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Objective:To explore the feasibility of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors (SPTs).Methods:23 patients with SPTs received 4DCT scanning simulation with the conventional scanning (CON), low voltage (LV), low current (LA) and low voltage combined with low current (LVA) in sequence. Based on the 4DCT images derived from the four sets of scanning parameters, the internal gross tumor volume (IGTV CON, IGTV V, IGTV A, IGTV VA) of SPTs were delineated and matched. Taking IGTV CON as reference, the tumor displacement and the centroid position of IGTV V, IGTV A and IGTV VA were compared with IGTV CON. The radiation doses under different scanning parameters were compared. Results:The volumes of IGTV CON, IGTV V and IGTV A were (12.26±12.30) cm 3, (12.21±12.16) cm 3 and (11.87±11.70) cm 3, respectively ( P=0.337). IGTV VA was (11.34±11.07) cm 3, significantly smaller than IGTV CON ( P=0.005). There was no significant difference in the centroid positions of IGTV CON, IGTV V, IGTV A and IGTV VA in three directions ( P=0.491, 0.360, 0.136). The Dice′s similarity coefficient (DSC VA) was significantly lower than DSC V and DSC A ( P=0.004, 0.030). The tumor displacement measured by the four sets of 4DCT images was similar in the LR direction ( P=0.470), and also in the AP direction ( P=0.108). For the displacement in the SI direction, LVA scanning was smaller than CON ( P=0.015). The radiation doses under four different scanning conditions were (397.0±140.3) mGy·cm, (175.0±61.8) mGy·cm, (264.8±95.3) mGy·cm and (116.8±41.2) mGy·cm, respectively ( P<0.001). Conclusions:LV or LA scanning exert no significant effect on the volume, centroid position of IGTV and the tumor displacement in 4DCT simulation for SPTs. The radiation dose that patients receive under LV and LV scanning is lower than that of CON. Consequently, LV or LA scanning is feasible in 4DCT simulation and target delineation for SPTs.
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Objective:To evaluate the spatial position and functional parameters of 18F-FDG PET-CT and diffusion-weighted imaging (DWI) before and during radiotherapy (RT) based on the medium of 3DCT in patients with esophageal cancer and to explore whether the high-signal area derived from DWI can be used for individualized definition of the volume in need of dose-escalation for esophageal cancer. Methods:Thirty-two patients with esophageal cancer treated with concurrent chemoradiotherapy or neoadjuvant chemoradiation sequentially underwent repeated 3DCT, 18F-FDG PET-CT and enhanced MRI scans before RT and at the 15 th time of RT. All images were fused with the 3DCT images by deformable registration. The gross tumor volume (GTV) was delineated based on PET Edge on the first and second 3DCT, PET-CT and DWI and corresponding T 2-weighted MRI (T 2W-MRI) fused images, and defined as GTV CTpre and GTV CTdur, GTV PETpre, GTV PETdur, GTV DWIpre and GTV DWIdur, respectively. SUV (SUV max, SUV mean, SUV peak), MTV, TLG, ADC (ADC min and ADC mean) values and △SUV (△SUV max, △SUV mean, △SUV peak), △MTV, △TLG, △ADC (△ADC mean and △ADC min) of lesions were measured before and during RT. Results:The differences in SUV (SUV max, SUV mean, SUV peak), MTV, TLG, ADC mean and ADC min of the GTV before and during RT were statistically significant (all P<0.001). The tumor ADC and SUV values before and during RT showed no significant correlation, and there was no correlation between △ADC and △SUV (both P>0.05). The conformity index (CI) of GTV PETpre to GTV DWIpre was significantly higher than that of GTV PETdur to GTV DWIdur ( P<0.001). The shrinkage rate of maximum diameter (△LD DWI)(24%) and the shrinkage rate of tumor volume (VRR DWI)(60%) based on DWI during RT were significantly greater than the corresponding PET-based △LD PET (14%) and VRR PET (41%)( P=0.017 and P<0.001). Conclusions:The location of high residual FDG uptake based on PET-CT yields poor spatial matching compared with the area with residual high signal based on DWI during RT. Tumor ADC and SUV values may play complementary roles as imaging markers for prediction of patterns of failure and for definition of the volume in need of dose-escalation. In addition, the shrinkage rates of tumor maximum diameter/volume based on DWI during RT are significantly faster than those based on PET-CT. Therefore, the feasibility of selecting boosting of the high signal area derived from DWI for individualized definition of the volume for esophageal cancer is not clear.
