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Objective To compare relevant dosimetric parameters of non-coplanar volumetric modulated arc therapy (VMAT) in treating brain tumors in conventional flattening filter (FF) or flattening filter-free (FFF) delivery mode,aiming to explore the appropriate evaluation method of accelerator for stereotactic radiosurgery (SRS).Methods Clinical data of 10 patients with single cranial tumor were retrospectively analyzed.All patients received non-coplanar VMAT at a prescription dose of 25 Gy in 1 fraction.Dosimetric parameters including conformity index (CI),heterogeneity index (HI),gradient index (GI50,GI25),gradient,volume of the brain tissue receiving larger than 10 Gy and 12 Gy (V10 and V12) and beam-on time were statistically compared between two treatment plans by paired sample t-test.Results When FFF-VMAT was compared with FF-VMAT in SRS for intracranial tumors,Paddick gradient index GI50 was 2.91±0.34 vs.3.07±0.35,6.91±0.28 vs.7.35±0.27 for GI25,(0.57±0.07) cm vs.(0.61±0.08) cm for gradient,respectively (all P＜0.05),whereas CI did not significantly differ (P＞0.05).For the normal brain tissues,the average dose was (160.64±43.64) cGy vs.(174.27± 53.98) cGy,(45.35± 30.32) ％ vs.(48.37± 30.88) ％ for V10 and (36.69±25.15) ％ vs.(39.48±25.37) ％ for V12,respectively (all P＜0.05).Conclusions Non-coplanar VMAT in FFF delivery mode can improve dose distribution and normal brain tissue sparing in the treatment of intracranial single tumors.Meanwhile,supplement of GI index and gradient index can implement comprehensive evaluation of the SRS planning.
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Objective@#To compare relevant dosimetric parameters of non-coplanar volumetric modulated arc therapy (VMAT) in treating brain tumors in conventional flattening filter (FF) or flattening filter-free (FFF) delivery mode, aiming to explore the appropriate evaluation method of accelerator for stereotactic radiosurgery (SRS).@*Methods@#Clinical data of 10 patients with single cranial tumor were retrospectively analyzed. All patients received non-coplanar VMAT at a prescription dose of 25 Gy in 1 fraction. Dosimetric parameters including conformity index (CI), heterogeneity index (HI), gradient index (GI50, GI25), gradient, volume of the brain tissue receiving larger than 10 Gy and 12 Gy(V10 and V12) and beam-on time were statistically compared between two treatment plans by paired sample t-test.@*Results@#When FFF-VMAT was compared with FF-VMAT in SRS for intracranial tumors, Paddick gradient index GI50 was 2.91±0.34 vs.3.07±0.35, 6.91±0.28 vs.7.35±0.27 for GI25, (0.57±0.07) cm vs.(0.61±0.08) cm for gradient, respectively (all P<0.05), whereas CI did not significantly differ (P>0.05). For the normal brain tissues, the average dose was (160.64±43.64) cGy vs.(174.27±53.98) cGy, (45.35±30.32)% vs.(48.37±30.88)% for V10 and (36.69±25.15)% vs.(39.48±25.37)% for V12, respectively (all P<0.05).@*Conclusions@#Non-coplanar VMAT in FFF delivery mode can improve dose distribution and normal brain tissue sparing in the treatment of intracranial single tumors. Meanwhile, supplement of GI index and gradient index can implement comprehensive evaluation of the SRS planning.
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Based on the four major classic studies of perioperative treatment of locally advanced gastric cancer (LAGC), the North American Intergroup-0116 trial, the European MRC MAGIC trial, the Japan ACTS-GC trial and Korea-China CLASSIC trial, the perioperative therapy of LAGC was divided into three major patterns in the world, namely, postoperative adjuvant chemoradiotherapy in the North America, perioperative chemotherapy in the Europe and postoperative adjuvant chemotherapy in the East Asia. In recent years, scholars around the world have done many researches on the perioperative treatment of gastric cancer. For instance the German FLOT4-AIO trial pushed the perioperative chemotherapy of gastric cancer to a high point, so the NCCN guide changed perioperative chemotherapy to the preferred recommendation, and rewrote the perioperative chemotherapy regimen. The ARTIST trial in Korea showed that the addition of radiotherapy to the adjuvant chemotherapy after D2 radical resection of gastric cancer could not improve the overall survival rate, and further defined adjuvant chemotherapy as the standard treatment in D2 resection of gastric cancer. Asian scholars are actively exploring the application of perioperative chemotherapy in LAGC. For Bulky N cases, neoadjuvant chemotherapy has been recommended as the standard treatment in the Japanese guidelines. The JOCG1509,the RESOLVE and other studies will provide more effective evidence-based recommendations for the best perioperative therapy options of LAGC in Asian countries. At present, it is not clear whether perioperative chemotherapy or postoperative adjuvant chemotherapy is better. In this article, the development course of the three patterns of perioperative therapy of gastric cancer, the research progress in the perioperative period of gastric cancer in recent years, and the changes of guidelines are reviewed in order to provide reference for clinical practice.
