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Glioma is the most common central nervous system tumor, mainly derived from the interstitial cells of the nervous system, showing diffuse and infiltrative growth, with the characteristics of high morbidity, high postoperative recurrence, high mortality and low cure rate. Currently, radical resection followed by radiotherapy and chemotherapy is the first choice of treatment. Accurate delineation of GTV-T is of significance for precision radiotherapy after surgery. In addition, CT/MR fusion imaging has been commonly used in the delineation of tumor targets in glioma. In recent years, PET/MR has been more and more widely applied in tumors. In this article, the application and differences between PET/MR and CT/MR for target delineation in glioma were reviewed.
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Artificial intelligence is the use of computer algorithms to copy or simulate human behavior, giving machines human-like ability. With the rapid development of radiotherapy technology, artificial intelligence has great potential value in all stages of radiotherapy. Image segmentation is the premise of target delineation using artificial intelligence. The commonly used methods in clinic mainly include automatic segmentation based on deep learning and atlas library. The technology of artificial intelligence in organs at risk delineation is relatively mature, which can significantly shorten the delineation time and improve the efficiency. The delineation of tumor targets has achieved some success, the accuracy still needs to be further improved. Artificial intelligence technology makes the target delineation more and more efficient, and the consistency and repeatability have been significantly improved. It is expected to provide more accurate and individualized treatment for patients.
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Objective:To compare the differences of postoperative clinical target volume of internal mammary lymph node (CTV ImlN) by different delineation methods, and to explore the reasonable method of CTV ImlN delineation after internal mammary lymph node dissection (ImlND). Methods:A total of 20 breast cancer patients who had undergone modified radical mastectomy (MRM) with ImlND on the affected side and had complete preoperative and postoperative CT images were selected. The CTV (CTV pr-I, CTV pr-a) of both sides of ImlN were delineated on preoperative CT images according to RTOG guideline. On postoperative CT images, three different methods including deformation image registration (DIR) method, visual contrast method and precise measurement method, were employed to delineate the postoperative CTV ImlN of the affected side. The targets were named as CTV DIR, CTV V and CTV M, respectively. The central displacement, target volume, degree of inclusion (DI) and conformity index (CI) of CTV pr-a, CTV V, CTV M and CTV DIR were compared. Results:The central displacement of CTV V, CTV M and CTV DIR from CTV pr-a was 2.17 cm, 1.44 cm and 1.25 cm, respectively. The target volume of CTV pr-a, CTV pr-I, CTV V, CTV M and CTV DIR was 2.10 cm 3, 2.17 cm 3, 2.04 cm 3, 1.88 cm 3 and 2.07 cm 3 respectively. There was no significant difference in the target volume (all P>0.05). The CI values of CTV V-CTV pr-a and CTV M-CTV pr-a were both 0.16, and that of CTV DIR-CTV pr-a was 0.43. The CI value of CTV DIR was significantly higher than those of CTV V and CTV M (both P<0.01). The DI values of CTV V-CTV pr-a, CTV M-CTV pr-a and CTV DIR-CTV pr-a were 0.26, 0.24 and 0.58, respectively. The DI value of CTV DIR was significantly higher than those of CTV V and CTV M (both P<0.01). Conclusions:It is difficult to accurately delineate the CTV ImlN for patients after ImlND. However, the spatial position fitness of the target region delineated by DIR method is better than those by visual contrast and precise measurement methods.
