Objective To observe the value of artificial intelligence iterative reconstruction(AIIR)for low-dose chest CT images of infants with congenital heart disease.Methods Totally 262 infants with congenital heart disease who would undergo chest CT scanning were prospectively enrolled and randomly divided into low-dose group(n=142)and conventional dose group(n=120).Chest CT scanning with tube voltage of 80 kVp and tube current of 10 mAs was performed in low-dose group,and hybrid iterative reconstruction(HIR,group A)and AIIR(group B)were used to reconstruct images,respectively.In conventional dose group,chest CT scanning with tube voltage of 80 kVp and tube current of 100 mAs was performed,and HIR was used to reconstruct images(group C).Then subjective and objective evaluation on image quality were performed,the results were compared among 3 groups,and the value of AIIR was analyzed.Results Significant differences of image quality and clarity of displaying structures were found among 3 groups(all P＜0.001).Among them,except for the clarity of interlobar fissure,no significant difference of subjective scores was found between low-dose AIIR images and conventional dose HIR images(all corrected P＞0.05),while subjective scores of low-dose HIR images were all lower than those of low-dose AIIR images and conventional dose HIR images(all corrected P＜0.05).Significant differences of standard deviation(SD),signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were found among 3 groups(all P＜0.001)and between each 2 groups(all corrected P＜0.05).The effective dose of low-dose group and conventional dose group was 0.09(0.08,0.10)and 0.85(0.75,1.03)mSv,respectively,and the former was lower than the latter(Z=-13.942,P＜0.001).Conclusion Using AIIR could obtain low-dose chest CT images of infants with quality comparable to conventional chest CT images.

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 observe the value of artificial intelligence iterative reconstruction(AIIR)for low-dose chest CT images of infants with congenital heart disease.Methods Totally 262 infants with congenital heart disease who would undergo chest CT scanning were prospectively enrolled and randomly divided into low-dose group(n=142)and conventional dose group(n=120).Chest CT scanning with tube voltage of 80 kVp and tube current of 10 mAs was performed in low-dose group,and hybrid iterative reconstruction(HIR,group A)and AIIR(group B)were used to reconstruct images,respectively.In conventional dose group,chest CT scanning with tube voltage of 80 kVp and tube current of 100 mAs was performed,and HIR was used to reconstruct images(group C).Then subjective and objective evaluation on image quality were performed,the results were compared among 3 groups,and the value of AIIR was analyzed.Results Significant differences of image quality and clarity of displaying structures were found among 3 groups(all P＜0.001).Among them,except for the clarity of interlobar fissure,no significant difference of subjective scores was found between low-dose AIIR images and conventional dose HIR images(all corrected P＞0.05),while subjective scores of low-dose HIR images were all lower than those of low-dose AIIR images and conventional dose HIR images(all corrected P＜0.05).Significant differences of standard deviation(SD),signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were found among 3 groups(all P＜0.001)and between each 2 groups(all corrected P＜0.05).The effective dose of low-dose group and conventional dose group was 0.09(0.08,0.10)and 0.85(0.75,1.03)mSv,respectively,and the former was lower than the latter(Z=-13.942,P＜0.001).Conclusion Using AIIR could obtain low-dose chest CT images of infants with quality comparable to conventional chest CT images.

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 explore the value of coronary CT angiography (CCTA) in the diagnosis of vulnerable plaques using intravascular ultrasound (IVUS) as the gold standard.Methods:A retrospective analysis was conducted on the clinical and imaging data of coronary artery disease patients who underwent both IVUS and CCTA examinations at Fuwai Central China Cardiovascular Hospital from December 2017 to March 2022. Based on the IVUS results, the coronary plaques were divided into vulnerable and non-vulnerable plaque groups. Finally, 43 patients with a total of 88 coronary artery plaques were included, of which 26 were vulnerable plaques. Plaque analysis were performed on the CCTA images, including qualitative parameters such as low-density plaques (LAP), "napkin-ring" sign (NRS), spotty calcification (SC) and positive remodeling (PR), and the quantitative parameters such as minimum lumen area (MLA), total plaque volume (TPV), lesion length, volume and proportion of calcified plaque and fibrous plaque. The differences of CCTA parameters between the two groups were compared using t-test, chi-square test, and rank sum test. The association between CCTA parameters and the risk of vulnerable plaque was evaluated by logistic regression. Different CCTA parameters were used to establish qualitative, quantitative, and hybrid models, and the diagnostic efficacy of different models for vulnerable plaque was evaluated using the receiver operating characteristic (ROC) curve. Results:There were significant differences in NRS ( χ2=14.22, P<0.001), MLA ( Z=3.25, P=0.001), lesion length ( Z=-3.28, P=0.001), TPV ( Z=-2.04, P=0.041), calcified plaque volume ( Z=-2.52, P=0.012) and fibrous plaque volume ( Z=-2.10, P=0.035) between vulnerable and non-vulnerable plaque groups. The logistic regression analysis showed that NRS ( OR=9.66, 95% CI 2.36-39.54), MLA ( OR=0.76, 95% CI 0.59-0.99) and lesion length ( OR=1.03, 95% CI 1.00-1.07) were independent risk factors for vulnerable plaques. The diagnostic efficacy of the hybrid model based on CCTA parameters was superior to the qualitative model [hybrid model: area under the ROC curve (AUC)=0.82, 95% CI 0.72-0.89; qualitative model: AUC=0.68, 95% CI 0.57-0.78; Z=2.57, P=0.010]. Conclusions:CCTA parameters NRS, MLA, and lesion length are independent risk factors for coronary vulnerable plaques. The diagnostic efficacy of the hybrid model based on CCTA parameters is superior to the qualitative model for vulnerable plaques.

