Objective To establish a reliable prediction model for radiation pneumonitis(RP)based on multi-regional radiomics analysis of localizable CT images.Methods A retrospective analysis was conducted on 185 patients who received radiotherapy from January 2021 to June 2023 in the Department of Radiotherapy,Xuzhou Cancer Hospital.Patients were classified as having RP or not based on imaging combined with clinical diagnosis.Three regions of interest(ROI)were defined in the localizable CT images:Lung,Lung-PTV and PTV,and their radiomics features were extracted.After feature screening using methods such as Mann-Whitney Utest,recursive feature elimination,and Lasso,a prediction model was established using support vector machine classification algorithm.The model performance was validated using 6 evaluation metrics:the area under the receiver operating characteristic curve(AUC),accuracy,specificity,sensitivity,positive predictive value,and negative predictive value.Results The prediction model consisted of 7 radiomics features.The clinical model of target-to-lung ratio,PTV model,Lung model,and Lung-PTV model achieved AUC values of 0.535,0.801,0.672,and 0.706 in the test set,respectively.The AUC value and accuracy of PTV model reached 0.843 and 0.775 in the training set,while 0.801 and 0.750 in the test set.PTV model was superior to Lung model,Lung-PTV model,and clinical model in predictive performance.The AUC values of the combined PTV+(Lung-PTV)model in the training and test sets were 0.867 and 0.806,respectively,higher than those of PTV model and Lung-PTV model.Conclusion The predictive ability of the prediction models constructed from radiomics features in different ROI for symptomatic RP varies.The radiomics prediction model using PTV as ROI exhibits superior predictive performance,and the combined multi-regional radiomics model can further improve the predictive ability for RP.

The radiation-free and unmarked body surface monitoring technology is developed for reducing the additional radiation dose generated by positioning error verification during radiotherapy positioning,and further reducing the positioning error and monitoring the displacement deviation of patients during radiotherapy in real time.At present,the widely used optical surface guided radiotherapy technology is also a type of radiotherapy guided by body surface monitoring.The system mainly uses optical imaging equipment as a tool to complete body surface scanning,three-dimensional reconstruction,real-time monitoring,etc.,thereby assisting doctors to carry out radiotherapy more accurately.Herein the study elaborates on the methods,technologies and research results of guided radiotherapy from the aspects of body surface markers,three-dimensional surface imaging systems and mobile devices,and provides prospects for future researches.

Objective To fabricate wall-less vascular tissue mimicking materials(TMM)with different tube diameters that match the hemodynamic parameters of human carotid arteries,and to investigate their hemodynamic characteristics.Methods TMM with different diameters and blood mimicking fluids containing scattering particles were fabricated.The variation laws of hemodynamic parameters under different flow velocities and TMM phantom diameters were verified.Key hemodynamic parameters including peak systolic velocity(PSV),end-diastolic velocity(EDV),and resistance index were measured using Doppler ultrasound,and their clinical application value in carotid artery diseases was evaluated.Results The fabricated samples exhibited a sound velocity of(1506.2±0.1)m/s and an attenuation of(0.76±0.01)dB/cm,and the vascular diameters were 4.0 and 6.0 mm,which corresponded to the normal clinical range of the external and internal carotid arteries,respectively.For the 4.0 mm TMM,both PSV and EDV were linearly correlated with flow velocity(R2=0.77,P<0.001;R2=0.74,P=0.001),and Pearson correlation analysis confirmed strong positive correlations(r=0.89,95%CI:0.82-0.93;r=0.94,95%CI:0.90-0.97,all P<0.001).For the 6.0 mm TMM,PSV and EDV also demonstrated significant linear correlations with flow velocity(R2=0.70,P=0.001;R2=0.61,P=0.005),with Pearson correlation analysis revealing strong positive correlations(r=0.86,95%CI:0.78-0.91;r=0.79,95%CI:0.68-0.87).All the data were consistent with hemodynamic parameters and followed the variation law of hemodynamic parameters.Conclusion The fabricated TMM and blood mimicking fluids meet the requirements for clinical ultrasound research on hemodynamics,and their material ratios can be used as a reference for the subsequent researches with diverse objectives.