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Objective Investigate the relationship between gross tumor volume (GTV)-related factors including GTV-T volume,the maximum thickness of the esophageal lesion plane and GTV-T volume/length(GTV-T volume divided by the length of the lesion calculated by the number of GTV-T layers) and the locoregional failure of radical intensity-modulated radiation therapy (IMRT) for esophageal carcinoma.Methods A total of 133 patients with esophageal cancer undergoing radical IMRT were enrolled.The factors related to GTV-T including GTV-T volume,the maximum thickness of the esophageal lesions,GTV-T volume/length were calculated.The relationship between GTV-T related factors and local recurrence of tumors was retrospectively analyzed.Results There was positively linear association between the locoregional failure rate of GTV-T and the volume of GTV-T.The volume of GTV-T tumor was 36 cm3,the maximum wall thickness was 2.5 cm,and the GTV-T volume/length was calculated as 5.3 cm2.These critical values could be utilized to predict the risk of locoregional failure of IMRT for esophageal carcinoma.Conclusions The GTV-T factors can be adopted to predict the local control and the risk of locoregional failure of radical IMRT for esophageal carcinoma to certain extent.
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Objective To compare the differences of gross tumor volume (GTV) and dose distribution between MRI-CT fusion imaging and CT-based imaging and investigate the dose difference in the therapeutic regime.Methods Ten patients diagnosed with primary tumors of the cervical vertebra between 2013 and 2014 were enrolled.Prior to radiotherapy,the imaging data of MRI examination (GE Discovery MR 750 3.0T) were collected,transfered into the Eclipse system and subject to fusion with CT images.GTV delineation,organ at risk (OAR) delineation and dose distribution discrepancy induced by target volume differences were analyzed and statistically compared between the MRI-CT fusion and CT-based images.GTV delineation and dose parameters among different radiologists between two approches were analyzed by analysis of variance (ANOVA) and paired t-test.Non-normally distributed variables were analyzed by Wilcoxon rank-sum test.The reliability of intraclass correlation coefficient (ICC) was assessed.Results The GTVMRI-CT volume was larger compared with the GTVCT volume.The volume overlap index was 0.84±0.17.The cordMRI-CT volume was significantly less than the cordCT volume (P=0.001).For 5 radiologists,the ICCMRI-CT was larger than ICCCT.The DmaxMRI-CT of the spinal cord was (46.00± 1.09) Gy,significantly less than (52.39±1.34) Gy for the DmaxCT(P=0.014).Conclusions It is unlikely to miss the target delineation on MRI-CT fusion imaging.MRI-CT fusion imaging can minimize the discrepancy of interobserver radiologists and cause dosimetric advantages.
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Objective Compared with chest CT,endoscopic ultrasonography (EUS) can more accurately determine the upper and lower margins of esophageal cancer,and marking the upper and lower margins of the esophageal cancer with titanium clip contributes to the delineation of target area of esophageal cancer during radiotherapy.To compare the effects of esophageal X-ray,chest computed tomography (CT)scan and EUS-assisted placement of marker clip in the determination of the length of gross target volume (GTV),aiming to provide reference for the determination of GTV during esophageal cancer radiotherapy.Methods Thirty patients who were initially diagnosed with thoracic esophageal cancer by histological and cytological examinations and scheduled to receive radiotherapy were recruited in this investigation.All patients received esophageal X-ray,CT scan,and EUS-assisted placement of marker clip.The length of GTV was quantitatively measured and statistically compared among three different methods.Results The length of GTV was (6.1 ± 1.4) cm,(6.8± 1.9) cm and (6.3± 1.9) cm determined by esophageal X-ray,CT scan and EUS-assisted placement of marker clip,respectively.Compared with CT scan,the length of GTV determined by EUS-assisted placement of marker clip did not significantly differ (P=0.11).The length of GTV determined by esophageal X-ray was significantly shorter than that by CT scan (P =0.03).Among all patients,the length of GTV determined by EUS-assisted placement of marker clip was longer compared with that by chest CT scan in 22.2％ of patients.The length of GTV determined by EUS-assisted placement of marker clip was the same as that by chest CT scan in 11.1％ of patients.The length of GTV determined by EUS-assisted placement of marker clip was shorter compared with that by chest CT scan in 66.7％ of patients.Conclusions EUS-assisted placement of marker clip differs from esophageal X-ray and CT scan in determining the length of GTV,which acts as one of the effective methods in the determination of the length of GTV during esophageal cancer radiotherapy.
