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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 detect the changes of heart volume during concurrent chemoradiotherapy for esophageal cancer based on repeated enhanced 4DCT.Methods Patients with squamous cell esophageal cancer underwent repeated enhanced 4DCT and 3DCT scans before and after 10,20 and 30 fractions of radiotherapy,respectively.The heart was contoured on 3DCT,end expiratory (EE) and maximum intensity projection (MIP) of 4DCTimages.The changes in theheart volume,blood pressure.and heart rate were statistically compared at different time points.Results A total of forty-six patients completed 4 fractions of 3DCT and enhanced 4DCT scans.Compared with the initial values,the heart volume was significantly decreased by 3.27％,4.45％ and 4.52％ after 10 fractions of radiotherapy,and reduced by 6.05％,5.64％ and 4.51％ following 20 fractions of radiotherapy on 3DCT,EE and MIP,respectively (P=0.000-0.027).The heart volume after 30 fractions of radiotherapy did not significantly differ from the initial volume (P＞ 0.05).After radiotherapy,there was a significant decrease inboth systolic and diastolic blood pressure (P =0.000 and P =0.009) and a significant ‖ increase in the heart rate (P=0.0 0 1) compared with those measured before radiotherapy.Conclusions Enhanced 4DCT scan can clearly reflect the changes of heart volume throughout concurrent chemoradiotherapy.The heart volume starts to shrink during the early stage of radiotherapy and continue to decrease until the middleand late-stage,whereas it restores to the initial volume after radiotherapy.Simultaneously,blood pressure declines and heart rate is accelerated during radiotherapy.
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Objective To compare the normal thickness of the esophageal wall measured by contrast?enhanced three?dimensional ( 3DCT ) , four?dimensional ( 4DCT ) , and cone beam computed tomography ( CBCT) ,and to provide a basis for target volume delineation in esophageal cancer. Methods From 2009 to 2016,thoracic contrast?enhanced 3DCT and 4DCT simulations were performed in 50 patients with lung cancer or metastatic lung cancer. Contrast?enhanced CBCT scans were acquired during the first three?dimensional conformal radiotherapy. The normal esophageal wall was contoured on 3DCT images, the end?exhalation phase of 4DCT images ( 4DCT50 ) , the maximum intensity projection of 4DCT images (4DCTMIP),and CBCT images. The wall thickness was measured on each segment and the average thickness of esophageal wall was obtained. Comparison of the thickness of a fixed segment of esophageal wall between different CT images was made by paired t test. Comparison of thickness on the same type of CT images between different segments of esophageal wall was made by one?way analysis of variance. Results For the thoracic and intra?abdominal segments,there was no significant difference in the thickness of esophageal wall between 3DCT and 4DCT50 images ( P= 0?056?0?550 );however, the thickness of esophageal wall was significantly smaller on 3DCT images than on 4DCTMIP or CBCT images (P=0?000?0?004).For the upper and middle thoracic segments,the thickness of esophageal wall was significantly larger on CBCT images than on 4DCTMIP images ( P= 0?008, P= 0?001 ) . On 3DCT, 4DCT50 , and 4DCTMIP images, the thickness of esophageal wall was significantly larger in the lower thoracic segment than in the upper or middle thoracic segments ( P=0.008~0?041);the intra?abdominal segment had a significantly larger thickness of esophageal wall than the thoracic segments ( all P=0?000 ) . There was no significant difference in wall thickness on CBCT images between three thoracic segments ( P=0.088~0?945) . Conclusions A uniform criterion can be adopted to judge the normal thickness of esophageal wall in gross tumor volume ( GTV ) delineation on 3DCT and 4DCT50 images for thoracic esophageal cancer. However,caution should be taken when 5 mm is used as a criterion for normal thickness of esophageal wall in GTV delineation on 4DCTMIP and CBCT images.
