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Triterpenoid saponins is an important secondary metabolites in medicinal plants, and the tetracyclic triterpenoid saponins, as one of the main categories, have very high medicinal value and market demand. However, there is no systematic review on the research. Thus, the elucidation of the biosynthetic pathway and metabolism of the medicinal plant tetracyclic triterpenoid saponins has important theoretical significance and broad application prospects.In this review, the biosynthetic pathway and metabolic regulation of medicinal plant of tetracyclic triterpenoid saponins were discussed. My focus in this paper was to introduce the research development of several metabolic biosynthetic pathways of tetracyclic triterpenoid saponins centered on dammarane type, and the gene improvement by methods such as metabolic pathway and other technological methods. This study provides references on secondary metabolic framework of medicinal plants of tetracyclic triterpenoid saponins, accurately locating secondary metabolism and its key enzymes, and promoting the sustainable uses of medicinal plant resources.
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Objective To quantitatively evaluate the image quality, stability and volume precision in kilovoltage cone beam CT (CBCT) on Varian linear accelerator. Methods The Catphan (R) 600 phantom was repeatedly scanned in the full-fan and half-fan CBCT scanning modes. A simulation fan-beam CT (FBCT) was used as a benchmark and results related to the low contrast resolution, spatial resolution,uniformity and image noise were compared with the CBCT using the treatment planning system. The comparison of image quality and long-term stability and volume precision was analyzed. Results Spatial resolution was no differences observed between FBCT and CBCT ( 6 lp/cm: 6 lp/cm , T = 18. 00 , P＞ 0. 05 ) .Low contrast resolution was, on average, 1. 65％ and 1. 74％ for both CBCTFull-Fan and CBCTHalf-Fan , and 1. 03％ for the FBCT ( T =6. 00, P ＜ 0. 05). Uniformity was, on average, 0. 005 and 0. 033 for both, and 0. 003 for the FBCT ( T=6. 00 , P ＜0. 05). In terms of image noise, the FBCT images were superior to the CBCT (T=30. 00, P＜O. 05). In valid scan range of the CBCT, reconstructed precision was high. There was no significant time trend in the image quality. Conclusions The image quality of kilovoltage CBCT is inferior to the conventional CT. However, tumor and soft tissues are visible in the CBCT images. The image stability and reconstructed precision is satisfying.
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Objective To investigate the dose calculation accuracy and feasibility of using kilovoltage cone-beam CT (KVCBCT) for esophageal cancer radiotherapy.Methods Hounsfield unit (HU) values and profile along the horizontal line of Catphan (R) 600 phantom in KVCBCT images acquired on Trilogy linear accelerator were compared to those in the planning CT.The KVCBCT value-density calibration curve was established.The intensity modulated radiotherapy plans were created on the planning CT images and copied to KVCBCT images.The dose distribution was recalculated by means of the KVCBCT value-density calibration curve in the treatment planning system.The dosimetric comparisons were performed between the KVCBCT and planning CT plans on the phantom and 10 patients with esophageal cancer.ResultsThe KVCBCT value was stable with a maximum variation of 1.6％,and there was no significant time trend.CT value profiles showed good agreement within 1％ variation except the peripheral regions.The dosimetric differences were less than 1.33％and 3.65％for the phantom case and the patient ones,respectively.The dose distribution comparison was also in good agreements.Conclusions The accurate dose caleulation based on KVCBCT for esophageal cancer is feasible.The KVCBCT images can be used for monitoring the dosimetric changes during the treatment.
