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Objective:To develop a remote training system for CT simulation positioning of radiotherapy using virtual reality technology, and to explore a new method of medical training.Methods:The 3DMax and Maya were employed to establish the 3D model. The unity3D engine was adopted to develop 3D virtual operation and interaction system. Java spring MVC architecture was utilized as the system background service. MySQL was used as the background database system. The users were assigned into two roles: teacher and student, and the modes were divided into teaching and assessment modes.Results:The function of the system covered the whole process of CT simulation positioning, mainly including modules of patient information management, CT simulation positioning machine cognition, body position fixation technology, CT positioning scanning, and emergency handling, etc. Since it was put into use in 2018, the system has been running stably, with 14 920 pages views and an 86.66% pass rate. Compared with the traditional training, the training efficiency has been significantly improved and has received unanimous recognition.Conclusions:The remote training system can effectively improve the clinical practice ability and humanistic care ability of the trainees, which has good autonomy, sharing, and innovation. At present, the system has been put online and has strong popularization with prospects for broad application.
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Objective To analyze the effect of the new conformal index(nCI)and the conventional conformal index(CI)on the treament planning quality of lung stereotopic radiotherapy(SBRT).Methods A total of 19 peripheral lung cancer patients,treated with SBRT in Fujian Medical University Union Hospital from 2014 to 2017,were analyzed retrospectively.Each patient was planned twice yielding identical CI and nCI.The prescription to 95％of planning target volume(PTV)was 48 Gy in four fractions,and renormalization was performed when needed for nineteen nCI plans.The Wilcoxon signed-rank test was used to examine the dosimetric index.Results The dose conformity plots indicate that nCI does not only reflect the dose to the organ at risk outside tumor,but also represents the dose distribution in the PTV.In addition,nCI was stricter with treatment planning qualities when the dose around PTV was closer to the prescribed dose.The value of target coverage(TC),the ratio of out-of-target volumes receiving 105％prescribed dose to the target volume(R105％),the ratio of volume covered by 50％isodose line to the target volume(R50％),and the ipsilateral lung V20were 98.70％,0.56,5.53,15.59％in the CI plans,vs.90％,0,4.99,14.42％in the corresponding nCI plans,respectively.All index were significantly lower in the nCI group(Z ＝-3.823,-3.180,-3.823,-3.783,respectively,P＜0.05).The ratio of the maximum dose to the 2 cm external margin from the PTV(D2 cm)to the maximum dose to the PTV were 63.70％and 64.07％respectively in the two groups,and the differences were not statistially significant(P＞0.05).The conformity values denoted a clinically favorable value as 1 between D95％and D99％of nCI plans,yet were not applicable to CI plans.Conclusions It is more clinically relavant to evaluate lung SBRT plans using nCI,TC and other indicators collectively than using CI alone.
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Objective To investigate the dosimetric performance of two algorithms for correcting the presence of tissue inhomogeneities,the finite site pencil beam (FSPB) and X-ray voxel Monte Carlo (XVMC) plans were implemented in the MONACO system,with the accuracy of application to clinic treatment of two algorithms were evaluated.Methods In a non-uniform artificial anthropomorphic phantom,regular open fields and intensity modulation radiated therapy (IMRT) plans of the MONACO were measured by using calibrated EBT2 films,and the dose accuracy of the two kinds of plans was analyzed by comparing the planned and measured plane dose.Results In an anthropomorphic phantom,the deviations between the calculated values by XVMC and the measured values by films were less than ± 2％.While the deviations of FSPB values between calculation and measurements was within ± 3％,except at the condition of 15 MV,10 cm ×2 cm field,the dose error in lung was up to 6.51％.The verification of individual IMRT beams based on films showed that the pass rates of calculation by XVMC and FSPB were larger than 90％ with γ criterion of 3％/3 mm and 4％/4 mm,respectively.At 3％/3 mm,the pass rates of FSPB were in the range of 80％-90％.At the same time,the pass rates of all individual fields were higher than 90％.Conclusions The accuracy of dose calculation of XVMC is better than that of FSPB when being in multi-segments and non-uniform media.The error of algorithm can be controlled within ±3％,for the calculation by XVMC.And the dose deficiency of PTV arising from algorithm can be avoided.
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Objective To evaluate the potential influencing factors associated with pathologic complete response ( pCR) after neoadjuvant chemoradiotherapy for locally advanced rectal cancer ( LARC) . Methods A retrospective analysis was performed on the clinical data 265 patients with stageⅡandⅢ( the 7th version of AJCC) rectal cancer admitted to our hospital from 2011 to 2013. All patients underwent neoadjuvant concurrent chemoradiotherapy ( CCRT ) followed by surgery with/or without induction chemotherapy during the interval between the complete of CCRT and surgery. The predictors associated with pCR were analyzed by univariate and multivariate logistic regression analyses. With the use of the independent predictive variables for pCR from multivariate analysis, a clinical risk score model was established according to the following criteria:no?risk group (0 factor);low?risk group (1 factor);high?risk group ( 2 factors) . Results Among these 265 patients, 50( 18. 9%) achieved pCR. The univariate analysis showed that carcinoembryonic antigen ( CEA) level before CCRT ( P=0. 017) , T stage before CCRT ( P=0. 001), interval between complete of CCRT and surgery (P=0. 000), and the maximum tumor thickness before CCRT ( P=0. 040) were significantly associated with pCR. The multivariate analysis showed that pre?CCRT CEA level ( P=0. 021 or 0. 446) and interval between the complete of CCRT and surgery ( P=0. 000 or 3. 774) were significant predictors of pCR. When stratifying for smoking status, only low pre?CCRT CEA level was significantly associated with pCR in the non?smoking patients ( P=0. 044) . For the prediction of pCR by the clinical risk score model, the sensitivity was 0. 805, the specificity was 0. 460, the area under the receiver operating curve was 0. 690 ( 95% CI= 0. 613?0. 767 ) , the positive predictive value was 35 . 4 9%, the negative predictive value was 8 6 . 5%, and the predictive accuracy was 7 3 . 9%. Conclusions For locally advanced rectal cancer, pCR can be achieved in some patients after neoadjuvant therapy. Low pre?CCRT CEA level and long interval time between CCRT and surgery are independent factors associated with pCR, and only low pre?CCRT CEA level is an associated factor in the group of nonsmokers. The clinical risk score model based on pre?CCRT CEA level>5 ng/ml and time interval from CCRT completion to surgery≤8 weeks can be used to predict pCR after neoadjuvant chemoradiotherapy for LARC.
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With deeper understanding for intervertebral disc degeneration,the development and clinical application of protocols in molecular biology,biological intervention in initial stage of intervertebral disc degeneration can retard even reverse the degeneration process. Gene therapy of intervertebral disc degeneration refers to the selection of animal models and gene carriers,application of target genes,etc. It is the key for gene therapy to build human-like animal model,select proper gene carrier and apply ideal target genes. Prior to clinical application,the safety and efficacy of gene therapy should be proved,thus many problems deserve further study.