Objective To fabricate wall-less vascular tissue mimicking materials(TMM)with different tube diameters that match the hemodynamic parameters of human carotid arteries,and to investigate their hemodynamic characteristics.Methods TMM with different diameters and blood mimicking fluids containing scattering particles were fabricated.The variation laws of hemodynamic parameters under different flow velocities and TMM phantom diameters were verified.Key hemodynamic parameters including peak systolic velocity(PSV),end-diastolic velocity(EDV),and resistance index were measured using Doppler ultrasound,and their clinical application value in carotid artery diseases was evaluated.Results The fabricated samples exhibited a sound velocity of(1506.2±0.1)m/s and an attenuation of(0.76±0.01)dB/cm,and the vascular diameters were 4.0 and 6.0 mm,which corresponded to the normal clinical range of the external and internal carotid arteries,respectively.For the 4.0 mm TMM,both PSV and EDV were linearly correlated with flow velocity(R2=0.77,P<0.001;R2=0.74,P=0.001),and Pearson correlation analysis confirmed strong positive correlations(r=0.89,95%CI:0.82-0.93;r=0.94,95%CI:0.90-0.97,all P<0.001).For the 6.0 mm TMM,PSV and EDV also demonstrated significant linear correlations with flow velocity(R2=0.70,P=0.001;R2=0.61,P=0.005),with Pearson correlation analysis revealing strong positive correlations(r=0.86,95%CI:0.78-0.91;r=0.79,95%CI:0.68-0.87).All the data were consistent with hemodynamic parameters and followed the variation law of hemodynamic parameters.Conclusion The fabricated TMM and blood mimicking fluids meet the requirements for clinical ultrasound research on hemodynamics,and their material ratios can be used as a reference for the subsequent researches with diverse objectives.

The radiation-free and unmarked body surface monitoring technology is developed for reducing the additional radiation dose generated by positioning error verification during radiotherapy positioning,and further reducing the positioning error and monitoring the displacement deviation of patients during radiotherapy in real time.At present,the widely used optical surface guided radiotherapy technology is also a type of radiotherapy guided by body surface monitoring.The system mainly uses optical imaging equipment as a tool to complete body surface scanning,three-dimensional reconstruction,real-time monitoring,etc.,thereby assisting doctors to carry out radiotherapy more accurately.Herein the study elaborates on the methods,technologies and research results of guided radiotherapy from the aspects of body surface markers,three-dimensional surface imaging systems and mobile devices,and provides prospects for future researches.

Objective To establish a reliable prediction model for radiation pneumonitis(RP)based on multi-regional radiomics analysis of localizable CT images.Methods A retrospective analysis was conducted on 185 patients who received radiotherapy from January 2021 to June 2023 in the Department of Radiotherapy,Xuzhou Cancer Hospital.Patients were classified as having RP or not based on imaging combined with clinical diagnosis.Three regions of interest(ROI)were defined in the localizable CT images:Lung,Lung-PTV and PTV,and their radiomics features were extracted.After feature screening using methods such as Mann-Whitney Utest,recursive feature elimination,and Lasso,a prediction model was established using support vector machine classification algorithm.The model performance was validated using 6 evaluation metrics:the area under the receiver operating characteristic curve(AUC),accuracy,specificity,sensitivity,positive predictive value,and negative predictive value.Results The prediction model consisted of 7 radiomics features.The clinical model of target-to-lung ratio,PTV model,Lung model,and Lung-PTV model achieved AUC values of 0.535,0.801,0.672,and 0.706 in the test set,respectively.The AUC value and accuracy of PTV model reached 0.843 and 0.775 in the training set,while 0.801 and 0.750 in the test set.PTV model was superior to Lung model,Lung-PTV model,and clinical model in predictive performance.The AUC values of the combined PTV+(Lung-PTV)model in the training and test sets were 0.867 and 0.806,respectively,higher than those of PTV model and Lung-PTV model.Conclusion The predictive ability of the prediction models constructed from radiomics features in different ROI for symptomatic RP varies.The radiomics prediction model using PTV as ROI exhibits superior predictive performance,and the combined multi-regional radiomics model can further improve the predictive ability for RP.

A dose reconstruction algorithm for electrionic portal imaging device(EPID)based on calibration and calculation is developed.The raw data of EPID in continuous acquisition mode are corrected for dark field and gain,and the gray level features of bright field are used to determine the field boundary.Subsequently,MU calibration,off-axis calibration and field size calibration are performed on the EPID data,and dose reconstruction is carried out based on the calibrated superimposed flux and the Monte Carlo model of the linac head.Nine cases of IMRT plans are selected for verification and measurement using EPID and MapCheck separately,and the passing rates between the two tools are compared under different gamma criteria(3%/3 mm and 2%/2 mm).For a planned case,the average passing rates of multiple cases verified by MapCheck under the two criteria were 99.02%±1.28%and 90.84%±4.49%,and the average passing rates of the EPID reconstruction models were 98.86%±1.19%and 91.39%±4.80%.Compared with MapCheck,the EPID reconstruction algorithm based on calibration and calculation has no significant difference in the passing rate of IMRT plan verification(P＞0.05),which meets the clinical requirements of dose verification.