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Objective:To explore the value of BLADE sequence in determining the target range of esophageal cancer radiotherapy through the correlation and consistency between measured esophageal cancer length on the MRI-BLADE sequence and the surgical pathological specimens.Methods:Clinical data of 36 patients who were pathologically diagnosed with esophageal carcinoma and received preoperative esophageal MRI in the Affiliated Cancer Hospital of Zhengzhou University between January 2016 to June 2019 were collected. The CT, DWI and BLADE sequence images of all participants were collected and imported into the Monaco system, by which the correlation and consistency between the tumor length measured based on these three imaging methods were statistically compared. Furthermore, the differences in gross tumor volume (GTV) delineated by different physicians in different images were compared.Results:The correlation coefficients of the tumor length measured by CT, DWI and BLADE and pathological specimen length were 0.467, 0.723 and 0.896, respectively. The consistency analysis indicated that all the differences between the BLADE sequence and pathological specimen length were within the 95% consistency limit. The consistency and correlation between the BLADE sequence and actual tumor length were significantly better than those between the DWI sequence and CT images (both P<0.05). The volume of DWI and BLADE images obtained by four physicians was significantly smaller than that of CT images (both P<0.05). The differences in GTV delineated by different physicians by these three imaging methods were insignificant (all P>0.05), but the GTV delineated by the four physicians on the BLADE sequence were more similar (all P>0.05). Conclusions:BLADE sequence can help physicians to determine the upper and lower boundaries of esophageal tumors more accurately and reduce the differences in GTV delineation among different physicians. And it can effectively improve the unity of individual′s understanding of the scope of target area delineation, and improve the objectivity of clinicians′ judgment of GTV. BLADE sequence can be used as an important imaging tool for accurate target delineation in radiotherapy.
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The development of medical image segmentation technology has been briefly reviewed. The applications of auto-segmentation of organs at risk and target volumes based on Atlas and deep learning in the field of radiotherapy have been introduced in detail, respectively. Then the development direction and product model for general automatic sketching tools or systems based on solid clinical data are discussed.
Subject(s)
Image Processing, Computer-Assisted , Radiotherapy/trends , Radiotherapy Planning, Computer-Assisted , Technology , Tomography, X-Ray ComputedABSTRACT
Target delineation is the key and difficult point in radiation oncology teaching. Combined with the teaching experience in department of cancer radio-chemotherapy, Zhongnan hospital of Wuhan university, this study focused on target delineation to explore the teaching mode and method of radiation oncology. Self-directed learning was combined with teacher's lecturing and guiding. By enhancing tumor imaging teaching and basic theory of tumor radiotherapy, students can grasp the essence and detail of target delineation and build individualized and precise radiotherapy. Finally, a new teaching mode combining students' autonomous learning with teachers' teaching and guide is established. Taking the radiation therapy of breast cancer as an example, We briefly described the concrete application of this teaching system.
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Target delineation is the key and difficult point in radiation oncology teaching. Combined with the teaching experience in department of cancer radio-chemotherapy , Zhongnan hospital of Wuhan university , this study focused on target delineation to explore the teaching mode and method of radiation oncology. Self-directed learning was combined with teacher's lecturing and guiding. By enhancing tumor imaging teaching and basic theory of tumor radiotherapy, students can grasp the essence and detail of target delineation and build individualized and precise radiotherapy. Finally, a new teaching mode combining students' autonomous learning with teachers' teaching and guide is established. Taking the radiation therapy of breast cancer as an example, We briefly described the concrete application of this teaching system.
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Modern medical imaging techniques,such as computed tomorgraphy (CT),magnetic resonance imaging (MRI) and position emission tomorgraphy/computed tomorgraphy (PET-CT) can accurately delineate the gross target volume (GTV) of hepatocellular carcinoma (HCC).Comparison of postoperative pathological subclinical lesions,imaging and clinical parameters contributes to the precise delineation of clinical target volume (CTV).Moreover,radiotherapy-assisted techniques,such as fourdimensional computed tomography (4DCT),compression of abdomen,active breathing control and respiratory gating,can minimize the internal target volume (ITV).In addition,immobilization with vacuum cushion and body membrane can reduce the set-up error,minimize the planning target volume (PTV) and avoid or decrease the irradiation error or missing irradiation.All these approach can minimize the target volume,elevate the dose and reduce the complications during radiotherapy for HCC.In this article,the research progress on the target delineation for external beam radiotherapy in HCC patients was reviewed.
