Objective To study the setup errors in three-dimensional conformal radiotherapy (3DCRT) for thoracic esophageal carcinoma using electronic portal imaging device(EPID) and calculate the margins from CTV to PTV. Methods Forty-one patients with thoracic esophageal carcinoma who received 3DCRT were continuously enrolled into this study. The anterior and lateral electronic portal images (EPI) were aquired by EPID once a week. The setup errors were obtained through comparing the difference between EPI and digitally reconstructed radiographs(DRR). Then the setup margins from CTV to PTV were calculat-ed. By using self paired design,22 patients received definitive radiotherapy with different margins. Group A: the margins were 10 mm in all the three axes;Group B: the margins were aquired in this study. The differ-ence were compared by Paired t-test or Wilcoxon signed-rank test. Results The margins from CTV to PTV in x,y and z axes were 8.72 mm, 10.50 mm and 5.62 mm, respectively. Between the group A and group B, the difference of the maximum dose of the spinal cord was significant(4638.7 cGy±1449.6 cGy vs. 4310.2 cGy±1528.7 cGy; t=5.48, P=0.000), and the difference of NTCP for the spinal cord was also significant (4.82%±5.99% vs. 3.64%±4.70%;Z=-2.70,P=0.007). Conclusions For patients with tho-racic esophageal carcinoma who receive 3DCRT in author's department,the margins from CTV to PTV in x, y and z axes were 8.72 mm, 10.50 mm and 5.62 mm, respectively. The spinal cord could be better protected by using these setup margins than using 10 mm in each axis.

Objective:To explore the effectof tumor volume on pulmonary dose-volume parameters by intensity-modulated radiation therapy (IMRT) in non-small cell lung cancer (NSCLC),and to provide a basis for pulmonary dose parameters in IMRT treatment.Methods:A total of 204 patients with NSCLC received IMRT were retrospectively analyzed from June,2009 to October,2013.The prescribed dose of planning target volume (PTV) for primary tumor was 60-66Gy (2.00-2.25 Gy,27-33 times in all).The fractional volume percent of the lung received a dose ＞5 or 20 Gy (V5,V20),and absolute volume of lung received a dose ＜5 Gy (AVS5).The mean lung dose (MLD) in normal tissues were analyzed.Regression model curve was used to analyze them along with the change of primary tumor volume.Results:With the increase in lung tumor volume,the V5,V20 and MLD presented quadratic equation curve,and AVS5 presented logarithmic equation.When the tumor volume,less than a certain value (294.6,283.2,304.9 cm3,respectively),the V5,V20 and MLD increased with tumor size and presented an increased quadratic curve;when the tumor volume was higher than a certain value (294.6,283.2,304.9 cm3 respectively),the V5,V20 and MLD was declined.The AVS5 was declined in a logarithmic curve along with the increase of tumor volume.Conclusion:With the increase in lung tumor volume,the change in rule ofV5,V20,MLD and AVS5 is not completely equivalent.When the tumor volume exceeds a certain boundary value (about 300 cubic centimeter),the corresponding tumor diameter is about 7-8 cm.In addition to the focus on pulmonary V5,V20 and MLD,we should also pay more attention to AVS5 restrictions in establishment ofIMRT in NSCLC.