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Objective To analyze the effects of gross tumor volume(GTV-T)and positive lymph node volume(GTV-LN)on the prognosis of radical concurrent chemoradiotherapy for esophageal squamous cell carcinoma(ESCC). Methods A total of 79 patients with stage N1ESCC undergoing radical radiotherapy in our hospital from 2012 to 2015 were enrolled as subjects. GTV-T and GTV-LN were calculated by the Pinnacle39.0 treatment planning system. The receiver operating characteristic(ROC)curves were used to evaluate the value of the GTV-LN/GTV-T ratio in the prediction of local recurrence(LR)and distant metastasis(DM)of ESCC. Results The median follow-up time was 17.2 months in all patients. The ROC curves were made using the GTV-LN/GTV-T ratio. The optimal cut-off values of GTV-LN/GTV-T ratio for predicting the risk of LR and DM were 0.34 and 0.59, respectively. The statistical analysis revealed that the LR rates were 50% and 8% in patients with GTV-LN/GTV-T ratios of<0.34 and ≥0.34, respectively(P<0.01), while the DM rates were 11% and 43% in patients with GTV-LN/GTV-T ratios of<0.59 and ≥0.59, respectively(P= 0.003). Conclusions The GTV-LN/GTV-T ratio may be a predictor of LR and DM in patients with ESCC. Further studies on the GTV-LN/GTV-T ratio may help to make personalized chemoradiotherapy strategies for patients with ESCC.
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Objective To explore the effect of pitch in three-dimensional computed tomography (3DCT)on the gross tumor volume(GTV)and spatial position of solitary pulmonary lesion(SPL), and to evaluate the feasibility of high-pitch 3DCT simulation for SPL. Methods Twenty-two patients with peripheral lung cancer or metastatic SPL were divided into groups A and B according to the tumor location. All patients underwent spiral CT scans at different pitches(pitchCON=0.938, pitchS=0.438, and pitchB=1.188)during free breathing. All GTVSwere delineated by the same radiation oncologist using the same contouring protocol. GTVCONgenerated at pitchCON, GTVSgenerated at pitches, and GTVBgenerated at pitchB were compared in terms of volume and geometric position, and GTVSand GTVBwere registered to GTVCONgained at the conventional pitch. The Friedman M and Wilcoxon rank-rum test were used for comparison. Results The volumes of GTVCON, GTVS, and GTVBwere 11.58± 16.42 cm3, 11.63± 17.73 cm3, and 12.09± 17.46 cm3, respectively(P=0.11). There were no significant differences in the centroid position in x,y,and z directions between GTVCON,GTVS,and GTVB(Px=0.33,Py=0.81, Pz=0.39). The same result was found in group B (Px=0.92,Py=0.05, Pz=0.37). The matching index(MI)between GTVSand GTVCONwas related to the tumor location,so was the MI between GTVBand GTVCON. Conclusions The pitch in 3DCT simulation has no significant effect on the GTV and spatial position of SPL. Increasing CT pitch appropriately can improve the scanning speed and shorten the duration of 3DCT simulation,so high-pitch 3DCT simulation is feasible for SPL.
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Objective To analyze the volume and position of the gross tumor volumes (GTV) in primary esophageal cancer based on contrast-enhanced three-dimensional (3D),four-dimensional (4D) and cone beam (CB) computed tomography (CT).Methods A total of thirty-four patients underwent 3D-CT and 4D-CT simulation scans for computer treatment plan and contrast-enhanced CBCT scans were conducted prior to the first treatment.GTV3D,GTV4D50,internal GTVMIP (IGTVMIP) and internal GTVCBCT (IGTVCBCT) were delineated on 3D-CT,4D-CT50 (the end expiratory phase),4D-CTMIP (the maximum intensity projection),and CBCT datasets,respectively.The IGTV10 was defined as 10 respiratory phases GTVs in 4D-CT.To evaluate the difference in position,volume and the volumes encompassed characteristic.Results The significant difference was observed in the volumes [IGTV10 ＞ (IGTVCBCT or IGTVMIP) ＞ (GTV3D or GTV4D50)] regardless of the tumor location.Regarding IGTV10 as the standard volume,the underestimations or overestimations between IGTV10 and IGTVCBCT were larger than that of between IGTV10 and JGTVMIP (t =-8.294--3.192,P ＜ 0.05).However,there was no significant difference between the areas of IGTV10 which excluded in IGTVCBCT and IGTV3D (P ＞ 0.05).The GTV4D50/ IGTVCBCT ratio for upper esophageal tumors was negatively correlated to motion vector (r =-0.756,P ＜ 0.05).The centroid coordinates of IGTVCBCT in AP direction were significantly different from the test volumes (GTV3D,GTV4D50,IGTVMIP and IGTV10) (t =-3.559--2.435,P ＜ 0.05).The IGTV10/IGTVCBCT ratio was positively correlated to motion vector (r =0.695,P ＜ 0.05) for middle esophageal tumors.The centroid coordinates of IGTVCBCT were significantly different IGTV10 (t =2.201,P ＜0.05) in AP direction.For distal esophageal tumors,the significant difference was observed in the centroid coordinate between IGTVcBcT and IGTVMIP (t =-2.365,P ＜ 0.05) in LR direction.The percentage of IGTV10 excluded the IGTVcBcT were significantly correlated to the motion vector (r =0.540,0.678,P ＜ 0.05) for both middle and distal esophageal tumors.The mean MI value of IGTVCBCT to the other four test volumes ranged from 0.65 to 0.72.Conclusions CBCT has much motion information than 3D-CT but less than IGTV10.CBCT was similar to MIP images based on respiration motion.However,the target motion information encompassed in CBCT and MIP images cannot be exchanged to each other.
