Application of Linear Accelerator on Boarding Kilovolt Fan Beam CT and Megavolt Cone Beam CT System on Set-up Errors During Radiation Treatment / 肿瘤防治研究

Objective To quantify the setup errors for the different anatomical sites of patients who received intensity-modulated radiotherapy (IMRT) with linear accelerator on-board kilovolt fan beam CT(kV-FBCT) as non-isocenter IGRT and megavolt cone beam CT (MV-CBCT) as isocenter IGRT. Methods A retrospective analysis was performedon 70 patients who underwent radiotherapy, kV-FBCT, and/or MV-CBCT scans after each routine setup prior to IMRT. The average displacement (M), systematic error (Σ), and random error (б) at different treatment sites in the left-right, anterior-posterior, and cranial-caudal directions were calculated according to the individual displacements. The formula 2.5Σ+0.7б was used to estimate the PTV margin in respective direction. For each single patient, the root mean square in three directions was used as 3D displacement. Results A total of 1130 displacements were recorded in the 70 patients. The PTV margin was estimated to be 1.9-3.1 mm in head and neck cancer, 2.8-5.1 mm in thoracic cancer, 4.6-5.1 mm in breast cancer, 3.0-5.5 mm in upper abdominal cancer, and 3.5-6.8 mm in pelvic tumor. For the 3D mean displacements, the head and neck, thoracic, breast, upper abdominal, and pelvic cancer were 2.4±1.0, 4.0±1.6, 4.1±2.0, 4.6±2.1, and 4.6±2.1 mm, respectively. The average 3D displacement obtained by kV-FBCT and MV-CBCT were 4.1 and 3.4 mm, respectively (P=0.212). Conclusion The quantitative setup-error data can be obtained using linear accelerator on-board FBCT, and the non-isocenter IGRT induced set-up error cannot be negligible.

First clinical application and dosimetric verification of total body irradiation with volumetric modulated arc therapy / 中华放射肿瘤学杂志

Objective:To investigate the implementation procedures and dosimetric verification of the first patient treated with total body irradiation (TBI) based on volumetric modulated arc therapy (VMAT).Methods:Two sets of CT images were acquired under the head-in first and foot-in first to contour the planning target volume (PTV) of the cranial and caudal segments to accomplish the treatment of the whole body length, on which two interrelated plans of 5 subsequent isocenters with a total of 15 VMAT fields were performed to cover all PTVs. The plans were prescribed to ensure 90% PTV dose coverage with a total dose of 12 Gy in 6 fractions. Firstly, a dose optimization was performed on the caudal CT images, then the cranial CT images were optimized based on the dose distribution of the caudal CT images. The evaluation of the final treatment plan was carried out based on a plan sum of both two sets of images. The parameters of PTV and organs at risk (OARs) were measured by dose volume histograms from the accumulated plan. The quality assurance comprised the verification of the VMAT plans for each individual isocenter via Delta4 phantom. The dose distribution in the overlapped region between two adjacent central fields was verified with EBT3 film. The absolute dose at the overlapped region between two images was measured via Pinpoint chamber. In vivo dosimetry on the patient′s skin was monitored by MOSFET dosimeters. The results of planning parameters and treatment duration were analyzed. Results:The mean doses of two segments of PTVs were 12.45 Gy and 12.37 Gy. The mean dose for the lung was 10.8 Gy. The machine unit (MU) and mean treatment delivery time were 2 883 MU and 24.3 min, and the mean total time per fraction was 121 min. The mean 3%/3 mmγ-analysis pass rate for each isocenter VMAT plan was (99.74±0.42)%, and the mean 5%/5 mmγ-analysis pass rate for the overlapped region was (90.11±2.72)%. The average deviation of absolute dose in the overlap region of the caudal and cranial images was (3.6±0.4)%. In vivo measurement of 8 points on the patient showed that the dose of each region was ranged from 1.57 Gy to 2.04 Gy. Conclusion:According to the results of dosimetric verification, TBI based on multi-isocenter VMAT can be applied in clinical practice, which remains to be improved in terms of dose distribution, measurement results and clinical efficiency.

Study on Biological Characters and Genetic Characteristics of Oidiomycetes Mutant Strains Like Bacterial Morphology / 现代检验医学杂志

