1.Analysis of beam characteristics of the first Mevion pencil beam scanning proton therapy system in China
Weiqing WU ; Xiaoguang LU ; Renchao ZHENG ; Zhiyi PENG ; Fei LIU ; Guangyuan HU ; Xianglin YUAN
Chinese Journal of Medical Physics 2024;41(3):282-288
Objective To present and discuss beam characteristics of the first Mevion S250i gantry-mounted accelerator pencil beam scanning proton therapy system in China.Methods The output dose was measured using a parallel-plate ionization chamber.The integrated depth dose was measured with a large-radius Bragg peak ionization chamber,covering 19 energy levels ranging from 227 MeV to 28 MeV,to analyze the proton beam characteristics.The spots in the air were measured with Phoenix flat panel detector on the beam central axis,and the precision of the delivery position was verified by measuring the multi-spot beam map.The interleaf leakage and penumbra reduction of adaptive aperture were measured to characterize its performance.Results The proton system was calibrated for a maximum energy of 227 MeV,with a(10×10)cm2uniform field delivering 1 Gy dose at a depth of 5 cm underwater.The system effectively modulated the proton beam range to the patient's surface,maintaining a constant 80%-80%Bragg peak width of 8.6 mm at all energy levels.The spot size of the highest energy beam at the isocenter was about 4 mm in the air,and the spot delivery position error was less than 1 mm.The interleaf leakage rate of the adaptive aperture for the highest energy beam was below 1.5%,and the penumbra was significantly reduced.Conclusion Mevion S250i proton therapy system demonstrates unique design and beam characteristics,which is reflected in the Bragg peak shape,spot size variation with energy,and penumbra sharpening of adaptive aperture;and these differences should be considered in treatment planning system modeling and planning for precision treatment.
2.Application of adaptive aperture in proton radiotherapy for brain tumors
Weiqing WU ; Xianglin YUAN ; Guangyuan HU ; Renchao ZHENG ; Qianxia LI ; Fei LIU ; Xiaoguang LU
Chinese Journal of Radiological Medicine and Protection 2024;44(1):24-28
Objective:To evaluate the clinical application value of the adaptive aperture by comparing intensity-modulated proton radiotherapy(IMPT) plans using and not using the aperture for brain tumors.Methods:A total of twenty patients treated with postoperative radiotherapy for brain tumors were enrolled in this study. IMPT plans were developed for each patient using and not using the adaptive aperture under the same optimization conditions. The target conformal index (CI) value, target homogeneity index (HI) value, and the dose to normal tissues of the two sets of plans were compared.Results:The IMPT plans designed using the adaptive aperture significantly increased the mean CI value from 0.58 to 0.66, while decreasing the mean 50% prescription dose volume from 797.70 cm 3 to 638.15 cm 3. These plans also reduced the irradiation doses to the cochlea, brainstem, optic chiasm, optic nerve, and lens ( t = 2.06, 3.02, 2.11, 2.58, 2.67, P < 0.05). Additionally, there was no significant difference in the HI value of the target volumes and the machine jumps (MU) between the two sets of plans ( P > 0.05). Conclusions:The adaptive aperture can significantly reduce the irradiation dose to normal tissues outside the target volumes, positively impacting the protection of organs at risk (OARs) around the target values. This demonstrates its great potential for clinical application.
3.Application of rapid daily quality assurance for pencil beam scanning proton therapy system
Renchao ZHENG ; Xiaoguang LU ; Weiqing WU ; Zhiping XIAO ; Fei LIU ; Guangyuan HU ; Xianglin YUAN
Chinese Journal of Medical Physics 2024;41(10):1206-1210
Objective To analyze the daily quality assurance(QA)measurement results of IBA Sphinx Compact device on the Mevion compact pencil beam scanning proton therapy system for evaluating its clinical application value in proton therapy.Methods The daily QA measurement of Mevion S250i proton therapy system was carried out with Sphinx Compact device for 30 consecutive days,and the measurement results were analyzed.Results The average deviation between the positioning laser and the image center was(0.42±0.27)mm in 30 days.All of the proximal and distal depth errors of the high-and low-energy pencil beams were within 0.50 mm.The position deviation of all the spots measured did not exceed 1.00 mm,and the size deviation was less than 7.5%.The deviation between the image center and the beam center was not more than 0.75 mm.The relative deviation of the flatness of the rectangular field was about 0.5%.The deviation of the output dose of the square field was within 1.0%.Conclusion The proton system daily QA measurement items recommended by AAPM TG-224 report can be accurately and rapidly measured with Sphinx Compact device.The device is a practical and efficient daily QA tool with high practical value in clinic.
