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Objective:To study the effects of gantry acceleration limitations of a linear accelerator (linac) on the dosimetry of volumetric modulated arc therapy (VMAT) plans, machine efficiency, and dose verification result of VMAT plans and to explore the optimal selection of gantry motion models in the Pinnacle treatment planning system.Methods:Ten cases of nasopharyngeal carcinoma, non-small cell lung cancer, sigmoid adenocarcinoma with retroperitoneal lymph node metastasis, and invasive ductal carcinoma of the breast were each selected for this study. Then two models were set up in the Pinnacle v9.10 treatment planning system, namely the one allowing gantry acceleration and the one limiting gantry acceleration. The same field arrangement, optimized target parameters, and optimized weights of VMAT plans were adopted in the two models, in order to analyze the dosimetric variations in targets and organs at risk (OARs) and compare the differences in treatment time and gamma passing rates.Results:The treatment time of the enrolled patients under the model allowing gantry acceleration was significantly lower than that of the patients under the model limiting gantry acceleration was adopted ( t=-6.751, -0.209, -19.523, -28.999; P< 0.05) and decreased by 15.27%, 18.07%, 19.71%, and 28.75%, respectively. Meanwhile, the conformity and uniformity of target areas were affected, while there was no statistical significance in the gamma passing rates in the validation of VMAT plans ( P>0.05). For the cases of nasopharyngeal carcinoma (NPC), the maximum dose to brainstem PRV increased by 1.25%. For the cases of lung cancer, the maximum dose to the spinal cord and lung V20 increased by 1.19% and 1.21%, respectively, while lung V5 decreased by 1.21%. For the cases of sigmoid adenocarcinoma with retroperitoneal lymph node metastasis, the mean doses to bilateral kidneys, livers, small intestine, and colon all increased. For the cases of breast cancer, lung V10 on the opposite side of cancer increased by 1.66% and the mean dose to the lungs on the same side of cancer decreased by 7.45%. Conclusions:The model allowing gantry acceleration allows the treatment time to be significantly shortened and the treatment efficiency improved. Although this model had the shortcomings such as affecting the conformity and uniformity of target areas to a certain extent and increasing the doses to some OARs, clinical requirements for dosimetry were still met. Therefore, it is recommended to use the model allowing gantry acceleration in the Pinnacle planning system.
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Objective@#To evaluate the long-term effect and safety of chrono-chemotherapy combined with intensity modulated radiotherapy (IMRT) in locally advanced nasopharyngeal carcinoma (NPC).@*Methods@#160 patients with locally advanced NPC were randomly divided into a chrono group and conventional group according to random number table. In the first stage, all patients underwent two cycles of induced chemotherapy, consisting of docetaxel, cisplatin and 5-Fu every 21 days. Notably, patients received chrono-moduated chemotherapy according to circadian rhythm in the chrono group, and conventional chemotherapy in the conventional group. Then, 21 days after the completion of first stage, three cycles of concurrent cisplatin chemotherapy every 21 days were given to all patients during IMRT. The median follow-up after the completion of radiotherapy was 31 months. Long-term side effects and the survival of patients were observed.@*Results@#Patients in the chrono group had significantly lower rates of hearing loss (22.72%), dysphagia (0) and neck fibrosis (4.54%) compared with those in the conventional group (39.13%、8.69%, 15.94%, respectively, all P<0.05). Meanwhile, the 1- year overall survival rates (97.0% vs 92.8%), 3-year overall survival rates (80.3% vs 81.2%), 1-year progression free survival rates (95.5% vs 87.0%), 3-year progression free survival rates (71.2% vs 73.9%), 1-year locoregional relapse-free survival rates (97.0% vs 95.7%), 1-year locoregional relapse-free survival rates (92.4% vs 92.8%), 1-year distant metastasis-free survival rates (97.0% vs 98.6%) and 3-year distant metastasis-free survival rates (90.9% vs 91.3%) between the chrono group and the conventional group were not statistically significant (all P>0.05).@*Conclusions@#Compared with conventional chemotherapy, chrono-chemotherapy combined with IMRT didn′t affect long-term survival, but reducing the incidence of adverse events in patients with locally advanced NPC.