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Objective To investigate the advantage of the intensity-modulated radiotherapy treatment (IMRT) by allowing dose heterogeneity in the target volume in esophageal cancer treatment planning.Methods Two sets of 5-field IMRT planning were designed for 10 esophageal cancer patients upon the condition of appropriate clinical tolerance level with the prescription dose of 60 Gy to 95% of the planned target volume (PTV) and the maximum dose of 45 Gy to the spinal cord:the IMRT with rigid restriction of the maximum homogeneous dose to the PTV within 63 Gy prescribing a homogeneous dose ( IMRThom ) and the IMRT allowing dose heterogeneity by loosening the constraints on maximum dose in the PTV to 69 Gy ( IMRTinhom ).Dosimetric comparison was conducted by using dose-volume histograms.Results Compared to IMRThom, the minimum dose (t = -3.37,P =0.012), maximum dose (t = - 23.58,P = 0.000), mean dose ( t = - 4.95, P = 0.002 ), and heterogeneity index ( t = - 11.06, P =0.000) in PTV of the IMRTinhom were all significantly increased, and the values of V5 (t = 6.96, P =0.000), V10(t=5.24,P=0.001) , V15(t=4.73,P=0.002) , V20(t=8.08,P=0.000) , V25(t=8.58,P = 0.000), and mean dose (t = 7.28,P = 0.000) of the normal lungs were all significantly lower.There were no significant differences in all the indexes for the mean dose to the heart and maximum dose to the spinal cord between these 2 set of planning.Conclusions The IMRT plan allowing dose heterogeneity in the PTV escalates the prescription dose and decreases the doses to the lungs.
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Objective To compare the difference region of interest volume (ROI) calculation method between Pinnacle and Eclipse treatment planning system. Methods To acquire CT image with 3 of slice thickness (1 mm, 3 mm, and 5 mm). Delineate 1, 2 and 5 slices square and circle contours in Pinnacle treatment planning system. Meanwhile 15 cases that include 5 cases with head neck tumor, 5 with thorax tumor and 5 with abdomen tumor were selected. Those image and ROI were transfer to Eclipse treatment plan system by DICOM RT protocol . The ROI volume was compared between two TPS . Results For ROI with small volume, the volume difference between TPS was obvious (for small volume ROI have 12 times difference, for big volume ROI almost same). The volume difference between TPS was influenced by many factors. The number of ROI slice and the magnitude of ROI was related with the difference between TPS (R2 = 1. 000, P = 0. 000). The CT thickness (R2 = 0. 200, P = 0. 972 ) and the shape of ROI ( R2 =0. 200, P = 0. 089) were not significant factors. The center of ROI on different axis was not affect the volume calculation in Pinnacle, which cause 3% different in Eclipse. The CT thickness was proportional to the ROI volume ( Pinnacle R2 = 0. 548, P = 0. 011; Eclipse R2 = 0. 502, P = 0. 027 ). In clinical case, optic chiasm and Len averagely have more than 35% volume difference between those two TPS. Conclusions We should pay more attention about the difference volume calculation algorithm between Pinnacle and Eclipse,especially when transfer small volume ROI to another TPS, which may have significant difference.
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Objective To study anti-radiation behavior of plasma sprayed boron carbide coatings. Methods The anti-radiation capacity of 16Mn steel which was coated with 0.1 mm plasma sprayed boron carbide were studied. The irradiation beams were 6,10,15 MY X-ray and 6,9,12,15 MeV electron emitted by accelerator, X-ray emitted by 60Co machine,fast neutron, and X-ray emitted by kilovoltage X-ray ma-chine. Results Anti-radiation capacity of plasma sprayed boron carbide coatings was not found for X-ray beams emitted by accelerator and 60Co machine. For electron beams,the anti-radiation capacity were found. The deeper of location, the stronger was anti-radiation. However, the anti-radiation capacity was not good. For fast neutron,the anti-radiation capacity was good. For X-ray emitted by kilovoltage X-ray machine,the anti-radiation was good,and only 0.1 nun plasma sprayed boron carbide had 15% attenuation. Conclusions The plasma sprayed boron carbide coatings have the anti-radiation capacity for X-ray emitted by kilovoltage X-ray machine in medical field.
