Objective To evaluate the impact of respiratory motion on lung dosimetry using 4D-CT during lung cancer radiotherapy.Methods Ten cases were randomly selected from non-small cell lung cancer (NSCLC) patients treated in our department.The 4D-CT machine was adopted for simulation before treatment and 10 respiratory phases were obtained for each patient.Target volumes were delineated on the maximum intensity projection (MIP) images,and plans were generated on average intensity projection (ALP) images.Plans were transferred to CT images of each respiratory phase,and we calculated the dosage on lungs and subsequently evaluated the volume dosage to lungs and the entire body.Results The mean dosage to lungs are greatly affected by the respiratory phase.This difference also depended on tumor location.When it was inside the lung,the average dosage shows the same trend as the respiratory motion,with the change rate of 2.18％,which was less than the change of lung volume 4.49％ (t =4.189,P ＜ 0.05).When the tumor was located nearby the lung,the mean dosage showed the opposite trend with respiratory motion,with the change rate of 3.76％,which was also less than the change of lung volume 4.49％ (t =25.007,P ＜ 0.05).The effect of respiratory motion on V5,V10,V20 of body was small,and the magnitude of change for whole body dosages were 0.47％,0.28％,0.17％ respectively,which was smaller than the change of lung volume 4.49％ (t =11.371,11.188,11.377,P ＜ 0.05).Volume dose of lung V5,V10,V20 and lung volume change trends were the same,and the magnitude of change for lung volume dosages were 2.39％,1.91％,1.80％ respectively,and were smaller than the change of lung volume 4.49％ (t =2.279,2.298,2.485,P ＜ 0.05).Conclusions The mean dosage to lungs shows a great difference between different respiratory phases.More attention should be paid when evaluating the lung volume during treatment planning.

Objective To compare the short- and long- term effects and safety of endoscopic balloon dilatation vs. placement of specially designed reclaimable self-expanding anti-reflux esophageal stents for achalasia. Methods A total of 129 patients with achalasia were divided into 2 groups to receive either endoscopic scopic balloon dilatation(,l=63)or endoscopic placement of specially designed reclaimable self-expandinganti-reflux esophageal stents (n = 66). The dysphagia symptom scores were recorded before and 1-month,6-month and 12-month after the procedure, respectively. The change in width of esophagus, procedure related complications, length and costs of hospitalization were also analyzed. Results Dysphagia symptom score was significantly decreased after the treatment in both groups (P < 0.05). The effective rates evaluated at 1-month, 6-month and 12-month after the procedure in balloon dilatation group were 100. 0% , 96. 7% and 91.5% , respectively, which in stenting group were 100.0% , 98. 0% and 97.1% , respectively. There was no significant difference in changes of symptom score at 1-month and 6-month after treatment between the 2 groups (P > 0.05) , while at 12-month after treatment, the decrease of symptom score in stenting group was significantly higher than that in balloon dilatation group (P<0. 05). After the treatment, the significant widening of the stricture and narrowing of the dilated esophagus were achieve in both groups (P < 0.05),while no significant difference between these 2 groups was observed in changes of width (P > 0. 05). Procedure related complications in balloon dilatation group included esophageal perforation (n =1) and upper gastrointestinal bleeding (n=4) , which was not occurred in stenting group, but complications included hyperplasia of granulation tissue (n = 1), stent dislocation (n =2) and defulvium (n = 1) was observed inthe latter group. The length of hospitalization was similar in 2 groups (P > 0. 05) , and the cost of hospitalization in stenting group was significantly higher than that of balloon dilatation group (P < 0. 05). Conclusion Compared with endoscopic balloon dilatation, the specially designed reclaimable self-expanding antireflux stents is a more ideal method for achalasia, with similar short-term effect, but better long-term effect and safety.

To explore the safety and efficacy for radiofrequency ablation of paroxysmal supraventricular tachycardia (PSVT) guided by Carto Univu three-dimensional mapping system.
 Methods: A total of 99 patients with PSVT underwent radiofrequency catheter ablation (RFCA) were assigned to a Carto Univu group (51 patients) and a two-dimensional X-ray group (48 patients) according to the mapping method. The operation time, X-ray exposure time, X-ray exposure dose, dose area product (DAP), operation success rate and complication rate were compared between the two groups.
 Results: The Carto Univu group and the two-dimensional X-ray group were not significant difference in the operation time, the X-ray exposure time of placing catheter, the X-ray DAP of placing catheter, the number of discharge, the discharge power, and the total discharge time (P>0.05). The mapping and ablation time, total exposure time, mapping and ablation DAP and total DAP in the Carto Univu group were significantly lower than those in the two-dimensional X-ray group (P<0.01). In the right accessory pathway cases, the mapping and ablation DAP and the total DAP in the Carto Univu group decreased compared with X-ray group (P<0.05), but it decreased more profound (P<0.01) in the left accessory pathway cases and the dual atrioventricular nodal pathways cases. Seven cases in the Carto Univu group achieved "zero X-ray", including 5 cases of the dual atrioventricular nodal pathways and 2 cases of the left accessory pathway. The immediate success rate for the two groups was 100%. After 3-12 months of follow-up, there was no recurrence in the Carto Univu group but 3 suspected recurrences in the two-dimensional X-ray group. In addition, no complications occurred in the two groups. 
 Conclusion: Carto Univu electroanatomic mapping system can guide PSVT safely and effectively during radiofrequency ablation and reduce radiation exposure to both doctors and patients. It is especially suitable for dual atrioventricular nodal pathways, which may even achieve "zero X-ray". Perhaps Carto Univu will be the first choice for RFCA of dual atrioventricular nodal pathways.
Catheter Ablation ; instrumentation ; methods ; Humans ; Imaging, Three-Dimensional ; instrumentation ; methods ; Operative Time ; Radiation Exposure ; prevention & control ; statistics & numerical data ; Radiography ; statistics & numerical data ; Recurrence ; Tachycardia, Supraventricular ; diagnostic imaging ; surgery ; Treatment Outcome