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Objective To investigate the acute adverse reactions of craniospinal irradiation with helical tomotherapy in medulloblastoma patients and its risk factors. Methods A total of 20 patients with medulloblastoma who received craniospinal irradiation with helical tomotherapy between October 2012 and September 2016 in Air Force General Hospital were selected. The acute adverse events of 20 patients during the treatment were record. According to National Cancer Institute Common Terminology Criteria Adverse Events (NCI-CTCAE) version 4.0, the adverse reactions were divided into the mild group (grade 0-Ⅱ) and severe group (grade Ⅲ-Ⅳ) adverse reactions. And the risk factors were also analyzed. Results The non-hematological adverse reactions included fatigue (55％), vomiting (45％) and headache (25％). The hematological adverse reactions included leukopenia (95％), thrombocytopenia (55％) and lower hemoglobin (45％), and the incidence of severe adverse reactions was 35％ (7/20), 20％ (4/20) and 0 ( 0/20 ) , respectively . Leukopenia occurred in 18 patients ( 90％) at the beginning of radiotherapy within 2 weeks, and thrombocytopenia occurred in 8 patients (40％) at the beginning of radiotherapy after 2 weeks. Single factor analysis showed that there were no statistical differences in hematological adverse events of gender, age and radiation dose of spinal cord (all P>0.05). The incidence of leukopenia for the patients who received the chemotherapy before the radiotherapy was higher than that for the patients without the chemotherapy before the radiotherapy (P< 0.05). Conclusions The hematological adverse reactions were the major acute adverse events during the craniospinal irradiation with helical tomotherapy in patients with medulloblastoma. Theincidence of leukopenia and thrombocytopenia is common, and the incidence of hematological adverse reactions is higher after the chemotherapy. Thus, the close monitoring of hemogram change and treatment of hematological adverse reactions in time during the radiotherapy should be taken into the consideration.
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Objective To introduce the therapeutic procedures of helical tomotherapy based total marrow irradiation(HT-TMI), and validate the feasibility of TMI. Methods At 1 week before bone marrow transplantation,12 patients received TMI conditioning regimen at a prescriptive dose of 12 Gy in 3 times,once daily. Patient immobilization, CT simulation, target delineation, plan design and dosimetric verification were implemented in sequence according to the TMI procedures. The dosimetric paramaters of the target and normal tissues were analysed. The correlation between the dose verification and image-guided results was observed. Results Compared with total body irradiation(TBI), TMI could significantly reduce the irradiation dose to normal tissues. The median dose D50of all normal tissues except the oral cavity were lower than 6 Gy,where The D50of lens,brain,lung and liver are (1.8±0.1) Gy, (5.7±0.2) Gy, (5.2±0.2) Gy, and (4.6±0.2) Gy, respectively. Pass rate of γ Index was larger than 95% with 3mm/3% criterian for each section. The positioning error of head and neck was relatively lower than that of pelvis at x-axis,and was higher at z-axis.Conclusions Helical tomotherapy based TMI is a feasible and reasonable approach,which has evident dosimetric advantage.
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Objective To identify dosimetric predictors for the development of gastrointestinal toxicity in patients with pancreatic adenocarcinoma treated with TOMO radiotherapy .Methods From January 2014 to Janu-ary 2015 ,we analysed the medical records of 68 pancreatic cancer patients who received helical tomotherapy from Air Force General Hospital .The stomach and duodenum were contoured separately to determine their dose volume histogram(DVH)parameters.Chi-square test was employed to analyze the count data .Spearman correlation anal-ysis was used to analyze the relationship between occurrence of gastrointestinal toxicity and clinical and physical factors.Logistic regression models was performed to identify risk factors associated with gastrointestinal toxicity . Results The median follow-up was 9 months(4~16 months).18 patients experienced grade II acute gastroin-testinal toxicity ,1 patient experienced grade Ⅲ acute gastrointestinal toxicity , whereas 17 patients experienced grade II late gastrointestinal toxicity ,1 patient experienced grade Ⅲlate gastrointestinal toxicity .On UVA,the vol-ume,Dmean,D1,D3,D5,D10,V5 to V40,and V5′to V45′of duodenum were significantly associated with GradeⅡor higher gastrointestinal toxicity ( P <0.05 ) .The MVA, V45′of duodenum was independent predictor for gradeⅡor higher gastrointestinal toxicity(P<0.05).The ROC analysis also showed that V45′of 0.5cm3 was the optimal threshold to predict for gastrointestinal toxicity for the entire cohort .Conclusion V45′of duodenum is of greater importance in the judgment of occurrence of hypofractioned radiation -induced gastrointestinal toxici-ty.