Objective:To investigate the optimal delay time in the quantitative assessment of myocardial fibrosis based on dual-energy CT extracellular volume fraction (DECT-ECV), using MRI as a reference.Methods:Thirty patients with confirmed or suspected of cardiomyopathy were prospectively enrolled in this study. All the patients underwent both cardiac DECT and MRI examination within one week. According to the imaging features of late gadolinium enhancement (LGE) on MRI, myocardial segments were classified into 3 types: ischemic LGE segments, non-ischemic LGE segments and negative LGE segments. According to the DECT delay time, the whole and segmental myocardium were divided into 3 groups: delay of 3 min (Group A), delay of 5 min (Group B) and delay of 7 min (Group C). Correlation and agreement between CT-ECV and MRI-ECV were performed on a basis of overall myocardium and segmental myocardium. Pearson or Spearman test was used for correlation analysis and Bland-Altman test was used for consistency analysis.Results:Thirty patients with 480 segments were finally included in our study. In the analysis based on overall myocardium, MRI-ECV was 33.12%±4.29%, and CT-ECV were 35.81%±4.48%, 36.02%±4.56%, and 36.58%±4.69% in Group A, B, and C, respectively. The agreement between DECT-ECV and MRI-ECV results was good, with the correlation coefficients of 0.878 (group A), 0.955 (Group B) and 0.947 (Group C) (all P<0.001). In the analysis based on segmental myocardium, as for the ischemic LGE myocardial segments, MRI-ECV was 34.60%(31.70%,39.40%), and CT-ECV were 37.50 (34.20, 41.90), 38.20%(36.20%, 40.60%)and 39.40%(35.50%,42.40%)in Group A, B, and C, respectively. The agreement between DECT-ECV and MRI-ECV results was good, with the correlation coefficients of 0.559, 0.695 and 0.682 (all P<0.001) for groups A, B and C, and as for non-ischemic LGE myocardial segments, MRI-ECV was 35.10% (32.68%, 38.70%), and CT-ECV were 38.15% (35.13%, 41.75%), 39.25% (35.78%, 42.20%) and 39.60% (35.88%,42.90%) in Group A, B, and C. The correlation coefficients of CMR-ECV and DECT-ECV of groups A, B and C were 0.531, 0.772 and 0.744 (all P<0.001), showing good agreement; as for negative LGE myocardial segments, MRI-ECV and CT-ECV of Group A, Group B, Group C were 28.50%(27.00%, 30.10%), 31.10%(28.70%, 34.60%), 31.30%(28.40%, 33.80%), 31.30%(29.20%, 34.80%). The correlation coefficients between MRI-ECV and DECT-ECV of group A, B and C were 0.273, 0.508 and 0.425 (all P<0.001), which also showed good agreement. Conclusions:DECT-ECV can be used for quantitative evaluation of myocardial histological features. DECT-ECV with a 5 min and 7 min delay shows good correlation and agreement with MRI-ECV. In order to make this technology more well-known and improve its application capability, our recommendation for clinical practice is a 5 min delay after contrast administration in clinical practice.

