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@#<b>Objective</b> To compare the set up errors derived from different registration methods of the X-ray volume imaging (XVI) system for radiotherapy in the treatment of middle/lower-segment esophageal cancer, and to provide a reference for radiation treatment of esophageal cancer. <b>Methods</b> We randomly selected 63 patients with middle/lower-segment esophageal cancer, and obtained their reconstructed XVI images at the first therapy to perform automatic registration with gray-value and bone registration methods. We acquired and compared the three translation errors (along <i>x</i> [left to right], <i>y</i> [head to feet], and <i>z</i> [front to back] axes) and three rotation errors (around the <i>x</i>, <i>y</i>, and <i>z</i> axes) derived from the two registration methods. <b>Results</b> Gray-value registration had significantly smaller translation errors along the <i>x</i> and <i>z</i> axes than bone registration (<i>x</i> azes <i>t</i> = −2.78, <i>z</i> azes <i>t</i> = −2.15, <i>P</i> < 0.05), but there was no significant difference along the <i>y</i> axes (<i>P</i> > 0.05). The rotation errors around the three axes were all smaller than 1°, and were smaller with gray-value registration than with bone registration, but without significant differences (<i>P</i> > 0.05). <b>Conclusion</b> We recommend gray-value registration for radiotherapy in the treatment of middle/lower-segment esophageal cancer. Manual verification or fine-tuning is recommended after automatic registration in clinical practice. Besides translation errors, rotation errors should also be paid attention to.
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Objective:To quantify the registration deviation between CT and cone-beam computed tomography (CBCT) images with different breathing rates and motion amplitudes under free breathing state.Methods:Using the QUASAR respiratory motion phantom, breathing rate and motion amplitude in the superior-inferior (SI) direction were changed to simulate free breathing motion under different states. The CT and CBCT images were acquired under different breathing rates and motion amplitudes, and static states, then the registration errors between CT and CBCT images and CT target volume were obtained and subject to quantitative analysis.Results:Using the static CT image as a reference, the changes in breathing rate exerted no significant effect on the registration error when the motion amplitude was constant. When the motion amplitude was 0.5, 1.0, 2.0, and 3.0 cm, the average registration errors were (0.213±0.020), (0.351±0.009), (0.654±0.010), and (0.972±0.022) cm, respectively. When the motion amplitude was 0.5 and 1.0 cm, the CT target volume varied from -16.92% to 18.78%. When the motion amplitude was 2.0 and 3.0 cm, the CT target volume changed from -16.44% to 81.78%.Conclusions:The changes in breathing rate under free-breathing state has no significant effect on the registration error between CBCT and CT images. When the motion amplitude is 0.5 and 1.0 cm, the CT target volume changes and the registration errors are small. When themotion amplitude is 2.0 and 3.0 cm, the registration errors exceed 0.5 cm and the CT target volume changes may exceed 20%.
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Objective:To assess the feasibility of deformable image registration (DIR) in evaluating cumulative dose distribution of bladder and rectum of cervical cancer patients during helical tomotherapy (HT)-based intensity-modulated radiotherapy (IMRT) and high-dose-rate(HDR) brachytherapy.Methods:Clinical data of 18 patients were retrospectively analyzed. Cumulative bladder/rectum D 2cm 3 and high-risk clinical target volume (HR-CTV) D 90% parameters were calculated and compared to two direct parameter-adding methods with two registration-adding methods. Equivalent uniform dose (EUD group) and overlapping high dose (OHD group) methods were employed as parameter-adding methods. The registration-adding methods including rigid image registration (RIR group) and deformable image registration (DIR group) were adopted based on a commercial image registration software (MIM Maestro ?). The dice similarity coefficient (DSC) and mean distance to agreement (MDA) were measured to assess the accuracy of RIR and DIR. Results:In the EUD, OHD, RIR and DIR groups, the cumulative doses of bladder/rectum D 2cm 3 and HR-CTV D 90% were (80.11±3.59) Gy (EQD 2Gy), (82.23±3.46) Gy (EQD 2Gy), (80.99±6.01) Gy (EQD 2Gy) and (81.19±3.11) Gy (EQD 2Gy)( P=0.516); (72.90±3.58) Gy (EQD 2Gy), (73.83±4.28) Gy (EQD 2Gy), (72.45±6.05) Gy (EQD 2Gy) and (71.98±2.89) Gy (EQD 2Gy)( P=0.625), and (85.51±2.91) Gy (EQD 2Gy), (87.65±3.46) Gy (EQD 2Gy), (81.53±3.63) Gy (EQD 2Gy) and (85.81±3.30) Gy (EQD 2Gy)( P<0.001), respectively. The mean DSC of the bladder, rectum and HR-CTV were 0.69, 0.65 and 0.63 with RIR; and 0.85, 0.81 and 0.78 with DIR ( P<0.001), respectively. In DIR, the average MDA of bladder, rectum, and HR-CTV were 2.88, 2.48 and 2.66 mm, respectively. Conclusions:The cumulative DVH parameters among 4 groups show no significant difference in the bladder/rectum D 2cm 3/D 0.2cm 3. Since the DIR group achieves satisfactory volume matching of greater than 0.8 with DSC analysis, it can yield acceptable results for clinical application between HT IMRT and HDR BT for cervical cancer.
