Objective:To compare the dosimetric parameters under different incremental modes between intensity-modulated radiation therapy(IMRT)and volume rotation intensity-modulated therapy(VMAT)for the target area of large volume brain metastases(BMs),and to explore the better way of treating BMs based on hypofractionated stereotactic radiotherapy(HSRT)of linear accelerator.Methods:A total of 30 BMs patients who underwent IMRT at The 971th Hospital of Navy of the CPLA from 2020 to 2023 were selected.In the treatment planning system(TPS),three types of IMRT plans and VMAT plans were designed,which included uniformity plan(Planuniformity)of target area dose,uniform increased plan(Planuniform increased-dose)and incremental plan(Planincremental)within target area.In the inside of the target area,the target area of high dose(GTVh)was set,and Planuniform increased-dose and Planincremental were designed to aim at GTVh.The differences of the doses of three types of treatment plans included Planuniformity,Planuniform increased-dose and Planincremental,which were respectively designed by using IMRT and VMAT,were analyzed.The mean dose(Dmean)of the target area,the 50%and 2%exposed doses(D50%and D2%)of the target area were observed and compared.The conformity index(CI),homogeneity index(HI),gradient index(GI),and the volume percentage(V10 Gy-V40 Gy)that normal brain tissue received 10 Gy-40 Gy also were observed and compared.Results:Compared with Planuniformity of IMRT,the Dmean of GTV of Planuniform increased-dose and Planincremental of IMRT increased by 10.13%and 17.9%,with statistically significant differences(t=13.680,12.771,P＜0.05).D50%increased by 8.9%and 10.8%,with statistically significant differences(t=15.190,9.929,P＜0.05).D2%increased by 15.2%and 46.4%,with statistically significant differences(t=52.320,8.746,P＜0.05).There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of IMRT(P＞0.05).Compared with Planuniformity of VMAT,the Dmean of GTV of Planuniform increased-dose and Planincremental of VMAT increased by 10.53%and 21.23%,with statistically significant differences(t=18.641,15.461,P＜0.05),and D50%increased by 9.1%and 13.4%,with statistically significant differences(t=11.382,10.952,P＜0.05),and D2%increased by 16.4%and 48.8%,with statistically significant differences(t=56.471,8.685,P＜0.05),respectively.There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of VMAT(P＞0.05).The normal brain tissue V20 Gy,V30 Gy and V40 Gy of Planuniform increased-dose and Planincremental of IMRT were respectively less than those of VMAT,and the differences of them between IMRT and VMAT were significant(tPlan uniform increased-dose=2.112,2.215,2.444,tPlan incremental=2.323,2.939,3.145,P＜0.05).There were no statistically significant difference in D2%,Dmean,and D50%between IMRT and VMAT(P＞0.05).Conclusion:On the premise of ensuring the safety of normal brain tissue at the edge of the target area,the synchronously increasing of the central dose of the target area will not significantly increase the dose for normal brain tissue.Both IMRT and VMAT can meet the requirements of increment in the inside of the target area,and VMAT has slightly better increment and higher efficiency within target area.The incremental of VMAT target area is slightly better,which also has better efficiency,while the enhancement effect of the dose of target area of Planincremental is better than that of the Planuniform increased-dose.The Plan incremental of VMAT is more suitable for HSRT treatment for BMs.