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Objective To examine the effects of gross tumor volume (GTV) and radiation dose on the prognosis of hepatocellular carcinoma (HCC) patients treated with whole body gamma knife.Methods The clinical data of 69 HCC patients who underwent body gamma knife treatment from January 2012 to June 2015 in the Radiotherapy Center of the PLA General Hospital were retrospectively reviewed.Based on a 50% or 60% isodose coverage of the planning target volume (PTV), patients were treated with a radiation dose of 4-5 Gy per fraction, and a total marginal dose of 36-50 Gy (median dose 45 Gy).Short-term efficacy, overall survival (OS), and the adverse effect of the treatment were evaluated.The optimal cut-off tumor volume was identified using the receiver operating characteristic curve, and survival was determined by the Kaplan-Meier method.Univariate and multivariate analyses were performed using the log-rank test and Cox proportional hazards regression model, respectively.Results The overall short-term response rate of the 69 patients was 67%.The 1-and 2-year OS rates were 62% and 40%, respectively, with a median survival of 18.6 months.The multivariate analysis showed that gross tumor volume (GTV)93 cm3(P=0.665).Conclusions GTV is an independent prognostic factor for overall survival of HCC patients.Although high-dose radiotherapy provides survival benefits to patients with small GTV, it is not necessarily suitable for patients with large GTV.
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Objective:This study aimed to compare rectal cancer tumor volume parameters measured by MRI sequences (T1WI, T2WI, and DWI) and/or CT with those by pathological specimen. Methods:Twenty-two patients with rectal cancer were prospectively enrolled. MRI sequences including T1WI, T2WI, and DWI, and/or CT of the pelvis were performed before operation. Volume parameters, such as tumor length along the rectal axis, maximum tumor width perpendicular to rectal axis, and tumor actual area in that perpendicular plane, were measured on T1WI, T2WI, DWI, and CT, respectively, for each patient. The respective pathological parameters were further measured in surgical specimen after total mesorectal excision. The two kinds of parameter values measured in imaging and pathology were statistically compared and accuracy appraisal was performed. Results:The mean Lpath-L was 4.06±1.14 cm. The mean LT1-L, LT2-L, LDWI-L, and LCT-L were 3.91± 1.51, 4.62±1.41, 3.39±1.05, and 3.94±1.23 cm, respectively. Correlation coefficients were 0.688, 0.635, 0.688, and 0.720 (P<0.05). An average 6 mm overestimation was found in T2WI, and 1 to 6 mm underestimation in T1WI, DWI, and CT in length values compared with those measured in surgical specimen. The mean Lpath-W was 2.56 ±0.94 cm. The mean LT1-W, LT2-W, LDWI-W, and LCT-W were 3.62±0.99, 3.66±0.76, 3.23±0.58, and 3.64±1.04 cm, respectively. The magnitude of mean overestimation ranged from 5.1 to 11.1 mm. The Apath was 4.30 ±2.83 cm2. AT1, AT2, ADWI, and ACT were 8.98±3.90, 8.99±3.43, 8.41±3.09, and 9.63±4.40 cm2, respectively, which double overestimated the tumor area in the perpendicular rectal plane. Conclusion:The difference in longitudinal length between MRI sequences/CT and pathological specimen was in the range of?6 mm to 6 mm. The mean maximum tumor width and areas in the maximum tumor perpendicular plane were overestimated. This study indicated that gross tumor volume delineation based on CT or MRI for rectal cancer irradiation should be conservative in the axial images of rectum, and meticulous consideration is required along the rectum.
