Use of magnetic resonance scanner with a linear accelerator during precision radiotherapy for breast cancer / 中华放射肿瘤学杂志

Magnetic resonance-guided radiotherapy (MRgRT) not only offers real time magnetic resonance (MR) imags with high-resolution and good soft tissue contrast to guide the delineation of the target volume during simulation and daily radiotherapy, but also reveals the position and shape changes of the target volumes and organs at risk (OAR) during treatment dynamically, which provides the evidence for the individual-adptive planning revision. Thus, MRgRT has the potential to dramatically impact cancer research and treatment. And this treatment mode is theoretically more suitable for the disease with obvious tissue deformation, such as breast. In this review, application of MR scanner with a linear accelerator (MR-linac) in radiotherapy workflows for breast cancer patients was summarized, and its implications and opportunities on breast cancer irradiation were highlighted.

Effect of cone-beam computed tomography image-guidance on the setup errors of stereotactic body radiotherapy for spinal metastatic tumors / 肿瘤研究与临床

Objective:To evaluate the effect of image-guided with cone-beam computed tomography (CBCT) based on volumetric modulated arc therapy (VMAT)-flattening filter free (FFF) on the setup errors of stereotactic body radiotherapy (SBRT) in patients with spinal metastatic tumors.Methods:The clinical data of 15 patients with spinal metastatic tumors who underwent SBRT in Jilin Cancer Hospital from August 2020 to January 2022 were retrospectively analyzed. The radiotherapy dose of bone metastasis was 32 Gy per 4 times and CBCT scanning was performed before and after radiotherapy. Every patient received radiotherapy 4 times; all 15 patients underwent SBRT 60 times in total and 120 CBCT volume images were finally obtained and analyzed. The systematic error (Σ) and random error (σ) were calculated at different correction threshold levels. The translational setup error and rotational setup error at the left-right (X axis), head-foot (Y axis) and front-back (Z axis) directions before and after radiotherapy were compared, which were expressed as Σ ± σ.Results:The pre-SBRT and post-SBRT translational setup errors were (0.14±0.27) cm and (0.07±0.19) cm, respectively ( P<0.001) in the X direction, (-0.05±0.33) cm and (0.00±0.19) cm, respectively ( P = 0.001) in the Y direction, (-0.13±0.19) cm and (-0.02±0.14) cm, respectively ( P = 0.012) in the Z direction. The pre-SBRT and post-SBRT rotational setup errors were (-0.31±0.76)° and (-0.09±0.34)°, respectively ( P < 0.001) in the X direction, (-0.13±0.88)° and (-0.07±0.36) °, respectively ( P < 0.001) in the Y direction, (0.10±0.51)° and (0.16±0.38)°, respectively ( P < 0.001) in the Z direction. Conclusions:CBCT correction could reduce Σ and σof the translational setup and rotational setup, increase the accuracy of SBRT based on VMAT-FFF for patients with spinal metastatic tumors.

Significance of target volume delineation of tumor bed according to metal clips or seroma in determing tumor bed position during radiotherapy after breast-conserving surgery for breast cancer / 肿瘤研究与临床