Objective:To compare the dosimetric parameters under different incremental modes between intensity-modulated radiation therapy(IMRT)and volume rotation intensity-modulated therapy(VMAT)for the target area of large volume brain metastases(BMs),and to explore the better way of treating BMs based on hypofractionated stereotactic radiotherapy(HSRT)of linear accelerator.Methods:A total of 30 BMs patients who underwent IMRT at The 971th Hospital of Navy of the CPLA from 2020 to 2023 were selected.In the treatment planning system(TPS),three types of IMRT plans and VMAT plans were designed,which included uniformity plan(Planuniformity)of target area dose,uniform increased plan(Planuniform increased-dose)and incremental plan(Planincremental)within target area.In the inside of the target area,the target area of high dose(GTVh)was set,and Planuniform increased-dose and Planincremental were designed to aim at GTVh.The differences of the doses of three types of treatment plans included Planuniformity,Planuniform increased-dose and Planincremental,which were respectively designed by using IMRT and VMAT,were analyzed.The mean dose(Dmean)of the target area,the 50%and 2%exposed doses(D50%and D2%)of the target area were observed and compared.The conformity index(CI),homogeneity index(HI),gradient index(GI),and the volume percentage(V10 Gy-V40 Gy)that normal brain tissue received 10 Gy-40 Gy also were observed and compared.Results:Compared with Planuniformity of IMRT,the Dmean of GTV of Planuniform increased-dose and Planincremental of IMRT increased by 10.13%and 17.9%,with statistically significant differences(t=13.680,12.771,P＜0.05).D50%increased by 8.9%and 10.8%,with statistically significant differences(t=15.190,9.929,P＜0.05).D2%increased by 15.2%and 46.4%,with statistically significant differences(t=52.320,8.746,P＜0.05).There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of IMRT(P＞0.05).Compared with Planuniformity of VMAT,the Dmean of GTV of Planuniform increased-dose and Planincremental of VMAT increased by 10.53%and 21.23%,with statistically significant differences(t=18.641,15.461,P＜0.05),and D50%increased by 9.1%and 13.4%,with statistically significant differences(t=11.382,10.952,P＜0.05),and D2%increased by 16.4%and 48.8%,with statistically significant differences(t=56.471,8.685,P＜0.05),respectively.There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of VMAT(P＞0.05).The normal brain tissue V20 Gy,V30 Gy and V40 Gy of Planuniform increased-dose and Planincremental of IMRT were respectively less than those of VMAT,and the differences of them between IMRT and VMAT were significant(tPlan uniform increased-dose=2.112,2.215,2.444,tPlan incremental=2.323,2.939,3.145,P＜0.05).There were no statistically significant difference in D2%,Dmean,and D50%between IMRT and VMAT(P＞0.05).Conclusion:On the premise of ensuring the safety of normal brain tissue at the edge of the target area,the synchronously increasing of the central dose of the target area will not significantly increase the dose for normal brain tissue.Both IMRT and VMAT can meet the requirements of increment in the inside of the target area,and VMAT has slightly better increment and higher efficiency within target area.The incremental of VMAT target area is slightly better,which also has better efficiency,while the enhancement effect of the dose of target area of Planincremental is better than that of the Planuniform increased-dose.The Plan incremental of VMAT is more suitable for HSRT treatment for BMs.

Objective:To compare and study the improvement of different iterative reconstruction(IR)algorithms of the tomotherapy(TOMO)Radixact system on the image quality of megavoltage computed tomography(MVCT)imaging system,and the influence of that on the precision of automatic registration,and to explore the reconstruction algorithm that is suitable for clinical application.Methods:Using the MVCT imaging system to respectively scan the Tomo-Phantom HE phantom and the Catphan 604 phantom,and to analyze three groups of images were generated by three kinds of reconstruction algorithms,which included the Standard(STD)algorithm,IR General(IR-G)algorithm and IR Soft Tissue(IR-ST)algorithm,in MVCT image.The noise index(NI),uniformity index(UI)of image,modulation transfer function(MTF),low contrast visibility(LCV)index and contrast-to-noise ratio(CNR)of three groups of images were calculated respectively.The Lucy phantom was used to test the accuracy of automatic registration algorithm.The registration data of four dimensions,included left-right(X-axis),head-foot(Y-axis),vertical(Z-axis)and free rotation(Roll)around the Y-axis,were used to conduct verification analysis for the influences of them on the precision of automatic registration.Results:The NI values of IR-G and IR-ST reconstruction algorithms were respectively 39.58±0.10 and 14.62±0.26,which were better than 39.58±0.10 of STD algorithm,and the UI values of them were respectively 19.87±0.83 and 15.84±2.51,which were better than 24.51±1.81 of STD algorithm,and LCV values of them were respectively 2.50±0.03 and 1.74±0.11,which were better than 3.67±0.04 of STD algorithm.All of them appeared significant increase,but the resolution with high contrast of MTF were respectively 0.23 and 0.21,which were lower than 0.32 of STD.The overall image quality of the IR algorithms was superior to that of the STD algorithm.In the accuracy test of the automatic registration algorithm,the registration precisions of IR-G and IR-ST algorithms on Y-axis were respectively(0.360±0.142)mm and(0.245±0.050)mm,which were significantly higher than 0.145±0.136 of STD algorithm,and the differences of them were significant(Z=6.0,15.0,P<0.05).The differences of registration precisions of other directions were not significant(P>0.05).Conclusion:The IR algorithm has advantages in terms of noise,uniformity and resolution with low-contrast,however,it shows reduction on resolution with high-contrast.This reduction of resolution with high-contrast do not lead to the decrease of the precision of automatic registration.

