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Purpose@#This study was aimed to investigate long-term survivals and toxicities of early-stage nasopharyngeal carcinoma (NPC) in endemic area, evaluating the role of chemotherapy in stage II patients. @*Materials and Methods@#Totally 187 patients with newly diagnosed NPC and restaged American Joint Committee on Cancer/ International Union Against Cancer 8th T1-2N0-1M0 were retrospectively recruited. All received intensity-modulated radiotherapy (IMRT)±chemotherapy (CT) from 2001 to 2010. @*Results@#With 15.7-year median follow-up, 10-year locoregional recurrence-free survival, distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were 93.3%, 93.5%, 92.9% and 88.2%, respectively. Multivariable analyses showed cervical lymph nodes positive and pre-treatment prognostic nutritional index ≥ 52.0 could independently predict DMFS (p=0.036 and p=0.011), DSS (p=0.014 and p=0.026), and OS (p=0.002 and p 45 years (p=0.002) and pre-treatment lactate dehydrogenase ≥ 240 U/L (p 0.05). Unsurprising, patients in IMRT+CT had more acute gastrointestinal reaction, myelosuppression, mucositis, late ear toxicity, and cranial nerve injury (all p < 0.05) than IMRT alone group. @*Conclusion@#Superior tumor control and satisfying long-term outcomes could be achieved with IMRT in early-stage NPC with mild late toxicities. As CT would bring more toxicities, it should be carefully performed to stage II patients.
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Objective:To evaluate the differences in the cumulative doses for cervical cancer between two different methods, and analyze the correlation between the severity of radiation proctitis and the cumulative dose of the rectum.Methods.:Clinical data of 278 patients with cervical cancer treated with radiotherapy were retrospectively analyzed. The total dose of radiotherapy was calculated by simple dose volume histogram parameter accumulation method (S-DVH group) and dose accumulation by deformation image registration (DIR group) in 49 patients with radiation proctitis. The rectal cumulative dose of the 278 patients with S-DVH was counted(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3). The correlation analysis was performed by Spearman’s correlation analysis. Results:The average cumulative dose(D 90%) difference of high-risk clinical target volume (HRCTV) between the S-DVH and DIR groups was 2 Gy (EQD 2Gy)[(88.66±5.75) vs. (86.66±5.54) Gy, P<0.05], and the average cumulative dose difference(D 2.0cm 3 and D 1.0cm 3) of bladder was 2.13 Gy[(82.46±6.91) vs.(80.33±6.86) Gy, P<0.05] and 2.35 Gy[(88.46±4.37) vs.(86.11±3.93) Gy, P<0.05], and the average cumulative dose difference(D 2.0cm 3 and D 1.0cm 3) of rectum was 1.99 Gy[(72.49±5.17) vs.(70.50±5.03) Gy, P<0.05] and 2.71 Gy[(78.87±4.50) vs.(76.16±4.14) Gy, P<0.05]. The rectal cumulative dose(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3) was positively associated with the grade of radiation proctitis. Conclusions:The cumulative doses differ between two groups, and are equally in an acceptable range. S-DVH method is a relatively simple method to evaluate the cumulative exposure dose. The cumulative doses of the rectum(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3) can be used to predict the incidence of radiation proctitis.
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Objective:To analyze the impacts of different registration ranges on the accuracy of multiple metastases treated with helical tomotherapy.Methods:According to the locations of target volumes, 28 patients with multiple metastases were divided into the head/chest group ( n= 15) and the chest/pelvis group ( n= 13). The CT and MVCT images acquired in first fraction were studied and compared in two groups, which were captured and matched with different registration ranges (all targets/the targets in proximity to the head/ the targets in proximity to the foot). The CTV MVCT volume coverage rate (CR) under the matched target volumes, the dice similarity coefficient (DSC) between the CTV CT and CTV MVCT, and the position deviation of the CTV geometric center were compared. Results:We observed similar results in the head/chest group and chest/pelvis group. Specifically, there was no significant difference in the CR, DSC and geometric center deviation between the two target regions when registered with all targets ( P>0.05). Regarding single target region registration, the DSC and geometric center deviation of this target were significantly superior to the other non-registered target ( P< 0.05). To a single target, the CR, DSC, and geometric center deviation obtained with registration presented the best performance, which was significantly greater than these parameters obtained with all targets registration, while the other side target area obtained the worst results ( P< 0.05). Conclusions:Registration of one target region may reduce the accuracy of other non-registered targets. We recommend that the image guidance ranges for multiple metastases treated with tomotherapy should include all target regions or independent registrations for different targets.