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Objective:To study the differences in the cumulative dose between deformable image registration (DIR) and simple dose-volume histogram (DVH) summation in the fractionated brachytherapy of cervical cancer, and to analyze the feasibility of the application of DIR in the dosimetry assessment of targets and organs-at-risk (OARs) in the brachytherapy.Methods:A retrospective analysis was conducted for 13 cases with primary cervical cancer treated with four fractions of interstitial brachytherapy guided by CT images. The four CT images of each cases were registered using an intensity-based DIR. Then, the cumulative doses (the D2 cm 3, D1 cm 3, and D0.1 cm 3 of the bladder, rectum, intestine, and colon and the D90for targets) after DIR were calculated and compared to those obtained using simple DVH summation. Afterward, the correlation between the dose difference and dice similarity coefficient (DSC) was analyzed. With the dose difference (the remaining dose of OARs caused by the DIR) as limits, a new plan was made for the latest CT to calculate the dose increase to targets. Results:Compared to simple DVH summation, DIR allowed the cumulative doses of the D2 cm 3 and D1 cm 3 of bladder to be decreased by (2.47±1.92) and (2.82±2.73) Gy, respectively on average ( t=-3.65, -2.93, P < 0.05), those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 of rectum to be decreased by (2.05 ± 1.61) Gy, (1.51 ± 1.58), and (3.21 ± 2.50) Gy, respectively on average ( t=-4.02, -3.02, -4.06, P < 0.05), and those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 to be decreased by (1.42 ± 0.99), (1.55 ± 1.28) Gy, and (2.43 ± 1.95) Gy, respectively on average ( t=-3.52, -2.96, -3.06, P < 0.05). There was no significant statistical difference in the D90 of targets, the D0.1 cm 3 of the bladder, and the D2 cm 3, D1 cm 3, D0.1 cm 3 of the colon ( P > 0.05) between both methods, and there was no distinct correlation between DSC and dose difference ( P > 0.05). The DIR increased the dose to targets, with a median value of 150 cGy. However, the accuracy of the DIR should be improved. Conclusions:In clinical practice of multiple fractions of brachytherapy for cervical cancer, it′s still recommended to adopt the simple dose summation method to assess the doses to targets and OARs.
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Objective:To propose a method of image similarity measurement based on structure information and intuitionistic fuzzy set and measure the similarity between CT image and CBCT image of radiotherapy plan positioning, aiming to objectively measure the setup errors.Methods:A total of four pre-registration images of a nasopharyngeal carcinoma patient on the cross-sectional and sagittal planes and a pelvic tumor patient on the cross-sectional and coronal planes were randomly selected. Five methods were used to quantify the setup errors, including correlation coefficient, mean square error, image joint entropy, mutual information and similarity measure method.Results:All five methods could describe the deviation to a certain extent. Compared with other methods, the similarity measure method showed a stronger upward trend with the increase of errors. After normalization, the results of five types of error increase on the cross-sectional plane of the nasopharyngeal carcinoma patient were 0.553, 0.683, 1.055, 1.995, 5.151, and 1.171, 1.618, 1.962, 1.790, 3.572 on the sagittal plane, respectively. The results of other methods were between 0 and 2 after normalization, and the results of different errors of the same method slightly changed. In addition, the method was more sensitive to the soft tissue errors.Conclusions:The image similarity measurement method based on structure information and intuitionistic fuzzy set is more consistent with human eye perception than the existing evaluation methods. The errors between bone markers and soft tissues can be objectively quantified to certain extent. The soft tissue deviation reflected by the setup errors is of significance for individualized precision radiotherapy.