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Humans , Combined Modality Therapy , History , Methods , Gastrectomy , History, 20th Century , History, 21st Century , Perioperative Care , History , Methods , Stomach Neoplasms , History , Pathology , General Surgery , TherapeuticsABSTRACT
Objective To compare the dosimetric and delivery efficiency between intensity-modulated radiation therapy (IMRT) plans based on Halcyon and Trilogy accelerator.Methods Clinical data of 12 patients with cervical cancer receiving Trilogy platform-based IMRT were retrospectively analyzed.The target area and organ at risk were introduced into the Eclipse version 15.1 TPS.The Halcyon-based IMRT was re-designed.The dose coverage of target area and organs at risk,monitor unit (MU) efficiency,delivery time and segment area and the differences between the proximal and distal segment area were statistically compared between two IMRT plans.Results The Halcyon treatment platform could meet the clinical objectives.Dose distribution of the target area was similar to that of the Trilogy plan (P＞O.05).The volumes in the bladder and rectum receiving 30 Gy and the volumes in the left femoral head receiving 20 Gy of Halcyon plan and the mean dose (D) of bladder,rectum and left femoral head were significantly lower compared with those of the Trilogy plan (P=0.001-0.043).The MUs of the Halcyon plan was 2 316.7± 209.7,significantly higher than 1 692.5± 259.5 of the Trilogy plan (P=0.000).The delivery time significantly differed between the Halcyon [(3.01±0.28) min] and Trilogy [(12.38± 1.49) min] (P=0.000).The average segment area of Halcyon plan for proximal and distal MLC was (43.7±32.5) cm2 and (28.8±25.4) cm2,the average segment area of Trilogy plan was (25.7±16.8) cm2,the ratio of the proximal and distal segment area was 1.73±0.43,ranging from 0.71 to 6.28.Conclusions Halcyon treatment platform can meet the clinical requirements and reduce the dosage coverage of normal tissues with better delivery efficiency.The ratio of proximal and distal segment areas should be considered during the plan design.
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Objective To analyze the dosimetric and delivery efficiency differences between IMRT plans based on Halcyon and Trilogy Accelerator for left side breast cancer.Methods A total of 10 patients with left side breast cancer based on the Trilogy platform were retrospectively analyzed.For each patient,plan based on Halcyon was redesigned using Eclipse Version 15.1 TPS.In order to evaluate plan quality,dose coverage of target and dose to organs at risk,monitor unit efficiency,segment size and delivery time were compared.Results Halcyon treatment platform could meet the clinical objective.Dose distribution of the target volume had no significant difference with the Trilogy plans (P＞0.05).Volumes receiving 10 Gy,20 Gy and D of the left lung were significantly reduced(Z=-2.22--1.78,P＜0.05).V5 of heart for Halcyon and Trilogy was(27.80±7.66)％ and (23.18±8.19)％,respectively(Z=-0.71,P＜0.05),while D was (7.03± 1.8)Gy and(7.11±2.40)Gy,respectively(P＞0.05).Halcyon increased the monitor unit from 1 526.2±227.7 by Trilogy to 1 770.5±383.9(Z=-0.71,P＜0.05),but decreased the delivery time from (12.38± 1.49) min by Trilogy to (3.01 ±0.28) min (Z =-3.42,P＜ 0.05).Conclusion Halcyon treatment platform can meet the clinical requirements,reduce dose to normal tissue with high delivery efficiency.