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Objective@#To assess the interobserver variations in delineating the planning target volume (PTV) and organs at risk (OAR) using different contouring methods during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), aiming to provide references for the quality control of multi-center clinical trials.@*Methods@#The PTV and OAR of CT image of 1 NPC patient manually delineated by 10 physicians from 8 different radiation centers were defined as the " manual contour group" , and the OAR auto-contoured using the ABAS software and modified by the physicians were defined as the " auto+ manual contour group" . The maximum/minimum ratio (MMR) of the PTV and OAR volumes, and the coefficient of variation (CV) for different delineated contours were comparatively evaluated.@*Results@#Large variation was observed in the PTV and OAR volumes in the manual contour group. The MMR and CV of the PTV were 1.72-3.41 and 0.16-0.39, with the most significant variation in the PTVnd (MMR=3.41 and CV=0.39 for the PTVnd-L). The MMR and CV of the manually contoured OAR were 1.30-7.89 and 0.07-0.67. The MMR of the temporal lobe, spinal cord, temporomandibular joint, optic nerve and pituitary gland exceeded 2.0. Compared with the manual contour group, the average contouring time in the auto+ manual group was shortened by 68% and the interobserver variation of the OAR volume was reduced with an MMR of 1.04-2.44 and CV of 0.01-0.37.@*Conclusions@#Large variation may occur in the PTV and OAR contours during IMRT plans for NPC delineated by different clinicians from multiple medical centers. Auto-contouring+ manually modification can reduce the interobserver variation of OAR delineation, whereas the variation in the delineation of small organs remains above 1.5 times. The consistency of the PTV and OAR delineation and the possible impact upon clinical outcomes should be reviewed and evaluated in multi-center clinical trials.
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Objective To assess the interobserver variations in delineating the planning target volume (PTV) and organs at risk (OAR) using different contouring methods during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC),aiming to provide references for the quality control of multi-center clinical trials.Methods The PTV and OAR of CT image of 1 NPC patient manually delineated by 10 physicians from 8 different radiation centers were defined as the "manual contour group",and the OAR auto-contoured using the ABAS software and modified by the physicians were defined as the "auto+manual contour group".The maximum/minimum ratio (MMR) of the PTV and OAR volumes,and the coefficient of variation (CV) for different delineated contours were comparatively evaluated.Results Large variation was observed in the PTV and OAR volumes in the manual contour group.The MMR and CV of the PTV were 1.72-3.41 and 0.16-0.39,with the most significant variation in the PTVnd (MMR=3.41 and CV =0.39 for the PTVnd-L).The MMR and CV of the manually contoured OAR were 1.30-7.89 and 0.07-0.67.The MMR of the temporal lobe,spinal cord,temporomandibular joint,optic nerve and pituitary gland exceeded 2.0.Compared with the manual contour group,the average contouring time in the auto+ manual group was shortened by 68％ and the interobserver variation of the OAR volume was reduced with an MMR of 1.04-2.44 and CV of 0.01-0.37.Conclusions Large variation may occur in the PTV and OAR contours during IMRT plans for NPC delineated by different clinicians from multiple medical centers.Auto-contouring+ manually modification can reduce the interobserver variation of OAR delineation,whereas the variation in the delineation of small organs remains above 1.5 times.The consistency of the PTV and OAR delineation and the possible impact upon clinical outcomes should be reviewed and evaluated in multi-center clinical trials.
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OBJECTIVE@#To compare the accuracy of different methods for image registration in image-guided adaptive brachytherapy (IGABT) for cervical cancer.@*METHODS@#The last treatment planning CT images (CT1) and the first treatment planning CT images (CT2) were acquired from 15 patients with cervical cancer and registered with different match image qualities (retained/removed catheter source in images) and different match regions [target only (S Group)/ interested organ structure (M Group)/body (L Group)] in Velocity3.2 software. The dice similarity coefficient (DSC) between the clinical target volumes (CTV) of the CT1 and CT2 images (CTVCT1 and CTVCT2, respectively) and between the organs-at-risk (OAR) of the two imaging datasets (OARCT1 and OARCT2, respectively) were used to evaluate the image registration accuracy.@*RESULTS@#The auto-segmentation volume of the catheter source using Velocity software based on the CT threshold was the closest to the actual volume within the CT value range of 1700-1800 HU. In the retained group, the DSC for the OARs of was better than or equal to that of the removed group, and the DSC value of the rectum was significantly improved ( < 0.05). For comparison of different match regions, the high-risk target volume (HRCTV) and the low-risk target volume (IRCTV) had the best precision for registration of the target area, which was significantly greater than that of M group and L group ( < 0.05). The M group had better registration accuracy of the target area and the best accuracy for the OARs. The DSC values of the bladder and rectum were significantly better than those of the other two groups ( < 0.05).@*CONCLUSIONS@#The CT value range of 1700-1800 HU is optimal for automatic image segmentation using Velocity software. Automatic segmentation and shielding the volume of the catheter source can improve the image quality. We recommend the use of interested organ structures regions for image registration in image-guided adaptive brachytherapy for cervical cancer.