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Objective@#To compare the adverse events, immune status, and short-term efficacy between chronomodulated chemotherapy (CCR) and routine chemotherapy (RCR) combined with intensity modulated radiotherapy (IMRT)in the treatment of patients with locally advanced nasopharyngeal carcinoma.@*Methods@#A total of 159 patients with newly diagnosed locally advanced nasopharyngeal carcinoma were randomized into the CCR group and the RCR group to evaluate the short-term efficacy and adverse events.@*Results@#No significant difference was found in CR, PR, SD, and PD between the CCR group and the RCR group (P>0.05), and no significant difference was observed in the response rate (CR+ PR) between the two groups (P>0.05). The incidence of leukopenia(Z=-2.222, P<0.05), neutropenia(Z=-1.999, P<0.05), vomiting(Z=-2.298, P<0.05), and oral mucositis(Z=-3.571, P<0.05)of the CCR group was lower than those of the RCR group with statistical significance. The CD16+ 56+ lymphocyte cell count was higher in the CCR group than that in the RCR group(Z=-2.332, P<0.05).@*Conclusions@#As a novel invention, CCR combined with IMRT can reduce the incidence and severity of treatment-related adverse events and improve immune status without diminishing clinical efficacy, therefore deserving clinical application.
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Objective To evaluate the differences of toxicities,therapeutic efficacy and immune function between induction chemotherapy followed by sinusoidal chrono-modulated infusion and flat intermittent infusion of cisplatin (DDP)with intensity-modulated radiotherapy (IMRT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC).Methods Seventy patients with biopsydiagnosed stages Ⅲ and Ⅳ B NPC (according to the 2010 UICC staging system) were treated with two-cycle induction chemotherapy before chemoradiotherapy in Guizhou Cancer Hospital.The TPF chemotherapy regimen was administered as follows:The TXT and DDP with the dose of 75 mg/m2 was carried out by bolus infusing for the first day,the 5-FU with 750 mg · m-2 · d-1 was carried out by continuous intravenous pumping for the first day to fifth day(120 h).The induction chemotherapy was 21 days per cycle,for two cycles.After that all patients were randomly treated with 2-3 cycles of sinusoidal chronomodulated infusion or flat intermittent constant rate infusion of DDP with IMRT.Using a multi-channel programmed pump,the patients were given 12 h continuous infusions of DDP (100 mg/m2) for day one,repeated every 3 weeks for 2-3 cycles.DDP was administered from 10:00 am to 10:00 pm.Concurrent radiotherapy regimen was administered as follows:GTVnx 69.96-73.92 Gy/33 f,PTVnx 69.96 Gy/33 f,PTVnd 69.96 Gy/33 f,PTV1 60.06 Gy/33 f,PTV2 50.96 Gy/28 f.Results The main toxicities of chemoradiotherapy in the group of sinusoidal chrono-modulated infusion were bone marrow suppression:leukocytes,and then nausea,oral mucositis and hemoglobin.The main toxicities of chemoradiotherapy in the group of flat intermittent constant rate infusion were bone marrow suppression:hemoglobin,leukocytes,and then nausea,oral mucositis.No significant differences were observed for toxicities(P ＞ 0.05).After concurrent chemoradiotherapy,the complete response rate (CR),partial response rate (PR),stable disease rate(SD),progressive disease rate (PD) and overall response rate (ORR) were 11.4％,85.7％,2.9％,0 and 97.1％ in the group of sinusoidal chrono-modulated infusion.The CR,PR,SD,PD,ORR in the group of flat intermittent constant rate infusion were 22.9％,74.2％,2.9％,0,97.1％,respectively.However,there was no significant differences of effect in the two Arms (P ＞ 0.05).For sinusoidal ehrono-modulated infusion and flat intermittent infusion group,the 2-year overall survival(OS) were 82.9％ and 94.3％ respectively,the 2-year progression-free survival(PFS) were 77.1％,91.4％ respectively,and the 2-year distant metastasis free survival (DMFS) were 82.9％,91.4％ respectively.The value of CD3 + in the group of sinusoidal chrono-modulated infusion was higher than the group of flat intermittent constant rate infusion after therapy (Z =3.254,P ＜ 0.05).The value of CD4 +,CD8 +,CD16 + CD56 +,CD19 +,and CD4 +/CD8 + had no differences in two Arms (P ＞ 0.05).Conclusions No significance differences on the toxicities,therapeutic efficacy and survival were observed between the two groups,but immune function might be improved in the sinusoidal chrono-modulated infusion group.