4.Acceptance test of beam performance and mechanical precision of the first Mevion type S250i proton therapy system in China
Weiqing WU ; Xiaoguang LU ; Renchao ZHENG ; Fei LIU ; Guangyuan HU ; Xianglin YUAN
China Medical Equipment 2024;21(9):13-17
Objective:To discuss the acceptance test of beam performance and mechanical precision of the first Mevion type S250i proton therapy system in China,and verify the stability and reliability of that in clinical treatment.Methods:According to the requirements of acceptance report of manufacturer,the output and range of machine unit(MU),the accuracy and stability of size and position of beam spot,the penumbra and position accuracy of adaptive aperture(AA)of Mevion type S250i proton therapy system,as well as the tests of mechanical properties and functions of the requirement of clinical use,were checked and tested for acceptance.Results:The maximum deviation of MU output was 1.3%,and the maximum deviation of the range was 0.037 g/cm2,and the maximum distal fall-off was 0.465 cm,and the minimum range of energy modulation was 0.21 g/cm2.The maximum deviations of the size of beam spot and the maximum deviation of the position were respectively 0.07 cm and 0.05 cm.The maximum AA penumbra was 0.007 cm,and the AA position accuracy was less than 0.1 cm.Conclusion:The acceptance test of the Mevion type S250i proton therapy system indicates that the parameters of the beam performance and mechanical precision can meet the requirements of the acceptance contract and AAPM-TG224 report of manufacturer,which has verified the machine has better favorable stability and reliability.
5.Measurements and assessment of radiation levels at the radiotherapy site of the first domestic single-vault proton therapy system
Renchao ZHENG ; Xiangjun YANG ; Xiaoguang LU ; Weiqing WU ; Zhiyi PENG ; Guangyuan HU ; Xianglin YUAN
Chinese Journal of Radiological Medicine and Protection 2024;44(10):879-885
Objective:To measure and assess relevant radiation doses at the radiotherapy site of the first domestic single-vault proton therapy system.Methods:The radiation levels of the therapy system during and after beam irradiation were measured, and annual effective doses were assessed for personnel at the site.Results:During beam irradiation, the highest radiation dose was detected at the shielded door of the equipment floor, with a gamma radiation level of 2.140 μSv/h and a neutron radiation level of 0.850 μSv/h. Neutron radiation disappeared immediately once the beams stopped. In contrast, the radiation activated originated mostly from gamma rays. A longer time after beams stopped was associated with lower induced radiation intensity at the same location. Furthermore, a farther distance from the irradiated object corresponded to lower induced radiation intensity at the same time. The assessment result reveal that the annual effective doses to the personnel were at the safe level, with physicists exposed to the highest dose of 2.138 mSv.Conclusions:The radiation level at the studied proton therapy site meets the safety requirement, and the treatment can be performed safely at this site.
6.The calibration of CT modeling for proton therapy treatment planning system
Renchao ZHENG ; Xiaoguang LU ; Weiqing WU ; Zu'an ZHENG ; Zhiping XIAO ; Junchao LI ; Xianglin YUAN
Chinese Journal of Radiation Oncology 2024;33(10):935-941
Objective:To verify and calibrate the CT modeling curves of three CT devices in RayStation proton treatment planning system (TPS).Methods:CT-mass density (CT-MD) curves were established by CT Hounsfield units of different tissue substitute materials obtained by scanning the model with CT equipment. CT-stopping power (CT-SP) curves were established by calculation based on the chemical composition of various human tissues. The equivalent water thickness of tissue substitute modules was calculated with different CT modeling curves in TPS. The actual equivalent water thickness of various modules was measured by a Bragg peak detector, and compared with the calculated values of TPS to verify the accuracy of different CT models.Results:The differences of CT modeling curves were significantly different under different tube voltage scanning protocols. Compared with CT-MD curves, CT-SP curves based on the stoichiometric calibration were more suitable for proton dose calculation. However, the values of stopping power corresponding to high CT values still needed to be optimized, and the calculation error after calibration was less than 3%.Conclusion:The method of verifying and calibrating CT unit curves of proton TPS is described, proving that the CT-SP curves after stoichiometric calculation are more suitable for proton dose calculation.