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In recent years,along with the clinical exploration and application of magnetic resonance simulation localization and radiotherapy equipment,more and more studies have been performed to focus on the excellent ability of MRI in identifying soft tissues,aiming to explore the potential application value of magnetic resonance imaging (MRI) in radiotherapy for breast cancer patients.In this article,the research progress on MRI in radiotherapy after breast-conserving surgery was reviewed to provide certain ideas and references for subsequent research.
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The delineation of clinical target volume(CTV)is a critical step in planning three-dimensional conformal radiation therapy(3D-CRT)or intensity-modulated radiation therapy(IMRT)for gastric cancer.Recommendations for target volume construction have been published for two-dimensional(2D)techniques,but are scarce for 3D CT-based CTV contouring.Recent advances and controversies in delineation of postoperative radiotherapy CTV for gastric cancer have been introduced.Further optimization of target volume for postoperative 3D-CRT/IMRT in gastric cancer is necessary.
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Objective To reconstruct the original three-dimensional conformation of tumor resection tissue through the study of breast-conserving surgery excision specimens for part-mount sub-serial section and pathological three-dimensional (3D) reconstruction,to establish a new margin assessment model,and to guide tumor bed delineation individually for radiotherapy.Methods From February 2016 to February 2017,thirtythree eligible breast cancer patients underwent breast-conserving surgery in Breast Cancer Center of Shandong Cancer Hospital were recruited.The excision specimens were prepared with part-mount sub-serial section,and residual tumors were microscopically outlined,scanned and registered by Photoshop software.The 3D model of residual tumors was reconstructed with 3D-DOCTOR software to evaluate margin status and record pathological type,tumor length and 3D negative margin distance.The gross tumor volume (GTV) was delineated based on clips placed in the lumpectomy cavity.CTV1 and CTV2 were defined by adding uniform 1.00 cm and 1.50 cm margin based on GTV respectively.CTV3 and CTV4 were defined by adding 1.00 cm and 1.50 cm margin based on 3D boundary of excision tumor respectively,and compared the volume differences of CTV1 and CTV3,CTV2 and CTV4.Results Based on the marginal assessment results of 3D pathological reconstruction,the rates of false negatives during the intraoperative rapid pathological examination and postoperative routine pathological margin evaluation were 6.7％ (2/30) and 3.4％ (1/29) respectively.The pathological type of pathological large slice and routine pathological examination was consistent with rate of 93.9％ (31/33).The M(QR) tumor lengths of routine pathological and pathological 3D reconstruction were 1.90 (1.50-2.40) cm and 2.00 (1.60-2.70) cm respectively,with statistical difference between the two groups (Z =-2.438,P =0.015).The M(QR) volumes for CTV1,CTV2,CTV3,CTV4 were 70.76 (49.84-78.07)cm3,110.11 (83.38-126.17) cm3,23.85 (16.46-31.49)cm3 and 38.74 (30.47-50.58) cm3 respectively.There were statistical differences between CTV1 and CTV3,CTV2 and CTV4 (Z =-4.372,P ＜0.001;Z =-4.372,P ＜0.001).Conclusion The application of pathological 3D reconstruction technology can largely compensate for the shortcomings of the traditional margin assessment model,make the decisions of adjuvant treatment after breast-conserving surgery more accurate,and guide the tumor bed delineation individually for radiotherapy.
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Objective To investigate the benefits of replanning after induction chemotherapy(IC) by analyzing the dosimetric impact of IC on intensity-modulated radiotherapy(IMRT)for locally advanced nasopharyngeal carcinoma(NPC)and the dosimetric characteristics of replanning after IC, and to provide data for the rational design of clinical radiotherapy plans. Methods 16 NPC patients underwent contrast-enhanced CT scan once before and after IC.Target volumes were delineated and the chemotherapy plans were created,defined as Plan-1 and Plan-2,respectively. Then the target structure after IC was copied to Plan-1, generating the third plan, defined as Plan-1-2. The paired t-test was used to compare the dosimetric parameters between Plan-1 and Plan-1-2 and between Plan-2 and Plan-1-2. Results Plan-1 vs. Plan-1-2:Plan-1-2 showed significantly reduced D meanof target volume compared with Plan-1(P<0.05). Plan-1-2 significantly increased D meanand D maxof the spinal cord(P<0.05),although significantly reduced D mean of the brain stem and D maxof the temporal lobes compared with Plan-1. Plan-1-2 also had significantly reduced conformity index(CI)and significantly increased homogeneity index(HI)for the target volume compared with Plan-1(P<0.05). Plan-2 vs. Plan-1-2:Compared with Plan-1-2, Plan-2 significantly increased D meanand D minof gross tumor volume(GTV)and primary GTV(P<0.05)and significantly reduced D meanof the temporal lobes and D maxand D meanof the spinal cord(P<0.05), with D max decreased to 430.48 cGy;Plan-2 had significantly increased CI and significantly reduced HI for the target volume compared with Plan-1-2(all P<0.05). Conclusions IMRT plan-1 after IC has worse dosimetric distribution,while replanning after IC has more dosimetric benefits.