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Brachytherapy is an integral part of radiotherapy treatment for cervical cancer.With the rapid development of medical imaging technology,three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer.After computed tomography (CT) and magnetic resonance imaging (MRI),3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics,economy,high efficiency and convenience.In this article,the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review,aiming to provide reference for subsequent research.
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Brachytherapy is an integral part of radiotherapy treatment for cervical cancer. With the rapid development of medical imaging technology, three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer. After computed tomography (CT) and magnetic resonance imaging (MRI), 3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics, economy, high efficiency and convenience. In this article, the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review, aiming to provide reference for subsequent research.
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With the development of image-guided surgery and radiotherapy, the demand for medical image registration is stronger and the challenge is greater. In recent years, deep learning, especially deep convolution neural networks, has made excellent achievements in medical image processing, and its research in registration has developed rapidly. In this paper, the research progress of medical image registration based on deep learning at home and abroad is reviewed according to the category of technical methods, which include similarity measurement with an iterative optimization strategy, direct estimation of transform parameters, etc. Then, the challenge of deep learning in medical image registration is analyzed, and the possible solutions and open research are proposed.
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Deep Learning , Diagnostic Imaging , Image Processing, Computer-Assisted , Neural Networks, Computer , ResearchABSTRACT
Objective To investigate the application of CT image and cone beam computed tomography (CBCT) image registration based on 3D Slicer software in image-guided radiotherapy for uterine cervical neoplasms. Methods Based on 3D Slicer software and Slicer RT toolkit, 10 positioning CT images and 50 CBCT images of 10 patients with uterine cervical neoplasms in Henan Provincial People's Hospital between January 2018 and October 2018 had rigid registration and b-spline deformation registration respectively. The dice similarity coefficient (DSC) and Hausdorff distance (HD) of the bladder, rectum, femoral head, spinal cord, and body of CT-CBCT images were compared by using paired t-test before and after the registration. Results Pre-registration, rigid registration and after b-spline deformation registration of CT images and CBCT images, the DSC in the bladder (0.459±0.177, 0.528±0.184, 0.542±0.187, respectively), the rectum (0.564±0.141, 0.632±0.091, 0.684±0.097, respectively), the femoral head (0.695±0.088, 0.833± 0.030, 0.865±0.027, respectively), the spinal cord (0.587±0.119, 0.746±0.085, 0.834±0.032, respectively) and the body surface (0.922±0.013, 0.948±0.011, 0.959±0.009, respectively) showed an increased trend; HD in the bladder (12.8±7.2, 12.2±7.1, 11.7±7.3, respectively), the rectum (5.0±1.8, 4.4±1.2, 3.4±1.2, respectively), the femoral head (3.6±1.2, 1.8±0.5, 1.5 ±0.5, respectively), the spinal cord (4.0 ±1.0, 2.7 ±1.3, 1.8 ±0.5, respectively) and the body surface (6.3±2.1, 5.2±2.0, 4.3±2.0, respectively) showed a decreased trend. The differences of pairwise comparison in the same parts were statistically significant (all P < 0.05). Conclusions Both rigid registration and b-spline deformation registration of CT-CBCT images based on 3D Slicer softwarecan improve the radiotherapy accuracy of uterine cervical neoplasms, and b-spline deformation registration has more significant advantages.