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Objective To evaluate the feasibility and accuracy of performing dose calculation on megavoltage cone-beam CT(MVCBCT) in the head and neck. Methods MiniCTQC phantom was imaged using MVCBCT scanner, and the MVCBCT value density calibration curve was established. Conventional CT and MVCBCT image of phantom and nasopharyngeal carcinoma(NPC) patient were acquired respectively. Two kinds of single field plan were designed for conventional CT image of phantom,and IMRT plan was used for conventional CT image of a NPC patient. The conventional CT plans were copied to MVCBCT image. The dose distribution was calculated for targets and normal tissues using the MVCBCT value density calibration curve,and compared with that of conventional CT. Results For all the cases,the differences between the calculated dose distributions using MVCBCT and CT were less than 3% and 3 mm in single field plan. In IMRT plan, DVHs of conventional CT and MVCBCT were in excellent agreement. The biggest difference between conventional CT and MVCBCT was 95 cGy with the error of 1.4%. On the isocenter plane,the passing rate was 95.5% ,99.4% ,93.8% ,98.7%, 100% ,94.5% ,97.3% ,95.6% ,99.3% and 99.4% for the beam angle of 0°,45°,90°,120°,160°,200°,240°,280° and 320°. Conclusions Performing dose calculation using MVCBCT in head-and-neck region was feasible, and the dose distributions on the conventional CT and MVCBCT were in excellent agreement.
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Objective To investigate dose characteristics of megavoltage cone-beam CT in the low MU and rotation way for imaging,and to improve the quality assuraflce. Methods Dose linearity,a parameter describing beam characteristics,was measured for different numbers of MUs on megavoltage conebeam CT accelerator.Dose stability was measured 5 times using exposure of 7 MUs,which was repeated another 5 times 6 hours after. Results Dose linearity was good using exposure between 5 and 20 MUs.The average dose among the first and second 5 measurements was(5.74±0.01)Gy and(5.76±0.01)Gy while exposure of the accelerator was 7 MU.The difference between the two doses was 0.41%. he dose was stability while megavoltage cone-beam CT image was in the low MU and rotation way. Conclusion Dose characteristics of megavoltage cone-beam CT in the low MU and rotation way for imaging can qualify clinically application.
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Background and purpose:Indensity modulated radiotherapy(IMRT) is an advanced method in radiotherapy field.Divect machine optimization technique is an good aritmetic for IMRT optimization.The purpose of this study was to compare the dosimetric differences between traditional technique and direct machine parameter optimization(DMPO) technique in the treatment of nasopharyngeal carcinoma(NPC) using step and shoot IMRT.Methods:Eleven patients of(NPC) were treated with step and shoot IMRT in Cancer Hospital,Fudan University from Feb.2005 to May 2006.Their plans(original plan,defined as treat) were archived for comparing with four kinds of IMRT plans(defined as DMPO100,DMPO90,DMPO80,DMPO70) with different predefined maximum number of segments(100,90,80,70,respectively),which were designed to use direct machine parameter optimization(DMPO) technique.We compared the total monitor units(MU),total segments,dose distribution and conformity index among the plans.Results:All the plans showed similar target coverage.Compared with traditional technique,IMRT plans with DMPO technique showed higher conformity index,and had similar uniformity except plan DMPO70.The dose distributions of DMPO100 and DMPO90 were similar or superior to the original plan(treat) in terms of critical organs.Without sacrificing plan quality,the total segments were about half of traditional plan if DMPO technique was used for planning.Moreover,the total monitor units(MUs) and the radiation time were decreased.Conclusions:Compared with traditional technique,plans designed with DMPO technique show sharp decrease in total segments without sacrificing plans quality in the treatment of nasopharyngeal carcinoma(NPC).The DMPO technique can also decrease the total MUs and radiation time.