Objective:To investigate the differences between the mental clips placed intraoperatively and the tumor bed's target volume delineation of seroma based on CT scanning during radiotherapy for breast cancer patients who received breast-conserving surgery in the persuit of a better solution to determine the tumor bed position.Methods:The clinical data of 13 patients with early breast cancer who received postoperative radiotherapy after breast-conserving surgery at Beijing Shijingshan Hospital and Beijing Shijitan Hospital of Capital Medical University from December 2020 to January 2022 were retrospectively analyzed. They all had surgical clips implanted during the surgery. The following methods were used to delineate the target volume of tumor bed, including gross target volume delineation of tumor bed based on the mental clips (GTVtb-Clip), the tumor bed's gross target volume delineation of seroma based on CT scanning (GTVtb-Seroma), and the combination of both (GTVtb-C+S). The volume, diameter on three coordinate axis, neutral point displacement and conformability of these delineation methods were compared.Results:The volume of GTVtb-Clip, GTVtb-Seroma and GTVtb-C+S was (25±10) cm 3, (38±17) cm 3, (49±20) cm 3, and the differences were statistically significant (all P<0.05). The diameter on X axis was (4.7±1.2) cm, (5.3±1.4) cm, (5.7±1.6) cm, respectively in GTVtb-Clip, GTVtb-Seroma and GTVtb-C+S; the diameter on Y axis was (4.6±1.7) cm, (5.0±1.6) cm, (5.7±1.7) cm, respectively in GTVtb-Clip, GTVtb-Seroma and GTVtb-C+S; the diameter on Z axis was (4.4±1.5) cm, (5.2±1.4) cm, (5.6±1.4) cm in GTVtb-Clip, GTVtb-Seroma and GTVtb-C+S. The differences in the diameter of GTVtb-Clip and GTVtb-C+S on X,Y, Z axis were statistically significant (all P<0.05); the differences in the diameter of GTVtb-Seroma and GTVtb-C+S on X, Z axis were statistically significant (all P<0.05); the difference in the diameter of GTVtb-Clip and GTVtb-Seroma on X axis was statistically significant ( P<0.05) .Neutral point displacement was (5.8±1.6) cm, (5.5±1.9) cm, (6.0±1.7) cm, respectively of GTVtb-Clip, GTVtb-Seroma, GTVtb-C+S, and the difference was not statistically significant ( P>0.05). Conformability of GTVtb-Clip and GTVtb-Seroma, GTVtb-Clip and GTVtb-C+S, GTVtb-Seroma and GTVtb-C+S was 0.412±0.112, 0.525±0.095, 0.774±0.112,respectively, and the differences were statistically significant (all P<0.05). Conclusions:During radiotherapy after breast-conserving surgery for breast cancer, compared with the single method, the combination of GTVtb-Clip and GTVtb-Seroma can better cover the real tumor bed, thus reducing the omission of tumor bed and recurrence rate. CT position should better take place at 4 to 8 weeks for patients receiving radiotherapy after breast-conserving surgery, and target volume of tumor bed will be delineated based on the postoperative changes of both mental clips and seroma.

Factors influencing the short-term efficacy of CT-guided 125I seeds implantation in the treatment of recurrent and metastatic tumors of head and neck / 中华核医学与分子影像杂志

Objective@#To analyze the factors influencing the short-term efficacy of CT-guided 125I seeds implantation in the treatment of recurrent and metastatic tumors in head and neck.@*Methods@#A total of 73 patients (61 males, 12 females; age: (59.1±11.5) years) with head and neck tumors recurrence and metastasis treated by 125I seeds implantation in Hebei General Hospital from January 2015 to April 2019 were retrospectively enrolled. The implanted seeds activity was 11.1-29.6 MBq, and the prescription dose was 80.0-145.0 Gy. CT examination was conducted 3 months after 125I seeds implantation. According to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, short-term efficacy was classified as effective (complete remission (CR), partial remission (PR)) and ineffective (stable disease (SD), progressive disease (PD)). Univariate analysis of factors affecting short-term effect (gender, age, history of radiation therapy, Karnofsky performance status (KPS) scores, pathological type, the longest diameter of tumor, implantation patterns, seeds activity, immediate postoperative dose delivered to 90% gross tumor volume (D90), and with adjuvant chemotherapy post-surgery or not) were conducted. Variables with P<0.2 were enrolled in logistic multivariate regression analysis. In addition, artificial neural network (ANN) was constructed with all influencing factors as independent variables and short-term efficacy as dependent variables. Finally, receiver operating characteristic (ROC) curve analysis was performed for the common influencing factors in logistic regression analysis and ANN analysis.@*Results@#There were 34 with effective results and 39 with ineffective results. Logistic regression analysis indicated that the longest diameter of tumor, immediate postoperative D90, with adjuvant chemotherapy post-surgery or not had significant impacts on the short-term efficacy (Wald values: 6.950, 4.804, 4.790, all P<0.05); According to results of ANN analysis, the top 5 in order of importance for short-term efficacy prediction were immediate postoperative D90, the longest diameter of tumor, age, seeds activity and gender. ROC curve analysis indicated that the longest diameter of tumor and immediate postoperative D90 were the best predictors for short-term efficacy, with the threshold of 5.25 cm and 110.05 Gy respectively, and the area under the curve (AUC) was 0.843 and 0.847 respectively (both P<0.001).@*Conclusions@#The short-term efficacy of 125I seeds implantation in the recurrence and metastasis of head and neck tumors is mainly related to the longest diameter of tumor and immediate postoperative D90. Patients with the longest diameter of tumor <5.25 cm and with D90>110.05 Gy can achieve better efficacy.