Subject(s)
Female , Humans , Brachytherapy , Methods , Reference Standards , Organs at Risk , Diagnostic Imaging , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Methods , Reference Standards , Radiotherapy, Image-Guided , Methods , Reference Standards , Software , Tomography, X-Ray Computed , Methods , Reference Standards , Uterine Cervical Neoplasms , Diagnostic Imaging , RadiotherapyABSTRACT
Objective To perform a preclinical test of a delineation software based on atlas-based auto-segmentation (ABAS),to evaluate its accuracy in the delineation of organs at risk (OARs) in radiotherapy planning for nasopharyngeal carcinoma (NPC),and to provide a basis for its clinical application.Methods Using OARs manually contoured by physicians on planning-CT images of 22 patients with NPC as the standard,the automatic delineation using two different algorithms (general and head/neck) of the ABAS software were applied to the following tests:(1) to evaluate the restoration of the atlas by the software,automatic delineation was performed on copied images from each patient using the contours of OARs manually delineated on the original images as atlases;(2) to evaluate the accuracy of automatic delineation on images from various patients using a single atlas,the contours manually delineated on images from one patients were used as atlases for automatic delineation of OARs on images from other patients.Dice similarity coefficient (DSC),volume difference (Vdiff),correlation between the DSC and the volume of OARs,and efficiency difference between manual delineation and automatic delineation plus manual modification were used as indices for evaluation.Wilcoxon signed rank test and Spearman correlation analysis were used.Results The head/neck algorithm had superior restoration of the atlas over the general algorithm.The DSC was positively correlated with the volume of OARs and was higher than 0.8 for OARs larger than 1 cc in volume in the restoration test.For automatic delineation with the head/neck algorithm using a single atlas,the mean DSC and Vdiff were 0.81-0.90 and 2.73％-16.02％,respectively,for the brain stem,temporal lobes,parotids,and mandible,while the mean DSC was 0.45-0.49 for the temporomandibular joint and optic chiasm.Compared with manual delineation,automatic delineation plus manual modification saved 68％ of the time.Conclusions A preclinical test is able to determine the accuracy and conditions of the ABAS software in specific clinical application.The tested software can help to improve the efficiency of OAR delineation in radiotherapy planning for NPC.However,it is not suitable for delineation of OAR with a relatively small volume.
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Objective To evaluate the impacts of slice thickness and registration frame range on the accuracy of cone-beam computed tomography ( CBCT) image-guided head and neck ( HN) radiotherapy, and to provide a basis for positioning correction in image-guided radiotherapy.Methods A planned CT scan was performed for an anthropomorphic HN phantom with slice thickness of 1 mm and 3 mm and simulated positioning errors in x, y, and z directions on the accelerator.CBCT scan and reconstruction were performed with slice thickness of 1 mm and 3 mm.Two different registration frame ranges were used ( range 1:from C7 to superior orbit;range 2:from C7 to calvaria ) .Automatic bony registration was performed for CBCT and planned CT images with slice thickness of 1 mm and 3 mm.The registration accuracy was evaluated.Results For range 1, the registration errors in x, y, and z directions with a slice thickness of 1 mm were significantly lower than those with a slice thickness of 3 mm (0.5±0.2 mm vs.-0.7±0.2 mm, P=0.00;0.5±0.3 mm vs. 1.0±0.3 mm, P=0.00;-0.1±0.5 mm vs.1.5±0.5 mm, P=0.00).For range 2, the registration errors in x, y, and z directions with a slice thickness of 3 mm were-0.4±0.2 mm, 0.5±0.2 mm, and 0.7±0.4 mm, respectively.Conclusions Engagement of calvaria in registration range can substantially enhance the registration accuracy in CBCT or CT images for HN.The registration error with slice thickness of 1 mm can be controlled within 1 mm.