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.

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.

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

When applying deep learning to the automatic segmentation of organs at risk in medical images, we combine two network models of Dense Net and V-Net to develop a Dense V-network for automatic segmentation of three-dimensional computed tomography (CT) images, in order to solve the problems of degradation and gradient disappearance of three-dimensional convolutional neural networks optimization as training samples are insufficient. This algorithm is applied to the delineation of pelvic endangered organs and we take three representative evaluation parameters to quantitatively evaluate the segmentation effect. The clinical result showed that the Dice similarity coefficient values of the bladder, small intestine, rectum, femoral head and spinal cord were all above 0.87 (average was 0.9); Jaccard distance of these were within 2.3 (average was 0.18). Except for the small intestine, the Hausdorff distance of other organs were less than 0.9 cm (average was 0.62 cm). The Dense V-Network has been proven to achieve the accurate segmentation of pelvic endangered organs.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Neural Networks, Computer ; Organs at Risk ; Pelvis ; Tomography, X-Ray Computed

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).

Objective To compare the dosimetric differences between helical tomotherapy (HT) and volume-modulated arc therapy (VMAT) in the treatment of upper thoracic esophageal carcinoma (UTEC).Methods A total of 10 patients with UTEC were randomly selected.HT plan and double-arc VMAT plan were designed and optimized for each patient.The prescription dose was 50 Gy/30 fractions for gross target volume (GTV), 66 Gy/30 fractions for planned target volume (PTV).The dose distribution and conformal index (CI), homogeneity index (HI) of target volume, the D1％, D5％, Dg5％, D99％, and dose of organ at risk (OAR) were analyzed by using the dose volume histogram (DVH).The monitor units and delivery time were also evaluated.Results For GTV and PTV, the D99％ of HT plans were slightly higher than those of VMAT plans (t =4.476, 3.756, P ＜ 0.05) , but no significant differences in D1％ , D5％ , D95％ , HI and CI (P ＞ 0.05) were found.The V10, V15, V20 and mean lung dose (MLD) to the total-lung of HT plans were all significantly lower than those of VMAT plans (t =-3.369,-4.824, -4.869,-3.657, P ＜ 0.05).There were no significant differences for V5, V30 and Dmax of cord (P ＞ 0.05).The monitor units and delivery time of VMAT plans were significantly lower than those of HT plans (t =13.970, 7.982, P ＜ 0.05).Conclusions Both HT and VMAT are appropriate for esophageal cancer radiotherapy.HT significantly reduces the radiation dose of the total-lung, while VMAT has obvious advantages in efficiency.

This study describes the development and implementation of EDR2 film and electronic portal imaging device (EPID) during RapidArc QA. The tests were designed to evaluate RapidArc performance using EDR2 film and EPID tools. The accuracy of MLC position during gantry rotation, the ability to vary and control the dose-rate and gantry speed, the synchronization of variable MLC speed and dose-rate were examined. The picket fence test of MLC in stationary gantry and RapidArc modes were implemented. The film and EPID showed a good consistency. During the evaluation of MLC speed, gantry speed and dose-rates, the dose of different parts in a field showed a good agreement, with the mean deviation of 0.24%vs 0.19%. The analysis of dose value was less than 2%. This study demonstrated that EDR2 film and EPID system can be used as reliable and efficient quality assurance tools for RapidArc delivery performance. Of course, the use of VMAT QA with EPID increases the efficiency of routine QA.

To investigate the dose effect of isocenter difference during IMRT dose verification with the 2D chamber array. The samples collected from 10 patients were respectively designed for IMRT plans, the isocenter of which was independently defined as P(o), P(x) and P(y). P(o) was fixed on the target center and the other points shifted 8cm from the target center in the orientation of x/y. The PTW729 was used for 2D dose verification in the 3 groups which beams of plans were set to 0 degrees. The γ-analysis passing rates for the whole plan and each beam were gotten using the different standards in the 3 groups, The results showed the mean passing rate of γ-analysis was highest in the P(o) group, and the mean passing rate of the whole plan was better than that of each beam. In addition, it became worse with the increase of dose leakage between the leaves in P(y) group. Therefore, the determination of isocenter has a visible effect for IMRT dose verification of the 2D chamber array, The isocenter of the planning design should be close to the geometric center of target.
Gamma Rays ; Humans ; Radiotherapy Dosage ; Radiotherapy, Intensity-Modulated ; instrumentation ; methods