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The delineation of clinical target volume (CTV) is a critical step in planning conformal radiotherapy for rectal cancer.Several guidelines suggest different subvolumes and anatomical boundaries in radiotherapy for rectal cancer, potentially leading to a misunderstanding of CTV definition.This article reviews recent advances in the delineation of CTV in radiotherapy for rectal cancer.
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Objective To study the correlation of positron emission tomography/computed tomography (PET/CT) under different standardized uptake value (SUV) thresholds and full time four-dimensional computed tomography (4DCT) in esophageal carcinoma target delineation and explore the optimum SUV value that can accurately reflect the spatial movement of the target.Methods Eighty-two patients with esophageal cancer initial treatment in this hospital were respectively performed the scanning localization by PET/CT and 4DCT on the same day.Then different SUV thresholds (≥2.0,2.5,3.0,3.5) and the percentage of maximum SUV value (≥20％ SUV 30％ SUV 40％ SUVmax) were selected to delineate the internal gross target volume (IGTV) PET/CT in PET/CT,the ten phases of the 4DCT were collected to obtain the full time target IGTV10,the target center offset,volume ratio and conformity index (CI) were compared between the two images,the relatively good SUV value with the registration in 4DCT target was picked out,then the correlation between the target center offset,volume ratio and CI with the IGTV10 volume,long axial diameter of IGTV10,displacement of head-to-foot direction and spatial motion was analyzed.Results When the SUV threshold was 2.0 or 20 ％ SUV the spatial matching degree of 4DCT and PET/CT images was better.The head-to-foot direction displacement and special motion displacement in the target center offset of IGTVPET2.0,IGTVPET20％ and IGTV10 showed the positive correlation (P＜0.05);the volume ratio had no correlation with the IGTV10 volume,IGTV10 long axial diameter,head-to-foot direction displacement and special motion displacement (P＞0.05);CI had positive correlation with IGTV10 volume and IGTV10 long axial diameter,while had negative correlation with the head-to-foot direction displacement and special motion displacement (P＜0.05).Conclusion When SUV taking 2.0 or 20％ SUV the esophageal carcinoma target volume of PET/CT is similar to that of full time 4DCT,but there are still some deviations in the conformity index,therefore the PET/CT threshold value and 4DCT time phase selection should be further studied.