Objective:A dose verification system of two-dimensional semiconductor matrix(SRS MapCHECK)was used to verify the dose of the clinical treatment plan of patients who underwent CyberKnife(CK),which realized rapid verification for individualization of radiotherapy plans of patients through analyzed the γ-passing rates of them.Methods:A total of 253 patients with tumor who received CK clinical treatment in the First Medical Center of Chinese PLA General Hospital from March 2021 to May 2023 were selected.Among of them,121 cases received CK treatment on head,and 30 cases received that on lung,and 102 cases received CK treatment on abdomen and other metastatic tumor.In the MultiPlan treatment plan system,the plan of patient was mapped to the integrated model composed of StereoPHAN model and SRS MapCHECK matrix dose verification system by the means of the plan image center overlap.The dose verification was conducted on the plan of each patient on the basis of ensuring the consistency of the number of beam,direction of beam and the monitor unit.The different γ analysis standards(1%/1 mm,2%/1 mm,3%/1 mm,1%/2 mm,2%/2 mm,3%/2 mm,1%/3 mm,2%/3 mm and 3%/3 mm)were adopted to conduct global analysis of absolute dose for each verification plan,and the threshold(TH)of low dose was set as 10%.Results:The γ passing rates of phantom verification plans of 253 patients were respectively(88.64±5.91)%,(95.43±3.40)%,(97.90±2.06)%,(96.51±2.35)%,(98.15±1.68)%,(99.06±1.12)%,(98.30±1.39)%,(99.09±0.97)%and(99.52±0.63)%under different analysis standards.The γ passing rates of other standards of patients with tumor on different parts were larger than 95%except the analysis result of 1%1 mm standard.The overall analysis result of the deviation of central point dose was(-1.30±2.17)%,among of which the tumor of head,abdominal tumors and other metastatic tumor were about approximately-2%,while that of lung tumors were approximately-3%.The deviation of abdominal and other metastatic tumor was the minimum.The correlation analysis showed that the target volume and the size of the minimum collimator were respectively correlated to the dose deviation of the center.Conclusion:SRS MapCHECK dose verification system can conveniently and quickly realize the individualized verification for the plan of patients who receive CK treatment.

Objective:To quantitatively analyze the differences in image quality and generated synthetic-computed tomography(sCT)between cone beam CT(CBCT)and iteration CBCT(iCBCT),which based on filtered back projection(FBP)and iterative reconstruction(IR)techniques of Varian Ethos adaption system.Methods:Using the special Catphan604 phantom of the test of CT image quality,five times of scanning series of CBCT and iCBCT were respectively performed based on thoracic and abdominal scanning protocols,so as to obtain four sets of images,and each set of image included the CBCT image,the composited sCT and iCBCT images based on CBCT,the composited sCT bases on iCBCT.The noise power spectrum(NPS),image uniformity(UI),modulation transfer function(MTF),low-contrast visibility(LCV)and contrast-to-noise ratio(CNR)of them were analyzed.Additionally,a retrospective analysis was conducted on images of six patients who underwent clinical radiotherapy,and the images of them were obtained by using thoracic and abdominal scanning protocols.The sCT images,which were generated by deformable registrations on the basis of CBCT and iCBCT,were analyzed,and they were compared with located CT images,and their mean absolute error(MAE)and root mean square error(RMSE)were further quantitatively analyzed.Results:Compared to CBCT,iCBCT significantly reduced NPS(thoracic images reduced by 0.08,abdominal images reduced by 0.06).The UI values of thoracic images and abdominal images of iCBCT were respectively 0.37 and 0.28,and those of CBCT were respectively 0.65 and 0.39.The LCV values of thoracic images and abdominal images of iCBCT were respectively 0.67 and 0.56,and those of CBCT were respectively 0.93 and 0.90.The MTF50％were 0.28 lp/mm except abdominal image of iCBCT was 0.29 lp/mm.The resolution rate of high contrast between iCBCT and CBCT was basic consistency.The differences of similarity analysis of the generated sCT and located CT bases on CBCT and iCBCT was no significant(P＞0.05).Conclusion:The image quality of iCBCT is superior to conventional CBCT.The accuracy of CT value of generated sCT bases on CBCT and iCBCT can meet requirement,and both of them can be used in the dose calculation of adaptive radiotherapy.

