Objective:To investigate the feasibility of segmented total marrow and lymphoid irradiation(TMLI)using Helical TomoTherapy(HT)in adults,and to analyze the impact of positional errors in the treatment on the actually received dose.Methods:Imaging data from four adult patients with acute myeloid leukemia were treated at the First Medical Center of the Chinese PLA General Hospital between November 2022 and December 2024 were retrospectively selected.The prescribed dose was 12 Gy in 3 fractions,and the heights range of patient was from 162 to 178 cm.The planning target volume(PTV)included the entire bone marrow and lymphatic drainage regions.The mid-femur was used as the dividing landmark,and the segmented location of head-in first(upper segmentation)and foot-in first(lower segmentation)were adopted to design plan for each segmentation.The upper segmentation used helical tomotherapy,and the lower segmentation used tomo direct therapy.The dosimetric parameters of planning target volume,and organ at risk(OAR)included eye lens,testicles and lungs were analyzed.The located computed tomography(CT)images of patients were used to simulate the changes of dosimetric parameters of each planning target region and OAR when the positions of patients moved 3,5,10 and 15 mm to outside of rack aperture.The changes of dose distribution of connection region of upper and lower segmentation were further analyzed.Results:The segmented irradiation technique can better achieve the cover(95%)of whole target region of TMLI under the condition of protecting normal organs.Under the condition with different position errors,the cover rate of the most of target region significant decreased.The largest dose of right lens increased 9.272%than primary under the 5 mm position error,and that of left and right lens increased respectively 40.199%and 67.898%under the 10 mm position error,and the max dose and mean dose of testicles increased respectively 5.847%and 5.240%under the 3mm position error.The mean dose of whole lung increased all under the error at different grades,which increased 3.021%under the 10mm position error.The non-uniformity of dose distribution of connection region increased after the position error was introduced,and the largest variation range reached to 4 Gy.Conclusion:The technique of segmented radiotherapy of Helical Tomotherapy has feasibility for TMLI of adult.But the error of the position of patients can reduce the cover of target region,and decrease the control rate for target region,and can lead to the occurrences of excessive doses on eye lens,testicles,lung and other OAR at the same time,which can increase the probability of occurring OAR injury.It should be high pay attention in treatment and implementation.

Objective:To compare the dosimetric parameters under different incremental modes between intensity-modulated radiation therapy(IMRT)and volume rotation intensity-modulated therapy(VMAT)for the target area of large volume brain metastases(BMs),and to explore the better way of treating BMs based on hypofractionated stereotactic radiotherapy(HSRT)of linear accelerator.Methods:A total of 30 BMs patients who underwent IMRT at The 971th Hospital of Navy of the CPLA from 2020 to 2023 were selected.In the treatment planning system(TPS),three types of IMRT plans and VMAT plans were designed,which included uniformity plan(Planuniformity)of target area dose,uniform increased plan(Planuniform increased-dose)and incremental plan(Planincremental)within target area.In the inside of the target area,the target area of high dose(GTVh)was set,and Planuniform increased-dose and Planincremental were designed to aim at GTVh.The differences of the doses of three types of treatment plans included Planuniformity,Planuniform increased-dose and Planincremental,which were respectively designed by using IMRT and VMAT,were analyzed.The mean dose(Dmean)of the target area,the 50%and 2%exposed doses(D50%and D2%)of the target area were observed and compared.The conformity index(CI),homogeneity index(HI),gradient index(GI),and the volume percentage(V10 Gy-V40 Gy)that normal brain tissue received 10 Gy-40 Gy also were observed and compared.Results:Compared with Planuniformity of IMRT,the Dmean of GTV of Planuniform increased-dose and Planincremental of IMRT increased by 10.13%and 17.9%,with statistically significant differences(t=13.680,12.771,P＜0.05).D50%increased by 8.9%and 10.8%,with statistically significant differences(t=15.190,9.929,P＜0.05).D2%increased by 15.2%and 46.4%,with statistically significant differences(t=52.320,8.746,P＜0.05).There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of IMRT(P＞0.05).Compared with Planuniformity of VMAT,the Dmean of GTV of Planuniform increased-dose and Planincremental of VMAT increased by 10.53%and 21.23%,with statistically significant differences(t=18.641,15.461,P＜0.05),and D50%increased by 9.1%and 13.4%,with statistically significant differences(t=11.382,10.952,P＜0.05),and D2%increased by 16.4%and 48.8%,with statistically significant differences(t=56.471,8.685,P＜0.05),respectively.There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of VMAT(P＞0.05).The normal brain tissue V20 Gy,V30 Gy and V40 Gy of Planuniform increased-dose and Planincremental of IMRT were respectively less than those of VMAT,and the differences of them between IMRT and VMAT were significant(tPlan uniform increased-dose=2.112,2.215,2.444,tPlan incremental=2.323,2.939,3.145,P＜0.05).There were no statistically significant difference in D2%,Dmean,and D50%between IMRT and VMAT(P＞0.05).Conclusion:On the premise of ensuring the safety of normal brain tissue at the edge of the target area,the synchronously increasing of the central dose of the target area will not significantly increase the dose for normal brain tissue.Both IMRT and VMAT can meet the requirements of increment in the inside of the target area,and VMAT has slightly better increment and higher efficiency within target area.The incremental of VMAT target area is slightly better,which also has better efficiency,while the enhancement effect of the dose of target area of Planincremental is better than that of the Planuniform increased-dose.The Plan incremental of VMAT is more suitable for HSRT treatment for BMs.