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OBJECTIVE: Considering the different prevalence rates of diseases such as asthma and chronic obstructive pulmonary disease in Asians relative to other races, Koreans may have unique airway structure and lung function. This study aimed to investigate unique features of airway structure and lung function based on quantitative computed tomography (QCT)-imaging metrics in the Korean Asian population (Koreans) as compared with the White American population (Whites). MATERIALS AND METHODS: QCT data of healthy non-smokers (223 Koreans vs. 70 Whites) were collected, including QCT structural variables of wall thickness (WT) and hydraulic diameter (Dh) and functional variables of air volume, total air volume change in the lung (ΔVair), percent emphysema-like lung (Emph%), and percent functional small airway disease-like lung (fSAD%). Mann-Whitney U tests were performed to compare the two groups. RESULTS: As compared with Whites, Koreans had smaller volume at inspiration, ΔVair between inspiration and expiration (p < 0.001), and Emph% at inspiration (p < 0.001). Especially, Korean females had a decrease of ΔVair in the lower lobes (p < 0.001), associated with fSAD% at the lower lobes (p < 0.05). In addition, Koreans had smaller Dh and WT of the trachea (both, p < 0.05), correlated with the forced expiratory volume in 1 second (R = 0.49, 0.39; all p < 0.001) and forced vital capacity (R = 0.55, 0.45; all p < 0.001). CONCLUSION: Koreans had unique features of airway structure and lung function as compared with Whites, and the difference was clearer in female individuals. Discriminating structural and functional features between Koreans and Whites enables exploration of inter-racial differences of pulmonary disease in terms of severity, distribution, and phenotype.
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Female , Humans , Asian People , Asthma , Racial Groups , Forced Expiratory Volume , Lung , Lung Diseases , Phenotype , Prevalence , Pulmonary Disease, Chronic Obstructive , Thorax , Trachea , Vital CapacityABSTRACT
PURPOSE: The image registration of radiographic image and digital surface data is essential in the computer-guided implant guide system. The purpose of this study was to examine the effects of using micro-screw on the working time and convenience of operators in the process of image matching for guided implant surgery. MATERIALS AND METHODS: A mandibular dental model was prepared in partial edentulism for Kennedy class I classification. Two micro-screws were placed on the each side of retromolar area. Radiographic and scan images were taken using computed-tomography and digital scanning. The images were superimposed by 12 operators in software in two different conditions: using remaining teeth image alone and using teeth and micro-screws images. Working time, operator convenience and satisfaction were obtained, and analyzed using the Mann-Whitney U test (α=.05). RESULTS: The working time was not statistically different between image registration conditions (P>.05); however, operator convenience and satisfaction were higher in the teeth and micro-screw assisted condition than in the teeth-alone assisted condition (P<.001). CONCLUSION: The use of microscrew for the image registration has no effect in working time reduction, but improves operator convenience and satisfaction.
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Classification , Models, Dental , ToothABSTRACT
Objective@#To explore the differences and correlation between the target volumes based on deformation registration (DIR) using preoperative prone diagnostic magnetic resonance (MR) imaging and postoperative prone computed tomography (CT) simulation imaging for patients undergoing breast-conserving surgery (BCS).@*Methods@#Eighteen breast cancer patients suitable for external-beam partial breast irradiation (EB-PBI) after BCS were enrolled. Preoperative prone diagnostic MR and postoperative prone CT scan sets were acquired during free breathing for all patients. The gross tumor volume (GTV) delineated on the preoperative diagnostic MR images was defined as GTVMRI, the clinical target volumes (CTVMRI+ 1 and CTVMRI+ 2)were defined as 10 and 20 mm margins around the GTVMRI, and the planning target volume (PTVMRI+ 1 and PTVMRI+ 2) were defined as 15 and 25 mm margins around the GTVMRI, respectively. Tumor bed (TB) delineated on the postoperative prone CT simulation images acquired during free breathing was defined as GTVTB, CTV and PTV were defined as 10 and 15 mm margins around the GTVTB, respectively. The target volume of the whole breast contoured on the MR and CT images were defined as CTVBreast-MRI and CTVBreast-CI, respectively. The MR and CT images were registered deformably in MIM software system.@*Results@#The GTVTB, CTVTB and PTVTB were significantly greater than GTVMRI, GTVMRI+ 1 and PTVMRI+ 1, respectively (Z=-3.593, -3.593, -2.983, P<0.05). Meanwhile, the CTVTB and PTVTB were significantly less than the CTVMRI+ 2 and PTVMRI+ 2, respectively(Z=-2.722, -2.853, P<0.05). The conformal index (CI) and degree of inclusion (DI) of GTVTB-GTVMRI, GTVTB-CTVMRI+ 1, CTVTB-GTVMRI and CTVTB-GTVMRI+ 1 based on center-coincidence of the compared targets were better than those based on DIR of the thorax(Z=-3.724、-3.724、-2.591、-3.593, P<0.05; Z=-3.724、-3.724、-3.201、-3.724, P<0.05).@*Conclusions@#For the patients enrolled for prone EB-PBI, target volumes delineated on the preoperative prone MR images were significantly smaller compared to that on the postoperative prone CT images, but a statistically significant positive correlation was found between the MR and CT target volumes. There were still relatively poor spatial overlap whether for the whole breast or the targets between the preoperative prone diagnostic MR images and the postoperative prone simulation CT images based on DIR. Therefore, it is infeasible to guide postoperative EB-PBI target delineation using the preoperative prone diagnostic MR images.