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OBJECTIVE: To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories. MATERIALS AND METHODS: A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories. RESULTS: The gross tumor volume could predict regional lymph node metastasis (p<0.0001) in the univariate analysis, and the multivariate analyses indicated that the gross tumor volume was an independent risk factor for regional lymph node metastasis (p=0.005, odds ratio=1.364). The Mann-Whitney U test showed that the gross tumor volume could distinguish N0 from the N1-N3 categories, N0-N1 from N2-N3, and N0-N2 from N3 (all p<0.0001). In the T1-T4a categories, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 12.3 cm3), N0-N1 from N2-N3 (cutoff, 16.6 cm3), and N0-N2 from N3 (cutoff, 24.6 cm3). In the T4a category, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 15.8 cm3), N0-N1 from N2-N3 (cutoff, 17.8 cm3), and N0-N2 from N3 (cutoff, 24 cm3). CONCLUSION: The gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict regional lymph node metastasis and N categories.
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Humans , Male , Female , Adult , Middle Aged , Aged , Young Adult , Stomach Neoplasms/pathology , Adenocarcinoma/secondary , Tumor Burden , Multidetector Computed Tomography/methods , Lymph Nodes/diagnostic imaging , Prognosis , Stomach Neoplasms/surgery , Stomach Neoplasms/diagnostic imaging , Adenocarcinoma/surgery , Adenocarcinoma/diagnostic imaging , Observer Variation , Multivariate Analysis , Retrospective Studies , ROC Curve , Neoplasms, Glandular and Epithelial/pathology , Lymph Nodes/pathology , Lymphatic Metastasis , Neoplasm StagingABSTRACT
Objective To investigate the effects of dosimetric differences in gross tumor volume ( GTV ) on local control and survival rates in patients with esophageal carcinoma undergoing three?dimensional ( 3D) radiotherapy,and to provide a basis for clinical treatment. Methods From January 2004 to December 2010, 548 patients with esophageal carcinoma received conventional fractionated 3D radiotherapy with a prescribed dose of 60 Gy. All patients were divided into low?dose group and high?dose group according to the dosimetric differences in GTV. The survival and local control rates were compared between the two groups. The survival rates were calculated using the Kaplan?Meier method and analyzed using the logrank test. The Cox regression model was used for the multivariate prognostic analysis. Results The number of sample were 456 and 216 patients at 5 and 7 years followed time. The 1?,3?,5?,and 7?year local control rates were significantly higher in the high?dose group than in the low?dose group ( 83?5% vs. 71?3%, 62?6% vs. 44?8%,57?5% vs. 41?7%,52?9% vs. 38?8%,P=0?000).The 1?,3?,5?,and 7?year survival rates were also significantly higher in the high?dose group than in the low?dose group ( 79?6% vs. 66?3%, 44?3% vs. 29?7%, 34?0% vs. 21?8%, 26?1% vs. 17?0%, P=0?000 ) . The univariate prognostic analysis using the Cox regression model showed that Dmin , Dmean , and D100 for GTV were prognostic factors ( P=0?000,0?001,0?000).In all the 548 patients,201 were assigned to the high?dose group and the others to the low?dose group. Compared with the high?dose group, the low?dose group showed significantly larger GTV (38?2 vs. 48?1 cm3,P=0?002) and more advanced T stages (P=0?035).The stratified analysis showed that the 1?,3?,5?,and 7?year local control and survival rates were significantly higher in the high?dose group than in the low?dose group,regardless of tumor location,GTV,TNM stage,or chemotherapy. The multivariate analysis using the Cox regression model indicated that tumor location and grouping based on the radiation dose to GTV were independent prognostic factors. Conclusions In 3D radiotherapy for treating esophageal carcinoma,a high?quality treatment plan and GTV dose assurance improve the survival rates in patients. The patients with lower Dmin ,Dmean ,and D100 for GTV than the prescribed dose have a poor prognosis.