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Objective To evaluate the dynamic variation of the dose-volume parameters of the left ventricular myocardium following heart beat in radiotherapy for esophageal cancer. Methods The left ventricular myocardium of 22 patients was contoured on 20 phases (0％-95％) of electrocardiography (ECG) gated heart 4DCT images. The radiotherapy plan was designed on the simulation CT images,and then the dose distribution of radiotherapy plan was imported into MIM Maestro system and 4D dose-volume histogram (DVH) was reconstructed. The variations of position,volume and dice similarity coefficient (DSC) of the left ventricular myocardium were analyzed. The changing ranges of Dmean ,V10,V20 ,V30 and V40 of the left ventricular myocardium during different phases were statistically compared. Results ( 1 ) The biggest displacement of the left ventricular myocardium was in Y axes. The maximum variation rate of volume and DSC of the left ventricular myocardium were (24.23±11. 35)％ and (184.33±128. 61)％ in different phases with statistical significance (both P<0. 05).(2) The maximum variation rate of Dmean of the left ventricular myocardium was (87.05± 38. 34)％ in different phases with the highest rate of 163. 52％ with statistical significance (P<0. 05).(3) The maximum variation values of V10,V20,V30 and V40 of the left ventricular myocardium were (13.64±4. 33)％,(12.84±4. 55)％,(11.62±4. 85)％ and (3.63±2. 56)％ with statistical significance (all P<0. 05). Conclusions The impact of heart beat on the dose-volume parameters of the left ventricular myocardium should be considered during esophageal cancer radiotherapy. Traditional static 3DCT-based assessment of the dose-volume parameters of the left ventricular myocardium can yield relatively large errors, which is probably reduces the prediction efficiency of the dose-volume parameters for radiation-induced heart injury.
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Objective To investigate the changes of the parameters related to planning and re-planning CT imaging features in lung cancer patients presenting with radiation pneumonitis ( RP) by using radiomics technique,and identify the parameters intimately related to the incidence of RP. Methods A total of 31 lung cancer patients who were diagnosed with grade ≥ 2 RP after receiving radiation therapy were selected in this study. For each patient, planning CT images before radiation therapy and re-planning CT images after 40 Gy radiation therapy were obtained. The affected and contralateral lungs were considered as the region of interest (ROI).After the automatic segmentation of normal lung tissues,the parameters related to radiomics features were extracted from ROI by using radiomics software. The differences of these parameters between planning and re-planning CT images were statistically compared. Results ( 1 ) For unilateral lung within each time interval,86 parameters related to radiomics features were extracted; ( 2) Twenty-two parameters significantly differed between the affected and contralateral lungs prior to radiotherapy;(3) Twelve parameters significantly differed between the affected and contralateral lungs on re-planning CT images;(4) Twenty-eight parameters significantly differed in the affected lung before and after radiation therapy;(5) Twenty-eight parameters significantly differed in the contralateral lung before and after radiation therapy. Conclusions The CT imaging radiomics features significantly differ between planning and re-planning CT scan in partial lung cancer patients presenting with RP.Monitoring the dynamic changes of these parameters plays a potential role in predicting the incidence of RP.
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Pseudomyxoma peritonei syndrome (PMP) is characterized by a gradual expansion of mucoid tumour and fluid at specific sites within abdominopelvic regions as a result of a perforated appendiceal adenoma. The standard therapy for PMP is combining cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy. Maximal tumor debulking surgery (MTD) may be beneficial in patients in whom complete cytoreductive surgery (CCRS) cannot be achieved. It is now recognized that CCRS is one of the strongest predictors of long term survival in patients with PMP. The 5-year survival rate in patients who underwent CCRS was 80.0 %-87.4 %, however the rate in patients who underwent MTD was only 24.0 %-39.2 %.This article reviews the pathological classification,diagnosis and treatment of PMP.