7.Safety and efficacy of enteromorpha prolifera enzymatic hydrolysate in improving scalp sensitive symptoms
Xi SUN ; Yu YU ; Xuyan QIN ; Xiaojie LENG ; Weiqing ZHENG
Chinese Journal of Medical Aesthetics and Cosmetology 2024;30(6):541-546
Objective:To evaluate the safety and efficacy of enteromorpha prolifera enzymatic hydrolysate in alleviating scalp sensitive symptoms.Methods:The inhibitory effects of different concentrations of enteromorpha prolifera hydrolysate on tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-6, and other inflammatory factors were observed through in vitro experiments. Subsequently, the abilities to scavenge [2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) and to promote proliferation of mouse fibroblasts were evaluated. A prospective study was conducted on 20 patients with scalp sensitivity at Qingdao Hiser Hospital Affiliated to Qingdao University from April 2023 to October 2023. The patients included 2 males and 18 females with an average age of (34.9±10.3) years. They were treated with a scalp essence containing 10% enteromorpha enzymatic hydrolysate for consecutive 28 days. Changes in scalp cuticle water content, transepidermal water loss (TEWL), and oil content were measured before and after 14 and 28 days of treatment. Expert interviewers assessed the skin irritation test to elucidate any undesirable side effects.Results:The results of in vitro experiments demonstrated that enteromorpha protophora enzymatic hydrolysate at different concentrations exhibited inhibitory effects on the expression of IL-1α, IL-6, and TNF-α, while it also displayed a dose-dependent ability to scavenge ABTS free radicals. Furthermore, it effectively promoted the proliferation of mouse fibroblasts, resulting in a significant increase of 43.22% in fibroblast viability when the concentration of enteromorpha protophora enzymatic hydrolysate was 0.10%. The outcomes from clinical trials revealed that after using a scalp essence containing enteromorpha protophora enzymatic hydrolysate for 14 and 28 days, there were significant improvements observed in terms of increased water content in the scalp epidermis, along with decreased oil content and TEWL value (all P< 0.001). Moreover, remarkable effective rates were achieved for treating various scalp conditions including redness (80.0%, 16/20), dandruff (80.0%, 16/20), itching (85.0%, 17/20), stinging sensation (90.0%, 18/20), and tightness (80.0%, 16/20) after using the scalp essence for 28 days. Adverse effects on the skin were not observed in any subject during the test period. Conclusions:The enzymatic hydrolysate of enteromorpha demonstrates both safety and efficacy in alleviating symptoms associated with scalp sensitivity.
8.Dissecting Causal Relationships Between Gut Microbiota, Blood Metabolites, and Stroke: A Mendelian Randomization Study
Qi WANG ; Huajie DAI ; Tianzhichao HOU ; Yanan HOU ; Tiange WANG ; Hong LIN ; Zhiyun ZHAO ; Mian LI ; Ruizhi ZHENG ; Shuangyuan WANG ; Jieli LU ; Yu XU ; Ruixin LIU ; Guang NING ; Weiqing WANG ; Yufang BI ; Jie ZHENG ; Min XU
Journal of Stroke 2023;25(3):350-360
Background:
and Purpose We investigated the causal relationships between the gut microbiota (GM), stroke, and potential metabolite mediators using Mendelian randomization (MR).
Methods:
We leveraged the summary statistics of GM (n=18,340 in the MiBioGen consortium), blood metabolites (n=115,078 in the UK Biobank), and stroke (cases n=60,176 and controls n=1,310,725 in the Global Biobank Meta-Analysis Initiative) from the largest genome-wide association studies to date. We performed bidirectional MR analyses to explore the causal relationships between the GM and stroke, and two mediation analyses, two-step MR and multivariable MR, to discover potential mediating metabolites.
Results:
Ten taxa were causally associated with stroke, and stroke led to changes in 27 taxa. In the two-step MR, Bifidobacteriales order, Bifidobacteriaceae family, Desulfovibrio genus, apolipoprotein A1 (ApoA1), phospholipids in high-density lipoprotein (HDL_PL), and the ratio of apolipoprotein B to ApoA1 (ApoB/ApoA1) were causally associated with stroke (all P<0.044). The causal associations between Bifidobacteriales order, Bifidobacteriaceae family and stroke were validated using the weighted median method in an independent cohort. The three GM taxa were all positively associated with ApoA1 and HDL_PL, whereas Desulfovibrio genus was negatively associated with ApoB/ApoA1 (all P<0.010). Additionally, the causal associations between the three GM taxa and ApoA1 remained significant after correcting for the false discovery rate (all q-values <0.027). Multivariable MR showed that the associations between Bifidobacteriales order, Bifidobacteriaceae family and stroke were mediated by ApoA1 and HDL_PL, each accounting for 6.5% (P=0.028) and 4.6% (P=0.033); the association between Desulfovibrio genus and stroke was mediated by ApoA1, HDL_PL, and ApoB/ApoA1, with mediated proportions of 7.6% (P=0.019), 4.2% (P=0.035), and 9.1% (P=0.013), respectively.