Objective:To investigate the influence of contrast-enhanced computed tomography(CECT)on dose calculation in magnetic resonance imaging(MRI)-guided online adaptive radiotherapy(oART)based on the electron density(ED)assignment method for rectal cancer.Methods:A retrospective analysis was conducted on the medical data of 15 patients with locally advanced rectal cancer at middle-low segments,who admitted to the Chinese PLA General Hospital between December 2023 and April 2025.All patients underwent both plain computed tomography(PCT)and CECT scans during location.The average HU and ED value of all organs that were extracted from PCT and CECT images in the treatment plan system were obtained,and the influences of contrast agent of intake on image characteristics of the structure of each organ(small intestine,femoral head,bladder)were analyzed.PCT was used as referred image to design reference plan(Pref).The synthetic CT(sCT)was simulated and generated on the basis of PCT and CECT,respectively.The beam flow field that was same with Pref was used to recalculate dose on sCT,and then,the online plan(PPCT)based on PCT,and the online plan(PCECT)based on CECT were obtained,respectively,which can simulate the online dose calculation of MRI-guided online adaptive radiotherapy(oART).The Pref was used as reference to compare dosimetric parameters for target region and organ at risk(OAR)through dose volume histogram(DVH)and planed evaluation indicators.Additionally,three dimension(3D)slicer software was used to perform γ analysis for the results of dose distribution,and explore the differences among PPCT,PCECT and Pref on dose distribution.Results:In terms of image characteristics,the HU values of soft-tissue organs(intestine,bladder,spinal cord,soft tissue)and planning target volume(PTV)in CECT were higher than those in PCT,and the differences of them were statistically significant(Zintestines=-2.188,Zbladder=-3.196,tspinal cord=-3.767,tsoft tissue=-10.083,tPTV=-4.693,P<0.05),while its influence was less on bone tissue.The statistical results of ED were consistent with those of HU.Regarding to dosimetric parameters,there was no statistically significant difference in target coverage rate between PPCT and Pref(P>0.05),and the D50%of the PPCT[(2724.25±19.91)cGy]was higher than that of the Pref[(2718.99±21.13)cGy],and the difference was statistically significant(t=-3.679,P=0.002).However,the target coverage rate of PCECT was 94.65(94.04,95.27)%,and the difference of that between PCECT and Pref was statistically significant(Z=-2.158,P=0.031).For OAR,the differences of Dmax value of the small intestine,and the V20 of the left femoral head between PPCT and Pref were significant(Z=-2.556,-2.529,P<0.05).The differences of the Dmax of small intestine,and the D50%of bladder between PCECT and Pref were significant(t=-4.821,2.171,P<0.05).The comparative γ passed rates of PPCT,PCECT and Pref under the standards of 3 mm/3%and 2 mm/2%were all above 95%,and the differences were not significant(P>0.05).Conclusions:The influence of CECT on dose calculation in MRI-guided oART based on ED assignment method for rectal cancer is relatively small,which can be directly used in the design of reference plan,but the maximum dose of radiation-sensitive organs such as the small intestine should be paid attention.