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Objective To study the clinical characteristics, diagnosis, treatment and prognosis of primary pulmonary peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). Methods Two cases of primary pulmonary PTCL-NOS were studied and relevant literature were reviewed. Results Case 1 diagnosed as primary pulmonary PTCL-NOS was a 44 years old woman and disease progressed after GLD (Gem+L-OHP+ DXM) chemotherapy regimen. At last, the patient died of respiratory failure after one month. Case 2 diagnosed as primary pulmonary PTCL-NOS was a 46 years old man and reach partial response after CHOP regimen, and still alive now.Conclusion Primary pulmonary PTCL-NOS is very rare. It is easy to be misdiagnosed due to non-specific clinical and imaging manifestations. Acquiring enough tissue specimens for pathologic examination is the key to a definitive diagnosis. At present, there is no standard chemotherapy regimen for these patients, the prognosis is relatively poor.
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ObjectiveThis study evaluates the feasibility of intensity-modulated radiation therapy (IMRT) to treat patients with 1 -5 brain metastases from non-small cell lung cancer (NSCLC).Methods 30 IMRT patients with brain metastases for NSCLC studied retrospectively.Whole brain radiotherapy plus three-dimensional conformal radiotherapy (WBRT + 3DCRT) and WBRT plus stereotactic radiotherapy ( WBRT + SRT) plans were generated.Planning target volume ( PTV ) and organs at risk dose were measured and compared by dose volume histogram.Differences were analyzed in the three techniques by Wilcoxon Z -test.Results D99％ of the shoulder ( D99％-D90％ ) from IMRT were higher than from WBRT +3DCRT and WBRT+SRT in all cases.From D15％ of slope (D90％-D10％) to D5％ of tail (D10％ -D1％ ),IMRT were lower than WBRT + 3DCRT and WBRT + SRT ( Z =- 4.72,P =0.000 and Z =- 4.72,P =0.000).D10％ and D5％ of IMRT were (35.1 ±1.42) Gy and (37.7 ±2.91) Gy,WBRT +3DCRT were (36.5±2.86) Gy and ( 39.1 ± 3.56) Gy ;WBRT + SRT were (36.2 ± 2.57) Gy and ( 38.7 ± 3.67) Gy.IMRT vs WBRT+ 3DCRT and WBRT + SRT were significant ( Z=-3.18,-3.18,P=0.001,0.001 and Z=- 4.11,- 3.02,P =0.000,0.002) in 13 patients with 3 - 5 brain metastases.The total mean monitor units were 14756.3,9614.8 and 9043.2 for IMRT,WBRT +3DCRT and WBRT + SRT plans,respectively,with a 38.7％ reduction from IMRT to WBRT + SRT (Z =-4.78,-4.78,P =0.000,0.000).The brain doses around metastases were similar in the three techniques with 1 -2 metastases,but IMRT was the best with 3 -5 metastases.ConclusionsIMRT can advance brain metastases dose and improve the planning target minimum dose and spare the dose around brain metastases.Only IMRT is the best choice for just sparing the dose around brain metastases among 3 -5 brain metastases.
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Objective To investigate the dosimetric influence of pure carbon fiber treatment tabletop of Elekta Precise new linear accelerator in radiotherapy.Methods Surface-axis distance (SAD) technology was employed for the measurement.Two groups of fields were set and both of them were SAD opposed portals ( one of them went through the tabletop,while the other did not).A PTW electrometer and a 0.6 cm3 Farmer ionization chamber were utilized for comparison measurement.Then dose attenuation of the main table board,extended body board,the extended board for head,neck and shoulders,and the joints of these boards were calculated.Results Under the energy of 6 MV,the dose attenuations of the following locations were:1.4％ - 7.2％ at the main treatment table board; 2.8％ - 38.7％,1.4％ -30.1％,1.5％ -20.8％ and 1.4％ - 11.2％,respectively at distances of 1,4,7 and 8 cm from the joint of the main table board ;0.5％ - 5.0％ at the extended body board; 4.7％ - 15.4％ at distance of 1cm from the joint of the extended body board; 0.5％ -3.3％ at the neck position of the extended board for head,neck and shoulders; 5.3％ - 16.7％ at the shoulder positions; and 6.8％ -30.4％ at the joint between the extended boards and the main table board.Conclusions The dose attenuations of the new linear accelerator pure carbon fiber treatment tabletop vary at different locations. Considerable higher attenuations are observed at the table board joints than other locations.