Objective:To investigate the clinical value of prospective ECG-gated high-pitch protocol scanning of third generation DSCT in the diagnosis of pediatric congenital heart disease (CHD).Methods:A total of 243 children with confirmed CHD who were expected to undergo surgical treatment were prospectively collected and randomly divided evenly into 3 groups, with first group for prospective ECG-gated high-pitch scanning in third generation DSCT (Flash 3rd), second group for prospective ECG-gated high-pitch scanning in second generation DSCT (Flash 2nd) and third group for prospective sequential scanning in third generation DSCT (Sequence 3rd). The SD value and SNR of aortic root and pulmonary artery of each child were recorded. The 5-point system is adopted with subjective scoring. Based on the result of operation, the diagnosis accuracy in 3 groups was analyzed. Results:The E values in Flash 3rd, Flash 2nd and Sequence 3rd group were 0.24 (0.19, 0.27), 0.11 (0.10, 0.14) and 0.44 (0.39, 0.48) mSv ( H=207.04, P<0.05), respectively. Subjective scores of group Flash 3rd and Sequence 3rd were significantly higher than that of group Flash 2nd [4 (4, 4) vs. 4(3, 4) vs. 3(3, 3), H=124.05, P<0.05] and no difference between these two groups. SD value of aortic root and pulmonary artery of group Flash 3rd and Sequence 3rd were significantly lower than that of group Flash 2nd( H= -40.27-33.38, P<0.05). SNR of aortic root and pulmonary artery of group Flash 3rd was significantly higher than that of group Flash 2nd and Sequence 3rd ( H=-0.90-51.42, P<0.05). Diagnosis accuracy of intracardiac malformation for group Flash 2nd was significantly lower than that of Flash 3rd and Sequence 3rd (77.7%, 90.9%, 88.9%, K=9.36, P<0.05), and there was no significant difference between the latter two groups. There was no difference in diagnosis accuracy of extracardiac malformation among 3 groups (88.6%, 94.8%, 92.2%, K=3.11, P=0.21). Conclusions:The prospective ECG-gated high-pitch scanning in third generation DSCT can take into account radiation dose and image quality, which has important clinical value in the diagnosis of CHD.

To study an automatic plan(AP) method for radiotherapy after breast-conserving surgery based on TiGRT system and and compare with manual plan (MP). The dosimetry parameters of 10 patients and the evaluation of scoring table were analyzed, it was found that the targets dose of AP were better than that of MP, but there was no statistical difference except for CI, The V5, V20 and V30 of affected lungs and whole lungs in AP were lower than all that in MP, the Dmean of hearts was slightly higher than that of MP, but the difference was not statistically significant, the MU of AP was increase by 16.1% compared with MP, the score of AP evaluation was increase by 6.1% compared with MP. So the AP could be programmed and automated while ensuring the quality of the plan, and can be used to design the plans for radiotherapy after breast-conserving surgery.
Breast Neoplasms/surgery* ; Female ; Humans ; Mastectomy, Segmental ; Organs at Risk ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Radiotherapy, Intensity-Modulated

Objective To investigate the plan quality between two treatment planning systems (TPSs) for volumetric modulated arc therapy (VMAT). Methods VMAT plans based on Varian Eclipse and Philips Pinnacle TPS were designed for 10 cervical cancer patients (2, 3 Arcs) and 10 prostate cancer patients ( 1, 2 Arcs) . The delivery system of VMAT was Varian ClinaciX machine, and RapidArc was used. The treatment plan quality between the two TPSs was evaluated based on dose distribution, delivery efficiency, and parameter settings. The differences between the two TPSs were compared using paired t-test. Results For cervical cancer patients, the 2-Arc VMAT plans based on the Pinnacle was slightly better than those based on the Eclipse in terms of the conformal index ( CI) of planning target volume ( PTV) , rectum V30 and V40 , and bladder V30 and V40 , and the homogeneity index ( HI) of PTV and PTV1 as well as CI of PTV1 in the Eclips were slightly better than those in the Pinnacle( P<005) Pinnacle were slightly worse than those in the Eclipse ( P>005) . The number of monitor units with 2-Arcs and 3-Arcs plans of the Eclipse was significantly smaller than those in the Pinnacle (P<005). For prostate cancer patients, The 1-arc VMAT plans of the Pinnacle TPS were slightly superior to those of the Eclipse TPS in terms of the HI of PTV, rectumV30 and V40 , and bladderV30 and V40 , but the former was slight inferior to the latter in terms of the CI of PTV (P<005). The number of monitor units of 1-arc and 2-Arcs plans showed no significant difference between the two TPSs (P>005). Conclusions For patients with cervical cancer and prostate cancer, the VMAT plans based on Varian Eclipse and Philips Pinnacle TPS can achieve a clinically acceptable dose distribution and show a little difference in the treatment plan quality. However, we will still need more cases to further study and determine the performance characteristics of the commercial TPSs for optimizing VMAT.

The treatment plans were designed based on planning CT of Catphan phantom's homogenic and heterogenetical module, respectively. With the OBI system, Catphan phantom was scanned under different scanning conditions. The dose was recalculated by applying treatment plans based on planning CT to the CBCT images with its individual hounsfield unit-electron density calibration curve. The dose distributions were compared with those of the original plan, the results ofHI showed a good agreement.CIs in the homogenic module were superior to those in the heterogenetical one. There is a good dose distribution for CBCT images under different scanning conditions. It is helpful for CBCT images directly used for dose re-calculation in adaptive radiation therapy (ART).