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Objective To investigate the dose distribution of esophageal stents carrying different diameters of radioactive 125I seeds in tumor target area. Methods A laser scanner was used to scan a piece of blank paper on which circles of 12 mm, 14 mm and 16 mm diameter and a 5 cm scale were drawn. The data were stored in JPEF format on the computer desktop. According to the circular diameter, simulations of the corresponding esophageal stents were established, which were divided into group A, group B and group C. By using image conversion program, 17 images with 5 mm slice-distance were created for each group; the images were transmitted to the computer treatment planning system (TPS) to simulate the 8 cm long esophageal stents of different diameters. TPS was used to sketch the gross tumor volume (GTV) in order to simulate the esophageal stent border that was used as the inner boundary of GTV, which was expanded 0.5 cm outward to be used as the external boundary of GTV. Beginning from the fifth level, the 4 cm-long GTV was drawn with circles. Setting the same prescription dose, from the fifth level to the thirteenth level the 125I seeds with 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9 mCi were successively loaded on the simulation of the esophageal stents. The distance between 125I seed layers was 1 cm; the average number of seeds distributed on each layer was 4 particles. The dose volume histogram (DVH) was obtained. The D90 (the dose received by 90% of the target) and V90 (the percentage of the GTV volume receiving 90% the prescription dose) were recorded.Result s The arithmetic mean D90 of group A, B and C was (77.24 ±19.92) Gy, (69.56 ±25.27) Gy and (56.38±20.08) Gy respectively, and no statistically significant differences existed between each other among the three groups (F=0.84,P=0.44). The V90 of group A, B and C was (77.76±30.73)%,(76.79±25.92)%and (64.10 ±32.49)% respectively, and no statistically significant differences existed between each other among the three groups (F=0.46,P=0.64). Conclusion When the diameter of radioactive esophageal stent is 12 mm, the activity of 125I seed of 0.6 mCi is recommended. When the diameter of radioactive esophageal stent is 14 mm or 16 mm, the activity of 125I seed of 0.7 mCi is recommended. Nevertheless, when the diameter of radioactive esophageal stent is 16 mm, distribution of every five 125I seeds on each layer is strongly recommended. These three kinds of esophageal stent diameter have no significant effect on the dosimetric parameters.
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Objective To explore the prediction value of the modified clinical staging standard of GTV volume on non-surgical treatment esophageal carcinoma by analyzing the GTV volume of esophageal carcinoma and the invasion degree of structures and surrounding organs as the T stage standard.Methods A retrospective analysis was performed for 701 esophageal cancer patients treated by definitive radiotherapy from Jan.2006 to Dec.2012.After grouping and analysis by the previous GTV volume staging standards, we put forward the idea that considering effects of invasion degree of structures and surrounding organs of tumor on the basis of GTV volume when it came to T stage, which would be re-classified by downgrading and reevaluation of survival and prognosis.Results There was no significant survival differences between T3 and T4 on previous GTV volume staging standards (P ＞ 0.05), and also had shown an inconspicuous survival difference between stage Ⅲ and stage Ⅳ when combined with three-group N stage(P ＞ 0.05).We had modified the T stage standards of GTV volume: Based on different size of GTV volume, and in consideration of the invasion of adjacent structures and organs, new T stages had shown good separation on a corresponding survival curve(x2 =59.702 ,P ＜0.05).In clinical TNM staging which combined with the new T stage and three-group N stages, the 701 patients were divided into stage Ⅰ , Ⅱ , Ⅲ and Ⅳ, with corresponding 5-year survival rates of 33.5％ , 26.3％ , 13.4％ , 9.2％ , respectively, which strongly revealing significant differences of survival rates (x2 =82.577, P ＜ 0.05).Conclusions The new T staging standard, which combined GTV volume with invasion degree of adjacent structures and organs, could accurately predict the prognosis of patients with radical radiotherapy of esophageal carcinoma.
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Objective To study the dose distribution in tumor target of radioactive esophageal stent covered with 125I seeds which are arranged at different distance. Methods According to the longitudinal and horizontal distance between the 125I seeds, the experiment was divided into group A (0.5 cm), group B (1.0 cm) and group C (1.5 cm). A sheet of white paper, on which a 2cm diameter circle was drawn and was marked with a 5 cm scale, was scanned with a laser scanner, and the scanning data were saved in JPEG format on the computer desktop. By using image conversion program, pictures of 17 layers with the layer space of 5 mm were created. The picture was transmitted to the computer treatment planning system (TPS) to simulate a 2 cm diameter and 8 cm length esophageal stent. Using TPS to delineate the tumor target area (gross tumor volume, GTV), which was used as the simulation of the inner boundary of the tumor target area, outward expansion of 0.5 cm being regarded as the outside border. An annular and 6cm length tube was delineated and it was used as the target area, and the same prescription dose was set, and in each group 125I seeds of 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9 mCi were successively loaded on the simulation of esophageal stent. With the help of TPS the DVH graph was obtained, and the D90 (the dose received by 90% of the target) and V90 (the percentage of the GTV receiving 90% the prescription dose) of the three groups were determined. The results were statistically analyzed. Results The arithmetic mean values of D90 of group A, B and C were (217.15± 19.92), (89.16±32.44) and (31.68±11.52) Gy respectively (F=159.18, P<0.05); and the arithmetic mean values of V90 of group A, B and C were (100.00±0.00)%, (86.47±21.36)%and (29.33±21.54)%respectively (F=32.11, P<0.05). Conclusion The 2 cm-diameter radioactive esophageal stent covered with 125I seeds, which have o.6mci activity and are arranged at 1.0cm distance in both longitudinal and horizontal directions, should be recommended in clinical practice.