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Objective To evaluate the therapeutic effects,acute and late side-effects of cisplatin plus 5-fluorouracil (PF) schemed chronomodulated chemotherapy combined with concurrent intensitymodulated radiotherapy(IMRT) for nasopharyngeal carcinoma.Methods A total of 48 nasopharyngeal carcinoma patients treated with chronomodulated chemotherapy plus concurrent IMRT were retrospectively studied.The radiation doses prescribed to the gross target volume GTVnx of nasopharyngeal,to the positive neck lymphnodes GTVnd,to the clinical target volume CTV1,and to CTV2 were 73.92-77.88,69.96,60.06-66.00 and 50.96-56.00 Gy respectively.The Kaplan-Meier survival analysis was used to calculate the local-regional progression-free rate.The acute and late side-effects were graded according to RTOG radiation morbidity scoring criteria.Results The complete remission (CR) rate was 41.6％(20/48) ; the partial remission (PR) rate was 47.9％ (23/48) ; the stable disease (SD) rate was 4.2％(2/48) ; and the local tumor control rate was 89.6％.Most of the patients had grade 1 to 2 acute side effects and grade 0 to 1 late side-effects.No grade 4 acute and late toxicity was observed.1,2,4-year survival rates were 93.8％,79.2％ and 64.5％,respectively.The DVH analysis showed that IMRT improved the total dose and dose per-fraction to the target volume with considerable dose reduction of the normal structures at the same time.Conclusions PF chronomodulated chemotherapy plus concurrent intensity-modulated radiotherapy for NPC could improve therapeutic effects with satisfactory tolerance of the side effects.
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ObjectiveTo investigate the delineation of gross tumor volume (GTV) in locally advanced nasopharyngeal carcinoma (LANC) according to imageological changes before and after induction chemotherapy (IC) in order to decrease high dose area and protect normal tissue better.MethodsBetween Mar 2010 to Jan 2011,11 patients with LANC were enrolled and treated with TPF regimen followed by intensity-modulated radiotherapy (IMRT) with concurrent chemotherapy,target volumes were delineated based on fused CT imaging before and after IC following project determination.Tumor target volumes after and before IC were respectively delineated according to imaging tumor residues and were overlaid by CTVnx in order to ensure radical doses for the imaging tumor volume before IC,the resulting differences of tumor target volumes of IC before and after were measured and analyzed by paired t-test.ResultsBefore and after IC,the average volumes of GTVnx were respectively 44.72 cm3 and 28.87 ( t =3.89,P =0.003 ),the average volumes of GTVnd were respectively 32.76 cm3 and 19.82 cm3 ( t =2.47,P =0.033 ),the volumes of maximum dose area in brainstem and spinal cord as well as eyeball decreased ( t =2.93-4.59,all P ＜0.05).ConclusionsLANC treated by 3 cycle TPF regimen followed by IMRT with concurrent chemotherapy showes significant shrinkage of tumor volume.The volume of high dose region which caused by normally recovered tissues were decreased by re-delineation of target volume in brainstem and spinal cord as well as eyeball of CT images after IC.