Factors influencing the short-term efficacy of CT-guided 125I seeds implantation in the treatment of recurrent and metastatic tumors of head and neck / 中华核医学与分子影像杂志

Objective To analyze the factors influencing the short-term efficacy of CT-guided 125I seeds implantation in the treatment of recurrent and metastatic tumors in head and neck.Methods A total of 73 patients (61 males,12 females;age:(59.1±11.5) years) with head and neck tumors recurrence and metastasis treated by 125I seeds implantation in Hebei General Hospital from January 2015 to April 2019 were retrospectively enrolled.The implanted seeds activity was 11.1-29.6 MBq,and the prescription dose was 80.0-145.0 Gy.CT examination was conducted 3 months after 125I seeds implantation.According to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1,short-term efficacy was classified as effective (complete remission (CR),partial remission (PR)) and ineffective (stable disease (SD),progressive disease (PD)).Univariate analysis of factors affecting short-term effect (gender,age,history of radiation therapy,Karnofsky performance status (KPS) scores,pathological type,the longest diameter of tumor,implantation patterns,seeds activity,immediate postoperative dose delivered to 90％ gross tumor volume (D90),and with adjuvant chemotherapy post-surgery or not) were conducted.Variables with P＜ 0.2 were enrolled in logistic multivariate regression analysis.In addition,artificial neural network (ANN) was constructed with all influencing factors as independent variables and short-term efficacy as dependent variables.Finally,receiver operating characteristic (ROC) curve analysis was performed for the common influencing factors in logistic regression analysis and ANN analysis.Results There were 34 with effective results and 39 with ineffective results.Logistic regression analysis indicated that the longest diameter of tumor,immediate postoperative D90,with adjuvant chemotherapy post-surgery or not had significant impacts on the shortterm efficacy (Wald values:6.950,4.804,4.790,all P＜0.05);According to results of ANN analysis,the top 5 in order of importance for short-term efficacy prediction were immediate postoperative D90,the longest diameter of tumor,age,seeds activity and gender.ROC curve analysis indicated that the longest diameter of tumor and immediate postoperative D90 were the best predictors for short-term efficacy,with the threshold of 5.25 cm and 110.05 Gy respectively,and the area under the curve (AUC) was 0.843 and 0.847 respectively (both P＜0.001).Conclusions The short-term efficacy of 125I seeds implantation in the recurrence and metastasis of head and neck tumors is mainly related to the longest diameter of tumor and immediate postoperative D90.Patients with the longest diameter of tumor ＜5.25 cm and with D90＞110.05 Gy can achieve better efficacy.

Image-Guided BrachyAblation (IGBA) en hepatocarcinoma: descripción de la técnica y reporte del primer caso en Chile / Image-guided brachyablation for hepatocarcinoma: report of one case

Eighty percent of hepatocarcinomas are inoperable at the moment of diagnosis. Liver transplantation is the treatment of choice in these cases, but local therapies are another alternative. Among these, Image-Guided BrachyAblation is a safe choice. We report a 76-year-old male with a hepatocarcinoma, who was considered inoperable due to the high surgical risk of the patient. A local treatment with Image-Guided BrachyAblation was decided. A brachytherapy needle was placed in the tumor under computed tomography guidance and a 15 Gy single dose was delivered from an Iridium-192 source. The patient had no immediate complications and at one month of follow up he continued without incidents.

Image guidance improves gain ratio in radioactive seeds brachytherapy / 中华核医学与分子影像杂志