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Objective To investigate dose escalation by metabolic sub-volume based on standard uptake values ( SUV) gradient of pre-treatment positron emission tomography/computed tomography ( PET/CT) for locally advanced non-small cell lung cancer ( NSCLC) radiotherapy. Methods The pre-treatment 18 F-FDG PET/CT images of 29 patients with locally advanced NSCLC were analyzed retrospectively. Gross tumor volume ( GTV) was delineated on the PET/CT fusion images. Tumor metabolic sub-volume was segmented according to the threshold of 50% and 75% maximum standard uptake values ( SUVmax ) . The region that under 50% SUVmax was defined as GTV1. From 50% to 75% SUVmax was defined as GTV2,and over 75% SUVmax was defined as GTV3. PTV (planning target volume), PTV1, PTV2 and PTV3 were extended from GTV, GTV1, GTV2 and GTV3, and different plans were designed subsequently. Plan 1 was designed for PTV with prescription dose 60 Gy, and Plan 2 was designed for PTV1, PTV2 and PTV3 with prescription dose 60-66 Gy, 66-72 Gy and≥72 Gy, respectively. The dosimetric parameters between tumor target and organs at risk (OARs) were compared. Results Compared to Plan 1, the absorbed dose in Plan 2 that covers 2% volume of the PTV ( D2 ) was increased from 66. 5 Gy to 78. 5 Gy and the dose was escalated by about 23. 2%. The average dose of PTV1, PTV2 and PTV3 increased by 2. 8% (62. 7-64. 4 Gy), 10. 3% (63. 5 -70. 0 Gy), 18. 7% (63. 8 -75. 8 Gy), and the average dose of PTV increased by 8. 9% (63. 2-68. 8 Gy). The sub-regional dose had been effectively improved. There was no significant difference in target coverage between Plan 1 and Plan 2 ( P >0. 05 ) . Homogeneity index (HI) was decreased with the escalation of maximum dose for Plan 2(t=23. 3, P<0. 05). There was no statistically significant difference in radiation dose of OARs between two plans ( P>0. 05 ) . Conclusions Dose escalation based on metabolic sub-volume from 18 F-FDG PET/CT was feasible, and radiation dose escalation of sub-volume with high metabolic activity can be achieved without increasing the OARs dose.
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Objective To investigate dose escalation by metabolic sub-volume based on standard uptake values ( SUV) gradient of pre-treatment positron emission tomography/computed tomography ( PET/CT) for locally advanced non-small cell lung cancer ( NSCLC) radiotherapy. Methods The pre-treatment 18 F-FDG PET/CT images of 29 patients with locally advanced NSCLC were analyzed retrospectively. Gross tumor volume ( GTV) was delineated on the PET/CT fusion images. Tumor metabolic sub-volume was segmented according to the threshold of 50% and 75% maximum standard uptake values ( SUVmax ) . The region that under 50% SUVmax was defined as GTV1. From 50% to 75% SUVmax was defined as GTV2,and over 75% SUVmax was defined as GTV3. PTV (planning target volume), PTV1, PTV2 and PTV3 were extended from GTV, GTV1, GTV2 and GTV3, and different plans were designed subsequently. Plan 1 was designed for PTV with prescription dose 60 Gy, and Plan 2 was designed for PTV1, PTV2 and PTV3 with prescription dose 60-66 Gy, 66-72 Gy and≥72 Gy, respectively. The dosimetric parameters between tumor target and organs at risk (OARs) were compared. Results Compared to Plan 1, the absorbed dose in Plan 2 that covers 2% volume of the PTV ( D2 ) was increased from 66. 5 Gy to 78. 5 Gy and the dose was escalated by about 23. 2%. The average dose of PTV1, PTV2 and PTV3 increased by 2. 8% (62. 7-64. 4 Gy), 10. 3% (63. 5 -70. 0 Gy), 18. 7% (63. 8 -75. 8 Gy), and the average dose of PTV increased by 8. 9% (63. 2-68. 8 Gy). The sub-regional dose had been effectively improved. There was no significant difference in target coverage between Plan 1 and Plan 2 ( P >0. 05 ) . Homogeneity index (HI) was decreased with the escalation of maximum dose for Plan 2(t=23. 3, P<0. 05). There was no statistically significant difference in radiation dose of OARs between two plans ( P>0. 05 ) . Conclusions Dose escalation based on metabolic sub-volume from 18 F-FDG PET/CT was feasible, and radiation dose escalation of sub-volume with high metabolic activity can be achieved without increasing the OARs dose.