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Objective To seek a optimization method for lung cancer planning with Helical TomoTherapy for reducing the low dose area of total lung.Methods CT images of thirty patients with unilateral lung cancer were selected.Seven plans (Groups A,B,C,D,E,F and G) were generated for each patient using an identical optimization procedure with the conditions that implemented contralateral lung with unblocked (control group),1/4 directional block,1/2 directional block,directional block,1/4 complete block,1/2 complete block and complete block,respectively.The benefits in different schemes of reducing the low dose area of normal lung tissue were estimated,in order to provide a reference treatment plan scheme in clinical.Results Groups B,C,D and E had less influence on the target than that of group A.And there were no statistical difference between the target dosimetric parameters.The median dose and average dose of group F were increased within 0.5 Gy.The conformal index of group G had great influence on the target.The low dose area of total lung were reduced effectively in Groups C,D,E,F and G,the average decrease of V5 and V10 was 8.06％-45.26％ and 6.21％-33.95％,respectively.The V20 decreased by 1.71％-3.78％ in directional block group,while V20 increased in complete block group (2.07％-5.07％).The single treatment time was increased by 8.51％-79.22％.Conclusions The results showed that the low dose area of total lung was higher for the plan without any block limitation.It could reduce the low dose area of total lung with directional block.We should lengthen the blocking arc of contralateral lung with directional block based on the fractional treatment time and the patient's physical condition.A certain arc of contralateral lung with complete block could effectively reduce low dose area.When complete block was used,it is suggested that the arc was no more than half of the contralateral lung.
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Objective To study the dose characteristics of Body γ Knife and Tomotherapy treatment plans for hepatocellular carcinoma,and compare their differences between organs at risk (OAR) dose and the range of low dose.Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected,the target volume and OAR were drew by doctor.Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station.The dosimetric characteristics were evaluated by dose volume histograms and were compared.To analyze the difference between the two techniques,the paired t-test was applied.Results The Dmax and Dmean of target with Body γ Knife were higher than Tomotherapy (P =0.002,0.000),but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife (P =0.001).The Dmax of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy (P =0.013,0.012),and it was also in the Dean of stomach and left kidney (P =0.010,0.023).In the volume dose comparison,the V40,V35,V30,V25 and V20 of normal tissue (all Body-PTV) and liver (all liver-GTV) with Body γ Knife were higher than Tomotherapy (P =0.001,0.001,0.001,0.007,0.029),but the V10 and V5 were lower (P =0.019,0.031),the Dmax of stomach,Dmean of right kidney and liver were no statistical difference (P =0.247,0.308,0.401).Conclusions Both treatment plans could meet the clinical dosimetric need,by the same prescription dose,Dmax and Dmean of target of Body γ Knife were higher than Tomotherapy.Tomotherapy had excellent dose-target conformal and could reduce the range of V25-V40 of OAR and normal tissue,but the range of V5-V10 was increased obviously.
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Objective To investigate the setup errors of head and neck tumor patients with head mask-ing by TomoTherapy with megavoltage CT (MVCT),and to measure the CTV -PTV margins.Methods There were 34 patients with head and neck tumor .All patients had received MVCT scanning before radiation was deliv-ered.The MVCT images were registered with the kilovoltage CT (kVCT)images,the setup errors of the left -right (x),anterior-posterior(y),superior-inferior(z)and transverse profile rotation(Roll)were obtained by matc-hing MVCT with kVCT,followed by calculating the reasonable CTV -PTV margins with the formula M=2.5∑+0.7σ.Results Six hundred and forty MVCT images in total were received for the patients ,the systemic ±random errors in x,y,z and Roll directions were ( -0.15 ±0.55) mm,(0.30 ±0.56) mm,(0.35 ±0.71) mm and (-0.07 ±0.52)°,the CTV-PTV margin in x,y and z directions were 3.31 mm,5.32 mm and 3.35 mm.Con-clusion we demonstrate a theoretic foundation for our CTV -PTV margins in head and neck tumor patients by analyzing the setup errors ,and it also can provide necessary quality assurance for precise radiation .