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Objective To study the impact of respiratory frequency and amplitude of patients with the thoracic or abdomen tumor on 4DCT' s reconstructed image.Methods 75 thoracic or abdomen tumor patients who performed a scanning with belly belt-type respiratory gating on 4DCT between November 2012 to March 2013 in our hospital were retrieved.Reviewed their respiratory frequency,amplitude and fault distance of 4DCT' s reconstructed image and analyzed the correlation fault distance of the reconstructed image.The correlation analysis was used by bivariate Spearman method.Results Among these reconstructed images,fault distance more than 6 mm could be seen in 11 cases,fault distance ranging from 3 mm to 6 mm could be found in 46 cases,and distance less than 3 mm could be detected in 18 case.Respiratory frequency correlated significantly with the amplitude (rs =0.369,P =0.000);the respiratory rate had a tight association with the fault distance of the reconstructed image (r,=0.273,P=0.018);and respiratory amplitude was associated obviously with the fault distance of the reconstructed image (r,=0.696,P=0.000).Conclusions Both 4DCT reconstructed image and respiratory amplitude are significantly correlated to the continuity of the respiratory frequency.The smaller the respiratory frequence and amplitude change are,the better continuity will be.
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Objective To investigate the differences in position and volume between planning target volumes (PTV) based on positron emission tomography?computed tomography (PET?CT) images with an standardized uptake value ( SUV) no less than 2?5, 20% of the maximum SUV ( SUVmax ), or 25% of SUVmax , three?dimensional ( 3D ) CT, and four?dimensional ( 4D ) CT in thoracic esophageal cancer. Methods Eighteen patients with thoracic esophageal cancer sequentially received chest 3DCT, 4DCT, and [18F]fluoro?2?deoxy?D?glucose (FDG) PET?CT scans. PTV3D was obtained by conventional expansion of 3DCT images;PTV4D was obtained by fusion of target volumes from 10 phases of 4DCT images. The internal gross tumor volumes ( IGTV) , IGTVPET2.5 , IGTVPET20%, and IGTVPET25%, were generated based on PET?CT images with an SUV no less than 2?5, 20% of SUVmax , and 25% of SUVmax , respectively. These IGTVs were expanded longitudinally by 3?5 cm and radically by 1 cm to make PTVPET2.5 , PTVPET20%, and PTVPET25%, respectively. Results PTV3D was significantly larger than both PTV4D and PTVPET(P=0?000 -0?044), while there was no significant difference between PTV4D and PTVPET ( P= 0?216 -0?633 ) . The mutual degrees of inclusion ( DIs ) between PTV3D and PTV4D were 0?70 and 0?95, respectively, which were negatively correlated with 3D?Vector ( P=0?039). The mutual DIs between PTVPET2.5, PTVPET20%, and PTVPET25% were 0?74, 0?72, 0?78, 0?73, 0?77, and 0?70, respectively, which showed no correlation with 3D?Vector (P=0?150 -0?822). The mutual DIs between PTV3D and PTVPET were 0?86, 0?84, 0?88, 0?63, 0?67, and 0?59, respectively. Conclusions It is difficult to achieve complete volumetric overlap of PTVs based on 3DCT, 4DCT and PET?CT in thoracic esophageal cancer due to different target volume information. PET scan during free breathing should be used with caution to generate PTVs in thoracic esophageal cancer.
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Objective To explore the influence of different reconstruction modes with time?weighted respiratory phases on the internal tumor volume ( ITV) of solitary pulmonary lesion ( SPL) , and to evaluate the feasibilities of 8 and 4 equal time?weighted respiratory phases in 4DCT simulation. Methods 24 patients with SPL underwent 4D scanning. Images were reconstructed with 10, 8 and 4 equal time?weighted phases of the respiratory cycles, respectively. Gross tumor volumes ( GTVs ) were delineated on the three sets of reconstructed images and fused into ITVs, which were ITV10 , ITV8 and ITV4 respectively. The differences of volumes, centroid of the ITVs and motions of GTV centroids in three?dimensional directions were compared. Statistical analysis was performed using the Friedman M test. Results The volumes of ITV10 , ITV8 and ITV4 were (9.09±12?29) cm3,(9.10±12?47) cm3 and (8.98±12?61) cm3(P=0?001), respectively. There were no differences between the volumes of ITV10 and ITV8 after the Bonferroni correction ( P=0?721) , while the opposite between those of ITV10 and ITV4 ( P=0?002 ) . The differences of centroid positions of ITV10, ITV8 and ITV4 in x?, y?and z?axes were all less than 1 mm ((12.22±7?71),(12.23± 7?71),(12.22±7?71),Px =0?668);(43.30±29?38),(43.30±29?40),(43.31±29?39),Py =0?643;(5.66±3?67),(5.66±3?67),(5.66±3?67),Pz=0?878), similar to the motions of GTV centroids in three reconstructed modes ((0.69±0?56),(0.69±0?68),(0.79±0?51) mm,Px=0?356;(3.13±3?78),(3.13± 4?05),(3.19±4?06) mm,Py =0?978;(1.18±1?31),(1.03±1?32),(1.16±1?34) mm,Pz=0?302). Conclusions There were no differences in volumes, centroid positions and motions between ITV10 and ITV8 . The quantity of reconstruction images and GTV delineations according to 8 time?weighted phases were both less than conventional 10 phases. 8 time?weighted respiratory phases mode was feasible in 4DCT simulation for SPL.