Objective To investigate whether quality assurance and quality control using multimodal image guidance and radiation dosimetry optimization could ensure and improve the targeting of 125I seeds brachytherapy.Methods A total of 287 patients (184 males,103 females,average age 61.9 years) with non-small-cell lung cancer (NSCLC) and 122 patients (average age 65.5 years) with prostate cancer who were diagnosed by pathology or imaging methods (coincidence imaging,CT,flexible fiberoptic bronchoscopy,ultrasonography) from October 2002 to October 2016 were retrospectively enrolled.All imaging methods were used to locate the target area.Optimization of radiation dosimetry was made according to treatment planning system (TPS) and evaluated by dose-volume histogram (DVH).125I seeds implantation was performed under the imaging guidance,followed by real-time location verification,dosimetric verification.Therapeutic efficacy was evaluated.Paired t test was used to analyze the data.Results The prescribed dose (PD) of planning target volume (PTV) was above 140 Gy.Immediate dosimetric verification was performed in 59 patients with NSCLC and 31 patients with pulmonary metastases.The radiation dose before and after the implantation was coincident in 93.2％ (55/59) of NSCLC and 93.5％ (29/31) of pulmonary metastases.The coincident rate of patients with dose delivered to 90％ GTV (D90)＞matched peripheral dose (MPD) was 93.2％ (55/59) and 87.1％ (27/31) respectively in NSCLC and pulmonary metastases.There was no significant difference in MPD,D90 and conformity index (CI) before and after implantation (t values:2.11-9.71,all P＞0.05).The average dose of the risk organs was significantly lower than the tolerance dose of the normal tissue.The incidence of radiation pneumonitis was 1.05％ (3/287).No other serious complications were found.Conclusion Targeted diagnosis and therapy of multimodal image guidance could be optimized to improve the effect of targeting and therapeutic gain ratio of 125I seeds brachytherapy.

Dosimetry evaluation for CT guided 125I seeds implantation assisted by three-dimensional-printing coplanar coordinate template in chest malignant tumor / 中华核医学与分子影像杂志

Objective To verify the accuracy of three-dimensional printing coplanar coordinate template (3D-PCCT) technology for 125I seeds implantations in chest tumor at dosimetry level.Methods From January 2016 to June 2017,a total of 22 patients (15 males,7 females;median age 62 years) with chest tumors who received 3D-PCCT assisted 125I seeds implantation in Peking University Third Hospital were enrolled in this retrospective study.There were 8 patients with primary lung cancer and 14 with metastatic carcinoma.The sites for implantation included lung (12 cases),mediastinum (2 cases) and chest wall (8 cases).The prescribed dose was 110-180 Gy.The preoperative plan design,puncture and seeds implantation guided by template were carried out and the dose distribution of postoperative plan was compared with that of preoperative plan.Dose parameters included dose delivered to 90％ gross tumor volume (D90),minimum peripheral dose,the percentage of GTV receiving 100％ prescription dose (V100),the percentage of GTV receiving 150％ prescription dose (V150),conformity index,external index of target volume,uniformity index,D2 cm3 of spinal cord and aorta,and V20 of affected side lung.Wilcoxon signed rank test was used to analyze the data.Results The median D90 was 150.4(125.6,187.0) Gy.Postoperative D90 was higher than the prescribed dose in 68％ (15/22) cases.For median value of most parameters,there were no significant differences between the postoperative plans and preoperative plans (all P＞0.05) except for the actual V100,which was lower than the preplanned (95.5％ vs 97.2％;P=O.040).Conclusion 3D-PCCT could provide good accuracy in 125I seeds implantation for chest tumor.

Synthesis of ultrasound contrast agents: characteristics and size distribution analysis (secondary publication)

PURPOSE: The purpose of this study was to establish a method for ultrasound (US) contrast agent synthesis and to evaluate the characteristics of the synthesized US contrast agent. METHODS: A US contrast agent, composed of liposome and sulfur hexafluoride (SF₆), was synthesized by dissolving 21 μmol 1,2-dihexadecanoyl-sn-glycero-3-phosphocholine (DPPC, C₄₀H₈₀NO₈P), 9 μmol cholesterol, and 1.9 μmol of dihexadecylphosphate (DCP, [CH₃(CH₂)15O]₂P(O)OH) in chloroform. After evaporation in a warm water bath and drying for 12-24 hours, the contrast agent was synthesized using the sonication process by the addition of a buffer and SF₆ gas. The size distribution of the bubbles was analyzed using dynamic light scattering measurement methods. The degradation curve was evaluated by assessing the change in the number of contrast agent bubbles using light microscopy immediately, 12, 24, 36, 48, 60, 72, and 84 hours after synthesis. The echogenicity of the synthesized microbubbles was compared with commercially available microbubbles (SonoVue, Bracco). RESULTS: contrast agent was synthesized successfully using an evaporation-drying-sonication method. Most bubbles had a mean diameter of 154.2 nm and showed marked degradation 24 hours after synthesis. Although no statistically significant differences were observed between SonoVue and the synthesized contrast agent, a difference in echogenicity was observed between the synthesized contrast agent and saline (P<0.01). CONCLUSION: We successfully synthesized a US contrast agent using an evaporation-dryingsonication method. These results may help future research in the fields of anticancer drug delivery, gene delivery, targeted molecular imaging, and targeted therapy.