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Objective To investigate the differences in tumor volume and metastatic tumors of the liver and regional lymph nodes between contrast-enhanced computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DWMRI) through a comparative analysis,as well the useful information for target volume delineation,and to guide radiotherapy in clinical practice.Methods A total of 40 patients with pancreatic cancer were enrolled and underwent contrast-enhanced CT and DWMRI in the same position.The target volume was delineated,the major axis of the maximum tumor section was measured,and the numbers of liver metastatic tumors and metastatic tumors of the lymph nodes with a diameter of 5-8 mm or＞8 mm were measured based on the CT and DWMRI images.The analysis was performed by using paired t-test or paired Wilcoxon rank sum test.Results The mean gross tumor volume (GTV) delineated by contrast-enhanced CT and DWMRI was 54.95 cm3 and 41.67 cm3(P =0.000),and the mean value-different value was 13.28 cm3.The major axis of the maximum tumor section measured by contrast-enhanced CT and DWMRI were 4.18 cm and 3.94 cm (P=0.000),respectively,and in two patients,dCT was smaller than dDWMRI.A total of 83 liver metastatic tumors were identified by contrast-enhanced CT,and 112 were identified by DWMRI;the liver metastatic tumors detected by contrast-enhanced CT accounted for 74％ of those detected by DWMRI.As for the metastatic tumors of the lymph nodes with a diameter of 5-8 mm or＞8 mm,103 or 46 were detected by contrast-enhanced CT,and 200 or 56 were detected by DWMRI,and the tumors detected contrast-enhanced CT accounted for 52％ or 82％ of those detected by DWMRI.There were significant differences in all data between contrast-enhanced CT and DWMRI.Conclusions GTV and the major axis of the maximum tumor section measured by DWMRI are lower than those measured by contrast-enhanced CT,and contrast-enhanced CT is sensitive in detecting the metastatic tumors of the liver and lymph nodes.However,it is necessary to conduct further controlled experiments with reference to pathology.
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As induction chemotherapy goes on,target volume,dose distribution in the surrounding organs at risk (OARs),and target dose conformity all change.Therefore,the question is how to develop reasonable radiotherapy plans in clinical practice.Induction chemotherapy followed by radiotherapy is commonly used around the world,but it is recommended to delineate the target volume based on the gross tumor volume before induction chemotherapy and not to reduce the dose.This point of view lacks the basis of evidence-based medicine.The experts and scholars in China clarify the advantages of radiotherapy plans after induction chemotherapy from the aspects of reducing the target volume,reducing the volume of high-dose region in the target volume,increasing the uniform dose coverage in target volume,reducing dose to OARs,and increasing dose conformity.However,at present,there are no objective data on its long-term efficacy and benefit.Besides,no consensus has been reached on how to delineate the target volume and determine the dose distribution after induction chemotherapy,and further studies are needed.
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Objective:To compare the therapeutic effects by different longitude margins of the gross tumor volume (GTV) based on elec-tive nodal irradiation (ENI) and to investigate the optimization of clinical tumor volume (CTV) in the radical chemoradiotherapy of esophageal squamous cell carcinoma (ESCC). Methods:ESCC patients treated with chemoradiotherapy for the first time in the First Af-filiated Hospital of Xiamen University from May 2009 to November 2012 were retrospectively studied. All patients were treated with ENI for radical radiotherapy, and the patients were divided into two groups:CTV1 group (with longitudinal external expansion length of less than 3 cm) and CTV2 group (with longitudinal external expansion length of more than 3 cm). The survival time and occurrence of side effects in patients were compared. Results:Among the 142 cases of patients, 82 and 61 cases were classified under CTV1 and CTV2, respectively. No significant difference in the overall survival (OS) and local recurrence-free survival (LRFS) rates was observed af-ter 1, 3, and 5 years of treatment between the two groups. The occurrence of side effects, such as bone marrow suppression, radiation pneumonitis, radiation esophagitis, and esophageal fistula, was less than 5%in both groups, and the data show that the side effect oc-currence in CTV1 was significantly lower. Conclusion:In the radical chemoradiotherapy of esophageal cancer using ENI, the OS rate of patients with a delineated CTV according to a 3 cm GTV longitudinal external expansion length is not lower than that of patients with a delineated CTV according to a GTV longitudinal external expansion length of more than 3 cm. The results provide a reference for the optimization of CTV in the radical chemoradiotherapy of ESCC.