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Objective To investigate the distribution rules of setup errors in different locations for tomotherapy.Methods 151 patients induding 53 head and neck tumors,45 thoracic tumors,20 abdominal tumors,and 33 pelvic tumors,who accepted tomotherapy were retrospectively analyzed in this study.The planning CT images of patients were obtained in simulation,and all patients underwent megavoltage CT (MVCT) scan before radiotherapy.And the setup errors were calculated by rigid registering MVCT images to planning CT images,and setup errors on + x(left),-x(right),+ y(in),-y(out),+z(ventral),-z (dorsal)axes were analyzed respectively.Results A total of 3 281 MVCT scans were performed on 151 patients,The setup errors on +x (left),-x(right),+y(in),-y(out),+z (ventral),-z (dorsal)axes were (1.61 ± 1.21),(1.76 ±2.11),(2.26 ± 1.74),(1.83 ± 1.47),(3.24±1.76) and (1.75 ± 1.61)mm for head and neck tumors;(2.43 ±1.88),(2.55 ± 1.92),(3.06 ±2.64),(3.90 ±2.91),(6.71 ±3.46) and (2.64 ±2.77)mm for thoracic tumors;(3.67±3.06),(2.37±1.77),(3.18±1.96),(3.98±3.01),(6.74±3.25) and (1.92±2.00) mm for abdominal tumors;(2.92 ±2.13),(2.17±1.68),(3.50±2.61),(3.72±2.66),(7.18± 3.43) and (1.92 ± 1.61)mm for pelvic tumors,respectively.The setup errors were different between +z and-z with statistically significant in all tumors (t =-4.119、-5.033、-3.763、-5.057,P ＜ 0.05).The setup errors on + z direction of patients immobilized with thermoplastic mask were smaller than those immobilized with vacuum cushions for thoracic tumors (t =-2.357,P ＜ 0.05).Conclusions The setup errors of head and neck tumors are less than other parts tumor in tomotherapy.The patients immobilized with thermoplastic mask can reduce the setup errors for thoracic tumors.The heterogeneity of setup errors on ventral-dorsal directions for the all parts of tumors should not be ignored.
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Objective To assess the feasibility for the automated treatment planning verification system Mobius3D (M3D) to perform an independent 3D dose calculation in intensity-modulated radiotherapy (IMRT) for cervical cancer.Methods Twenty patients with cervical cancer were randomly selected.With treatment planning systems (Pinnacle,Version 9.2;Eclipse,Version 13.5),all IMRT plans were divided into 7 fields to meet the dosimetric goals.The optimized plans were exported to the M3D server.The percentage differences in the volume of region of interest (ROI) and the dose calculation of target volume and organ at risk (OAR) were evaluated for the two treatment planning systems,and theγ passing rate was used to assess the accuracy of M3D calculation.Results The difference in the volume of ROI for Pinnacle 9.2 to M3D was less than that for Eclipse 13.5 to M3D,with maximum differences of 0.22％±0.69％ and 3.5％±1.89％ for Pinnacle 9.2 and Eclipse 13.5,respectively.The differences in the dose calculation of target volume and OAR for the two treatment planning systems to M3D were within ± 1％.After recalculating by M3D,the dose difference between Pinnacle 9.2 and M3D was smaller than that between Eclipse 13.5 and M3D,but the mean differences were all within ±3％.The γ passing rates for target volume and OAR were more than 95％ on average.Conclusions The method of utilizing the automated treatment planning verification system to validate the accuracy of plans is convenient.It can be used as a secondary check tool to improve accuracy in IMRT dose calculation.
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Objective To study the feasibility of defining the internal gross tumor volume (IGTV) of hepatocellular carcinoma applying the enhanced four-dimensional computed tomography (4DCT) images with deformable registration technology.Methods Ten HCC patients who accepted radiation therapy were selected in this study.The 4DCT in free breathing,non-enhanced 3DCT and arterial phase enhanced 3DCT in end inspiration breath holding associated with active breathing coordinator were acquired sequentially.4DCT were sorted into ten series CT images according to breath phase,and named CT00,CT10..…CT90.Gross tumor volume (GTV) were contoured on different CT series and the IGTV1 was merged by ten phases GTVs of 4DCT.The GTV of enhanced 3DCT was registered to different CT series of 4DCT and the IGTVDR was obtained by merging the GTVs after deformable registration.The target volumes differences were compared by paired t-test.Results The edge of tumor was difficult to define on 4DCT and non-enhanced 3DCT images.The enhanced 3DCT image showed clearer tumor edge,and the GTV increased by mean 37.99％ compared to GTV on 4DCT different series images and non-enhanced 3DCT image (P =0.002).The GTV after deformable registration on 4DCT different phase images increased by mean 36.34％ (P =0.011),which were similar to GTV on enhanced 3DCT image (P =0.632).The IGTVDR increased by 19.91％ (P =0.017),compared to IGTV1.Conclusions The contrast-enhanced 4DCT image which was obtained by combining enhanced 3DCT and 4DCT images with deformable registration technology could raise the position precision of the HCC IGTV effectively.