Conclusion
The current MR study provides evidence supporting the causal relationships between several specific GM taxa and stroke and potential mediating metabolites.
9.Small-molecule anti-COVID-19 drugs and a focus on China's homegrown mindeudesivir (VV116).
Qiuyu CAO ; Yi DING ; Yu XU ; Mian LI ; Ruizhi ZHENG ; Zhujun CAO ; Weiqing WANG ; Yufang BI ; Guang NING ; Yiping XU ; Ren ZHAO
Frontiers of Medicine 2023;17(6):1068-1079
The coronavirus disease 2019 (COVID-19) pandemic has stimulated tremendous efforts to develop therapeutic agents that target severe acute respiratory syndrome coronavirus 2 to control viral infection. So far, a few small-molecule antiviral drugs, including nirmatrelvir-ritonavir (Paxlovid), remdesivir, and molnupiravir have been marketed for the treatment of COVID-19. Nirmatrelvir-ritonavir has been recommended by the World Health Organization as an early treatment for outpatients with mild-to-moderate COVID-19. However, the existing treatment options have limitations, and effective treatment strategies that are cost-effective and convenient for tackling COVID-19 are still needed. To date, four domestically developed oral anti-COVID-19 drugs have been granted conditional market approval in China. These drugs include azvudine, simnotrelvir-ritonavir (Xiannuoxin), leritrelvir, and mindeudesivir (VV116). Preclinical and clinical studies have explored the efficacy and tolerability of mindeudesivir and supported its early use in mild-to-moderate COVID-19 cases at high risk for progression. In this review, we discuss the most recent findings regarding the pharmacological mechanism and therapeutic effects focusing on mindeudesivir and other small-molecule antiviral agents for COVID-19. These findings will expand our understanding and highlight the potential widespread application of China's homegrown anti-COVID-19 drugs.
Humans
;
Ritonavir/therapeutic use*
;
COVID-19
;
Antiviral Agents/therapeutic use*
;
China
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Nitriles
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Lactams
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Proline
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Adenosine/analogs & derivatives*
;
Leucine
10.Clinical features of primary bilateral macronodular adrenal hyperplasia
Weiwei ZHOU ; Tingwei SU ; Yu ZHU ; Lei JIANG ; Fukang SUN ; Yiran JIANG ; Jun DAI ; Cui ZHANG ; Hongchao HE ; Xu ZHONG ; Luming WU ; Sichang ZHENG ; Weiqing WANG
Chinese Journal of Endocrinology and Metabolism 2023;39(12):1023-1027
Objective:To investigate the clinical profile of primary bilateral macronodular adrenal hyperplasia(PBMAH) and sex difference.Methods:One hundred and forty cases of PBMAH were recruited in our center from 2014, and all patients were evaluated for hormone secretion, adrenal imaging, and metabolic parameters.Results:Overt Cushing′s syndrome accounted for 76.4% of PBMAH cohort and 47.9% were female. The overt group had higher serum cortisol and 24 h urinary free cortisol levels, lower adrenocorticotropic hormone, higher serum cortisol after low-dose dexamethasone suppression tests, larger total adrenal size, and a higher percentage of obesity, hypertension, diabetes mellitus, and hypokalemia than the subclinical group(all P<0.05). When compared with the male group, the female group had smaller adrenal size( P<0.001), lower HbA 1C( P=0.003), higher total cholesterol( P=0.005), and lower density lipoprotein-cholesterol levels( P=0.035). Further, 24 h urinary free cortisol in the male group was found to be positively correlated with diastolic blood pressure, fasting glucose, 2 h postprandial glucose after oral glucose tolerance test(OGTT), and HbA 1C after adjusted for age, body mass index, and onset duration, and was negatively correlated with body mass index and potassium levels. While 24 h urinary free cortisol in the female group was positively correlated only with diastolic blood pressure, fasting glucose, and 2 h postprandial glucose after OGTT(all P<0.05). During follow-up, 80.0% of patients achieved remission after unilateral adrenalectomy, with a recurrence rate of 17.9%. Conclusion:PBMAH related metabolic disorder is more pronounced in overt Cushing′s syndrome and males. Unilateral adrenalectomy as an effective treatment can benefit the majority of patients.

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