Objective:To evaluate the dosimetric characteristics, safety and effectiveness of magnetic resonance-guided fractionated stereotactic radiotherapy (FSRT) for brain tumors.Methods:Clinical data of 8 brain tumor patients treated with magnetic resonance-guided FSRT in the Radiotherapy Department of the First Medical Center of the PLA General Hospital from July 2023 to February 2024 were retrospectively analyzed. Online adaptive radiotherapy was adopted for all patients. Adapt-to-position (ATP) or adapt-to-shape (ATS) radiotherapy was chosen by radiologists. Each adaptation was initiated after the radiotherapy plan was re-examined. The radiotherapy fractionation plan was 21-30 Gy/3-5 F. Clinical characteristics, radiotherapy plans and plan parameters were analyzed by statistical description. Median ( Q1， Q3) was used to describe continuous data and percentage was used to describe categorical data. Results:In this study, 9 lesions were treated a total of 41 times, including 20 times (49%) of ATP plan and 21 times (51%) of ATS plan. The median target area coverage rate was 95.1% (95%, 99.8%), the median target area maximum dose rate was 1.15 (1.07, 1.31), the median conformity index (CI) was 0.75 (0.69, 0.86), the median homogeneity index (HI) was 1.09 (1.06, 1.21), and the median gradient index (GI) was 4.73 (3.36, 8.45), respectively. After ATS plan, the median reduction in gross target volume (GTV) was 8.22 cm3 (1.2, 10.1 cm3), and the median reduction in brain tissue V12 Gy was 30.46 cm3 (8.34, 31.13 cm3).The median follow-up was 3.2 months (1.4, 6.1 months). No radiation necrosis was found in any patient. There were 2 cases of acute brain edema during radiotherapy (both were mild). Except for 1 case who died due to systemic disease progression, the remaining patients had no local recurrence, and achieved good quality of life. Conclusions:The parameters of the treatment plan of magnetic resonance-guided FSRT are generally acceptable. The adaptive plan can effectively reduce the dose of normal brain tissues. It is safe and feasible to use the magnetic resonance-guided FSRT for brain tumors.

Objective:To evaluate the efficacy and safety of oral anisodine hydrobromide tablets in the treatment of nonarteritic anterior ischemic optic neuropathy (NAION).Methods:A multicenter nonrandomized controlled trial was conducted.A total of 282 acute NAION patients (282 eyes) were recruited from 16 hospitals in China from July 2020 to May 2021.Patients were divided into two groups according to treatment methods, which were control group (124 cases, 124 eyes) receiving regular treatment including citicoline sodium plus Ginkgo biloba leaf liquid extract or Ginkgo biloba leaf extract tablets plus mecobalamin, and experimental group (158 cases, 158 eyes) receiving treatment in control group plus oral anisodine hydrobromide tablets 1 mg, twice daily for 2 to 3 months.Best corrected visual acuity (BCVA), visual field index (VFI), peripapillary retinal nerve fiber layer (pRNFL) and radial peripapillary capillary vessel density (RPC) were assessed at 1, 2, 3, and 6 months after enrollment using the standard decimal visual acuity chart, 750i Humphery visual field analyzer, Cirrus HD-OCT 4000/Cirrus HD-OCT 5000, RTVue-XR optical coherence tomography respectively.The primary outcomes were BCVA and VFI, and the secondary outcomes were pRNFL, RPC, and the side effects during the follow-up.The study adhered to the Declaration of Helsinki.All patients were fully informed about the treatment and purpose of this study and voluntarily signed the informed consent form.The study protocol was approved by Chinese PLA General Hospital (No.S2020-021-01). Results:In all, 242 patients (242 eyes) completed the follow-up of BCVA, and 98 patients (98 eyes) completed the VFI follow-up.In terms of visual function, BCVA and VFI improved significantly over time in the two groups, and BCVA and VFI were better in experimental group than in control group at various follow-up time points (all at P<0.05). In terms of structure, pRNFL gradually decreased in both groups with the extension of treatment, and pRNFL was significanthy thinner in experimental group than in control group at various follow-up time points (all at P<0.05). There was no significant difference in RPC between the two groups at the last follow-up ( P>0.05). There were two cases with side effects and one case was discontinued due to side effects 25 days after enrollment. Conclusions:Oral anisodine hydrobromide can improve visual acuity and visual field in NAION and accelerate the regression of optic disc edema, with good safety.

