIQ, all patients were randomly assigned to the morning class, afternoon class and evening class. Traditional manual appointment regimen was adopted for the morning class, 30 min appointment regimen for the afternoon class, and 15 min appointment regimen for the evening class, respectively. The differences in patient waiting time for treatment, fixedness of treatment time, and lateness rate under different appointment regimens were compared. The fixedness of treatment time and waiting time was determined by one-way ANOVA, and the 2×3 Chi-square test was adopted for the lateness rate. Results:The waiting time in the 15 min appointment, the 30 min appointment and manual appointment groups were (27.08 ± 17.21), (34.57± 19.12) and (41.50 ±20.94) min, respectively. There was statistical significance among three appointment regimens ( F=254.97, P<0.001). The waiting time was the shortest in the 15 min appointment group, followed by the 30 min appointment group, and the manual appointment group (all P<0.001 for two-group comparison). The fixedness of treatment time in the 15 min appointment, the 30 min appointment and the manual appointment groups were (15.60±7.87), (18.69±8.94) and (24.30±15.10) min, respectively. There was statistical significance among three groups ( F=25.23, P<0.001). Among them, the fixedness of treatment time in the 15 min appointment group was the highest, followed by the 30 min appointment group, and the manual appointment group (all P<0.001). The lateness rates in the 15 min appointment, the 30 min appointment and the manual appointment groups were 5.7%, 6.2% and 9.6%, respectively. The lateness rate in the manual appointment group was higher than those in the 15 min appointment and the 30 min appointment groups ( χ2=19.24、14.90, both P<0.001), but there was no statistical significance in the lateness rate between the 15 min appointment and 30min appointment groups ( χ2=0.39, P=0.535). Conclusion:In the clinical practice of conventional intensity-modulated radiotherapy technology carried out by conventional linear accelerator, the 15 min appointment regimen can shorten the waiting time for radiotherapy and improve the fixedness of daily radiotherapy time, which is worthy of clinical promotion.

Objective:To evaluate the accuracy of the optical surface imaging system (OSI) using stereotactic radiosurgery (SRS) algorithm in single-center non-coplanar treatment of multiple brain metastases.Methods:Data of phantom and 15 patients with multiple brain metastases who underwent single-center non-coplanar radiotherapy in West China Hospital of Sichuan University from February to April 2022 were retrospectively analyzed. kV/MV and OSI imaging were used for imaging of the patients and phantoms under the same non-coplanar couch angle, respectively. The accuracy of OSI imaging of the phantoms and patients was evaluated using kV/MV imaging as reference image. The difference between the OSI and kV/MV systems is defined as accuracy, and the percentage of the absolute difference ≤1.00 mm in the translational direction or ≤0.50° in the rotational direction is defined as the threshold pass rate. Origin software was used to draw radar maps and Bland-Altman plots for statistical analysis.Results:When OSI images were used for the phantom imaging, the average differences in six-dimensional directions of lateral, long, vertical, rotational, roll and pitch were 0.03 mm, -0.09 mm, -0.27 mm, 0.04°, 0.17° and -0.19°, respectively. The maximum values were -2.20 mm, -2.30 mm, -1.20 mm, 0.60°, -1.00°, and -1.00°, respectively. When OSI system was utilized for the imaging of 15 patients, the average differences in six-dimensional directions were 0.44 mm, 0.16 mm, -0.20 mm, -0.11°, 0.10°, and -0.12°, respectively. The maximum values were -1.80 mm, 2.00 mm, 0.90 mm, -0.90°, -0.70°, and 0.80°, respectively. The translational errors mainly occurred in the lateral and long directions. The qualified rates of the threshold values of the phantoms and patients were 77% and 75% in the lateral direction, 82% and 89% in the long direction, respectively. In addition, 57% and 56% of patients met the threshold conditions of ±1.00 mm and ±0.50° in the six-dimensional directions, respectively.Conclusions:The OSI system using new SRS algorithm cannot meet the high accuracy requirements of single-center non-coplanar radiotherapy for multiple brain metastasis, especially in the lateral and long directions. It is not recommended for non-coplanar image guidance.

Objective:To investigate the dosimetric feasibility of cardiac stereotactic body radiotherapy (CSBRT) using volumetric-modulated arc radiotherapy (VMAT)-like technique on the Unity MR-linac.Methods:A retrospective analysis was conducted on 12 refractory arrhythmia patients who underwent CSBRT at West China Hospital, Sichuan University, from April 2021 to December 2022. Four different treatment plans were designed for each patient based on the average phase of 4DCT: VMAT plan based on a linear accelerator, VMAT-like plan with magnetic field based on Unity, VMAT-like plan without magnetic field based on a Unity, and static intensity-modulated radiation therapy (IMRT) plan with 7 beams based on Unity. The VMAT-like plans used static IMRT beams evenly distributed at 30 angles. Evaluation metrics included conformity index (CI), homogeneity index (HI), gradient index (GI), dosimetric parameters of organs at risk (OAR), optimization time, and monitor unit (MU). These metrics among groups were analyzed using the Wilcoxon paired signed-rank test.Results:The CI of the VMAT plan was better than that of the VMAT-like plan with magnetic field (0.84 vs. 0.81, P=0.005). The GI of the VMAT-like plan without magnetic field was significantly lower than that of VMAT-like plan with magnetic field ( P=0.015). The CI and HI of the IMRT plan were both inferior to VMAT-like plan with magnetic field ( P=0.034). The average dose to the heart and lungs in VMAT-like plan with magnetic field was higher than those in the VMAT plan and VMAT-like plan without magnetic field (both P<0.05). The magnetic field significantly increased the dose to the skin, tissue-lung interface, and outside the margins (all P<0.05). The optimization time of the VMAT-like plan with magnetic field was longer than that of the IMRT plan, but it required fewer MUs ( P=0.001). The quality of the IMRT plans was poor and did not meet clinical requirements. Conclusion:The quality of CSBRT plans based on VMAT-like techniques meets clinical requirements, but attention must be paid to the dosimetric effects of the magnetic field.

