Purpose:To obtain the optimum irradiation technique in different plans of conventional radiotherapy(2DRT)and conformal radiotherapy(3DCRT)and between different conformal radiotherapy techniques for esophageal carcinoma as compared by 3D-TPS.Methods:10 patients with esophageal carcinoma were enrolled in this study.The conventional treatment plan and four conformal technique plans were created for each patient.Plan 1 was the same as the 2DRT,plan 2 consisted of anterior and two posterior oblique fields,plan 3 consisted of posterior and two anterior oblique fields,plan 4 consisted of 2 dynamic arc fields.Different plans were compared using DVH.Results:①On average,PTV of 2DRT was the same as that of 3DCRT in DVH.The difference in maximum dose to spinal cord was obvious.The left lung dose in D_(mean)?D_(min)?V_(30) in 2DRT was significantly increased as compared to 3DCRT(P

Background and purpose:Now 3-dimensional conformal radiotherapy(3DCRT)and intensitymodulated radiotherapy(IMRT)are widely used in the treatment of head and neck tumor.For the parotid,this target area is located on the side of the head and the tumor has a concave shape.What kind of radiation method can be used more eriectively to achieve dose uniformity and protection organs at risk is the topic of much discussion.The postoperative irradiation of parotid tumor is varied in the techniques used.In this study,3-dimensional conformal radiotherapy (3DCRT),intensity-modulated radiotherapy(IMRT)and simplified forward planned multi-segment radiotherapy (MSRT)were compared to conventional planning techniques in order to investigate the potential advantages of these new treatments.Methods:The conventional planning included the large opposed lateral fields with 2 or 3 weight ratio at the target lateral(2F-2D)and the unilateral field with mixture of 6 MV photon and electron beams(X+E).The 3D techniques included 3DCRT,MSRT and IMRT.Their dose distributions were calculated and compared for 8 patients treated in our center.Different beam arrangements were used for 3D techniques.In each case.the dose of PTV was prescribed to 60 Gy.All plans were compared using dose-volume histogram data.The conformity index(CI)and heterogeneity index(HI)of dose were used to evaluate the dose coverage of the target volume.Dose sparing of brain stem.spinal cord and the contra lateral parotid was also compared.To compare IMRT and MS RT,the timing ofplanning and radiation delivery was recorded.Results:Compared to conventional planning,the 3DCRT,MSRT and IMRT plans produced adequate target coverage,and the CI showed 3DCRT plans(0.78)produced poorer target coverage than MSRT(0.81)and IMRT(0.85).MRST and IMRT plans showed a significant reduction in maximum dose to the spinal cord,brainstem and the contra lateral parotid,compared to the conventional plans,while the 3DCRT plan did not show significant sparing of these structures.MSRT and IMRT plans produced better dose coverage among all the techniques.The efficacy of beam delivery comparing between two modulated planning showed MSRT was better.Conclusion:For postoperative irradiation of parotid cancer,3D planning techniques generated better target dose-coverage,without compromising the dose-sparing advantages of important structures.A satisfactory dose distribution can be obtained using MSRT and such a simple technique may be suitable for replacing IMRT.

Objective To study the immobilization effect and keep the accurate treating position of Body-Fix (R) device in the patients with vertebral metastatic tumor treated by hypofractionated intensitymodulated radiotherapy.Methods From October 2008 to February 2010,six nasopharyngeal carcinoma patients with 10 treated lesion with vertebral metastasis who were treated by hypofractionated intensitymodulated radiotherapy and immobilized by the Body-Fix (R) device were enrolled in this study.Three sets cone beam CT images were taken and recorded when patient was underway the initial setup,position correction and after radiation delivery.Comparing these images with the planning CT images to get the setup errors and the intrafractional position shifting,and the immobilization effect of Body-Fix (R) device was analyzed.Results In the upper,middle and lower sections of the vertebrae,the intrafractional setup errors in the left-right direction were (-0.6±0.5) mm,(-0.1 ±1.0) mm,(0.0±0.4) mm,with in the superior-inferior direction (1.0 ± 1.4) mm,(4.8 ± 5.7) mm,(0.0 ± 0.3) mm and in the anterior-posterior direction (1.2 ± 5.2) mm,(-0.3 ± 0.3) mm,(0.0 ± 0.5) mm,respectively.Conclusions With Body-Fix (R) device,the intrafractional setup errors can be minimized within 2 mm which make the accurate spinal radiosurgery technique possible.

Objective To establish a rat model of radiation-induced optic neuropathy ( RION) by delivering a single radiation dose to the optic chiasm. The aim of our study was to analysis the feasibility and effectiveness of manganese-enhanced magnetic resonance imaging ( MEMRI) in RION. Methods 34 Wistar rats were randomized to the control group(4 rats), the 2-month group(5 rats),the 4-month group(4 rats) and the 6-month group(11 rats) according to the different feeding period after irradiation. MEMRI scan were performed when the respective feeding periods of all groups expired. The rats were then killed for histological studies with hematoxylin and eosin stain, Luxol Fast Blue stain, and electron microscopy analysis. Results The ratio of RION in the four groups were 0/3, 1/5, 2/4 and 11/11, respectively (χ2 =15?443, P<0?05). There was an inverse correlation between the relative optical density value in the LFB stain and the interval between irradiation and pathological examination(R= -0?643,P<0?05). The number of glial cells in the HE stain in the four groups were 194 ± 65, 234 ± 19, 124 ± 11 and 345 ± 98, respectively(R=0?590,P<0?05). When compared MEMRI scan with the corresponding histological examination, we found that there was loss of signals of optic nerve on MEMRI imaging in one of 5 rats in the 2-month group, while no significant histological difference was found between this rat and the others. Conclusions RION can be non-invasively detected and semi-quantitative analysed by MEMRI scan. Moreover, RION can be early diagnosed by MEMRI scan which is capable to show physiological change in advance of pathological change.

ObjectiveTo evaluate the efficacy and toxicity of gemcitabine plus cisplatin (GP)chemotherapy combined with intensity-modulated radiation therapy (IMRT)in locoregionally advanced nasopharyngeal carcinoma (NPC).Methods71 patients (Stage Ⅲ:41,Stage ⅣA:30) with locoregionally advanced NPC were entered this study.Neoadjuvant chemotherapy was consisted of cisplatin 25 mg/m2 intravenously on d1-3 and gemcitabine 1000 mg/m2 in 30 minutes intravenous infusion on days 1 and 8,every 3 weeks for 2 cycles.Adjuvant chemotherapy consisted of 2 cycles of the same GP regimen was given at 28 days after the end of radiotherapy.The prescription doses was 66.0-70.4 Gy to the gross tumor volume,66 Gy to positive neck nodes,60 Gy to the high-risk clinical target volume,54 Gy to the low-risk clinical target volume.ResultsThe overall response rate to neoadjuvant chemotherapy was 91.2％,acute toxicity was mainly grade 1-2 myleosuppression.All patients completed IMRT.The median follow-up duration was 38 months.The 3-year nasopharyngeal local control,regional control,distant metastasis-free survival rate and overall survival rate were 93％,99％,91％,90％,respectively.Severe late toxicities included grade 3 trismus in 1 patient,grade 3 hearing impairment in 2 patients and cranial nerve palsy in 2 patients,respectively.No grade 4 late toxicities were observed.Conclusions The combination of GP chemotherapy and IMRT for locoregionally advanced nasopharyngeal carcinoma is well-tolerated,convenient,effective,and warrants further studies of more proper cycles of GP regimen.

Objective To study the effect of different fraction interval with same total radiation dose on tumor growth delay and survival in C57BL mice implanted with lewis lung cancer,and to determine whether prolonged fraction interval will decrease the tumor response to radiation. Methods Forty-eight mice were implanted with lewis lung cancer in the back legs.When the diameter of transplanted tumor reached 0.8 to 1 cm,the mice were randomized into 6 groups:normal control group,single fraction of 18 Gy group,18 Gy in 2 fractions of 9 Gy at 30 min interval group,18 Gy in 7 fractions of 2.57 Gy at 5 min inter val group,18 Gy in 2 fractions of 9 Gy at 60 min interval group and 18 Gy in 7 fractions of 2.57 Gy at 10 rain interval group.The maximal and minimal diameters of the tumor were measured and record every other day to study the tumor growth tendency,the tumor growth delay and the mice survival time. Results The tumor growth delay of groups at prolonged fraction interval was shorter than the group with single fraction of 18 Gy (P < 0.05).The tumor growth delay of groups at fraction interval of 30 rain was longer than that of groups at interval of 60 rain (P < 0.05).There was no significant difference of the tumor growth delay be tween the groups with same delivery time (P >0.05).The mice survival time of the groups with prolonged fraction interval was shortened when omparing to the group with single fraction of 18 Gy.While the difference was not significant between the groups at fraction interval of 30 min and 60 min. Conclusions The pro longed fraction interval but same total radiation dose shortens the tumor growth delay and survival time in the mice implanted with Lewis lung cancer.The longer fraction interval impairs the tumor control more signifi candy.However the difference of the effect on mice survival time is not significant between the groups at fraction interval of 30 min and 60 min.