Ferroptosis is a form of regulated cell death, characterized by excessive membrane lipid peroxidation in an iron- and ROS-dependent manner. Celastrol, a natural bioactive triterpenoid extracted from Tripterygium wilfordii, shows effective anti-fibrotic and anti-inflammatory activities in multiple hepatic diseases. However, the exact molecular mechanisms of action and the direct protein targets of celastrol in the treatment of liver fibrosis remain largely elusive. Here, we discover that celastrol exerts anti-fibrotic effects via promoting the production of reactive oxygen species (ROS) and inducing ferroptosis in activated hepatic stellate cells (HSCs). By using activity-based protein profiling (ABPP) in combination with bio-orthogonal click chemistry reaction and cellular thermal shift assay (CETSA), we show that celastrol directly binds to peroxiredoxins (PRDXs), including PRDX1, PRDX2, PRDX4 and PRDX6, through the active cysteine sites, and inhibits their anti-oxidant activities. Celastrol also targets to heme oxygenase 1 (HO-1) and upregulates its expression in activated-HSCs. Knockdown of PRDX1, PRDX2, PRDX4, PRDX6 or HO-1 in HSCs, to varying extent, elevated cellular ROS levels and induced ferroptosis. Taken together, our findings reveal the direct protein targets and molecular mechanisms via which celastrol ameliorates hepatic fibrosis, thus supporting the further development of celastrol as a promising therapeutic agent for liver fibrosis.

Objective:To summarize and evaluate the target and dose design of 125I seed brachytherapy treatment plan of pediatric borderline tumor in head neck region. Methods:Eleven patients underwent definitive 125I brachytherapy or combined with surgery in Peking University Hospital of Stomatology from January 2010 to December 2018 were retrospective analyzed. The target region was set by extending the tumor gross region by 0.5 to 1.0 cm. The prescription dose and activity ranged from 80 to 120 Gy and 18.5 MBq, respectively. The treatments were performed according to the plan under general anesthesia. Response and toxic reaction were recorded during follow-up. The preoperative and postoperative dosimetric results were compared; and the local control rate, objective response rate, complete response rate and acute toxic reaction rate were calculated. Results:There was no statistically significant difference between preoperative and postoperative dosimetric results ( P>0.05). The follow-up time ranged from 33 to 131 months, with a median of 48 months. The local control rate, objective response rate, complete response rate and acute toxic reaction rate were 100%, 100%, 71.4% and 81.8%, respectively. Conclusions:Under well-designed target and dose, 125I brachytherapy for treatment of pediatric borderline tumor in head neck region would bring ideal therapeutic and toxic outcomes, and could be regarded as a feasible therapy.

Hepatic stellate cells(HSCs)are essential drivers of fibrogenesis.Inducing activated-HSC apoptosis is a promising strategy for treating hepatic fibrosis.18beta-glycyrrhetinic acid(18β-GA)is a natural com-pound that exists widely in herbal medicines,such as Glycyrrhiza uralensis Fisch,which is used for treating multiple liver diseases,especially in Asia.In the present study,we demonstrated that 18β-GA decreased hepatic fibrosis by inducing the apoptosis in activated HSCs.18β-GA inhibited the expression of α-smooth muscle actin and collagen type Ⅰ alpha-1.Using a chemoproteomic approach derived from activity-based protein profiling,together with cellular thermal shift assay and surface plasmon reso-nance,we found that 18β-GA covalently targeted peroxiredoxin 1(PRDX1)and peroxiredoxin 2(PRDX2)proteins via binding to active cysteine residues and thereby inhibited their enzymatic activities.18β-GA induced the elevation of reactive oxygen species(ROS),resulting in the apoptosis of activated HSCs.PRDX1 knockdown also led to ROS-mediated apoptosis in activated HSCs.Collectively,our findings revealed the target proteins and molecular mechanisms of 18β-GA in ameliorating hepatic fibrosis,highlighting the future development of 18β-GA as a novel therapeutic drug for hepatic fibrosis.