Research progress of image-guided radiation therapy for hepatocellular carcinoma Zhou Qingxiang, Wang Jianting, Zhai Fushan / 肿瘤研究与临床

Hepatocellular carcinoma is a common malignant tumor, which has a poor prognosis and a high mortality rate. Under the influence of respiratory motion, the position error of liver cancer is relatively high. The image-guided radiotherapy is a combination of radiotherapy and imaging device, which can detect and correct the error caused by the movement of the organs and the position of the pendulum to improve the accuracy of radiotherapy.

Clinical efficacy of daily online image-guided stereotactic body radiation therapy for lung cancer / 中华放射肿瘤学杂志

Objective To analyze the clinical efficacy of daily online cone-beam computed tomography (CBCT)-guided stereotactic body radiation therapy (SBRT) for primary and metastatic lung cancer and its related factors.Methods From May 2009 to May 2013,36 patients with lung cancer were treated with SBRT,including 24 patients with primary lung cancer and 12 patients with metastatic lung cancer.The biologically effective dose at 10 Gy was ≥ 100 Gy in 85.7％ of 42 lesions.Before each delivery,CBCT was acquired,and online automatic or manual registration was performed to make the tumors on CBCT within the planning target volume/primary gross tumor volume;the setup threshold was not set,and the couch was moved for correction.Results The 1-,2-,and 3-year sample sizes were 36,29,and 26,respectively.The 1-,2-,and 3-year local control (LC) rates were 96％,89％,and 72％,respectively.The 1-,2-,and 3-year cancer-specific survival (CCS) rates were 82％,74％,and 64％,respectively.The 1-,2-,and 3-year overall survival (OS) rates were 78％,64％,and 53％,respectively.Univariate analysis found no factors associated with LC.Multivariate analysis revealed no factors associated with OS.Both univariate and multivariate analyses showed that only tumor location (central type or peripheral type) was associated with CCS;the mean values (95％ confidence intervals) of CCS in patients with central-type and peripheral-type lesions were 21.4 months (13.2-29.6 months) and 42.3 months (35.7-49.0months),respectively (P=0.024).Conclusions Daily online image-guided SBRT for primary or metastatic lung cancer can lead to a satisfactory LC.

Interfractional Variation of Radiation Target and Adaptive Radiotherapy for Totally Resected Glioblastoma

This study aimed to evaluate the effects of volume adapted re-planning for radiotherapy (RT) after gross total resection (GTR) for glioblastoma. Nineteen patients with glioblastoma who underwent GTR and postoperative RT were analyzed. The volumes of the surgical cavity on computed tomography (CT) obtained one day after GTR (CT0), the first RT simulation CT (sim-CT1), and the second simulation CT for the boost RT plan (sim-CT2) were compared. The boost RT plan was based on the surgical cavity observed on the sim-CT2 (boost RTP2) and was compared with that based on the surgical cavity observed on the sim-CT1 (boost RTP1). The volume reduction ratios were 14.4%-51.3% (median, 29.0%) between CT0 and sim-CT1 and -7.9%-71.9% (median, 34.9%) between sim-CT1 and sim-CT2 (P < 0.001). The normal brain volumes in boost RTP1 were significantly reduced in boost RTP2, especially at high dose levels. Target volume in sim-CT2 which was not covered with the boost RTP1, developed in five cases (26.3%). The surgical cavity volume was reduced following surgery in patients with glioblastoma who underwent GTR. The application of volume-adapted re-planning during RT could decrease the irradiated volume of normal brain and prevent a target miss for boost RT.

Study of inter-fractional variations and adaptive radiotherapy in pancreatic cancer / 中华放射肿瘤学杂志