Objective To investigate the changes of the morphology,structure and biological characters of mutated Candida and through its genetic characteristics,research and reveal the mechanism of the variation at the molecular level.Methods Used different nutritional conditions,different growth conditions and different azole antifungal agents to induce mutation of the standard strains of Candida albicans.In clinical study,Candida mutant strains was isolated from vaginal secretions,pleu-ral effusion and gastric juice samples in patients of poor effect with Antifungal therapy,and studied on the morphological characteristics,and the nuclear structure,the biochemical reaction,the drug resistance,the bacterial composition and the ge-netic characteristics of above variants,etc.Results Mycelial?morphology:Candida were prone to mutation like bacteria, mutant bacteria could show G+ Aureus shape,G+ Bacillus,G+ long filamentous,G- Aureus shape,G- Bacillus and G- long filamentous;Nuclear structure:Candida mutant strains changed like prokaryotes under the electron microscope because it lost the original structure of eukaryotic cells.Biochemical reaction:there were 5 different items in 20 biochemical test ob-served.Drug sensitivity test:Candida mutated to antifungal drugs being originally sensitive was completely resistant,sensi-tive and resistant originally was completely sensitive,and the same as ordinary bacteria resistant.The cell component chan-ges:there was significantly different in Candida variant strain and the atavism of variant strain identified by mass spectrome-try.The most conservative fungalgene expression:Candida mutated had conservative gene expression of eukaryotes.It could be demonstrated that oidiomycetes mutant strains like bacterial morphology with prokaryotic cell biological characteristics was derived from Candida with eukaryotic cells.Conclusion Candida was prone to variation like bacterial morphology.The biological characteristics of mutant resembled prokaryote.There was a qualitative change among the standard strains of Can-dida albicans,mutant strains of oidiomycetes like bacterial morphology and the atavism of variant strain with clear genetic re-lationship under the electron microscope in the form of nuclear matter.The study on biological evolution,especially contact in prokaryotic cells and eukaryotic evolution has very important significance.

Smac Involved in Promoting TGF-β1 Treated Mesangial Cells Apoptosis Induced by Triptolide / 天津医药

Objective To investigate the effects of Triptolide on apoptosis of cultured rat mesangial cells treated by TGF-β1 and the role of Smac in this process. Methods The mesangial cells were pre-treated with different concentrations of Triptolide for 24 hours, then stimulated with TGF-β1 for 24 hours. Apoptotic cells were detected by TUNEL assay. Smac transcription level was determined by Real time-PCR analyses. Smac expression level was assessed using Western blot anal-yses. Localization of Smac was shown by confocal fluorescence microscopy. Results Compared with control group, TGF-β1 inhibited apoptosis and Smac transcription and expression in rat mesangial cells. By contrast, Triptolide promoted mesangial cells apoptosis. In Triptolide groups, Smac mRNA and protein levels were up-regulated. Additionally, in normal and TGF-β1 groups Smac protein was mainly localized in mitochondriawhile in Triptolide groupit was mainly localized in cytoplasm and nucleus with increased fluorescence intensity. Conclusion Triptolide could promote the effect that TGF-β1 inhibited apop-tosis of mesangial cells, through both up-regulation the expression of Smac and stimulating it translocation from mitochon-dria to cytoplasm and nucleus.

Effects of triptolide on proliferation and apoptosis in rat mesangial cells induced by transforming growth factor β1 and related mechanisms / 中华肾脏病杂志

Objective To investigate the effects of triptolide on proliferation,apoptosis and the changes of Ski,Smad3,Smad7 and collagen type I(ColI) in cultured rat mesangial cells induced by transforming growth factor (TGF)-β1.Methods Cultured HBZY-1 rat mesangial cells were divided into 5 groups:(1)normal control group; (2)TGF-β1 group (10 μg/L); (3)-(5)triptolide (0.4,2,10 μg/L)+TGF-β1 (10 μg/L) groups.The cell proliferation was detected by MTT.Apoptosis of mesangial cells was detected by TUNEL assay.The expressions of Ski,Smad3,Smad7 mRNA were examined by real-time quantitative PCR.The expressions of Ski,Smad3,Smad7 and ColI protein were detected by Western blotting.The localizations of Ski and Smad3 protein were detected by laser confocal fluorescence microscope.Results Compared with the normal control,TGF-β1 (10 μg/L) significantly stimulated mesangial cells proliferation,while decreased apoptosis.The mRNA and protein expressions of Ski,Smad7,Smad3 and ColI protein expression in TGF-β1 group were increased (P ＞0.05).In comparison with TGF-β1 group,triptolide could significantly inhibit TGF-β1-induced mesangial cells proliferation in dose-dependent manner,and promote the apoptosis of mesangial cells.In TGF-β1 group,mRNA and protein expresscons of Ski and Smad7 were increased (P＜0.05),Smad3 mRNA and protein were decreased (P ＞0.05),and ColI protein was decreased (P＜0.01).In comparison with TGF-β1 group,fluorescence intensity of Ski,Smad3 proteins was significantly increased in cytoplasm,while decreased in nucleus.Conclusions Triptolide can inhibit TGF-β1-induced mesangial cells proliferation through regulating the expressions of Ski,Smad7 mRNA and protein,inhibiting Ski.Smad7 translocation to the nucleus,and down-regulating Smad3 mRNA and protein expression.Triptolide can promote apoptosis of mesangial cells.