Objective:To investigate the influence of contrast-enhanced computed tomography(CECT)on dose calculation in magnetic resonance imaging(MRI)-guided online adaptive radiotherapy(oART)based on the electron density(ED)assignment method for rectal cancer.Methods:A retrospective analysis was conducted on the medical data of 15 patients with locally advanced rectal cancer at middle-low segments,who admitted to the Chinese PLA General Hospital between December 2023 and April 2025.All patients underwent both plain computed tomography(PCT)and CECT scans during location.The average HU and ED value of all organs that were extracted from PCT and CECT images in the treatment plan system were obtained,and the influences of contrast agent of intake on image characteristics of the structure of each organ(small intestine,femoral head,bladder)were analyzed.PCT was used as referred image to design reference plan(Pref).The synthetic CT(sCT)was simulated and generated on the basis of PCT and CECT,respectively.The beam flow field that was same with Pref was used to recalculate dose on sCT,and then,the online plan(PPCT)based on PCT,and the online plan(PCECT)based on CECT were obtained,respectively,which can simulate the online dose calculation of MRI-guided online adaptive radiotherapy(oART).The Pref was used as reference to compare dosimetric parameters for target region and organ at risk(OAR)through dose volume histogram(DVH)and planed evaluation indicators.Additionally,three dimension(3D)slicer software was used to perform γ analysis for the results of dose distribution,and explore the differences among PPCT,PCECT and Pref on dose distribution.Results:In terms of image characteristics,the HU values of soft-tissue organs(intestine,bladder,spinal cord,soft tissue)and planning target volume(PTV)in CECT were higher than those in PCT,and the differences of them were statistically significant(Zintestines=-2.188,Zbladder=-3.196,tspinal cord=-3.767,tsoft tissue=-10.083,tPTV=-4.693,P<0.05),while its influence was less on bone tissue.The statistical results of ED were consistent with those of HU.Regarding to dosimetric parameters,there was no statistically significant difference in target coverage rate between PPCT and Pref(P>0.05),and the D50%of the PPCT[(2724.25±19.91)cGy]was higher than that of the Pref[(2718.99±21.13)cGy],and the difference was statistically significant(t=-3.679,P=0.002).However,the target coverage rate of PCECT was 94.65(94.04,95.27)%,and the difference of that between PCECT and Pref was statistically significant(Z=-2.158,P=0.031).For OAR,the differences of Dmax value of the small intestine,and the V20 of the left femoral head between PPCT and Pref were significant(Z=-2.556,-2.529,P<0.05).The differences of the Dmax of small intestine,and the D50%of bladder between PCECT and Pref were significant(t=-4.821,2.171,P<0.05).The comparative γ passed rates of PPCT,PCECT and Pref under the standards of 3 mm/3%and 2 mm/2%were all above 95%,and the differences were not significant(P>0.05).Conclusions:The influence of CECT on dose calculation in MRI-guided oART based on ED assignment method for rectal cancer is relatively small,which can be directly used in the design of reference plan,but the maximum dose of radiation-sensitive organs such as the small intestine should be paid attention.

Objective:To compare the dosimetric parameters under different incremental modes between intensity-modulated radiation therapy(IMRT)and volume rotation intensity-modulated therapy(VMAT)for the target area of large volume brain metastases(BMs),and to explore the better way of treating BMs based on hypofractionated stereotactic radiotherapy(HSRT)of linear accelerator.Methods:A total of 30 BMs patients who underwent IMRT at The 971th Hospital of Navy of the CPLA from 2020 to 2023 were selected.In the treatment planning system(TPS),three types of IMRT plans and VMAT plans were designed,which included uniformity plan(Planuniformity)of target area dose,uniform increased plan(Planuniform increased-dose)and incremental plan(Planincremental)within target area.In the inside of the target area,the target area of high dose(GTVh)was set,and Planuniform increased-dose and Planincremental were designed to aim at GTVh.The differences of the doses of three types of treatment plans included Planuniformity,Planuniform increased-dose and Planincremental,which were respectively designed by using IMRT and VMAT,were analyzed.The mean dose(Dmean)of the target area,the 50%and 2%exposed doses(D50%and D2%)of the target area were observed and compared.The conformity index(CI),homogeneity index(HI),gradient index(GI),and the volume percentage(V10 Gy-V40 Gy)that normal brain tissue received 10 Gy-40 Gy also were observed and compared.Results:Compared with Planuniformity of