Objective:To explore the regular variation pattern of tumor volumes of the patients with non-small cell lung cancer (NSCLC) before and after targeting treatment of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI),and to clarify its clinical value.Methods:The materials of 39 NSCLC patients with EGFR-TKI targeting treatment were retrospectively analyzed. The tumor volumes were detected by volume measurement software of TPS and Image J image processing software,then the absolute and relative tumor volume changes of the NSCLC patients before and after targeting treatment were analyzed by paired sample comparison symbol Wilcoxon rank test. Results:The absolute tumor volumes (mm3 )of the patients with NSCLC before and 1 month after targeting treatment were 14 822.11 (7 524.73,54 999.41)and 7 954.42 (3 499.73,29 396.83),respectively, and there was statistically significant difference (Z=-3.257,P=0.001);the absolute tumor volumes of the patients with NSCLC 1 and 2 months after targeting treatment were 8 358.47 (4 394.36,24 430.05)and 7 028.76 (3 634.98,21 056.71),respectively,and there also was statisticaliy significant difference (Z=-2.213,P=0.027).When the original tumor volume before targeting treatment was regarded as 1,the relative tumor volume of 1 month after targeting theatment was 0.612 6 (0.313 8,0.853 7),and there was significant difference (Z=-3.855,P<0.001);the relative tumor volumes of 1 month and 2 months after targeting treatment were 0.608 4 (0.364 3,1.044 3)and 0.423 0 (0.248 8,0.877 7),respectively,and there also was statistically significant differernce (Z=-2.173,P=0.030);but the differences between other consecutive months (from 3 months to 6 months)had no statistically significant differences (P>0.05);the changes of tumor relative volume presented platform stage after 3 months.The tumor relative volumes of 7-9 months after EGFR-TKI treatment reached the bottom.Conclusion:The average primary tumor volume of the NSCLC patients is obviously reduced 1 and 2 months after TKI targeting treatment. It may be optimal to carry out radiotherapy in 3-9 months after EGFR-TKI targeting treatment.

Objective: To evaluate the effect of tumor shape and location on pulmonary dose-volume parameters by intensity-modulated radiation therapy (IMRT) in patients with non-small cell lung cancer (NSCLC), aiming to provide a reference basis for establishing limits of the pulmonary dose-volume parameters during IMRT. Methods: Clinical data of 208 NSCLC patients undergoing radical IMRT from June 2009 to June 2016 were retrospectively analyzed. According to the tumor shape and location, 208 cases were divided into the vertical bar group (n=127) and the horizontal bar group (n=81), the superior lung group (n=103) and the inferior lung group (n=105). Regression model curve was used to evaluate the effect of tumor shape and location upon the common pulmonary dose-volume parameters(V₅, V₂₀, MLD, AVS₅ and AVS₂₀). Results: In all groups, the fitting curves of V₅, V₂₀ and MLD were manifested in the quadratic equation pattern, and AVS₅ and AVS₂₀ in the logarithmic equation manner. In the vertical bar group, the V₅(P=0.015), V₂₀(P=0.047) and MLD (P=0.012) were significantly higher, whereas the AVS₅(P=0.044) was significantly lower compared with those in the horizontal bar group. No statistical significance was observed in AVS₂₀ between two groups (P=0.490). The tumor location exerted significant effect upon V₅ alone (P=0.009). Conclusions When the tumors presents in the vertical bar shape, the limits of the common lung dose-volume parameters are likely to exceed those of tumors in the vertical bar shape. Lung tumors located in the inferior lobe exerts a more significant effect upon the low-dose region volume compared with the tumors in the superior lobe.

Objective: To calculate out the Hausdorff distance based on the scripting in RayStation treatment planning system, which was then applied in measuring the deformation error of brain stem during image automatic registration between CT and MR. Methods: Scripting was edited in RayStation system (version 4.7) by using IronPython. The set of point coordinates on the contour of any two region of interest (ROI) had been found firstly, then the Hausdorff distance between the two point sets was calculated out. A graphical user interface (GUI) was designed by using XAML to acquire the visualized output of Hausdorff distance. GUI appeared when the script was run, where two ROIs was selected, then the corresponding Hausdorff distance and the running time were displayed by pressing the "Calculate" button. Results: The mean Hausdorff distance of brain stem in 20 patients with head and neck neoplasms was 1.20 cm while the mean elapsed time was 11.01s. Conclusions Hausdorff distance of any two ROIs can be calculated out by using the developed method. GUI is designed to realize the visual interaction with RayStation system. Therefore, the RayStation system satisfies the demands of Hausdorff distance calculation in both clinical and research work.