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Objective To investigate the variations of the spatial position and overlap ratio for gross tumor volume (respiratory phase 50％) (GTV50) and internal gross tumor volume (IGTV) of primary thoracic esophageal cancer during conventional fractionated radiotherapy based on repeated four-dimensional computed tomography (4DCT) scans.Methods Thirty-three patients with thoracic esophageal cancer underwent contrast-enhanced 4DCT scans before radiotherapy and at the 10th and 20th fractions of radiotherapy.Scans were registered to the baseline 4DCT scan using bony landmarks.The GTV50 was delineated by the same radiotherapist on each 4DCT imaging data set,and the IGTV was constructed accordingly.The target volume,degree of inclusion (DI),and matching index (MI) were compared in different phases.Results The volumes of GTV50 and IGTV decreased along with treatment course.No significant changes in the centroid position were observed for the GTV50 and IGTV.The median DIs of the target volumes at the 10th and 20th fractions in the original target volume were 0.75 and 0.63(P =0.000) for GTV50 and were 0.79 and 0.66(P=0.000) for IGTV,while the median MIs were 0.61 and 0.56(P=0.002) for GTV50 and were 0.68 and 0.58 (P =0.005) for IGTV.A positive correlation between the variation of volume ratio and the variation of DI was found for GTV50 and IGTV (r =0.632,r =0.783),and the variation of volume ratio was also positively correlated with the variation of MI (r =0.387,r =0.483) ;the 3D vector was negatively correlated with the MI (r =-0.455,r =-0.438).Conclusions During conventional fractionated radiotherapy,the variation of spatial position is less than 0.8 cm for GTV50 and IGTV of primary thoracic esophageal cancer,and the decline of the target leads to varying degrees of decreases in DI and the MI.
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This study aims to determine a reasonable clinical staging standard for patients with esophageal carcinoma who were receiving non-surgical treatment. The patients were staged on the basis of the (2004 and 2009 editions of clinical staging stan-dards. The prognosis of patients with different staging standards, as well as the effect of gross tumor volume-tumor (GTV-T) on clinical T stage and prognosis, was observed. Methods:Data on 219 patients with esophageal carcinoma who were receiving radical radiothera-py were retrospectively analyzed. Prior to radiotherapy, all patients underwent examinations, including esophageal barium meal and po-sitioning CT scan, for use in the radiation treatment planning system to outline the target range and to calculate the volume of GTV-T. All patients were staged with the use of the aforementioned clinical staging standards. Prognostic outcomes of the patients were ob-served. Results:For all patients, the one-, three-, and five-year overall survival rates were 70.8%, 35.6%, and 20.7%, respectively. The survival curve resolution of patients who were staged with the use of the 2009 edition of clinical staging standards was better than that of the patients who were staged with the use of the 2004 edition. Survival difference was significant (χ2=29.497, P<0.001). The clinical T stage positively correlated with GTV-T (r=0.615, P<0.001). GTV-T could thus affect prognosis at different T stages. Conclusion:Both esophageal carcinoma clinical staging standards could reflect the prognosis of patients undergoing radiotherapy, but the 2009 edi-tion appeared more accurate than the 2004 edition.