IMRT,the Dmean of GTV of Planuniform increased-dose and Planincremental of IMRT increased by 10.13%and 17.9%,with statistically significant differences(t=13.680,12.771,P＜0.05).D50%increased by 8.9%and 10.8%,with statistically significant differences(t=15.190,9.929,P＜0.05).D2%increased by 15.2%and 46.4%,with statistically significant differences(t=52.320,8.746,P＜0.05).There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of IMRT(P＞0.05).Compared with Planuniformity of VMAT,the Dmean of GTV of Planuniform increased-dose and Planincremental of VMAT increased by 10.53%and 21.23%,with statistically significant differences(t=18.641,15.461,P＜0.05),and D50%increased by 9.1%and 13.4%,with statistically significant differences(t=11.382,10.952,P＜0.05),and D2%increased by 16.4%and 48.8%,with statistically significant differences(t=56.471,8.685,P＜0.05),respectively.There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of VMAT(P＞0.05).The normal brain tissue V20 Gy,V30 Gy and V40 Gy of Planuniform increased-dose and Planincremental of IMRT were respectively less than those of VMAT,and the differences of them between IMRT and VMAT were significant(tPlan uniform increased-dose=2.112,2.215,2.444,tPlan incremental=2.323,2.939,3.145,P＜0.05).There were no statistically significant difference in D2%,Dmean,and D50%between IMRT and VMAT(P＞0.05).Conclusion:On the premise of ensuring the safety of normal brain tissue at the edge of the target area,the synchronously increasing of the central dose of the target area will not significantly increase the dose for normal brain tissue.Both IMRT and VMAT can meet the requirements of increment in the inside of the target area,and VMAT has slightly better increment and higher efficiency within target area.The incremental of VMAT target area is slightly better,which also has better efficiency,while the enhancement effect of the dose of target area of Planincremental is better than that of the Planuniform increased-dose.The Plan incremental of VMAT is more suitable for HSRT treatment for BMs.

Objective:To investigate the feasibility of segmented total marrow and lymphoid irradiation(TMLI)using Helical TomoTherapy(HT)in adults,and to analyze the impact of positional errors in the treatment on the actually received dose.Methods:Imaging data from four adult patients with acute myeloid leukemia were treated at the First Medical Center of the Chinese PLA General Hospital between November 2022 and December 2024 were retrospectively selected.The prescribed dose was 12 Gy in 3 fractions,and the heights range of patient was from 162 to 178 cm.The planning target volume(PTV)included the entire bone marrow and lymphatic drainage regions.The mid-femur was used as the dividing landmark,and the segmented location of head-in first(upper segmentation)and foot-in first(lower segmentation)were adopted to design plan for each segmentation.The upper segmentation used helical tomotherapy,and the lower segmentation used tomo direct therapy.The dosimetric parameters of planning target volume,and organ at risk(OAR)included eye lens,testicles and lungs were analyzed.The located computed tomography(CT)images of patients were used to simulate the changes of dosimetric parameters of each planning target region and OAR when the positions of patients moved 3,5,10 and 15 mm to outside of rack aperture.The changes of dose distribution of connection region of upper and lower segmentation were further analyzed.Results:The segmented irradiation technique can better achieve the cover(95%)of whole target region of TMLI under the condition of protecting normal organs.Under the condition with different position errors,the cover rate of the most of target region significant decreased.The largest dose of right lens increased 9.272%than primary under the 5 mm position error,and that of left and right lens increased respectively 40.199%and 67.898%under the 10 mm position error,and the max dose and mean dose of testicles increased respectively 5.847%and 5.240%under the 3mm position error.The mean dose of whole lung increased all under the error at different grades,which increased 3.021%under the 10mm position error.The non-uniformity of dose distribution of connection region increased after the position error was introduced,and the largest variation range reached to 4 Gy.Conclusion:The technique of segmented radiotherapy of Helical Tomotherapy has feasibility for TMLI of adult.But the error of the position of patients can reduce the cover of target region,and decrease the control rate for target region,and can lead to the occurrences of excessive doses on eye lens,testicles,lung and other OAR at the same time,which can increase the probability of occurring OAR injury.It should be high pay attention in treatment and implementation.