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Objective To evaluate the effect of different methods of deformable image registration on the dose evaluation in adaptive radiotherapy for lung cancer. Methods By using Raystation Ver4. 5 treatment planning system platform, two algorithms ( Hybrid-and Biomechanics-based deformable image registration) and two orders (CT images before and during radiotherapy as reference images) were adopted. Four deformable image registration methods were utilized to calculate the accumulative dose. Eleven patients of lung cancer received adaptive radiotherapy for 35. 0-61. 6 Gy were recruited. The mean doses of lung,heart and GTV and the D98 and D2 of GTV were statistically compared using four methods. Results With the four deformable image registration methods, the standard deviation of the mean lung dose of 11 lung cancer patients was ranged from 0. 07 to 0. 70 Gy,0. 01 to 0. 79 Gy for the mean heart dose,0. 01 to 2. 23 Gy for the mean GTV dose,0. 02 to 6. 51 Gy for the D98 of GTV and 0. 01 to 0. 97 Gy for the D2 of GTV,respectively. Conclusion The selection of deformable image registration method causes uncertainty to the calculation of accumulative dose during adaptive radiotherapy for lung cancer.
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Objective To measure the irradiation doses from the image beam line (IBL) of Artiste linac under the 2Dplanar,MV CBCT,6 MV 2Dplanar and Somatom CT modes to select an appropriate image-guided mode combined with the irradiation sites. Methods The head, chest and pelvic phantom doses from the IBL under the 2Dplanar,MV CBCT and 6 MV 2Dplanar modes were measured by using IBA Dose 1 electrometer and FC65 ionization chamber.The irradiation doses of Somatom CT scans of the head, chest and pelvis were measured using IBA Dosimax plus A system and the measurement results were analyzed. Results In the head and neck, the average irradiation dose was 16. 60 mGy under IBL 2Dplanar mode, 58. 73 mGy under IBL MV CBCT mode, 19. 83 mGy under 6 MV 2Dplanar mode and 7-9 mGy under Somatom CT. In the chest, the average irradiation dose was 14. 08 mGy under IBL 2Dplanar mode, 49. 17 mGy under MV CBCT mode, 18. 97 mGy under 6 MV 2Dplanar mode and 9-11 mGy under Somatom CT mode.In the pelvis, the average irradiation dose was 13. 36 mGy under IBL 2Dplanar mode, 45. 65 mGy under MV CBCT mode, 17. 52 mGy under 6 MV 2Dplanar mode and 12-15 mGy under Somatom CT mode. Conclusions In the head and neck, the image quality under IBL 2Dplanar mode is recommended, which is qualified for image registration standards. Somatom CT mode is suitable for the chest. In the pelvic region, IBL 2DPlanar mode can be applied when the intestinal cavity and bladder are well filled, and MV CBCT mode can be chosen if they are poorly filled.
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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.
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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 explore the feasibility of applying customized guide, based on digital image processing and 3D printing technology, to bone biopsy. Methods • Eleven patients (6 males and 5 females; 7-69 years old, average age of 36 years) diagnosed with bone tumor from July 2017 to March 2018 in Shanghai Ninth People's Hospital were enrolled in this study. Routine CT and/or MRI data were taken as reference in designing the customized biopsy guide for 3D printing by Medraw Print software. Needle insertion points were set under the supervision of surgeons to avoid damaging important anatomical structures such as nerves and blood vessels. 3D printed customized guide was designed to match local surface. The success of the puncture was confirmed by X-ray or CT, and the accuracy of the puncture results was evaluated by the pathological results of resection operation as a reference standard. The complications were analyzed. Results • The 11 patients included 4 cases with neoplasms in femur, 3 cases in pelvis, 2 cases in tibia, 1 case in scapula and 1 case in metacarpal. The needling positions in operation were consistent with the preoperative virtual design, and the guide plates fitted perfectly to the body surface. The results of biopsy of 8 patients (88.9%) matched with the postoperative pathology, while another 2 patients did not receive bone tumor resection because of the benign biopsy. No complications were observed during or after the procedure. Conclusion • Customized guide by digital image processing and 3D printing may have a great value in improving the accuracy of preoperative tumor diagnosis and the effectiveness of its treatment.