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Objective To define a suitable threshold setting for gross tumor volume (GTV)when using 18F-fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in Nasopharyngeal carcinoma(NPC).Methods Sixteen NPC patients respectively received PET/CT and MRI scan before their radiation treatment.All of the images were transferred to the radiotherapy planning system (TPS).MRI/CT-based primary GTV was defined as GTVf.Biological target volumes (BTVs) were derived from PET/CT-based GTVs of primary tumors.The BTVs were defined as the volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax).GTVfs were compared with BTVs.The suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level were observed to be the fittest GTVf.The suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax.Results Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the GTVf.The sTL was [20.93％±6.51％(15％-40％)],whereas the sSUV was [2.27±0.48(1.56-3.25)].The sTL was inversely correlated with the SUVmax sTL =-0.144ln(SUVmax) + 0.5548 (R2 =0.85,F =78.57,P＜0.01.The sSUV showed a linear correlation with the SUVmax sSUV =0.104(SUVmax) + 1.0398,(R2=0.75,F=41.88,P＜0.01).The sTL was not associated with the value of GTVf.Conclusions In PET/CT-based BTV for NPC,SUVmax threshold method is feasible.sTL is not a fixed value,which is correlated with the SUVmax instead of the value of tumor.
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Objective To observe the relationship between computed tomography-gross tumor volume (GTV) and non-surgical T stage in patients with esophageal squamous cell carcinoma (ESCC) and the survival rates of patients with different GTVs,and to investigate the impact of GTV on the prognosis of ESCC after three-dimensional radiotherapy.Methods A retrospective analysis was performed on 223 ESCC patients without lymph node metastasis and distant metastasis who were hospitalized from July 2003 to January 2009.The prescribed doses of three-dimensional radiotherapy ranged from 50-70 Gy.These patients were divided into 3 or 4 groups according to different percentile intervals of GTVs.The Spearman rank correlation analysis was used for investigating the relationship between non-surgical T stage and GTV.The Kaplan-Meier method was used for calculating survival rates,and the log-rank test was used for survival difference analysis.Results The follow-up rate was 98.2％.A total of 163 patients were followed up for at least 3 years.The median GTVs of patients with T1 +2 ESCC,T3 ESCC,and T4 ESCC were 19.31 cm3,33.69 cm3,and 41.25 cm3,respectively,exhibiting a positive correlation between non-surgical T stage and GTV (P =0.000).The 5-year survival rates were 59％,43％,and 24％ (P =0.000) in 3 GTV-based groups and were 55％,51％,31％,and 24％ (P =0.004) in 4 GTV-based groups.The primary cause of death for the patients with GTVs of ≤35 cm3 and ＞35 cm3 was failure of local control (57.9％ vs 52.1％) ; 21.9％ and 13.8％ of the patients with a GTV of ＞ 35 cm3 died of uncontrol and excessive bleeding,versus 9.4％ and 3.1％ of the patients with a GTV of ≤ 35 cm3 (P =0.046 ; P =0.029) ;2 of the patients with a GTV of ＞ 35 cm3 died of grade 5 radiation pneumonitis.Conclusions GTV is positively correlated with nonsurgical T stage in esophageal cancer patients who receive radiotherapy.The 3-level and 4-level grading of GTV can be used for prognostic evaluation,and the 3-level grading of GTV is more closely related to prognosis.The patients with a larger GTV have higher incidence of uncontrol and bleeding and risk of treatment-related death than those with a smaller GTV after radiotherapy.
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Objective To investigate the gross tumor volume (GTV) changes in nonoperatively treated lung cancer patients during radiotherapy by off-line analysis using kilovoltage cone-beam computed tomography (KVCBCT).Methods Eighteen nonoperatively treated lung cancer patients were divided into group A (n =13) to receive conventional radiotherapy (1.8-2.2 Gy/fraction) and group B (n =5) to receive accelerated radiotherapy (5-8 Gy/fraction).Group A was further divided into subgroup A1 (n =10) and subgroup A2 (n =3) according to GTV changes.Each patient in group A underwent KVCBCT scan before treatment once a week,and each patient in group B underwent KVCBCT scan before each treatment.KVCBCT and CT images were registered in the treatment planning system to analyze GTV changes.Results Of all patients in group A,77％ showed ＞ 20％ GTV reduction.Subgroup A1 had the maximum GTV reduction in the 4th week of treatment (the 20th treatment) ;Subgroup A1 had a mean reduction of (0.94 ± 9.94)％,with a maximum value of-56.76％.Subgroup A2 showed no correlation between GTV changes and treatment time.Group B had a mean GTV reduction of (-7.41 ± 1.76)％,with a maximum value of -15.91％.Of all patients in group B,71％ showed ≤ 10％ GTV reduction.Small GTV changes were observed in group B.Conclusions There are no regular GTV changes in nonoperatively treated lung cancer patients during radiotherapy.Adaptive radiotherapy is recommended in the cases where GTV is reduced over 20％ in the 20th treatment.