Objective:To investigate the regulatory role of mesenchymal stem cells(MSCs)on radiation-induced lung injury in mice by the ferroptosis pathway.Methods:The mice were divided into normal control group,MSCs-treated group(MSCs group),single irradiation group(IR group)and IR combined with MSCs group(IR+MSCs group)according to random number table method before irradiation.A mouse model of radiation-induced lung injury was constructed using whole thorax irradiation with cobalt 60(60Co)(20Gy each time),and TNF-α and IL-6 levels of mouse were detected by enzyme-linked immunosorbent assay(ELISA).The injury of lung tissue in mice was assessed using hematoxylin eosin(HE)staining and Masson staining.Western Blot was used to examine the expression levels of ferroptosis-related proteins in lung tissue,including nuclear factor erythroid NF-E2 related factor 2(Nrf2),4-Hydroxynonenal(4-HNE)and glutathione peroxidase 4(GPX4).The expression level of prostaglandin-endoperoxide synthase 2 Gene(PTGS2)in the lung tissue of mice was detected by using quantitative polymerase chain reaction(qPCR),and the level of reactive oxygen species(ROS)in the lung tissue of mice was detected after radiation by using dihydroethidium(DHE),and the level of malondialdehyde(MDA)content in the lung tissue was detected after radiation.And then,the level of oxidative damage in the lung tissue of mice was assessed.Results:Elisa results showed the serum TNF-α and IL-6 levels in mice after irradiation in IR group were significantly higher than those in normal control group(F=53.60,10.65,P＜0.05),respectively.The HE and MSCs staining of pathological analysis showed that MSCs treatment could significantly relieve both early radiation-induced pneumonitis and advanced pulmonary fibrosis.After radiation,the 4-HNE expression level was upregulation and the Nrf2 expression level was downregulation in the lung tissues of mice,whereas MSCs were able to significantly reduce the 4-HNE expression and upregulate the Nrf2 expression.The mRNA expression level and MDA content of the ferroptosis gene PTGS2 were significantly increased,which were significantly higher than those of normal control group,while MSCs were able to significantly reduce its expression,and the differences were statistically significant(F=105.8,7.693,P＜0.05).Conclusion:MSCs is able to relieve significantly ionizing radiation-induced ferroptosis of lung epithelial cells,thereby relieve radiation-induced lung injury.

Objective:To compare and study the improvement of different iterative reconstruction(IR)algorithms of the tomotherapy(TOMO)Radixact system on the image quality of megavoltage computed tomography(MVCT)imaging system,and the influence of that on the precision of automatic registration,and to explore the reconstruction algorithm that is suitable for clinical application.Methods:Using the MVCT imaging system to respectively scan the Tomo-Phantom HE phantom and the Catphan 604 phantom,and to analyze three groups of images were generated by three kinds of reconstruction algorithms,which included the Standard(STD)algorithm,IR General(IR-G)algorithm and IR Soft Tissue(IR-ST)algorithm,in MVCT image.The noise index(NI),uniformity index(UI)of image,modulation transfer function(MTF),low contrast visibility(LCV)index and contrast-to-noise ratio(CNR)of three groups of images were calculated respectively.The Lucy phantom was used to test the accuracy of automatic registration algorithm.The registration data of four dimensions,included left-right(X-axis),head-foot(Y-axis),vertical(Z-axis)and free rotation(Roll)around the Y-axis,were used to conduct verification analysis for the influences of them on the precision of automatic registration.Results:The NI values of IR-G and IR-ST reconstruction algorithms were respectively 39.58±0.10 and 14.62±0.26,which were better than 39.58±0.10 of STD algorithm,and the UI values of them were respectively 19.87±0.83 and 15.84±2.51,which were better than 24.51±1.81 of STD algorithm,and LCV values of them were respectively 2.50±0.03 and 1.74±0.11,which were better than 3.67±0.04 of STD algorithm.All of them appeared significant increase,but the resolution with high contrast of MTF were respectively 0.23 and 0.21,which were lower than 0.32 of STD.The overall image quality of the IR algorithms was superior to that of the STD algorithm.In the accuracy test of the automatic registration algorithm,the registration precisions of IR-G and IR-ST algorithms on Y-axis were respectively(0.360±0.142)mm and(0.245±0.050)mm,which were significantly higher than 0.145±0.136 of STD algorithm,and the differences of them were significant(Z=6.0,15.0,P<0.05).The differences of registration precisions of other directions were not significant(P>0.05).Conclusion:The IR algorithm has advantages in terms of noise,uniformity and resolution with low-contrast,however,it shows reduction on resolution with high-contrast.This reduction of resolution with high-contrast do not lead to the decrease of the precision of automatic registration.