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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 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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Objective To investigate the variations of the spatial position and overlap ratio of the internal target volume (ITV) and planning target volume (PTV) of primary thoracic esophagus carcinoma using repeated four-dimensional computed tomography (4D-CT) scanning during conventional fractionated radiotherapy.Methods Thirty patients with thoracic esophageal carcinoma were included whose 4D-CT scans were conducted before radiotherapy and between every ten fractions.The gross tumor volumes (GTVs) were delineated by the same radiation oncologist on each 4D-CT image phase,and the ITV and PTV were constructed afterwards.Results No significant difference of the isocenters was observed for the ITV and PTV during the treatment course,yet both the volumes of the ITV and PTV decreased.The median DI (the degree of inclusion) of the target acquired subsequently in the original target were 0.85,0.77 (Z=-3.10,P ＜0.05) for ITV and 0.86、0.82(Z =-2.49,P ＜0.05)for PTV respectively during entire treatment.The variation of volume ratio correlated strongly with the variation of DI (the DI of the target acquired subsequent in the original target) (rITV =0.71,rPTV =0.77,P ＜0.05).The variation of volume ratio and the variation of the matching index (MI) were positively correlated (rITV =0.47,rPTV =0.59,P ＜ 0.05).The 3D vectors of ITV and PTV motions were negatively correlated with the corresponding MI (rITV =--0.52,rPTV =-0.36,P ＜ 0.05).If the initial PTV was used for treatment planning,8.80％ and 6.37％ of the target volume would be missed at the tenth and twentieth fraction (Z =-0.55,P ＞ 0.05),respectively.In the meanwhile,11.45％ and 18.49％ of the normal tissues would be wrongly irradiated at the corresponding time points (Z =-2.49,P ＜ 0.05).Conclusions The variations of the spatial position of all targets were all less than 0.6 cm.The DI and the MI of the target decrease by various degrees during the treatment course,which lead to target mispositioning and normal tissue irradiation at different levels.
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Objective To study the PTV by ng 4DCT and compare target,target displacement and dose distribution of 3D and 4D planning for thoracic middle or lower esophageal cancer,evaluate the clinical value of 4DCT in esophageal cancer radiotherapy.Methods From Jan to Dec 2012patients with primary esophageal cancer underwent 3DCT simulation scans first,then followed by 4DCT simulation scan.PTV and OARs were sketched in the ordinary 3DCT and 4DCT respectively.And designing two sets of radiotherapy plan for each patient:3D and 4D plan.We compare PTV,PTV displacement and OARs dosimetry's differences in the 3D plan and 4D plan.Using the paired t-test or Wilcoxon sign-rank test to compare the difference between the two sets of plans.Results The volume of PTV4D was larger than the PTV3D (195.19 cm3 vs.175.67 cm3,P =0.001) in all patients.The center displacement had only significantly difference (displacement was 0.25 cm,P =0.014) in left-right direction for 10 patients of thoracic middle esophageal cancer.The center displacement had no significantly different in the three direction for 9 patients of thoracic under esophageal cancer (P=0.722,0.307,0.208).The dose target area of V100,V95 and V90 in Plan3DC were significantly than those in Plan-3D for 19 patients of thoracic middle-lower esophageal cancer (88.62％ vs.95.69％,P=0.000;95.17％ vs.99.79％,P=0.001;97.19％ vs.99.99％,P=0.001).In 4D plan the lung V5,V20 and Dmean of heart were higher than that in 3D plan for all patients (39.49％vs.37.44％,P=0.016;19.93％ vs.18.87％,P=0.018 and 2607.74 cGy vs.2389.16 cGy,P=0.004).Conclusions 4DCT positioning technology can accuracy determine individualized expanding boundary by target area of radiotherapy for thoracic middle or lower esophageal cancer.The enlarging target volume increase the dose of radiotherapy for lung,and in the dose range in the 4D plan,but the increased dose of heart should be noted.