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Objective To compare the geometric differences of gross tumor volumes(GTV)and displacements of selected clips propagated by rigid image registration(RIR)and deformable image registration (DIR)at end-inhale phase(CT0)and end-exhale phase(CT50)based on four-dimensional computed tomography(4DCT)of the whole breast after breast-conserving surgery(BCS). Methods Forty-four patients who underwent 4DCT simulation scans after BCS were selected. The GTV and displacements of selected metal clips at CT0and CT50were manually delineated by the same radiotherapy physician. Subsequently,the GTV and displacements of selected clips from CT0images were transformed and propagated to CT50images using RIR and DIR.The geometric differences of GTV and displacements of surgical clips from DIR were compared with those from RIR based on the dice similarity coefficient(DSC)and the displacements of the center of mass(COM)in the three-dimensional(3D)directions. Results The mean DSC was 0.86± 0.04 for RIR and 0.87± 0.04 for DIR(P=0.000).The displacements of COM in 3D directions from RIR were significantly greater than those from DIR(1.22 mm vs. 1.10 mm,P=0.000).In the anterior-posterior direction,the displacements from RIR were significantly greater than those from DIR for both GTV and selected clips(P=0.000).However,in the left-right and superior-inferior directions,there were no significant differences in displacements between RIR and DIR for both GTV and the selected clips(all P>0.05). Conclusions DIR can improve the overlap for GTV registration from 4DCT scans at CT0and CT50.Furthermore,DIR is superior to RIR in reflecting GTV and the displacements of selected clips in anterior-posterior direction induced by respiratory movement.
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Objective To evaluate the clinical significance of personalized biomechanical modeling of prostate deformation based on ultrasound elastography for magnetic resonance imaging(MRI)-transrectal ultrasound(TRUS)image registration.Methods A total number of 5 patients and 1 commercial prostate phantom were imaged via transrectal ultrasound elastography,3D-TRUS and MRI from June 2016 to December 2016.A personalized biomechanical model via the patient-specific ultrasound elastography was made for the deformable registration of prostate MRI and 3D-TRUS images.The registration accuracy was evaluated by the target registration error(TRE)and also the t-test was conducted to validate the statistical significance of our results.Results All the 5 sets of patient data as well as the phantom data were successfully registered.The TRE value of the phantom data was 1.65 mm.The mean TRE value of 5 patients was 1.31 mm,compared with the 2.52 mm TRE value of the registration method without patient-specific biomechanical properties via elastography,was approximately 48% lower(P <0.05).Conclusions Personalized biomechanical modeling of prostate deformation based on ultrasound elastography for MRI-TRUS image registration possesses important clinical significance and is a promising way to provide more quality guidance and improve the accuracy of prostate biopsy.
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Objective To explore the feasibility of constructing three-dimensional model after the unicompartmental knee arthroplasty using the point-to-point image registration technology,so as to provide experimental basis for further application and optimization.Methods Patients of medial compartment knee osteoarthritis undergoing UKA were chosen and their postoperative three-dimensional knee models were established based on the MRI and CT scans.The virtual prosthetic replacement and finite element models were constructed using point-to-point image registration technology,and the kinematic changes were analyzed.Results The complete postoperative three-dimensional knee models of UKA were established,and the kinematic charateristics were similar to those conducted in traditional methods.Conclusion The virtual surgery can be performed using the point-to-point image registration technology,and it is both easier and more convenient than the traditional methods.
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With the development of computer techniques and medical software in image analysis and visualization,medical image registration as a key step before image processing(e.g., image fusion)is important in research and medical diagnosis. Therefore, many studies have focused on medical registration methods and algorithms. Up to now, several registration methods have been applied in clinical practice. In this paper,we make a classification and analysis of registration methods clinically applied in radiotherapy. How to improve the accuracy,efficiency,and robustness of medical image registration remains an issue to be solved in the future.