Objective:A dose verification system of two-dimensional semiconductor matrix(SRS MapCHECK)was used to verify the dose of the clinical treatment plan of patients who underwent CyberKnife(CK),which realized rapid verification for individualization of radiotherapy plans of patients through analyzed the γ-passing rates of them.Methods:A total of 253 patients with tumor who received CK clinical treatment in the First Medical Center of Chinese PLA General Hospital from March 2021 to May 2023 were selected.Among of them,121 cases received CK treatment on head,and 30 cases received that on lung,and 102 cases received CK treatment on abdomen and other metastatic tumor.In the MultiPlan treatment plan system,the plan of patient was mapped to the integrated model composed of StereoPHAN model and SRS MapCHECK matrix dose verification system by the means of the plan image center overlap.The dose verification was conducted on the plan of each patient on the basis of ensuring the consistency of the number of beam,direction of beam and the monitor unit.The different γ analysis standards(1%/1 mm,2%/1 mm,3%/1 mm,1%/2 mm,2%/2 mm,3%/2 mm,1%/3 mm,2%/3 mm and 3%/3 mm)were adopted to conduct global analysis of absolute dose for each verification plan,and the threshold(TH)of low dose was set as 10%.Results:The γ passing rates of phantom verification plans of 253 patients were respectively(88.64±5.91)%,(95.43±3.40)%,(97.90±2.06)%,(96.51±2.35)%,(98.15±1.68)%,(99.06±1.12)%,(98.30±1.39)%,(99.09±0.97)%and(99.52±0.63)%under different analysis standards.The γ passing rates of other standards of patients with tumor on different parts were larger than 95%except the analysis result of 1%1 mm standard.The overall analysis result of the deviation of central point dose was(-1.30±2.17)%,among of which the tumor of head,abdominal tumors and other metastatic tumor were about approximately-2%,while that of lung tumors were approximately-3%.The deviation of abdominal and other metastatic tumor was the minimum.The correlation analysis showed that the target volume and the size of the minimum collimator were respectively correlated to the dose deviation of the center.Conclusion:SRS MapCHECK dose verification system can conveniently and quickly realize the individualized verification for the plan of patients who receive CK treatment.

Objective:To quantitatively analyze the differences in image quality and generated synthetic-computed tomography(sCT)between cone beam CT(CBCT)and iteration CBCT(iCBCT),which based on filtered back projection(FBP)and iterative reconstruction(IR)techniques of Varian Ethos adaption system.Methods:Using the special Catphan604 phantom of the test of CT image quality,five times of scanning series of CBCT and iCBCT were respectively performed based on thoracic and abdominal scanning protocols,so as to obtain four sets of images,and each set of image included the CBCT image,the composited sCT and iCBCT images based on CBCT,the composited sCT bases on iCBCT.The noise power spectrum(NPS),image uniformity(UI),modulation transfer function(MTF),low-contrast visibility(LCV)and contrast-to-noise ratio(CNR)of them were analyzed.Additionally,a retrospective analysis was conducted on images of six patients who underwent clinical radiotherapy,and the images of them were obtained by using thoracic and abdominal scanning protocols.The sCT images,which were generated by deformable registrations on the basis of CBCT and iCBCT,were analyzed,and they were compared with located CT images,and their mean absolute error(MAE)and root mean square error(RMSE)were further quantitatively analyzed.Results:Compared to CBCT,iCBCT significantly reduced NPS(thoracic images reduced by 0.08,abdominal images reduced by 0.06).The UI values of thoracic images and abdominal images of iCBCT were respectively 0.37 and 0.28,and those of CBCT were respectively 0.65 and 0.39.The LCV values of thoracic images and abdominal images of iCBCT were respectively 0.67 and 0.56,and those of CBCT were respectively 0.93 and 0.90.The MTF50％were 0.28 lp/mm except abdominal image of iCBCT was 0.29 lp/mm.The resolution rate of high contrast between iCBCT and CBCT was basic consistency.The differences of similarity analysis of the generated sCT and located CT bases on CBCT and iCBCT was no significant(P＞0.05).Conclusion:The image quality of iCBCT is superior to conventional CBCT.The accuracy of CT value of generated sCT bases on CBCT and iCBCT can meet requirement,and both of them can be used in the dose calculation of adaptive radiotherapy.