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Objective To monitor the performance constancy of the HS-126E automatic X-ray film processor and to investigate the effects of chemical processing time on the reproducibility of film dosimetry.Methods With films having identical exposure,15 ready-pack Kodak X-omat-V films from the same batch were divided into 5 groups and exposed one by one under the identical conditions.One group of test film was processed per day from Monday to Friday with identical temperature and time.All films were digitized with a Vidar VXR-16 bit film digitizer. The average optical density(A) at irradiation field center was analyzed with RIT113 film dosimetry system software.At the same time,another 10 films in 5 groups from the same batch were exposed with vertical method and processed to get the calibration data and sensitometric curves.The film sensitivities,i.e.,ratio of A to delivered dose,were calculated and compared between groups.Another 15 films in 5 groups were exposed with horizontal method and processed similarly to the test films,the point dose at 1.5?cm depth on the central axis was calculated with sensitometric curve and compared with the value measured by ion chamber.Results Variations of A value in each group was less than 2%.During the processing period,a trend of decrease along with time in mean A value decreased day by day was observed.Both the standard deviations and coefficients of variation in all groups were within 2%.One-way ANOVA showed that there was a significant difference of the mean A value among all films from Monday to Friday(P
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7000?cGy). The cumulative incidence of cranial nerve Ⅸ-Ⅻ palsies increased in patients with advanced N stage. Patients in the first group of treatment field had the highest risk to progress cranial nerve Ⅸ-Ⅻ palsies, followed by the second group, and the third group had the lowest risk. Only 1 in 34 patients with brachytherapy developed cranial nerve palsy. Conclusions Our retrospective data show that the radiation-induced cranial nerve palsy is a common complication in NPC patients after radiotherapy and the incidence seems to increase with the duration of the follow-up. Factors that potentially affect the injury of cranial nerve Ⅰ-Ⅶ and Ⅸ-Ⅻ are different, because of the different anatomy. Controlling the doses to the nasopharyngeal region and using faciocervical fields may help to lower the incidence of cranial nerve palsy.
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Objective To calibrate and assess the dose distribution of 125 I seed brachytherapy. Methods Twenty 125 I seeds, each with activity of 12.2 MBq, were implanted on the circumference of a circle 15mm across in a phantom. Into a designed prostate model, 70 125 I seeds were implanted in four planes. The absorbed dose rate of the target volume was monitored by Farmar 2570 dosimeter and thermoluminescence dosimeters (TLD) with the isodose curves drawn on Kodak films. Results The central dose rates of the circular target volume assessed by Farmar 2570 and TLD were 8.4, 7.9 cGy/h in the phantom and 12.0, 11.1 cGy/h in the prostate model. For the target volume of the prostate model, the total absorbed dose was 24?219 cGy. The dose rate 4 cm from the prostate cancer as shown by the isodose curves was only 10% of the central dose rate. Conclusion The central dose rate of target volume measured by the two methods are similar.
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Objective To probe into regul ar patterns of move and diffusing of Oncomelania s nails in rivers with cement banks and determine the control strategy. [WT5 ”HZ]Methods The part of Sunan Canal from the estuary to Xin feng Railway Bridge was taken as the experimental zone. The revival of snail spo ts destroyed before the canal dredging, snail status on cement banks, snails on obstacles, floaters and ships in the rivers and floating snails were investigate d and compared with the situations before the dredging. Results Twelve destroyed snail spots were investigated and two of them presented snails, apart from the estuary 3.2 km and 4.3 km. The rate with sna il s on obstacles in frame in the rivers was 0, significantly lower than the 87% be fore the dredging(P
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ObjectiveTo evaluate the app li cation value of the Dipstick Dye Immuno assay (DDIA) for screening chemotherapy targets of schistosomiasis in a lower endemic area. Methods[ WT5”BZ]In a lower endemic area of schistosomiasis a random sample of 463 individuals from a natural village were examined using miracidium hatching metho d, Kato Katz's method, DDIA, DGS COPT and ELISA. The positive rates of these a ss ays were compared. ResultsThe positive rate of stool examination was 3.9% in 463 individuals. The positive rate of DDIA was 15 8%. The positive rate in 18 stool positive subjects was 94 4% with Youden In dex 0 81. The positive rate of DGS COPT was 8 9% . The positive rate in 18 stool po sitive subjects was 72 2% with Youden Index 0 66. The positive rate of ELISA w as 18 4%. The positive rate in 18 stool positive subjects was 83 3% with Youden In dex 0 68. ConclusionDDIA was more suitable for application in screening target population in lower endemic areas than other im munoassys.