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Objective To study the morphology of normal liver and tumors by breathing motion of hepatocellular carcinoma patients,through comparing the modified demons algorithm and FFD algorithm based on B-spline,and combing four-dimensional computed tomography (4DCT).Methods The 4DCT images of 8 HCC patients were segmented into 10-series which were named CT0,CT10 … CT80,CT90 according to the respiratory phases,CT0 and CT50 are defined to be end-inhale and end-exhale respectively.CT50 was chosen as the reference image.We used the modified demons algorithm and FFD algorithm based on B-spline to deform the images.Linear interpolation was used in both mode 1 and mode 2.The normalized mutual information (NMI),Hausdorff distance (dH) and registration speed were used to verify the registration performance.Results The average NMI for the end-inhale and end-exhale images of 8 HCC patients after demons registration in mode 1 improved 4.75％ with FFD algorithm based on B-spline(P =0.002).And the difference of dH after demons reduced 15.2％ comparing with FFD model algorithm (P =0.02).In addition,demons algorithm has the absolute advantage in registration speed(P =0.036).Conclusions The breathing movement for deformation of normal liver and tumor targets is significant.These two algorithms can achieve the registration of 4DCT images and the modified demons registration can deform 4DCT images effectively.
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Objective To investigate the correlations between the displacements of surgical clips,skin markers and the gross tumor volume (GTV) delineated by surgical clip and seroma based on fourdimensional computed tomography (4DCT) during normal breathing.Methods On each of the 10 respiratory phases of 4DCT with 15 patients of breast cancer,the surgical cavity,which was defined as GTV and formed by both surgical clips and seroma,all surgical clips in the cavity,and skin markers on the skin were delineated by the same radiation oncologist.The center displacements of GTV,selected boundary surgical clips and skin markers in the left-right (LR),anterior-posterior (AP),and superior-inferior (SI) directions were recorded and analyzed by Pearson method.Results In the AP direction,there was a positive correlation between the displacements of the GTV and the inner clip (r =0.643,P =O.013).In the SI direction,the displacement of GTV was positively correlated with those of the lower clip and the skin marker at anterior body midline (r =0.857 and 0.643,P =0.002 and 0.013).In the LR and AP directions,there was a positive correlation between the displacements of the outer clip and the ipsilateral skin marker (r =0.757 and 0.697,P =0.001 and 0.025),but they were negatively correlated with each other in the SI direction (r =-0.647,P =0.043).In the AP direction,there was a positive correlation between the displacements of the inner clip and the skin marker at the anterior body midline (r =0.738,P =0.015).Conclusions The correlations between the displacement of GTV delineated by surgical clips and seroma and the displacements of surgical slips and skin markers vary under different conditions,and so does the correlation between the displacements of surgical clips and skin markers.
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Objective To study preliminary the accuracy of clinical target volume (CTV) and internal target volume (ITV) automatically generated by an in-house deformable registration software on fourdimensional CT (4DCT),and evaluate its feasibility of clinical application.Methods Clinic treated one lung cancer patient and one liver cancer patient were selected for the study.CTV was delineated by radiation oncologist according to a single respiratory phase image of 4DCT scanning,and then deformed to the other phases and generated the CTVdefm on each phase image.Differences between the CTVdefm and CTVmanu were then compared.A composite ITVcopm was created by overlapping all the CTVdefm of 10 phases and compared with the ITVMIP which was contoured on the maximum intensity projection (MIP) CT images,including the shape,volume and geometric center position of the ITV contour.Results For the tested lung case,average volume difference between the CTVdefm and CTV was (-2.59 ± 5.02)％ for the all 10 phases,and the vector departure of the two ITV centers was (1.04 ± 0.89) mm.The ITVcomp almost completely matched the ITVMIP on the tested liver case with a volume difference smaller the 1％ and only 1.4 mm vector departure between their geometric centers.Conclusion The validity of the CTVdefm and ITVcomp gained from automatic deformation of manual delineation reference based on 4DCT images were preliminary evaluated and proved to be good enough for clinic planning.