Objective:To evaluate the accuracy and stability of stereotactic radiosurgery (SRS) algorithm in optical surface imaging (OSI) system in non-coplanar radiotherapy.Methods:Three OSI imaging systems were used to measure the phantom repeatedly at different couch rotation angles to analyze the accuracy and stability of OSI system. Seven patients with multiple brain metastases who underwent single-center non-coplanar radiotherapy were randomly selected, and the accuracy and stability of OSI for patient imaging were analyzed. Stability is defined as the difference between the two OSI measurements when the couch is turned from 0° to a non 0° angle, and then back to 0°, using the 0° cone beam CT (CBCT) as the "gold standard". Accuracy is defined as the difference between OSI and CBCT (at 0° couch angle) measurement data. The measurement data with normal distribution were described as Mean ± SD. The data with non-normal distribution were expressed as M (Q). The difference of the former data was compared by one-way ANOVA, and the difference of the latter data was assessed by Kruskal-Wallis H nonparametric test. Results:For non-coplanarity, the translation accuracy of the phantom and the patient was ≤ 1.30 mm and ≤ 1.00 mm, and the rotation accuracy was ≤ 0.50° and ≤ 0.60°, respectively. The translation errors mainly occurred in the left-right and head-foot directions. In terms of stability, the maximum standard deviation of phantom coplanar translation and rotation was 0.06 mm and 0.06°. The maximum standard deviation of patient translation and rotation was 0.17 mm and 0.19°.Conclusions:Although the new SRS algorithm improves the non-coplanar accuracy, it still cannot meet the precise requirements of non-coplanar single isocenter radiotherapy for multiple brain metastases, especially in the left-right and head-foot directions. When the couch rotation angle is large, OSI is not recommended for image-guided radiotherapy. However, its high stability can be used to monitor the intrafractional motion of patients.

Objective:To retrospectively analyze the setup errors of thermoplastic head and shoulder molds alone or combined with vacuum pad in hypofractionated stereotactic radiotherapy (HFSRT) for non-small cell lung cancer (NSCLC) with brain metastases.Methods:Fifty-four NSCLC patients with brain metastases who received HFSRT from 2017 to 2019 were enrolled in this study. Twenty-four patients were fixed with thermoplastic head and shoulder molds (group A), and 30 patients were fixed with thermoplastic head and shoulder molds plus vacuum pad (group B). The interfraction and intrafraction setup errors were acquired from cone-beam CT online image registration before and after the HFSRT. Optical surface system was applied in monitoring the intrafraction setup errors. The setup errors in each direction between two groups were analyzed by independent samples t-test. Results:For the interfraction setup errors of the whole group, the proportion of the horizontal setup errors of ≥3mm was 7.0% to 15.4% and 7.0% to 12.6% for the rotation setup errors of ≥2°. In group A, the anteroposterior setup error was (1.035±1.180)mm, significantly less than (1.512±0.955)mm in group B ( P=0.009). In group A, the sagittal rotation setup error was 0.665°±0.582°, significantly less than 0.921°±0.682° in group B ( P=0.021). For the intrafraction setup errors of the whole group, the proportion of horizontal setup errors of ≥1mm was 0% to 0.7%, whereas no rotation setup error of ≥1° were observed. In group B, bilateral, anteroposterior and sagittal rotation setup errors were (0.047±0.212)mm, (0.023±0.152)mm and 0.091°±0.090°, significantly less compared with (0.246±0.474)mm, (0.140±0.350)mm and 0.181°±0.210° in group A ( P=0.004, P=0.020, P=0.001), respectively. Optical surface monitoring data were consistent with the obtained results. Conclusions:Thermoplastic head and shoulder molds (with or without vacuum pad) combined with online image registration and six-dimensional robotic couch correction can be applied in HFSRT for brain metastases from NSCLC. The intrafraction setup errors in group B are smaller than those in group A. Optical surface system has certain value in monitoring the intrafractional movement.

In order to adapt to different target shapes and protect the surrounding normal tissues, the design of two-dimensional electron beam radiotherapy planning requires additional lead blocks. But the Pinnacle treatment planning system can not directly shape the lead block conformity to the size of the beam field given by the doctor. Every time, physicists need to manually drag the lead block to form the required beam field. When meeting a two-dimensional electron beam treatment planning with the same field parameters as before, physicists need to rearrange the field for dose calculation, which greatly reduces the design efficiency of the two-dimensional electron beam treatment planning. In this study, we independently developed a two-dimensional electron beam radiotherapy planning system based on Qt Creator. The system can quickly design a two-dimensional electron beam radiotherapy plan, which reduces the repeated work of physicists.
Electrons ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted