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Purpose@#This study was aimed to investigate long-term survivals and toxicities of early-stage nasopharyngeal carcinoma (NPC) in endemic area, evaluating the role of chemotherapy in stage II patients. @*Materials and Methods@#Totally 187 patients with newly diagnosed NPC and restaged American Joint Committee on Cancer/ International Union Against Cancer 8th T1-2N0-1M0 were retrospectively recruited. All received intensity-modulated radiotherapy (IMRT)±chemotherapy (CT) from 2001 to 2010. @*Results@#With 15.7-year median follow-up, 10-year locoregional recurrence-free survival, distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were 93.3%, 93.5%, 92.9% and 88.2%, respectively. Multivariable analyses showed cervical lymph nodes positive and pre-treatment prognostic nutritional index ≥ 52.0 could independently predict DMFS (p=0.036 and p=0.011), DSS (p=0.014 and p=0.026), and OS (p=0.002 and p 45 years (p=0.002) and pre-treatment lactate dehydrogenase ≥ 240 U/L (p 0.05). Unsurprising, patients in IMRT+CT had more acute gastrointestinal reaction, myelosuppression, mucositis, late ear toxicity, and cranial nerve injury (all p < 0.05) than IMRT alone group. @*Conclusion@#Superior tumor control and satisfying long-term outcomes could be achieved with IMRT in early-stage NPC with mild late toxicities. As CT would bring more toxicities, it should be carefully performed to stage II patients.
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Objective:To analyze the predicting values of hematological indicators for the pathological response in patients with gastric adenocarcinoma after preoperative neoadjuvant therapy and radical surgery.Methods:The absolute count of neutrophils (NE), lymphocytes (LY) and monocytes (MO) of 102 patients with locally advanced gastric adenocarcinoma in a multi-center randomized phase Ⅲ clinical trial (NCT01815853) from June 2013 to Feburary 2019 were retrospectively analyzed. Patients were divided into the chemotherapy alone group (ChT, 3 cycles of XELOX regimen) and the chemoradiation group (CRT, 1 cycle of induced XELOX regimen and 4500 cGy/25f radiotherapy plus concurrent extenuated 2 cycles of XELOX regimen), 51 cases in each group. The pathological response indicators of tumors after radical surgery included tumor regression grade, pathological complete regression, pathological T stage (ypT), N stage (ypN) and TNM stage (ypTNM).Results:Univariate regression analysis and ROC curves demonstrated a significant association between the absolute neutrophil count (NE) and ypT, lymphocyte-to-monocyte ratio (LMR) and ypN 0, and LMR and ypTNM reduction in the entire cohort of patients. Multivariate regression analysis showed that higher NE (>4.10×10 9/L) was significantly associated with higher probability of ypT reduction ( OR=3.308, P=0.007). Higher LMR (>3.46) was significantly associated with higher ypN 0 probability ( OR=4.276, P=0.005) and better ypTNM reduction ( OR=2.805, P=0.019). In subgroup analysis, higher NE (>4.10) was significantly correlated with higher probability of ypT reduction ( OR=3.750, P=0.030) in the CRT group, and higher LMR (>3.46) was significantly associated with higher ypN 0 probability ( OR=8.500, P=0.050) and the probability of ypTNM stage reduction ( OR=4.000, P=0.026) in the ChT group. Conclusions:Pretreatment NE and LMR in the peripheral blood serve as independent predictors for tumor pathological responses after preoperative treatment, and immune condition is correlated with tumor regression after radical surgery in patients with locally advanced gastric cancer.
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PURPOSE: This study aims to investigate the feasibility of contouring target volume according to residual tumor and decreasing the dose to the tumor regression field after induction chemotherapy (IC) in locoregionally advanced nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: From August 2009 to August 2013, patients with stage III–IVB NPC were treated with IC and concurrent chemoradiotherapy. Gross tumor volume of nasopharynx (GTVnx)–residual and gross tumor volume of cervical lymph node (GTVnd)–residual were contoured according to post-IC residual primary tumor and any N+ disease, respectively. The tumor regression field was included in CTVnx1/CTVnd1 and prescribed a dose of 60 Gy. Outcomes and toxicities of all patients were evaluated. RESULTS: A total of 57 patients were enrolled. At a median follow-up of 68 months, three cases displayed locoregional recurrence and one case showed both distant metastasis and locoregional recurrence. All locoregional recurrences were in the GTVnx-residual/GTVnd-residual and in-field. The 5-year overall, locoregional relapse-free, distant metastasis-free, and progression-free survival rates were 82.2%, 87.7%, 85.8% and 80.3%, respectively. CONCLUSION: After IC, contouring of GTVnx-residual/GTVnd-residual as residual tumor volume and distribution 60 Gy ofradiation dose to the tumorregression field may be feasible and need further investigation.
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Humans , Chemoradiotherapy , Disease-Free Survival , Follow-Up Studies , Induction Chemotherapy , Lymph Nodes , Nasopharynx , Neoplasm Metastasis , Neoplasm, Residual , Radiotherapy, Intensity-Modulated , Recurrence , Tumor BurdenABSTRACT
Objective To analyze the 10-year survival outcome and failure patterns for patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT),aiming to provide reference for optimized treatment for NPC.Methods Clinical data of 866 patients with NPC receiving IMRT from January 2001 to December 2008 were retrospectively analyzed.Survival analysis was performed using the Kaplan-Meier estimator.Univariate analysis was carried out by log-rank test and multivariate analysis was performed using Cox proportional hazards model.Results The median follow-up time was 132 months.The 10-year local recurrence-free survival (LRFS),distant metastasis-free survival (DMFS),progression-free survival (PFS) and disease specific survival (DSS) were 92.0％,83.4％,75.7％ and 78.6％,respectively.A total of 210 patients died including 124 patients (59.0％) from distant metastasis,which was the primary cause of death,and 47 (22.3％) from local regional recurrence.Independent negative factors of DSS included age＞50 years (P=0.00),LDH ≥ 245 IU/L (P=0.00),Hb＜ 120 g/L (P=0.01),T2-T4 staging (P=0.00),N1-N3 staging (P=0.00) and GTV-nx＞20 cm3(P=0.00).The 10-year LRFS,DMFS and DSS of stage Ⅱ NPC patients did not significantly differ after IMRT alone and chemoradiotherapy (P=0.83,0.22,0.23).For patients with stage Ⅲ NPC,the 10-year LRFS and DSS in the chemoradiotherapy arm were significantly higher than those in the IMRT alone (P=0.01,0.01),whereas no statistical significance was observed in the DMFS between two groups (P=0.14).The overall survival of stage Ⅳa+Ⅳb NPC patients is relatively poor.Conclusions IMRT can improve the long-term survival of NPC patients.Distant metastasis is the primary failure pattern.Patients with stage Ⅰ-Ⅱ NPC can obtain satisfactory survival outcomes after IMRT alone.The addition of chemotherapy can further enhance the LRFS and DSS of stage Ⅲ NPC patients.However,the optimal therapeutic strategy remains to be urgently investigated for stage a+ Ⅳb NPC patients.
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Objective To investigate the clinical and dose-volume factors for damages to organs at risk(OARs)during preoperative chemoradiotherapy for gastric cancer, and to provide a reference for optimization of radiotherapy plans to avoid or reduce damages to OARs.Methods A total of 58 patients with locally advanced gastric adenocarcinoma undergoing neoadjuvant treatment were enrolled as subjects.In those patients,30 received preoperative chemoradiotherapy combined with surgery and adjuvant chemotherapy, while others received preoperative chemotherapy combined with surgery and adjuvant chemotherapy. The preoperative chemotherapy group received 2-3 cycles of xeloxregimen(capecitabine+oxaliplatin)before surgery and 3-4 cycles of xeloxregimen after surgery(a total of 6 cycles). The preoperative chemoradiotherapy group received preoperative radiotherapy(45 Gy in 25 fractions)combined with 2 cycles of concurrent xeloxchemotherapy at 14-21 days after the first cycle of xeloxregimen, as well as 3 cycles of xeloxchemotherapy after surgery. The analyses of clinical and dose-volume factors for damages to OARs were performed based on laboratory indices and clinical symptoms during the treatment. Results In all the patients,the incidence rates of liver injury(LI), renal injury(RI), and duodenum injury(DI)before surgery were 22%,48%,and 33%,respectively;the incidence rates of LI and RI after treatment were 35%and 49%, respectively. After appropriate treatment, neither LI nor DI affected the treatment of gastric cancer. RI healed without any special treatment. Compared with preoperative chemotherapy, preoperative chemoradiotherapy caused higher incidence of LI(P=0.00,0.03).RI was only associated with glomerular filtration rate before radiotherapy(P=0.08,0.13). A V3.5of ≤98.96% for the liver reduced LI, while a D2ccof ≤48 Gy for the duodenum reduced DI. Conclusions Preoperative chemoradiotherapy is safe for treating gastric cancer. Compared with preoperative chemotherapy, preoperative chemoradiotherapy does not increase the risk of RI. However,preoperative chemoradiotherapy tends to increase LI.Further studies are needed to improve the treatment method.
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Objective To establish a Loop-mediated Isothermal Amplification (LAMP) for Pseudomonas aeruginosa rapid detection. Method 152 P. aeruginosa strains isolated from nasal swabs and 30 reference strains were applied. P. aeruginosa ATCC15442 was used to develop LAMP amplification and evaluate sensitivity and specificity. Results Sensitivity of LAMP was 103 times higher than PCR, with DNA amount as 132 fg. When LAMP was applied to 30 reference strains and 152 P. aeruginosa strains , the specification was 100% while iden-tification rate reached 94.7%. Conclusion The establishment LAMP showed a promising prospect in P. aerugi-nosa rapid detection.
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Objective To develop a network management system for tumor radiotherapy information that integrates process management and quality assurance functions, and to investigate its clinical value. Methods Based on the requirements of radiotherapy process quality assurance and control, the client-server ( C-S) pattern, along with SQL SERVER 2008 database structure, international standard DICOM 3.0, DICOM RT, and HL7 protocols, and system hardware and self-developed software in local area network, was adopted to establish the network management system for radiotherapy information, and clinical tests were performed to evaluate the operation performance of this platform.Results ( 1 ) The interactive integrated management platform and client-side functional modules with a uniform interface were developed.( 2) The safe and reliable standardized data interface was developed, which could be connected to accelerators, treatment planning systems, and hospital information systems developed by mainstream manufacturers.( 3) The modules for radiotherapy process management and quality assurance and management were designed and developed.( 4) The platform passed all the tests before operation and had been used in clinical departments for almost 3 years, which confirmed that the system was safe and stable during operation and that all functions designed were realized.Conclusions The integrated management platform meets the requirements for application and management of radiotherapy information and data, improves the overall work efficiency in radiotherapy department and the level of quality assurance and control, and holds promise for clinical application as a good tool for tumor radiotherapy departments.
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Objective To investigate the impact of planning parameter settings on plan quality and delivery efficiency of VMAT for nasopharyngeal carcinoma with two treatment planning systems (TPS),as references for clinic plan optimization. Methods 25 patients with nasopharyngeal carcinoma were selected and planned for SIB?VMAT treatment. The same planning aims were used in the two kinds of TPS ( TPS?1 and TPS?2). Multiple planning parameters were set for plan optimization. Dose distribution to the target volumes and organs at risk,monitor unit ( MU) and delivery time were compared. Paired t?test or one?way ANOVA was used for the data which was in accordance to normal distribution;otherwise, nonparametric Wilcoxon signed rank test or nonparametric Friedman test was used. Results More segments lead to better plan quality and less MU but longer delivery time ( Minor impact was observed when segment number was larger than 120) in TPS?1,while it had little impact on both plan quality and delivery efficiency in TPS?2. Comparing to single?arc plans,dual?arc VMAT achieved no significant benefit in plan quality but had more MU and longer delivery time in TPS?1 ( P= 0?000 ) . However, dual?arc VMAT plans had better dose distribution in TPS?2, decreased the maximum and mean dose for spinal cord in 3?9% and 13?7%respectively (P=0?000,0?000).Changing the settings of maximum or minimum dose rate did not affect the plan quality in both of the tested TPSs. Increasing the maximum or minimum dose rate reduced the delivery time but the latter increased the number of MU ( P=0?000,0?000) . Conclusions VMAT plan quality and delivery efficiency is affected significantly and differently by planning parameter settings for two TPSs. Trial test should be conducted for different TPS to determine the optimal parameter settings.
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Objective To investigated the protective ways of intensity modulated radiotherapy (IMRT)for submandibular gland function in patients with nasopharyngeal carcinoma.Methods From March 2010 to November 2012,101 patients with nasopharyngeal carcinoma were enrolled into study.They were treated with IMRT and evaluated by face to face dry mouth questionnaire during the follow-up of 3,6,12,18,24 and more than 24 months,meanwhile,their dose volume histogram of submandibular gland were taken into consideration.Results The average contralateral median dose and that of ipsilateral submandibular gland were (45.69±7.22) Gy and (51.64±8.20) Gy,respectively,and the V35,V40,V45,V50 were 95.82 ％,69.99 ％,46.90 ％,25.50 ％,and 100 ％,96.50 ％,82.24 ％,60.98 ％,respectively.There were positive relationship between the xerostomia grading of 3,6,and 12 months after radiotherapy and the average dose of submandibular gland or the V35,V40,V45,V50.After 6 month,the xerostomia in 77.2 ％ (78/101) was significantly improved,and after 12 months,less than 5 ％ of patient complained about G3 or more grade of xerostomia.Conclusions When using IMRT in nasopharyngeal carcinoma,it' s necessary to reduce the irradiated volume and the dose of submandibular gland.It is confined that the median dose of contralateral submandibular gland should be less than 40-45 Gy,and V40 or V45 ≤66.7 ％ or ≤50 ％,which can effectively protect the function of salivary gland.
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ObjectiveTo evaluate the local failure and the impact on survival by prospectively comparing involved field radiotherapy (IFRT) and elective nodal irradiation (ENI) in combination with concurrent chemotherapy for locally advanced non-small cell lung cancer ( LA-NSCLC ).Methods LANSCLC patients were treated with 2 cycles of carboplatin ( AUC =5 - 6,d1 ) combined with paclitaxel ( 175mg/m2 ),followed assessment without distant metastasis,then randomized into IFRT (45 patients) or ENI (54 patients) arm.IFRT included primary tumor,ipsilateral hilar and positive mediastinal lymph nodes;ENI included the primary lesion,ipsilateral hilar,hilateral mediastinal lymph node drainage and bilateral supraclavicular area.The prescription dose was given as high as possible with V20 ≤35％ and spinal cord dose ≤50 Gy,combined weekly paclitaxel 40 mg/m2 concurrent chemotherapy.The Kaplan-Meier method was used to estimate survival data and the log-rank method was used to test distribution of survival time between arms.ResultsThe follow-up rate was 99％.49,29 and 17 patients were followed-up for 1-,2-and 3-year,respectively.More patients from group IFRT received ＞60 Gy than ENI (49％ vs.26％,x2 =5.59,P =0.018 ).The local failure rates were 29％ and 36％,respectively ( x2 =0.46,P =0.497 ).The 1-,2-and 3-year local tumor progression-free survival rates were 76％,69％,65％ and 80％,53％,49％ ( x2 =0.74,P =0.389),respectively; the 1-,3-and 5-year overall survival rates were 80％,41％,33％ and 69％,32％,13％ (x2 =3.97,P =0.046),respectively.There were no significant differences in acute and late toxicities between the arms ( x2 =3.910 - 0.155,P =0.142 - 0.925 ).ConclusionsIFRT improved radiation dose and survival rate and did not increase the failure of elective lymph node region compared with ENI.The toxicities were no differences between IFRT and ENL Further investigation with big size sample is warranted.
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ObjectiveTo compare planning quality,treatment efficiency and delivery accuracy for initial treated nasopharyngeal carcinoma (NPC) with step & shoot intensity modulated radiation therapy (ssIMRT) and volumetric modulated arc therapy (VMAT).These results will help make a clinic choice of the therapeutical technique.MethodsTwenty-six NPC cases were planned with the same dose prescription and objective constrains by means of 9-field ss-IMRT and VMAT respectively.Compare:( 1 ) plan dosimetric distribution,conformity index and homogeneity index of the targets,the average dose,maximum dose and interested dose-volume histograms of organs at risk (OAR) et al;(2) delivery times of the therapy plans ;(3) the accuracy of treatment plans dose verification.ResultsBoth therapeutical plans can achieve the clinic dosimetric demands.Compared to ss-IMRT,VMAT had less inferior target coverage.The CI and HI of the PGTV was 0.57 and 0.08 ( ss-IMRT),0.48 and 0.12 (VMAT) respectively ( t =-4.52,- 8.33,P =0.000,0.000).Except of brain stem,VMAT had higher mean dose and maximum dose of OARs than ss-IMRT (t=-9.57 - -3.71,P=0.000 -0.001).The spinal cord D1cc and parotids D50％ were increased by 11.9％ and 6.5％ averagely.The treatment times of ss-IMRT and VMAT were 803.7 s and 389.3 s respectively (t =24.12,P =0.000),while V MAT decreasing by 51.6％.The pass ratios of γ (3mm,3％ ) from the dose verification were 99.4％ (ss-IMRT) and 98.0％ (VMAT) respectively ( t =5.19,P =0.000).ConclusionsThe dose distribution of VMAT for initial treated nasopharyngeal carcinoma can achieve the clinic demands,but slightly worse than 9-field ss-IMRT.VMAT has the advantage of high efficiency and dosimetric accuracy.
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ObjectiveTo test a three-dimensional dose verification system,which reconstructing dose to anatomy based on modeling and online measurements ( RDBMOM ),and to evaluate the accuracy and feasibility of its application in clinical intensity-modulated radiotherapy (IMRT) quality assurance.Methods Phantom plans of regular and irregular fields were selected for the testing.All test plans were implemented and the dose distributions were measured using the thimble ion-chamber and two-dimensional ion-chamber array,the accuracy of RDBMOM were then evaluated by comparing the corresponding results.Two practical treated nasopharyngeal carcinoma IMRT plans were verified with RDBMOM and the clinic significancy were valued.ResultsCompared with measurements of the thimble ion-chamber,deviations of RDBMOM were within 1％ in all tested cases except small field of 3 cm ×3 cm.The largest deviation of reconstructed dose in IMRT cases was 2.12％.The dose profile reconstructed by RDBMOM coincided with the measurement using two-dimensional ion-chamber array.The γ rates (3％/3 mm) were 94.56％ - 100％.The RDBMOM verification of IMRT cases shown that the γ rate ＞ 99％ in total and ＞ 98％ in planning target volume,deviation in D95 ＜0.4％,but the largest deviations in mean dose of the parotids and lens were 2.97％ and 59.58％ respectively.ConclusionsAccuracy of the tested system satisfies the demand of IMRT dose verification.RDBMOM is able to provide information of volumetric dosimctry and anatomical location of dose error,which is benefit for evaluating the clinical value of verification results.
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Objective To explore the incidence, clinical characteristics, and prognosis of radiation encephalopathy (REP) in nasopharyngeal carcinoma (NPC) patients after intensity-modulated radiotherapy (IMRT). Methods 870 NPC patients confirmed pathologically and without distant metastasis received radical IMRT,570 of which received chemotherapy simultaneously,and followed up for 6 -104 months (with a median of 40 months),undergoing magnetic resonance imaging (MRI) once every 3 months within the first 3 years after treatment and then once every year.The clinical manifestations were observed.In 29 of these 42 patients diagnosed as with REP,the dose distributions of REP lesions were evaluated.Results 4.83％ of the NPC patients (42/870) were diagnosed as with REP.There were 39 cases with pure temporal lesion (bilateral in 6 cases),with a median latency period of 30 months (6 -56 months),2 cases with pure cerebral stem lesion both with a latency period of 14 months,and one case with lesions in temporal lobe and cerebral stem with the latency period of 18 months.REP was not observed in the stage T1-2 patients.The incidence rate of REP was 3.09％ for the stage T3 patients and 14.35％ for the stage T4 patients.Twenty-two patients underwent following-up MRI after initial diagnosis of REP.After medication or surgical treatment the conditions became better or stable in the most cases. Dosimetric analysis of 32 injured temporal lobes in 29 patients found that the maximal dose was in the contrastenhanced lesions in 27 injured temporal lobes and in edema regions in 5 injured temporal lobes.For each patient,the maximal dose in the normal temporal lobe was lower than that in the injured temporal lobe.In the same patient,the maximal dose,minimal dose,and mean dose of contrast-enhanced lesions were all higher than those in the edema region.Conclusions The incidence of REP after IMRT is high,especially in local advanced NPC patients. Active treatment stabilizes or improves the REP condition. REP is positively correlated with dose of irradiation to brain tissue.
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Objective In order to explore the ways of reflecting the dose distribution in the implementation of the of IMRT (intensity modulated radiation therapy),a 2D diode array (2D-DA) was used in verifying the composite dose distribution of IMRT plans in the way of multi-gantry-angle composite (MGAC).Methods IMRT quality assure (QA) plans of 27 patients,based on the 2D-DA and solid water phantom,were designed and verified in two ways of single-gantry-angle composite (SGAC) and MGAC verifications.The comparison and analyzation of the dose distributions of the TPS calculation and the measurement of the 2D-DA were done.Results (1) When the beam central axes were not superposed with the detectors'plane of the 2D-DA,the verification passrate of SGAC and MGAC planar dose distribution of 27 patients'IMRT plan were 94.56%±4.28% and 94.81%±3.80% (the criteria:rvalue,3 ram/3%),respectively.There was no statistical difference between the results of two sets (t =-0.213,P＞0.05).(2) When one of the beam central axes was superposed with the detectors'plane of the 2D-DA,the verification passrate of MGAC planar dose distribution were 79.72%±12.77%.Conclusions Using the 2D-DA with a proper phantom,there was no statistical difference in the SGAC and MGAC verifications of IMRT plans when the beam central axes were not superposed with the detectors'plane.However,the MGAC dose distribution can provide more about the clinical dosimetry,and the errors in the implementation of the of IMRT were easier located.
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Objective:To inspect the dosimetry characteristic of a 2-D ionization chamber array and its response to oblique incident electron beam.And to discuss feasibility to using it to validate the electron arc therapy plan.Materials and methods:(1)The 2-D ionization chamber array was calibrated referring to a themble chamber,comparing the response to electron beams with incidence angle ranged from-50°to 50°.(2)Phantom test plans of 6 and 10MeV electron beam arc therapy were designed,with the beam rotation arcs of 30°,60°and 90° respectively,symmetric to the Central axis of 0°gantry angle.Dose distribution of each plan was verifled with the 2-D array.Results:(1)Measurement differences between the central detector of the array and the thimble chamber were less than 2%,under the planned oblique inddent 6/10MeV electron beam.(2)For the all test plans,dose error was less than 3%at dmax in the symmetric axis of the electron beam arcs.Off-axis dose error was less than 2%within the central 70%area of the profile in non-rotating direction,and smaller than 1.5%in the rotational direction.The measured dose distribution had good agreement with the TPS calculation in isodose curves between 100%and 20%.The gammapass rates(△D=5%,△d=5cm)were 99.98%、99.89%、99.74%、98.64%、99.16%and 99.44%respectively for 6 and 10 MeV plans with electron beam arcs of 30°,60°and 90°.Conclusion:it is practicable using the tested 2-D ionization chamber array to verify and validate the electron beam arc therapy plan.
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Objective To investigate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma treated with intensity-modulated radiation therapy (IMRT). Methods From February 2001 to December 2006, 419 patients with nasopharyngeal carcinoma in Cancer Center of Sun yatsen University received IMRT. The number of patients with stage Ⅰ,Ⅱ,Ⅲ and Ⅳ disease was 28, 113, 202 and 76, respectively. In all, 182 and 237 patients received radiotherapy alone and chemoradiotherapy. The prescription doses were as follows:66-70 Gy/25 -30 f to GTV_(nx), 60 -64 Gy/25 -30 f to GTV_(nd), 55 -62 Gy/25 -30 f to CTV_1, and 42 -54 Gy/25 -30 f to CTV_2. Results The median follow-up time was 49 months (6 -94 months). The number of patients with follow-up of 1-, 3-, and 5-year were 419,360 and 166, respectively. Twenty-one, 13 and 57 patients had local recurrence, regional recurrence and distant metastasis, respectively. The 5-year local control (LC) rate, regional control (RC) rate and free from distant metastasis survival rate was 92.7%, 95.8% and 85.5%, respectively. The 5-year disease-free survival (DFS) and disease-specific survival (DSS) was 76. 3% and 84.4%, respectively. In univariate analysis, T stage, primary tumor volume, N stage and volume of cervical nodes before treatment were significant predictors of DFS and DSS, favoring the patients with early T stage (84. 1% vs. 67.6% ,Χ~2 = 12. 16, P = 0. 000 : 92. 1% vs. 75. 1% ,Χ~2 = 14. 86 . P = 0. 000) , primary tumor volume less than 20 cm~3 (89. 1% vs. 62. 9% ,Χ~2 =14. 13,P=0.000;96.2% vs. 72. 1% ,Χ~2 =38. 76,P=0.000), early N stage (81.1% vs. 64. 5%, Χ~2 = 15.49, P = 0. 000; 87. 8% vs. 76. 1%, Χ~2 = 10. 89, P = 0. 001) and volume of cervical nodes less than 5 cm~3 (83. 3% vs. 68. 8%, Χ~2 = 14. 13, P = 0. 000 ; 90. 0% vs. 78. 1%, Χ~2 = 10. 71 ,P =0. 001). Multivariate analysis showed that primary tumor volume (Χ~2 = 26. 81, P = 0. 000 and Χ~2 = 28. 47, P = 0. 000) and N stage (Χ~2 = 4. 92, P = 0. 026 and Χ~2 = 9.50, P = 0. 002) were independent predictive factors for both DFS and DSS. No grade 4 acute and late toxicities were observed. In 243 patients with follow-up time more than 3 years, only 2. 8% suffered from grade 3 late toxicifies. Conclusions IMRT with or without chemotherapy can improve the long-term survival of patients with nasopharyngeal carcinoma, especially in LC and RC. Distant metastasis becomes the main treatment failure. Primary tumor volume and N stage are significant prognostic factors. Acute and late toxicities are acceptable.
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Objective To explore a fast and precise registration algorithm for megavolt (MV) portal images(PIs) used for radiotherapy positioning verification, and find auto analysis method of set-up error using the computed image processing and mutual information comparison technology, which provide a basis for the development of automatic image guidance software. Methods MV PIs of patients undergoing radiotherapy were tested, pre-processed with noise reduction technique based on improved filtering algorithm and contrasted by gray-scale transforming using partial derivative threshold. The bone structures were then highlighted but soft tissues and the cavities were restrained simultaneously. Improved particle swarm optimization and powell hybrid algorithm were used to optimize and transform the mutual information based on wavelet multiresolution analysis when registering the Pls with digital reconstructed radiographs (DRRs) of treatment planning or X-ray simulation-film images(SIs). Application of the designed registration algorithm was verified and evaluated through simulated set-up shifts of head and neck phantom. Results The improved noise reduction algorithm satisfactorily met the requirements for contrast of bony structures in the MV PIs. The established mutual information registration method well behaved in both accuracy and speed of registration calculation. The processing of automatic registration took only 31.4 seconds averagely for the PIs and X-ray Sis of head-neck phantom. Mean errors of automatic registration of PIs and X-ray Sis in horizontal, vertical and rotational reduced by 62. 74% ,67. 32% and 66. 61% respectively compared with manual registration in the testing of 20-cases head and neck phantom. Conclusions A precise image registration algorithm and set-up error analysis method based on MV portal images is established, and it can meet the clinical application in registration accuracy and speed.
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Objective To evaluate the dosimetry of high-energy electron beams by using GafChromic EBT film. Methods The percent depth doses of electron beams of 4 MeV,6 MeV,8 MeV,10MeV, 12 MeV and 15 MeV were measured with EBT. The results were then compared with the measurements with diode detector in RFA and parallel plate chamber in water tank. Results The percent depth dose curves using EBT film had a good agreement with those using the other two detectors. Furthermore, no differences were found between up-right and tilt setup methods. When film upper edge is higher than water surface, a sharp drop of measurement results using EBT film was observed in comparison with those from diode detector in build-up region. Conclusions EBT film can be applied to measure percent depth doses of high-energy electron beams. During the EBT film measurements, the film should be tilted at the angle of 5degrees to the central axis of the field. When choosing up-right setup method, the edge of the film should be parallel to the water surface.
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Objective To evaluate the value of L-(methyl-11C)-labeled methionine positron emissions tomography (MET PET) and MRI in target volume delineation for postoperative radiotherapy for brain high grade glioma (HGG).Methods Thirty-seven patients with supratentorial HGG were included.Both MRI and MET PET scan were performed in the same treatment position for all patients.The consistency to determine residual tumor between MRI and MET PET was analyzed.Imaging data of MET PET and MRI were coregistered using the BrainLAB image fusion software.The extension of the volume with high uptake (VMET) on MET PET were compared quantitately with the enhancing area on MRI T1W gadolinium enhancement (VGd) and the hyperintensity area on MRI T2W (VT2).Results Both MET PET and MRI were positive for 19 patients and negative for 7 patients.The consistency between these two scans was 70.3%.MET PET was integrated with MRI in 30 patients with positive MET uptake.VMET were partially or entirely outside VGd in 29 patients and VT2 in 17 patients, whereas VGd and VT2 were partially or entirely outside VMET in all patients.The maximal distance from the margin of VMET to VGd was ≥ 2.0 cm in 50%patients and the corresponding distance of VMET to VT2 was ≥ 1.0 cm in 33% patients.Conclusions The differences are existing between MET PET and MRI in determination and identification of the location and extension of residual tumor for patients with HGG.The integration of MET PET and MRI can accurately delineate radiation target volume.
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Objective To observe the physique and anatomy changes in patients with nasopharyngeal carcinoma (NPC) during intensity-modulated radiotherapy (IMRT), using repeated CT images and deformable registration technique, and analyze their impact on delivery dose distribution.Methods Ten NPC patients were randomly selected from those who had received IMRT treatment.Gross tumor volume of nasopharyn (GTVnx), GTV of metastastatic lymph node (GTVnd), clinical target volume (CTV) and normal tissue or organ (OAR) were re-contoured on the in-course repeated CT images using a kind of deformable registration and auto-segmentation software according to the original planning contouring.Changes in volume of treatment targets and organs at risk were evaluated and the trends were then analyzed.Dose distributions were recalculated with repeated CT images and compared to the original plans.Results The volume of GTVnx were decreased by 6.44%,10.23% and9.72%(F=1.34,P=0.278) in the 2-,4-and 6-week after IM RT comparing with before IM RT, with 6.59%, 30.98 % and 35.13 % (F = 9.22, P =0.000) in GTVnd, 0.73%, 1.86% and 1.41% (F=0.33,P=0.722) in CTV1, -1.78%, -6.47%and -9.34% (F =16.89 ,P =0.000) in CTV2, 13.96%, 32.97% and 37.77%(F=17.17,P=0.000)in the left parotid , and 3.56% , 29.57% and 35.63% (F = 13.49 , P = 0.000) in the right parotid.The mean dose change rate of GTVnx were -0.39%, 0.08% and 0.32% (F =0.15 ,P =0.860) in the 2-,4- and 6-week after IMRT comparing with planning faction dose, with 0.53%, 1.19% and 0.69% (F=0.81,P=0.455) in GTVnd, 1.95%, 2.70% and 3.78% (F=0.61,P=0.552) in the spinal cord,0.32%, 0.81% and 0.62% (F=0.03,P=0.975) in the brain stem, 4.50%, 4.66% and 7.20% (F=0.33,P=0.725) in the left parotid, 2.20%, 7.17% and 7.12% (F= 1.24,P=0.306) in the right parotid.Conclusions The GTVnd, CTV2 and parotids shrinks obviously along with the treatment times for NPC patients during IMRT.Although changes in fraction dose of GTV, CTV, spinal cord, stem and parotids are not significant, further study with larger samples is needed.