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Objective To compare the position,volume and matching index (MI) of patientspecific internal gross tumor volume (IGTV)delineated by 4 different approaches based on three- dimensional and four - dimensional CT ( 3 DCT and 4 DCT ) image for primary esophageal cancers.Methods Thirteen patients with primary esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing,and the patient were divided into group A (tumor located in the proximal thoracic esophagus) and B (tumor located in the mid-and distal thoracic esophagus).IGTV were delineated using four approaches: The gross tumor volume (GTV) contours from 10 respiratory phases were combined into IGTV10 ;IGTV2 was acquired by combining the GTV from 0％ and 50％ phases; IGTVMIP was the GTV contour delineated from the maximum intensity projection (MIP) ;IGTV3D was acquired from the enlargement of 3 DCT-based GTV by each spatial direction on the motion amplitude measured in the 4DCT.ResultsTarget movement in lateral (LR),anterio-posterior (AP),superio-inferior (SI) directions showed no statistically significant difference (0.11 cm,0.09 cm,0.18 cm,respectively; χ2 =1.06,P=0.589),and there was no statistically significant difference in centroid positions between IGTV10 and IGTV2 or IGTV3D in group A (t =-2.24,-0.00,P =0.089,- 1.000 ),MI between IGTV10 and IGTV2,IGTV10 and IGTV3D were 0.88,0.54,respectively. For group B, target movement amplitude in SI direction was bigger than in LR, AP ( 0.47 cm,0. 15cm,0. 12 cm,X2= 12.00,P = 0.002).Therewasno significantdifference betweenIGTV10 andIGTV3D inLR, AP, SI ( t =- 0.80.- 0.82,- 1.16,P = 0.450.0.438.0.285 ), MI was 0.59 ; but the target center coordinates was demonstrated significant difference in SI between IGTV10 and ICTV2 for group B ( t = 2.97.P = 0.021 ), Mlwas 0.86.Thevolume of IGTVMIPwassmaller thanIGTV10 ( t =- 2.84,P = 0.025 ), but the position of IGTv10 and ICTVMIp were with no statistically significant difference in the LR,AP,SI ( t =- 0.25,0. 84. - 1.22,P = 0. 809,0.429.0.263 ) ,MIbetweenIGTV10andIGTVMIp was 0.78.Conclusions Patient-specific IGTV can be acquired from 4DCT with correct target coverage while avoiding a geographic miss for the thoracic esophageal cancer,but IGTV2 and IGTVMIP can not contain all the information about primary tumor position,shape.and size at different phases of the respiratory cycle.