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Objective To optimize the method for radiotherapy target delineation after breast cancer surgery, and to observe its advantage in raising work efficiency. Methods Ten physicians in our department were selected, and 20 patients who received breast?conserving surgery were randomly selected. The 10 physicians delineated the targets for these patients with the method in the control group and the method in the study group, and the time required for each delineation was recorded. The method in the control group was commonly used in daily practice and the method in the study group was optimized. The independent?samples t test was applied to compare the differences between the two groups. Results With the optimized method, the average time of delineation in the study group was less than that in the control group ( 51 min vs. 65 min, P=0. 029) . The time curves for delineation in the control group were relatively flat;the time curves for delineation in the study group were high at first, then decreased gradually, and finally became flat. The time for each physician to finish delineation skillfully was relatively stable, while in the study group, the time started to decrease after delineation for the first few patients, with an apparent learning process. Conclusions The optimized method for target delineation in breast cancer is feasible, reliable, and easy to master, and can increase work efficiency, which is more obvious in physicians with rich experience in delineation.
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Objective To analyze the patterns and distribution of lymph node metastasis in patients with adenocarcinoma of the esophagogastric junction ( AEG). Methods The pathological data of 393 patients with AEG from 2006 to 2009 were analyzed. The patterns and distribution of lymph node metastasis were analyzed in patients with different Siewert subtypes, depths of tumor invasion, and maximum diameters of the tumor, and the high?risk lymphatic drainage areas were investigated. Between?group comparison was performed by χ2 test. Results The metastatic rate and ratio of abdominal lymph nodes in AEG were 69?? 2%and 31?? 31%, respectively. The incidence rates of lymph node metastasis in the cardia, lesser curvature, left gastric artery, splenic artery, splenic hilum, mesenteric root, and abdominal aorta were the highest. The metastatic rate and ratio of mediastinal lymph nodes were 16?? 4% and 8?? 3%, respectively. The incidence rates of lymph node metastasis in the lower paraesophageal, esophageal hiatus, and superior diaphragmatic areas were the highest. Compared with Siewert type II and type III AEG, Siewert type I AEG had a significantly higher mediastinal lymph node metastatic rate (P= 0?? 003) and a significantly lower abdominal lymph node metastatic ratio (P= 0?? 002).The metastatic ratios of lymph nodes in multiple abdominal regions were higher in patients with stage T3+T4 AEG and a maximum tumor diameter of ≥6 cm than in the control group, while the metastatic ratios of mediastinal lymph nodes in groups with different maximum tumor diameters were similar. The metastatic ratios of lymph nodes in the greater curvature, hepatoduodenal ligament, and inferior diaphragmatic areas were lower than 10% in all groups. Conclusions In radiotherapy for AEG, the abdominal high?risk lymphatic drainage areas involve the cardia, lesser curvature, left gastric artery, splenic artery, splenic hilum, mesenteric root, and abdominal aorta, while the mediastinal high?risk lymphatic drainage areas involve the lower paraesophageal, esophageal hiatus, and superior diaphragmatic areas. In addition, the personalized target volume design should be based on the patterns of lymph node metastasis with different Siewert subtypes and clinical pathological characteristics.
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Objective To investigate the application value of CT/MR image fusing in gross tumor volume (GTV) delineation of esophageal squamous cell carcinoma.Methods Twenty-nine patients with esophageal squamous cell carcinoma to be treated with radical surgery underwent routine CT scanning,MR T2-weighted imaging (T2WI) and diffusion weighted imaging (DWI) before surgery.Diffusion-sensitive gradient b values were taken at 400,600,and 800 s/mm2.GTVs were delineated on the CT image,CT/ MR T2WI,and CT/MR DWI respectively.The MR T2W1 image was used as the intermediary for the fusion of the CT image and MR DWI image.The length of GTVs measured under different imaging conditions were compared with the length of the resected specimen of esophagus.Results The GTV length was (44.94 ± 18.46) and (45.05 ±21.47) mm on the CT images and CT/MR T2WI images respectively.When the b values were 400,600,and 800 s/mm2,the esophageal carcinoma GTV length on CT/MR DWI images was (42.12 ± 17.79),(41.18 ± 17.17) and (39.77 ± 17.66) mm,respectively.The coefficient between the esophageal carcinoma GTV lengths on CT/MR DWI images and the pathological lesion lengths was 0.928,0.926 and 0.927 respectively.Conclusions CT/MR DWI images displays esophageal carcinoma GTV length more accurately,thus guiding the delineation of GTV effectively.