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Objective To analyze the setup errors of bone metastases patients by tomotherapy with megavoltage CT (MVCT) and calculate the CTV-PTV margins.Methods 30 patients with bone metastases were enrolled.All patients received tomotherapy,fixed with body net and received MVCT scanning before radiation.The MVCT images were registered with the kilovoltage CT (kVCT) images,the setup errors of X (lateral),Y (vertical),Z (longitudina) and Roll (transverse profile rotation) were obtained according to the formula M =2.5Σ+0.7σ calculated CTV-PTV margin.Results 30 patients were received 494 MVCT images.The errors of systemic±random were (2.85±0.77) mm,(3.11±0.95) mm,(2.21±0.55) mm,and (0,55±0.24)° on X,Y,Z and Roll directions,respectively.The CTV-PTV margins were 3.64 mm,4.17 mm,and 2.86 mm on X,Y,Z directions,respectively.Conclusion The application of image-guided technology for bone metastases can correct positioning in time,which greatly reduces setup errors of the fractionated treatment,further improves the treat accuracy and has a positive value in guiding clinical radiotherapy.
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Tomotherapy plans were produced using a combination of field widths (1 cm, 2.5 cm and 5 cm) and pitches (0.15, 0.30, and 0.45) for seven patients with brain metastases from lung cancer, the plans were compared with dosimetric parameters, protection of organs at risk (OAR) dose and treatment times. All plans were defined that CTV with 30Gy and GTV 50 Gy by ten fraction synchronously. The results showed that the mean dose and CI for GTV was statistical difference (P = 0.002 1, P = 0.012 8), OARs were within the normal range, the treatment time increased inversely proportional to the jaw width, but had lesser impact on the pitch. This study showed plans produced with 5 cm jaw was an effective method for patients with brain metastases from lung cancer.
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Aged , Female , Humans , Male , Middle Aged , Brain Neoplasms , Diagnostic Imaging , Lung Neoplasms , Pathology , Radiotherapy Planning, Computer-Assisted , Methods , Radiotherapy, Intensity-Modulated , Methods , Tomography, Spiral ComputedABSTRACT
Fourteen patients with pancreatic carcinoma were selected. Two treatment plans were designed for each patient, including gamma knife and Tomotherapy. The dose characteristics were evaluated by DVH and were compared. The results showed that the gamma knife plan had the higher maximal and mean target dose than Tomotherapy. Body gamma knife can increase the target dose significantly, and decrease the OAR dose. Tomotherapy had excellent dose-target conformality, and it can control doses of duodenum and stomach easily, but it had larger low dose region.
Subject(s)
Humans , Pancreatic Neoplasms , Radiotherapy , Radiosurgery , Methods , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , MethodsABSTRACT
OBJECTIVE To investigate the sensitivity to vancomycin of Enterococcus in clinic and the genotype and homology of glycopeptides-resistant strains.METHODS The sensitivity to vancomycin in 72 enterococci strains was detected with agar dilution;the existence of vanA,vanB,vanC1 and vanC2 in enterococci was detected by PCR and ERIC-PCR.RESULTS More than 50% of enterococci intermediated to vancomycin were resistant to other antimicrobial agents commonly used in clinic,except for teicoplanin and linezolid.Gene of vanC2 was present in two strains,but none with vanA and vanB.The ten strains of enterococci intermediated to vancomycin were divided into eight types,in which type A(3 strains) was isolated from the same hospital.CONCLUSIONS Multidrug resistance is observed in enterococci resistant to vancomycin,which are sensitive to teicoplanin and linezolid.Gene of vanC2 is found in some of them,suggesting clone transmission happen among strains.