Objective To study the correlation between the occurrence of encephaledema and the target dose-volume after the low dose stereotactic radiosurgery of epilepsy.Methods Totally 136 epilepsy patients treated by low dose stereotactic radiosurgery with Novalis System were analysed retrospectively.The target doses and volumes of the patients were analysed by drawing out the scatterplot and conducting the binary Logistic regression to all of the data.An equation was obtained to predict the occurrence of radiation induced encephaledema in certain range of target volume and dose.Results Among all of 136 patients,different degree of local encephaledema occurred in 19 cases after the radiosurgery.Higher occurrence of radiation induced encephaledema was observed when the target central dose (i.e.90％ isodose circling the target)was more than 18 Gy or the target volume more than 30 cm3.Moreover,in patients with multitargets the doses of different targets devoted to each other,which could lead to the occurrence of local encephaledema.The equation to predict the occurrence probability was obtained by regression analysis.By testing this equation in all of 136 patients the coincidence percentage was 94.7％.Conclusions The target dose and volume could be effective parameters in certain range to predict the occurrence probability of radiation induced encephaledema.This equation would help to establish and optimize the therapeutic planning system.So it could finally reduce the side-effect of low dose stereotactic radiosurgey in epilepsy patients.The equation has some clinical value.

Objective:To investigate the predictive value of tumor regression rate after induction chemotherapy for survival of patients with locally advanced nasopharyngeal carcinoma.Methods:A total of 161 patients with stage Ⅲ-ⅣA nasopharyngeal carcinoma newly diagnosed at the Daping Hospital of Army Medical University from January 2009 to December 2012 were selected as the research subjects. The relationships between tumor size changes before and after induction chemotherapy and survival time were analyzed. Kaplan-Meier method was used to draw the survival curve accompanied with log-rank test. Cox regression analysis was used to analyze the risk factors affecting the prognosis of patients with nasopharyngeal carcinoma.Results:There were statistically significant differences in the tumor regression rate of primary lesions between N 1and N 2-3( Z=2.177, P=0.029), T 1-2and T 3-4( Z=-4.501, P<0.001)patients after induction chemotherapy. In N 1stage patients, the 5-year overall survival (OS) rates of patients with primary lesions achieving objective response ( n=18) and those without objective response ( n=19) after induction chemotherapy were 88.89% and 57.45%, and patients with cervical lymph node metastatic lesions achieving objective response ( n=19) and those without objective response ( n=18) were 86.72% and 49.10% respectively, with statistically significant differences ( χ2=6.023, P=0.014; χ2=7.441, P=0.006). In N 2-3stage patients, the 5-year OS rates of patients with primary lesions achieving objective response ( n=81) and those without objective response ( n=43) after induction chemotherapy were 77.56% and 50.70%, and patients with cervical lymph node metastatic lesions achieving objective response ( n=85) and those without objective response ( n=39) were 75.11% and 52.04% respectively, with significant differences ( χ2=8.037, P=0.005; χ2=7.268, P=0.007). Univariate Cox regression analysis showed that in patients with stage N 1, the tumor regression rate of primary lesions ( HR=0.048, 95% CI: 0.004-0.644, P=0.022), the efficacy of primary lesions ( HR=0.174, 95% CI: 0.037-0.830, P=0.028), the efficacy of cervical lymph node metastatic lesions ( HR=0.154, 95% CI: 0.033-0.725, P=0.017) after induction chemotherapy were significantly associated with OS; in N 2-3stage patients, the tumor regression rate of primary lesions ( HR=0.178, 95% CI: 0.056-0.564, P=0.003), the tumor regression rate of cervical lymph node metastatic lesions ( HR=0.081, 95% CI: 0.020-0.324, P<0.001), the efficacy of primary lesions ( HR=0.422, 95% CI: 0.228-0.781, P=0.006), the efficacy of cervical lymph node metastatic lesions ( HR=0.439, 95% CI: 0.238-0.813, P=0.009) after induction chemotherapy were significantly associated with OS. In multivariate Cox regression including N stage and tumor regression rate, N stage and efficacy, the interaction items were not statistically significant (all P>0.05). In T 1-2stage patients, the 5-year OS rates of patients with primary lesions achieving objective response ( n=45) and those without objective response ( n=13) after induction chemotherapy were 77.55% and 84.62%, and patients with cervical lymph node metastatic lesions achieving objective response ( n=43) and those without objective response ( n=15) were 78.89% and 80.00% respectively, with no significant differences ( χ2=0.239, P=0.625; χ2=0.005, P=0.943); in T 3-4stage patients, the 5-year OS rates of patients with primary lesions achieving objective response ( n=54) and those without objective response ( n=49) after induction chemotherapy were 78.90% and 45.00%, and patients with cervical lymph node metastatic lesions achieving objective response ( n=61) and those without objective response ( n=42) were 75.10% and 42.89% respectively, with significant differences ( χ2=13.615, P<0.001; χ2=12.752, P<0.001). Univariate Cox regression analysis showed that in patients with stage T 1-2, the tumor regression rate, the efficacy of primary lesions and cervical lymph node metastatic lesions after induction chemotherapy were not related to OS (all P>0.05); in T 3-4stage patients, the tumor regression rate of primary lesions ( HR=0.121, 95% CI: 0.033-0.444, P=0.001), the tumor regression rate of cervical lymph node metastatic lesions ( HR=0.126, 95% CI: 0.036-0.442, P=0.001), the efficacy of primary lesions ( HR=0.297, 95% CI: 0.150-0.588, P<0.001), the efficacy of cervical lymph node metastatic lesions ( HR=0.329, 95% CI: 0.173-0.625, P=0.001) after induction chemotherapy were significantly associated with OS. Multivariate Cox regression analysis showed that the interaction test of T stage and the efficacy of primary lesion trended to be statistically significant ( P=0.062). Conclusion:In patients with stage Ⅲ-ⅣA nasopharyngeal carcinoma, the responsiveness to induction chemotherapy in stage T 3-4patients has important value in predicting survival prognosis.