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ObjectiveTo measure the displacement of solitary pulmonary lesion (SPL) using fourdimensional CT (4DCT), and to compare the planning target volume using 4D maximum intensity projection (MIPMIP) ( PTV4DMIP ) with the empirical PTV3D.Methods Data were acquired from 24 consecutive patients with SPL. For each patient, respiration-synchronized 4DCT images and standard axial CT scans were obtained during free breathing.In lung window setting,the 4D technique was used to measure the displacement of SPL in three dimensions. We compared an PTV created using the MIP (PTV4DMIP) to the PTV created from the gross tumor volume (GTV) enlarged isotropically for each spatial direction by 1.0 cm and 1. 5 cm in the PTV3D1.0cm and PTV3D1.5cm. Results The SPL located in the lower lobe showed significant difference with the upper and middle lobe in y axis (0. 44 cm,0. 92 cm, t =2. 87, P =0. 000),but there was no difference in both x and z axis (0. 27 cm,0. 39 cm,t =1.44 ,P =0. 116 and 0. 29 cm,0. 40 cm,t =1.51, P =0. 227). SPL showed significantly greater displacement in y axis than in both x and z axis [0.60 cm and0. 31 cm (t =4.23,P=0.000) ,0.60 cm and 0.32 cm (t =4.65,P=0. 000)], but there was no significant difference between x and z axis (0. 31 cm,0. 32 cm,t =0. 33 ,P =0. 741 ). There was no statistically difference between the peripheral lung cancer and the pulmonary metastasis tumor in three directions ( x axis : 0. 37 cm,0. 32 cm, t =0. 52, P =0. 223 ; y axis : 0. 54 cm, 0. 95 cm, t =- 1.38, P =0.061;z axis:0.42 cm,0.37 cm, t=0.29, P=0.859).Both PTV3D1.0cm and PTV3D1.5cm showed significantly greater volume than PTV4DMIP(46. 73 cm3 ,86. 52 cm3 and 30. 02 cm3 ,t =- 11.35, - 12. 09,P =0. 000,0. 000). ConclusionsThe displacement of SPL in y axis is much greater than x and z axis. The empirical PTV3D is much bigger than PTV4DMIP, which suggests that 4DMIP provide adequate coverage of the moving target and minimize dose to normal tissues.
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Objective This study was to assess the three-dimensional gross tumor volume(GTV)motion of lung cancer caused by respiration using four-dimensional computed tomography(4DCT),and to analyze the influenee factors.Methotis Four-DCT scans of 22 lung focuses in 21 patients with lung cancer were analyzed.The gross tumor volume was contoured in all 10 respiration phases of 4DCT scans.The changes in volume of GTV,the 3D motion of the centroid,boundary of GTV and the 3D spatial motion vectors were calculated and the irdluenee factors were analyzed.Results The average change in volume of GTV was+14.3%(0.2%.42.5%)/-8.4%(0.4%-38.6%),the average movement amplitude of GTV centroid and GTV boundary were(0.18±0.12)cm,(0.20±0.16)cm,(0.53±0.59)cm and(0.42±0.23)cm,(0.41±0.22)cm,(0.57±0.70)cm in medio-lateral,vertro-dorsal,cranio-caudal(CC) direction,respectively.The CC movement was larger than other directions(Z=-2.12,P=0.034;Z:-2.10,P=0.035),and no significant difference was observed in 3D motion of GTV boundary(Z=-0.81.P=0.417;Z=-0.86,0.391).The CC motion of GTV eentroid in lower lobe was larger than that in upper lobe[(0.87±0.64)and(0.35±0.49)cm,(t=-2.12,P=0.047)],and no significant difference was found in other directions[(0.23±0.10)and(0.19±0.18)em(t=-0.49,P=0.629),(0.21±0.13)and(0.17±0.11)cm(t=0.76,P=0.460)].There was no correlation of the 3D movement and 3D spatial motion vector of GTV to the volume of GTV(r=-0.306,-0.062,-0.279,-0.300;P=0.189,0.796.0.234,0.199).Conclusions GTV motion of patients with lung cancer is individual,the CC movement is the moat obvious,using 4DCT to assess is comparatively accurate.The motion amplitude of lower lobe focuses is larger.No significant correlation of the GTV motion to the volume was observed.Larger sample study is needed to analyze the influence of adjacency to the GTV motion.
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Objective To investigate the motion characteristics of primary thoracic esophageal carcinoma with four-dimensional computed tomography(4DCT).Methods Sixteen patients with primary thoracic esophageal carcinoma received respiratory gated 4DCT imaging,mapping the GTV1-GTV10 on every patient's each subsequent CT image of 10 images in the full-respiratory phase,and measuring the displacement of each centre of GTV.These displacements and directions were analyzed on different segments of esophagus.Results The mean total lung volume and GTV volume was 2993.5 cm3,35.00 cm3 and 3362.12 cm3,34.84 cm'respectively on end-expiration and end-inspiration phases(t=12.36,P=0.000and t=-0.61,P=0.546).The total mean peak to peak displacement of GTV were 0.65 mm,0.55 mm,and 2.03 nnn in x,y-and z-axis direction,respectively(F=41.14,P=0.000).The motion in x-axis,y-axis and z-axis were 0.50 mm,0.48mm,1.23 mm in the upper segment(F=5.45,P=0.017),0.68 mm,0.62 mm,1.97 mm in the middle segment(F=27.74,P=0.000),0.72 mm,0.38 mm,3.05 mm in the lower segment,respectively(F=15.61,P=0.000).Conclusions The displacement of tumor in z axis is more notable than x-,y-axis in thoracic esophageal carcinoma.The displacement of tumor x-,y-and z-axis is different in different segment of thoracic esophageal carcinoma.