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Objective To evaluate clinical factors as predictors of radiation pneumonitis(RP)in advanced stage non-small cell lung cancer(NSCLC)patients treated with concurrent radiochemotherapy when gross tumor volume is 70 Gy. Methods Data of 84 patients with histologically proved NSCLC treated with 3DCRT or IMRT were collected. To evaluate the correlation between clinical parameters and radiation pneumonitis(RP). The clinical parameters were considered: pathological type, therapy agents, age,gender, stage, karnofsky performance status(KPS), smoking status, diabetes, chronic obstructive pulmonary disease(COPD). Results The occurrence of grade 1,2 RP was 63%, 33%, respectively. In univariate analysis, diabetes was significantly associated with RP of ≥ grade 1(x2 =4.03, P = 0.045)and ≥grade 2(x2 = 15.59 ,P =0.000). KPS was significantly associated with RP of ≥grade 1(x2 =3.98 ,P = 0.046)and ≥grade 2(x2 = 5.21, P = 0.023). In logistic multivariate analysis, diabetes was significantly associated with RP of ≥grade 1(x2 =5.50,P =0.019)and ≥grade 2(x2 = 12.92,P =0.000). KPS was significantly associated with RP of ≥ grade 1(x2 = 6.29, P = 0.012)and ≥ grade 2(x2 = 6.61, P =0.010). Conclusion The definite statistical significant risk factors of RP are diabetes and KPS.
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Objective To identify the best technique of postmastectomy radiation therapy (PMRT).Methods Twenty-eight patients with stage Ⅱ or Ⅲ invasive breast cancer were treated with modified radical mastectomy and radiotherapy sequaciously involving the supraclavicular region and the chest wall.Three different techniques were developed for each patient:two tangential conformal fields ( half field) in the chest wall plus supraclavicular intensity modulated radiotherapy (3D-CRT + IMRT),integrated chest wall and supraclavicular IMRT(IMRT),and two tangential conformal fields (half field) in the chest wall plus single field electron beam radiotherapy in the supraclavicular region( 3D-CRT + E).The dose distributions of the target areas and the irradiated volumes of the ipsilateral lung ( V5,V10,V20,and V45)were estimated with the dosage volume histogram (DVH).The dosage prescription was 50.4 Gy (1.8 Gy × 28 f).Results The conformity index (CI) of the 3D-CRT + IMRT group was (0.61 ± 0.03),not different from that of the IMRT [ (0.62 ±0.03),q =2.16,P ＞0.05],and the CI levels of these 2 groups were both higher than that of the 3D-CRT + E group [ (0.44 ± 0.02 ),q =20.50,22.66,P ＜0.01 ].The heterogeneity index (HI) of the 3D-CRT + IMRT group was ( 1.17 ±0.02),not different from that of the IMRT [ (1.15 ±0.02),q =1.66,P ＞0.05],and the HI levels of these 2 groups were both lower than that of the 3D-CRT + E group[ ( 1.24 ±0.04),q =3.91,5.58,P ＜0.01 ].The levels of V5 and V10 of the ipsilateral lungs of the 3D-CRT + E group(48.70％ ±3.24％,38％.56％ ±3.70％ ) and 3D-CRT + IMRT group (49.12％ ±3.03％,38.38％ ± 3.56％ ) were all significantly lower than those of the IMRTgroup [(77.18％ ±8.01％,53.07％ ±6.85％),V5,q =20.35,20.05,P＜0.01; V10,q=12.10,12.24,P ＜0.01 ] and there were not significant differences in the V5 and V10 levels between the 3D-CRT + E and 3D-CRT + IMRT groups ( q =0.30,0.14,P ＞ 0.05 ).The levels of V20 of the ipsilateral lungs of the 3D-CRT + IMRT group (26.57％ ±2.51％ )and IMRT group (25.22％ ±2.77％) were all significantly lower that those of the 3D-CRT + E group [ (31.79％ ± 3.00％ ),q =5.27,8.21,P ＜ 0.01 ]and there were not significant differences in the V20 level between the 3D-CRT + IMRT and IMRT groups (q=2.76,P ＞ 0.05 ).There were not significant differences in the V45 levels among these 3 groups (F =0.69,P ＞ 0.05).Conclusions The 3D-CRT + IMRT technique in PMRT effectively reduces the radiated dose on the ipsilateral lung.