60 cm 3). Primary tumor volume was found to be an independent prognostic factor of local control in multivariant analysis without any statistical significance to predict the disease-free survival or distant relapse-free survival rates. Conclusion The greater volume disparity with the same T stage and the data extension overlap with different T stages are demonstrated and the primary tumor volume may be considered as a prognostic factor in the treatment of nasopharyngeal carcinoma.

Background and purpose:Studies have shown that some molecular markers could serve as prognostic factors for nasopharynx carcinoma, but the predictive role of catenins and cyclin D1 remains uncertain for the disease. Our paper is to investigate the expression of catenins(?-,?- and ?-) and cyclin D1 in nasopharyngeal carcinoma as well as to analysis their relation to clinic factors and prognosis. Methods:We retrieved 38 paraffin-embedded specimens of nasopharynx carcinoma, immunohistochemistry was used to examine the expression of ?-,?- and ?-catenin , cyclin D1 and tumor proliferation activity marker ki-67.Results:Reduced expression of ?-,?- ,?-catenin and cyclin D1 was observed in most of the tumors. Our preliminary study demonstrated that there was no significant correlation between their expression with T-stage, N-stage, clinical stage and primary tumor volume, as well as with ki-67 stain. In unviarance analysis, patients with reduced expression of ?-catenin had poorer prognosis than those with high expression, 5 year overall survival and disease free survival rates of these two groups were 53.2%, 29.0% and 81.9%, 76.0%, respectively(P

Objective To retrospectively analyze the treatment outcomes and failure patterns in patients with head?and?neck cancer of unknown primary head?and?neck cancer of unknown primary, and to compare the efficacy between elective mucosal irradiation and ipsilateral neck treatment. Methods The clinical data of patients with head?and?neck cancer of unknown primary who were admitted from January 2007 to December 2013 were retrospectively collected. Thirty?one patients received elective pharyngeal mucosal irradiation and 61 patients only received ipsilateral neck treatment. The SPSS 19. 0 software was used for comparison of the survival and local control between the two groups. Results In the 92 patients, the median age was 57 years;79. 3% had metastasis to level Ⅱ lymph nodes;the median follow?up time was 36. 5 months;the 3?year overall survival, mucosal control, and neck control rates were 89. 0%, 86. 6%, and 82. 4%, respectively. Primary sites were found in 15 patients, containing nasopharynx in 4 patients, oropharynx in 3 patients, oral cavity in 3 patients, throat and hypopharyngeal part in 3 patients, maxillary sinus in 1 patient, and esophagus in 1 patient. The patients undergoing elective pharyngeal mucosal irradiation had significantly higher 3?year mucosal control and neck control rates than those undergoing ipsilateral neck treatment ( 100% vs. 74. 9%, P= 0. 040;87. 5% vs. 62. 2%, P= 0. 037 ) . There was no difference in the 3?year overall survival rate between the two groups ( 83. 5% vs. 88. 7%, P= 0. 910 ) . Conclusions For patients with head?and?neck cancer of unknown primary, elective pharyngeal mucosal irradiation can reduce the incidence of primary site and increase the neck control rate. A new standard for target volume delineation should be established as soon as possible for elective prophylactic pharyngeal mucosal irradiation.

Objective To evaluate set-up errors by megavoltage cone-beam CT in head and neck cancers treated with precision radiotherapy. Methods From April 2007 to March 2008, 22 patients with nasopharyngeal carcinoma (15 patients) ,parotid carcinoma (4 patients) and brain glioma (3 patients) were enrolled, among whom 7 patients underwent three-dimensional conformal radiotherapy (3DCRT) and 15 received intensity modulated radiotherapy (IMRT). The radiation dose was 56. 0 -70.4 Gy in 28 -32 fractions within 6 -7 weeks. Megavoltage cone-beam scan was performed weekly before treatment. The isocenter displacement was calculated by comparing megavoltage cone-beam CT and planning CT in left-right (LR), cranio-caudal (CC), and anterior-posterior (AP) directions. Results Totally 129 sets of megavoltage cone-beam CT images were obtained for 22 patients. The frequency of isocenter shift more than 0. 3 cm,0. 4 cm and 0. 5 cm were 28,15 and 9, respectively. The maximum mean set-up error was found in CC, which was about 0. 1 cm more than that in LR and AP. The frequency of isocenter shift direction was almost identical in LR and CC, which was more frequent (about 75%) in the posterior direction. Conclusions During the course of radiation of brain tumor and head and neck cancer, the enlarging tendency of set-up errors has been found in all the three directions. The isocenter shift in AP was more frequent to the posterior direction.