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Objective To compare and analyze the dosimetric characteristics of the intensity-modulated arc therapy (RapidArc) combined with active breathing coordinator (ABC) in the thoracic esophageal carcinoma radiation therapy. Methods Ten thoracic esophageal carcinoma patients undergoing radiotherapy were selected for this study.The CT simulations were performed under three breath patterns respectively:moderate deep inspiration breath-hold (mDIBH) with ABC aid; Set the trigger threshold to 80％ of the peak of the respiration curve; and free breathing (FB).Based on the corresponding CT image sets,three treatment plans were generated for each patient respectively:Arc-ABC( three small arcs),ArcFB (consisted of two coplanar full arcs) and IMRT-FB plan.The following dosimetric parameters were compared among different plans:D2％,D98％,V95,homogeneity index ( HI),conformal index ( CI ) the percentage of volume receiving dose of over x Gy (Vx),monitor unit (MU),control points and treatment time.Results The planning target volume ( PTV ) of FB was 376 cm3 which decreased to 260 cm3 after using ABC.For mDIBH and FB patients,the total lung volumes were 5964.6 cm3(35％ more than FB) and 3838.8 cm3 respectively; the heart volumes were 524.4 cm3 and 642.7 cm3 respectively. No significant difference was observed among Arc-ABC,IMRT-FB and Arc-FB in terms of D2,D98,V95,CI and HI.For Arc-ABC plans,there were significant decreases of radiation dose in total-lung's V10,V20,V30,V40 and mean lung dose ( F =4.38,5.34,4.07,3.89,4.28,P ＜0.05).Various dose decreases of heart V20,V3,V40,Dmean and spinal cord Dmax were observed,yet no statistically significant difference existed.The MUs and total control points of Arc-ABC plans were significantly lower than other plans ( F =26.86,12.56,P ＜ 0.05 ).Conclusions When thoracic esophageal carcinoma patients were treated with radiotherapy,the combined utilization of RapidArc and ABC can potentially decrease the volume of irradiated lung yet escalate the dose in target.
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Purpose To investigate the dosimetric differences among RapidArc (RA) plans which were designed on different target volumes in hepatocellular carcinoma (HCC).Methods A total of 10 HCC patients underwent 3D-CT scan under free breathing ( FB),end inspiration hold ( EIH ) associated with active breath coordinator (ABC) and 4D-CT scan.The 4D-CT were sorted into 10 sets of CT images according to respiratory cycle.The gross tumor volume (GTV) was manually contoured on different CT images.The individual internal gross target volume ( IGTV1 ) was obtained from 4D-CT,and the individual margins from GTVFB to IGTV1.IGTV2 were obtained from GTVFB using individual margins.The planned target volumes (PTV-1,PTV-2,PTV-3 and PTV-4 ) were obtained from GTVFB,IGTV1,IGTV2 and GTVEIA applying different margins.The RA plans (RA1,RA2,RA3 and RA4 ) were designed from different PTVs,and for RA1,RA2 and RA3 the simple 358° arc were used,while three 135° arcs were used for RA4.The dosimetric differences were compared.Results The PTV-1 and PTV-3 were larger than PTV-2 and PTV-4; the mean values of PtV-1/PTV-2 and PTV-1/PTV-4 were 2.5 and 1.9,respectively.There were no significant differences in conformal index,homogeneity index,maximum dose,and minimum dose of PTV among 4 RA plans.The irradiation dose of normal liver of RA3 and RA4 were 8.23 Gy and 7.63 Gy respectively,both significantly lower than those of RA1 and RA2 (10.21 Gy,9.62 Gy,x2 =10.68,P ＜0.05 ),and the V30of RA3 and RA4 were 5.24％ and 5.05％ respectively,both significantly lower than those of RA1 and RA2 (7.76％,6.12％,x2 =14.76,P ＜ 0.05 ).There were no significant differences in irradiation doses of stomach and duodenum among different plans.Conclusions Using 4D-CT or ABC technology with RapidArc in HCC can define the target volume accurately and achieve prefect dose distribution sparing more normal liver volume,compared to the traditional margins.4D-CT and ABC play similar roles in sparing normal liver.