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Objective To analyze relation of comprehensive parameters of the dose-volume V5,V10 and V20 with radiation pneumonitis (RP) in patients with advanced stage non-small-cell lung cancer (NSCLC) treated with three-dimensional conformal (3DCRT) or intensity-modulated radiation therapy (IMRT).Methods Data of 90 patients with histologically proved NSCLC treated with 3DCRT or IMRT between November 2006 and July 2009 were collected.The median radiation dose of 70 Gy (range, 61 - 80 Gy) was delivered with late-course accelerated hyperfractionated radiotherapy (LAHRT).The V5 ,V10 ,V20,V30 and mean lung dose (MLD) were calculated from the dose-volume histogram system.The RP was evaluated according to the common toxicity criteria 3.0(CTC 3.0).Results The range of V5 ,V10 and V20 was 36% - 98%, 27% - 78% and 19% - 54%, respectively, with a median value of 66%, 48% and 31%, respectively.The RP of grade 1,2,3,4 and 5 was observed in 29,23,5,1 and 1 patients.The V5,V10 ,V20, contralateral V10, GTV,PTV, and numbers of fields were all significantly associated with RP of ≥grade 1 (χ2=2.04, 2.05, 2.01, 4.62, 6.50, 5.61, 5.61, and P= 0.044, 0.043, 0.047, 0.030,0.010,0.020,0.020).The V5, V10, V20, V30, and MLD were all significantly associated with RP of ≥ grade 2 (χ2= 2.05,2.20,2.96,4.96,5.20, and P = 0.040,0.030,0.000,0.030,0.020).In Logistic regression analysis, GTV was the only factor significantly associated with RP of ≥ grade 1 (χ2= 4.06, P =0.044).The V20 was the only factor significantly associated with RP of ≥grade 2(χ2=9.61,P=0.002).The RP of ≥grade 2 was significantly increased when V20 was more than 31%.The RP of ≥grade 2 was significantly increased when V20, V10 and V5 were more than 31%, 48% and 66%, respectively.The RP of ≥ grade 2 was significantly increased when V20 was more than 31% and V5 was more than 66%.Conclusions The comprehensive parameters combined with V5, V10 and V20 are effective in predicting RP.
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Objective To analyze the clinical outcome of concurrent ehemo-radiotherapy in stage Ⅳ non-small cell lung cancer(NSCLC).Methods From Jan.1997 to Dec.2006,214 patients with patho logically or cytologically proven stage Ⅳ NSCLC were included in this analysis.Of those patients,98 re ceived radiotherapy concurrently with 3-week cycle chemotherapy(group A),18 received radiotherapy con currently with weekly chemotherapy(group B) ,44 received chemotherapy alone,37 received radiotherapy a lone and 13 received sequential chemo-radiotherapy.The primary tumor was treated by three-dimensional conformal radiotherapy(3DCRT) or conventional radiotherapy with conventional fraefionation or late-course accelerated hyperfraction (LA H RT).Group A received 21-28 days cycle cisplatin-based chemotherapy (cis platin combined with PTX,DTY,NVB or Vp-16) ,and group B received weekly DDP combined with PTX or topteeon for 4-6 weeks.Results The follow-up rate was 99%.The 1-and 2-year overall survival rates of group A,group B,chemotherapy alone,radiotherapy alone and sequential chemo-radiotherapy were 41% and 11% ,16% and 0,31% and 7% ,34% and 10% ,26% and 3% ,respectively(x2 = 11.18,P=0.025).The patients with concurrent 3DCRT,LAHRT and radiotherapy dose≥70 Gy had better survival in group A than those in chemotherapy alone group.Patients who received≥2 cycles chemotherapy with concurrent radio therapy had longer survival time than those who had ≥2 cycles chemotherapy alone. Conclusions Con current chemotherapy and 3DCRT,LAHRT with the dose ≥70 Gy can improve the overall survival of patients with stage Ⅳ non-small cell lung cancer.
