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OBJECTIVE To provide reference for exploring alternative resources of Gentiana rigescens from the plants of Gentiana. METHODS The contents of four components （gentiopicroside， swertiamarin， swertioside and amarogentin） in the roots and rhizomes from 3 plants of Gentiana （G. rigescens， G. cephalantha， G. delavayi） were determined by high-performance liquid chromatography （HPLC）. The chemical compositions in the above roots and rhizomes were identified by ultra-performance liquid chromatography electrospray ionization quarter-time of flight mass spectrometry （UPLC-ESI-Q-TOF-MS）， and the differences were analyzed by principal component analysis （PCA）. RESULTS Four active components such as gentiopicroside， swertiamarin， swertioside and amarogentin were detected in the roots and rhizomes of G. rigescens and G. cephalantha， and the contents of the four components were similar in both. The contents of gentiopicroside in the root and rhizome of G. cephalantha and G.rigescens were more than four times of the limit standard of the Chinese Pharmacopoeia （Part Ⅰ） in 2020； However， only swertiamarin， swertioside and amarogentin were detected in the roots and rhizomes of G.delavayi， and the contents of swertioside and amarogentin were 34.12 and 8.81 times of those of G. rigescens， respectively. In addition， a total of 33 compounds 术。E-mail：515227235@qq.com were identified from the roots and rhizomes of 3 plants of Gentiana by UPLC-ESI-Q-TOF-MS， mainly iridoids. Additionally， G. rigescens and G. cephalantha contained xantones， G. delavayi contained flavonoids. PCA showed that there was a small difference between G. rigescens and G. cephalantha； however， there was a big difference between G. delavayi and G. rigescens. CONCLUSIONS The difference between the roots and rhizomes of G. cephalantha and G. rigescens from the same origin is small and there is substitutability； while the difference in the chemical components from roots and rhizomes between G. delavayi and G. rigescens is great and G. delavayi cannot be used as medicine instead of G. rigescens.
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Objective:To study the impact of the Varian real-time position management (RPM) respiratory gating system on radiotherapy planning dosimetry.Methods:The radiotherapy plans of 40 cases with thoracic or abdominal tumors were retrospectively selected in this study. The motion phantom for quality control was adopted to generate respiratory gating signals, and the 30%-60% stable phase at the end of expiratory was selected as the respiratory gating window. The dose verification for the abovementioned radiotherapy plans was performed using the Portal Dosimetry (PD) system under RPM respiratory gating mode with the Edge accelerator. Afterwards, dose analysis was performed with different γ passing rate criteria and the distribution characteristics of γ values were analyzed. Finally, the verification results between the non-gating mode and the gating mode were compared.Results:Under the respiratory gating mode, the passing rates of all intensity-modulated radiation therapy/volumetric-modulated arc therapy (IMRT/VMAT) plans with or without flattening filters were over 95.5% by γ criteria of (3%, 3 mm) or (3%, 2 mm) and were over 90% by stricter γ criteria of (2%, 2 mm). All plans met the clinical requirements recommended by the American Association of Physicists in Medicine (AAPM). The passing rates of dose verification under non-gating mode were slightly better than those under respiratory gating mode, and the differences between the two modes were statistically significant (3%/3 mm, Z =-1.45; 3%/2 mm, Z =-2.86; 2%/2 mm, Z =-3.70; 1%/1 mm, Z =-4.52; P<0.05). There was no significant difference in the minimum and maximum values of γ and the share of γ > 1.5 of plan verification result under the two modes. However, the average value and standard deviation of the γ were generally smaller under the non-gating mode. Conclusions:The impact of the introduction of RPM respiratory gating technology on dose is clinically acceptable, and the execution of these plans in this gating mode is safe and reliable.
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Objective:To compare the dosimetric differences between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) on planning target volume (PTV) and organ-at-risk (OAR) for breast cancer after modified radical mastectomy, aiming to provide evidence-based reference for clinical practice.Methods:According to strict inclusion and exclusion criteria, literature search was performed in PubMed, Cochrane Library, FMRS, CNKI, Wanfang Data and VIP full text databases from the inception of databases up to March 2020. The controlled clinical trials of dosimetric comparison between VMAT and IMRT for breast cancer following modified radical mastectomy were selected. The meta-analysis was performed using Stata14 software.Results:The meta-analysis included 281 patients from 13 observational studies. Compared with IMRT, VMAT significantly increased the PTV dose coverage D 95%( P<0.001) and significantly improved the PTV homogeneity index (HI, P<0.001) and conformity index (CI, P=0.004). Compared with IMRT, VMAT more effectively decreased the ipsilateral lung V 20Gy (WMD=1.332, P=0.027) and contralateral lung V 10Gy ( P=0.003). There were no significant differences in theD mean, V 5Gy, V 10Gy and V 30Gy of the ipsilateral lung, D mean and V 5Gy of the contralateral lung, D mean, V 10Gy and V 30Gy of the heart between VMAT and IMRT (all P>0.05). Compared with VMAT, IMRT reduced the cardiac V 5Gy ( P=0.001). However, sensitivity analysis of included literature on cardiac V 5Gy showed that the P value was reversed, indicating that the stability of the results was poor. VMAT significantly shortened the delivery time ( P<0.001) and the number of monitor units ( P<0.001) compared to IMRT. Conclusion:Compared with IMRT, VMAT can achieves superior target dose coverage, HI and CI, better protection for the ipsilateral and contralateral lung, fewer monitor units and shorter delivery time.
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OBJECTIVE:To study the chemical components of Swertia nervosa. METHODS:Silica gel column chromatogra-phy was used for purification and analysis of compounds’structure based on physicochemical properties and spectral data. RE-SULTS:Five compounds were isolated and identified in petroleum ether portion of S. nervosa,involving 1-hydroxy-3,7,8-trime-thoxyxanthone (1),1,8-dihydroxy-3,7-dimethoxyxanthone (2),1,8-dihydroxy-3,5-dimethoxyxanthone(3),1-hydroxy-3,5-dime-thoxyxanthone(4)and β-sitosterol(5). CONCLUSIONS:Compound 1,3 and 4 are isolated from S. nervosa for the first time,and the study has laid a foundation for the quality evaluation of S. nervosa.
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Objective To verify the wedge angle of virtual wedge and the relation between wedge factor and beam energy, field size, wedge angle and to study the difference in percent depth dose (PDD) of virtual wedge field, hard wedge field and open field.Methods Using wedge angle and wedge factor of 15?,30?,45?and 60? virtual wedge of Siemens Mevatron 6?MV and Primus 8?MV, 18?MV X rays were measured by RFA-plus 3D water phantom and RK finger chamber the PDD of the virtual wedge field, hard wedge field and open field were measured by Kodak XV-2 verifying film and FDM-300 film dosimeter. These PDDs were normalized to Dmax then compared. Results There was good conformation between virtual wedge measured by four point method and set value. The virtual wedge was almost equal to 1,with a maximal variation of 0.031 no matter what the value of beam energy, field size or wedge angle was. Generally, for certain energy and field size, the wedge factor of larger wedge angle was slightly larger than smaller wedge angle. For certain energy and wedge angle, the wedge factor of larger field was also a little larger than smaller field. The PDD of virtual wedge field was similar to that of open field. Conclusions The four point method measurement for virtual wedge angle is good for daily QA. Radiotherapy of virtual wedge field is not only simpler than hard wedge field,but also spares the beam output. The PDD comfarmation between virtual field and open field simplifies radiation treatment planning and increases the accuracy of wedge field therapy.