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Objective To investigate the correlation of position movement of primary tumor with interested organs and skin markers,and to investigate the correlation of volume variation of primary tumors and lungs during different respiration phases for patients with lung cancer at free breath condition scanned by four-dimensional CT (4DCT) simulation.Methods 16 patients with lung cancer were scanned at free breath condition by simulation 4DCT which connected to a respiration-monitoring system.A coordinate system was created based on image of T5 phase,gross tumor volume (GTV) and normal tissue structures of 10 phases were contoured.The three dimensional position variation of them were measured and their correlation were analyzed,and the same for the volume variation of GTV and lungs of 10 respiratory phases.Results Movement range of lung cancer in different lobe differed extinct:0.8 - 5.0 mm in upper lobe,5.7 -5.9 mm in middle lobe and 10.2 - 13.7 mm in lower lobe,respectively.Movement range of lung cancer in three dimensional direction was different:z-axis 4.3 mm ± 4.3 mm＞ y-axis 2.2 mm ± 1.0 mm ＞ x-axis 1.7 mm ± 1.5 mm ( x2 =16.22,P =0.000),respectively.There was no statistical significant correlation for movement vector of GTV and interested structures (r =-0.50 - -0.01,P =0.058 - -0.961 ),nor for volume variation of tumor and lung ( r =0.23,P =0.520 ).Conclusions Based on 4DCT,statistically significant differences of GTV centroid movement are observed at different pulmonary lobes and in three dimensional directions.So individual 4DCT measurement is necessary for definition of internal target volume margin for lung cancer.
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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.
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Objective To investigate the influence of respiratory motion on target dose distribution in radiotherapy for patients with lung tumors. Methods The Big Bore Brilliance CT with bellows system was used to gain the 4DCT sets and respiratory frequency information of the patients. The moving ranges of the tumors in left-right (LR), anterior-posterior (AP) and cranial-caudal (CC) directions were measured from the center coordinate values of gross tumor volume of ten time-phase CT sets in the treatment planning sys-tem. Then a breathing model was used to simulate the tumor motions due to respiration. A 4-dimensional motion table was used to mimic the motion of lung tumor in beams-eye-view (BEV). A 2-dimensional semi-conductor beams measurement system was fixed to the table to measure the 2-dimensional dose distribution of static and dynamic targets using the treatment beams at gantry angle of 0°. Finally, the differences of the dose distribution between the static and moving phantom were compared and analyzed with the statistical soft-ware R. Results When the amplitude (half of the moving rang) in the CC direction was 1 cm, the passing ratio of relative dose difference ≤4% in one beam field was minimal (1.1%), and there was 58% maximal relative dose absence. The 4% passing ratios media in the CC direction were 94.7%, 79.4%, 58.6% and 37.1% in <0.25, 0.25-<0.50, 0.50- <0.75 and ≥0.75 mm amplitude (X<'2>=29.20,P=0.000), but were all similar in the AP and LR directions. The mean value of the relative dose change in the high dose area was smaller than the low dose area in the 89% beam fields. When only the CC direction was consid-ered, the 4% passing ratio of 3.6 s and 8.2 s period was 72% and 60%, respectively. Conclusions The amplitude in the CC direction is a factor impacting the dose distribution of the moving target. The influence of respiratory motion on high dose area is more than that on low dose area. When the other respiratory param-eters are fixed, the motion of long period has more influence on the dose than that of short period. Special at-tention should be paid to the patients with tumor of more than 0.5 cm amplitude in the CC direction when planning the intensity modulated radiotherapy.