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ObjectiveTo investigate the dosimetric difference in the application of RapidArc using 6 and 15 MV X-rays for radiotherapy of multiple hepatic malignancy.MethodsA total of 12 cases with multiple hepatic tumors ( primary 5 cases and secondary 7 cases) were selected.All patients underwent the three dimensional CT simulation in free breathing.For each patient,RapidArc plans with single or two 358° arcs using 6 or 15 MV X-rays were designed respectively,the prescription dose was 2Gy per fraction × 25 fractions.The dosimetric differences were compared among RapidArc plans.ResultsAll of RapidArc plans could meet the clinicalrequirement.There were no significant differences in the conformity index ( CI ),homogeneity index ( HI),the maximum dose and the minimum dose of PTV among RapidArc plans ( P ＞ 0.05).All the CI could get to 0.91 and HI could get to 0.88.In the RapidArc plans with two 358° arcs,the Vs,V10,V15 of normal liver were higher than with single arc,while V20,V25,V30,V35,V40 were lower than with single arc.There were no significant differences in the different radiation dose of normal liver,stomach,duodenum and spinal cord among different plans ( P ＞0.05 ).The monitor units of RapidArc plans using 6 MV X-rays increased 12％ compared to 15 MV averagely.CondusionThe 6 MV X-ray would be selected chiefly in the radiotherapy of multiple haptic tumor using RapidArc with whole arc(s).
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Objective To compare the dosimetric characteristics of intensity-modulated arc therapy( IMAT ),fixed-gantry intensity-modulated radiotherapy ( IMRT ) and 3-dimensional conformal radiotherapy (3D-CRT) for the thoracic esophageal cancer.Methods A total of 15 patients with thoracic esophageal cancer were enrolled.3D-CRT,5-field IMRT( IMRT5 ),7-field IMRT( IMRT7 ),9-field IMRT ( IMRT9 ),single arc ( Arc1 ) and double arc ( Arc2 ) RapidArc plans were generated for each patient.All plans were prescribed 40 Gy in 20 fractions and 19.6 Gy in 14 fractions to PTV at 95％ isodose line.Results RapidArc and all IMRT treatment plans in dosimetric parameters of target volumes were obviously better compared to 3-dimentional conformal treatments( t =5.77,3.52,P ＜ 0.05 ).The result of V95 of PTV for 3D-CRT,IMRT5,IMRT7,IMRT9,Arc1 and Arc2 plans was 91.55 ±2.90,96.66 ±1.05,96.87 ± 1.23,96.81 ± 1.16,94.98 ± 1.41 and 95.93 ± 1.32,respectively.The best conformation index in PTV was observed in the RapidArc plans ( t =3.76,10.01,P ＜ 0.05 ),and the best homogeneity index in PTV was observed in the IMRT plans( t =3.93,3.37,P ＜ 0.05 ).In terms of organ sparing,no statistical difference was observed between IMRT and RapidArc plans( P ＞ 0.05 ),while 3D-CRT provided the lowest number of V1 cGy and V5 cGy for total lung.Compared with the IMRT treatment plans,the number of monitor units was lower in all 3D-CRT and RapidArc cases with differences of 75％.Conclusions All the IMRT and RapidArc plans could offer high quality treatment for patients.3D-CRT might show advantage in low-dose region to organs at risk.Compared with IMRT,no obvious advantage in PTV dosimetric parameters could be observed in RapidArc plans.
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Objective To evaluate the accumulated doses to normal tissues and organs at risks (OARs) of patients with lung cancer in radiotherapy plans by using the deformable registration method,and make comparison with the empirical calculation method.Methods Ten patients with lung cancer were analyzed retrospectively.3D-CRT or IMRT plans were designed before treatment. CT to simulator was rescanned and the same treatment plan was redesigned during radiotherapy. Based on the deformable registration method,the Mimvista software was used to calculate the accumulated doses to normal tissues and OARs in two CT images respectively.The empirical estimation algorithm was calculated by the linear relationship between the fractions and the total prescribed dose.Results The target coverage of patients had no significant difference in two plans.There were no significant differences in all the dose volume parameters for normal tissues and OARs,except the mean dose to right lung( t =2.98,P ＜ 0.05 ) when the the same plan was conducted in position-setting and reposition CT images.Conclusions The empirical estimation for the accumulated dose could be used to evaluate the dose and volume parameters for normal tissues and OARs in lung cancer by the same plan.