Objective To investigate the therapeutic effect and safety of microneurosurgery associated with Gamma Knife radiosurgery on the large meningiomas in sellar region, and to clarify its clinical curative effect. Methods The clinical data of 34 patients with large meningiomas in sellar region underwent microsurgery were retrospectively analyzed.All of them underwent microsurgery,and then treated with Gamma Knife radiosurgery in one month after operation if there were residual tumors.The tumor removal of situation,complication,rate of symptom remission,and recurrence rate were analyzed.Results Among the 34 patients,total resection (7 cases of Simpson grade Ⅰ and 12 cases of Simpson grade Ⅱ)was achieved in 19 cases (55.9%),subtotal resection (Simpson grade Ⅲ )in 14 cases (41.2%), and partial resection (Simpson grade Ⅳ )was achieved in 1 case (2.9%).The major complications were cranial nerve injuries (such as oculomotor nerve, trochlear nerve and abducens nerve,n=6),the contralateral limb paresis (n = 2),postoperative bleeding (n = 1),CSF leak with infection (n=3),and secondary epilepsy (n = 3 ); no death occurred postoperatively. All these patients were followed up for about 3 to 48 months.Postoperative headache disappeared in 24 cases (80%),and 6 cases were alleviated (20%);postoperative vision improved in 12 cases (80%),remained unchanged in 2 cases (13.3%)and deteriorated in 1 case (6.7%); postoperative olfactory function improved in 5 cases (62.5%) and 3 cases unchanged (37.5%); 5 cases recoverd from the ocular motility disorder (71.4%), and 2 cases unchanged (28.6%);7 cases recoverd from thehemiplegia (100%).One of the total resection cases (5.2%)and two of the non-total resection (13.3%)suffered from tumor recurrence.All of the non-total resection cases were treated with Gamma Knife radiosurgery.Conclusion The clinical effect of microneurosurgery associated with Gamma Knife radiosurgery in treatment of large meningiomas in sellar region is satisfactory.

Objective To investigate the difference of translational error and rotational error in the ra-diotherapeutic positioning after breast cancer modified radical surgery by using the two fixation methods of the cervicothoracic thermoplastic membrane and body thermoplastic membrane based on conical beam CT (CBCT) images.Methods A total of 82 patients with radiotherapy after breast cancer modified radical sur-gery admitted and treated in this hospital from January 2022 to September 2023 were selected as the study subjects and divided into the cervicothoracic membrane group (using the cervicothoracic thermoplastic mem-brane,n=52) and body membrane group (using the body thermoplastic membrane,n=30) according to the radiotherapeutic fixation methods.All patients weekly conducted the CGCT scanning in the first time radio-therapy and radiotherapeutic period.The verification image conducted the retification with the planned image. The translational errors in the left and right direction (X),head and foot direction (Y) and abdominal and dor-sal direction (Z) were recorded,as well as the rotation errors around the axis under the two fixing methods,including the rotation error of the X-axis rotation direction (Rx),Y-axis rotation direction (Ry),and Z-axis rotation direction (Rz).The differences in positioning errors were compared between the two groups. Results There was no significant difference in X,Y,Z,Rx,Ry and Rx positioning error between the two groups after the first treatment,1-week treatment and 2-week treatment (P>0.05).After 3-week treatment,the positioning errors in X[0.21(0.12,0.27)mm vs. 0.22(0.20,0.35)mm],Y[0.20(0.11,0.24)mm vs. 0.25(0.16,0.37)mm],Z[0.15(0.08,0.25)mm vs. 0.20(0.15,0.29)mm],Rx[0.57(0.22,1.10)° vs. 1.00 (0.70,1.50)°],Ry[0.50(0.30,1.20)° vs. 1.10(0.60,1.40)°]and Rz[0.30(0.20,0.80)° vs. 0.90(0.40,1.50)°]in the cervicothoracic membrane group were smaller compared with the body membrane group (P<0.05).After 4-week treatment,the positioning errors in X[0.19(0.12,0.27)mm vs. 0.25(0.21,0.31)mm],Y[0.21(0.11,0.27)mm vs. 0.26(0.22,0.32)mm],Z[0.12(0.05,0.28)mm vs. 0.22(0.13,0.35)mm],Rx[0.80(0.49,1.10)°vs. 1.20(0.80,1.80)°],Ry[0.55(0.20,1.12)°vs. 1.10(0.80,1.30)°]and Rz[0.61 (0.29,1.10)°vs. 1.10(0.80,1.40)°]in the cervicothoracic membrane group were also smaller compared with the body membrane group (P<0.05).Conclusion The thecervicothoracic thermoplastic membrane could re-duce the positioning error in the breast cancer radiotherapy compared with the body thermoplastic membrane.

The current situation of tumor radiotherapy teaching is far behind the development of radiotherapy technologies. The construction of a teaching system based on an artificial intelligence-powered automatic target delineation system and a standardized cancer radiotherapy case library is operable and practical for realizing the standardization and homogenization of clinical target volume delineation teaching, improving students' precision and speed of target volume delineation, and promoting students' learning interest, initiative, and efficiency, which can bring new vitality to the development of radiotherapy education and is worthy of further exploration and promotion.