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Objective To analyze the normal lung dose-volume histogram(DVH) varieties in the former and later period(P1 and P2)of three dimensional conformal radiation therapy(3DCRT) plans and the compound (Pc) plan in non-small cell lung cancer(NSCLC),and to access the feasibility to modify the target volume during the treatment course.Methods Twenty-one NSCLC patients who had received accelerated hyper-frationation 3DCRT in P2 were included in the study.Both of the P1 and P2 plans were redesigned to a total dose of 70 Gy with V20 smaller than 35%.When the target volume was modified and P2 plan was rede signed using accelerated hyper-frationation 3DCRT of 30 Gy after P1 plan of 40 Gy,the Pc plan was compoun ded by transmitting the parameters(such as target volume,irradiation field and dose) of P1 plan into P2 plan. Total lung volume and target volumes(GTV,PTV) of P1 and P2 were evaluated.MLD,V5,V10,V20 and V30 of P1,P2 and Pc were calculated.Results The total lung volume in P1 and P2 plans was not significantly dif ferent(t = 0.19,P = 0.850).The volumes of GTV,PTV in P2 were obviously smaller than P1 (t = 2.88,P = 0.009 ; t = 4.01 ,P = 0.001) .When comparing P2 with P1 ,MLD were 16.5 Gy Vs 17.8 Gy (t = 2.60, DOI:10.3760/cma.j.issn.1004-4221.2009.01.057 P = 0.017),V30 was significantly decreased (t = 2.19,P = 0.041),but V5,V10 and V20 had no significant difference.Similar differences were found in MLD,V5 ,V10 ,V20 and V30 when comparing Po to P1.P2 plans had significantly smaller MLD,Vs,V10,V20 and V30 than Pc plans.Fourteen patients with decreased PTV were further analyzed.The V30 and MLD decreased significantly (t = 3.00,P = 0.0 I 0;t = 2.38,P = 0.033), but V5 ,V10,V20 had no difference when comparing P1 and P2 plans.Among these 14 patients,the V10 and V30 decreased significantly(t = 2.76,P = 0.033 ; t = 3.60,P = 0.011) when P2 plans were generated using the same field number and beam angles in P1 plans in 7 patients.The parameters were similar in P1and Pc plans,but increased significantly when comparing to P2.Various parameters were the same among P1,P2 and Pc plans when P2 plans were designed using 1-2 different fields and angles in the other 7 patients.The differ ences were not significant between P1 and P2 plans in 7 patients with the same or increased PTV.Expansion or contraction of PTV significantly influenced MLD and V2o (r =-0.62,P = 0.03 ; r = O.48,P = 0.029). Conclusions When the tumor regresses,the high dose volume of the lung decreases with modifying the tar get volume and replanning in the later period using accelerated hyper-frationation 3DCRT.The low dose vol ume of the lung may decrease if the field orientations are same throughout the treatment.It is rational to eval uate the normal lung DVH of the whole plan when the physical parameters of the later period plan are the same as the former one.
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Objective To analyze the low dose-volume associated with radiation-induced lung injury (RILI) in patients with advanced non-small cell lung cancer (NSCLC) treated by three-dimensional confor-real radiation therapy (3DCRT). Methods Data of 100 patients with histologically proved NSCLC treated with 3DCRT or IMRT between November 2006 and January 2009 were collected. Nine patients treated with radiotherapy alone and 91 with radiotherapy combined with chemotherapy. A median dose of 70 Gy (range,60-80 Gy) was delivered with late-course accelerated hyperfractionated radiotherapy (LAHRT). Twenty-four patients received dose of 61-69 Gy and 76 received more than 70 Gy. The V_5 ,V_(10) ,V_(20) ,V_(30)and mean lung dose (MLD) were calculated from the dose volume histogram system. The RILI was evaluated according to Common Toxicity Criteria 3.0(CTC 3.0). Results The range of V_5 ,V_(10) ,V_(20) ,V_(30) was 37%-98%,27%-78%, 17%-54% and 9%-31%, respectively, with a median value of 65%, 47.5%, 31% and 24%, respectively. The acute RILI of grade 1, 2, 3, 4 and 5 was observed in 34, 27, 8, 1 and 1 patients,respectively. The chronic RILI of grade 1, 2 and 3 was observed in 46, 14 and 2 patients, respectively. V_5 ,V_(10) ,V_(20) and MLD were significantly correlated with acute RILI of ≥ grade 1. V_5 ,V_(20) ,V_(30) and MLD were significantly correlated with acute RILI of ≥ grade 2. The acute RILI of ≥ grade 2 was significantly in-creased when V_5, V_(20) and V_(30) were more than 65%, 31% and 24%, respectively. The acute RILI of ≥ grade 3 was significantly increased when V_5 was more than 65%. The acute RILI of ≥ grade 1 was signifi-candy increased when V_(20)was more than 31%. The gross tumor volume and planning target volume were sig-nificantly correlated with the acute RILI of ≥ grade 1 and chronic RILI of ≥ grade 2. Conclusions The dose-volume V_5 and V_(10) are effective in predicting RILI.