ObjectiveTo quantitatively characterize the inter-fractional anatomy variations and advantages of dosimetry for the adaptive radiotherapy in pancreatic cancer.MethodsA total of 226 daily CT images acquired from 10 patients with pancreatic cancer treated with image-guided radiotherapy were analyzed retrospectively.Targets and organs at risk (OARs) were delineated by the atlas-based automatic segmentation and modified by the skilled physician.Various parameters,including the center of mass (COM) distance,the maximal overlap ratio (MOR) and the Dice coefficient (DC),were used to quantify the inter-fractional organ displacement and deformation.The adaptive radiation therapy (ART) was applied to handle the daily GT images.The dose distributions parameters from the ART plan were compared with those from the repositioning plan.ResultsThe inter-fractional anatomy variations of pancreas head were obvious in the pancreatic cancer irradiation.The mean COM distance,MOR and DC of pancreas head after the bony or soft tissue alignment and registration was ( 7.8 ± 1.3 ) mm,( 87.2 ± 8.4 )％ and ( 77.2 ±7.9)％ respectively.Compared with the repositioning plan,the ART plan had better target coverage and OARs sparing.For example,the mean V100 of PTV was improved from (93.32 ± 2.89) ％ for repositioning plan to ( 96.03 ± 1.42) ％ for ART plan with t =2.79,P =0.008 and the mean V50.4 for duodenum was reduced from (43.4 ± 12.71 )％ for the repositioning plan to (15.6 ± 6.25)％ for the ART plan with t =3.52,P=0.000.ConclusionsThe ART can effectively account for the obvious inter-fractional anatomy variations in pancreatic cancer irradiation and be used to escalate the radiotherapy dose for the pancreatic cancer,which will lead to a promising higher local control rate.

Actual dose variations of the parotid glands and spinal cord during helical tomotherapy for patients with loco-regional advanced nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective To quantify dose variations of the parotid glands and spinal cord in nasopharyngeal carcinoma (NPC) patients during helical tomotherapy (HT) by using megavolt (MV) CT and planned adaptive application. Methods Five patients with advanced local-regional NPC were treated by HT with a prescription dose of 70 Gy in 35 fractions in primary tumor and involved lymph nodes. Daily MV CT scans were registered with the planning CT images. The parotid glands were re-contoured every 4 fractions to a total of 45 times, and location of the spinal cord were corrected by MVCT IGRT system every 2 fractions to a total of 85 times. The actual doses delivered to these organs were evaluated by using the planned adaptive application software of HT system. Results At the end of therapy, the mean volume of the parotid gland was decreased by 42% (left) and 33% (right) , respectively. The average V1 of the parotid was increased by 26. 0% (left) and 31.4% (right), and the D50 increased by 15. 8% (left) and 17. 3% (right), respectively. The average Dmax of the spinal cord was increased by 1.3%. Conclusions During HT, the parotid glands receive a higher actual dose due to the volume shrinkage, while the Dmax of the spinal cord changes little. By using adaptive radiation therapy technique, constant monitoring anatomic changes of organs at risk and selective replanning are necessary during radiation therapy for NPC.

Investigation of six-degree-of-freedom image registration between planning and cone beam computed tomography in esophageal cancer / 中华放射肿瘤学杂志

Objective To explore six-degree-of-freedom (6-DF) registration methods between planning and cone beam computed tomography (CBCT) during image-guided radiation therapy (IGRT) in esophageal cancer.Methods Thirty pairs of CBCT images acquired before radiation and the corresponding planning computed tomography (CT) images of esophageal cancer were selected for further investigation.Registration markers for 6-DF image registration were determined and contoured in those images.The results of registration as well as time cost were compared among different registration methods of bone match, gray value match, manual match, and bone plus manual match.Results Contouring bone and spinal canal posterior to the target volume of esophageal carcinoma as registration marker could make 6-DF registration quick and precise.Compared with manual match, set-up errors of v rotation in bone plus manual match (-0.55° vs.-0.88°, t=2.55, P=0.020), of x-axis and v rotation in bone match (0.12 mm vs.-2.33 mm, t=5.75, P=0.000; -0.35° vs.-0.88°, t=3.00, P=0.007), and of x-axis and w rotation in gray value match (7.20 mm vs.-2.33 mm, t=3.10, P=0.006; -0.10° vs.-0.59°, t=2.81, P =0.011) were significantly different.Compared with manual match, the coincidence rate of bone plus manual match was the highest (85.55%), followed by bone match and gray value match (74.45% and 74.45%).The time cost of each registration method from longest to shortest was:6.00 -10.00 minutes for manual match, 1.00 - 5.00 minutes for bone plus manual match, 0.75 - 1.50 minutes for gray value match, and 0.50 - 0.83 minutes for bone match.Conclusions Registration marker is useful for image registration of CBCT and planning CT in patients with esophageal cancer.Bone plus manual match may be the best registration method considering both registration time and accuracy.