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ObjectiveTo study the feasibility of RapidArc (RA) associated with active breath coordinator (ABC)for hepatocelluar carcinoma (HCC)radiotherapy comparing of three-dimensional conformal radiotherapy (3DCRT),intensity modulated radiotherapy (IMRT),RA treatment plans in different breath status.Methods12 HCC cases were selected.Three series CT scanning were completed in Free Breathing (FB),End Inspiration Hold (EIH) and End Expiration Hold (EEH) associated with ABC device.3DCRT,IMRT and RA (three 135° arcs) treatment plans were respectively designed on planning target volume (PTV) in different breath status.The dosimetric differences among 3 DCRT,IMRT and RA,among RA plans under different breath status were compared.ResultsThe PTV in FB was larger than in EEHand EIH (160.8 cm3,89.5 cm3,83.1 cm3,F=6.63,P=0.004). The conformity index and homogeneity index of RA plans were better than IMRT and 3DCRT ( 0.92,0.90,0.77,F =72.55,P =0.000 ;0.90,0.89,0.84,F =125.49,P =0.000 ) ;the V20,V30,V40 of normal liver in 3DCRT were higher than IMRT and RA (24％,20％,19％,F=3.56,P =0.032;13％,10％,10％,F=5.74,P =0.004;8％,5％,6％,F =3.72,P =0.027).The normal liver mean dose,V10,V20,V30,V40 of RA plans in FB were higher than in EEH and EIH ( 13.46 Gy,10.25 Gy,9.48 Gy,F =3.627,P =0.038 ;46％,35％,32％,F =2.96,P=0.066;24％,16％,16％,F=3.69,P=0.036;13％,8％,8％,F=4.28,P=0.022;8％,5％,5％,F =2.39,P =0.108 ).The duodenum D5 cm3 of RA in EEH was lower than in FB and EIH (8.78 Gy,19.35 Gy and 11.67 Gy,F =1.56,P =0.224 ).The mean monitor units for 3 DCRT,IMRT,RA was 254.06 MU,626.33 MU and 550.28 MU ( F =147.35,P =0.000 ),while the mean treatment time was 135 s,540 s and 130 s respectively (F =62.83,P =0.000).ConclusionsThe RapidArc applying three 135°arcs with ABC in HCC radiotherapy can achieve better PTV coverage than IMRT with fewer monitor units,shorter treatment time and sparing more normal liver.
ABSTRACT
Objective To research the feasibility of using three-dimensional CT (3DCT) associated with active breathing control (ABC) in determination of the individual internal tumor volume (ITV) for hepatocellular carcinoma (HCC) comparing the four-dimensional CT (4DCT).Methods After 4DCT scans of 15 HCC patients who had accepted TACE,completed the 3DCT scans associated with ABC in three ways of breathing:free breathing ( FB),end inspiration hold ( EIH),end expiration hold (EEH).4DCT images were sorted into 10 phases and the maximum intensity projection (MIP) images were constructed.The GTVs were manually contoured on 4DCT and 3DCT images (labeled as GTV0,GTV10.….GTV90,GTVMIP,,GTVFB,GTVEIH and GTVEEH).GTV0…GTV90,GTV0 and GTV50,GTV0,GTV20 and GTV50,GTVEIH and GTVEEH were respectively merged into IGTV1,IGTV2,IGTV3,IGTV4.The volume and geometry displacement of GTVs and IGTVs were compared.Results All patients were compatible with the ABC technique and completed the CT scans in two ways.The motion of diaphragm measured between 4DCT and 3DCT images was not significantly different ( 1.39 cm and 1.39 cm,t =-0.02,P =0.983 ),it was similar to the volume difference among GTV0,GTV20,GTV50,GTVEIH,GTVEEH and GTVFB (56.4,54.6,55.5,55.6,55.2,59.7 cm3,F =0.01,P =1.000 ).The comparison result of volume difference among IGTV1,IGTV2,IGTV3,IGTV4 and GTVMIP (77.9,71.4,73.4,72.3 and 66.3 cm3,F =0.02,P =1.000)were similar to the differences of geometry displacement in x,y and z axial among them (F =0.48,0.04,0.02,P =0.750,0.997,0.999,respectively).Conclusion The application of 3DCT associated with ABC in determination of the individual IGTV for HCC is feasible and safe comparing to 4DCT.