Objective:To investigate the prediction of the tumor proliferation antigen(Ki-67) expression status in breast cancer patients based on ultrasound radiomics combined with clinicopathologic features.Methods:Breast cancer patients who underwent 2D ultrasound and Ki-67 examination from January 2018 to February 2022 in Changzhou Second People′s Hospital, Nanjing Medical University were retrospectively analyzed. Among them, 427 patients from Chengzhong campus were randomly divided into training and validation sets in the ratio of 8∶2, and 229 patients from Yanghu campus were used as an independent external test set. Radiomics features were extracted from the region of interest of 2D ultrasound images, and the Mann-Whitney U test, recursive feature elimination, and minimum absolute shrinkage and selection operators were used to perform feature dimensionality reduction and to establish a radiomics score(Rad-score). Subsequently, single/multifactor logistic regression regression analyses were used to construct a joint prediction model based on Rad-score and clinicopathological features. Model performance and utility were assessed using the subject operating characteristic area under the curve (AUC), calibration curve, and decision curve analyses. Results:The AUCs of the joint model for predicting Ki-67 expression status in breast cancer in the training, validation, and test sets were 0.858, 0.797, and 0.802, respectively, which were superior to those of the radiomics (0.772, 0.731, and 0.713) and clinical models (0.738, 0.750, and 0.707). Calibration curve and decision curve analyses indicated that the joint model had good calibration and clinical value.Conclusions:A joint model based on ultrasound radiomics and clinicopathological features can effectively predict the Ki-67 expression status of breast cancer, which is expected to become a non-invasive tool for Ki-67 detection and provide clinicians with an important auxiliary diagnostic and therapeutic decision-making basis.

Objective:To evaluate the feasibility of 3D reconstruction techniques based on multi-depth cameras for daily patient positioning in radiotherapy.Methods:Through region of interest (ROI) extraction, filtering, registration, splicing and other processes, multi-depth cameras (Intel RealSense D435i) were used to fuse point clouds in real-time manner to obtain the real optical 3D surface of patients. The reconstructed surface was matched with the external contour of the localization CT to complete the positioning. In this article, the feasibility of the system was validated by using multiple models. Clinical feasibility of 5 patients with head and neck radiotherapy, 10 cases of chest radiotherapy and 5 cases of pelvic radiotherapy was also validated. The data of each group were analyzed by paired t-test. Results:The system running time was 0.475 s, which met the requirement of real-time monitoring. The six-dimensional registration errors in the model experiment were (1.00±0.74) mm, (1.69±0.69) mm, (1.36±0.87) mm, 0.15°±0.14°, 0.25°±0.20°, 0.13°±0.13° in the x, y, z, rotational, pitch and roll directions, respectively. In the actual patient positioning, the mean positioning errors were (0.77±0.51) mm, (1.24±0.67) mm, (0.94±0.76) mm, 0.61°±0.41°, 0.69°±0.55°, and 0.52°±0.35° in the x, y, z, rotational, pitch and roll directions, respectively. The translational error was less than 2.8 mm, and the positioning error was the largest in the pelvic region. Conclusions:Real-time 3D reconstruction techniques based on multi-depth cameras is applicable for patient positioning during radiotherapy. The method is accurate in positioning and can detect the small movement of the patient's position, which meets the requirements of radiotherapy.

Objective A quality control(QC)system based on the electronic portal imaging device(EPID)system was used to realize the Multi-Leaf Collimator(MLC)position verification and dose verification functions on Primus and VenusX accelerators.Methods The MLC positions were calculated by the maximum gradient method of gray values to evaluate the deviation.The dose of images acquired by EPID were reconstructed using the algorithm combining dose calibration and dose calculation.The dose data obtained by EPID and two-dimensional matrix(MapCheck/PTW)were compared with the dose calculated by Pinnacle/TiGRT TPS for γ passing rate analysis.Results The position error of VenusX MLC was less than 1 mm.The position error of Primus MLC was significantly reduced after being recalibrated under the instructions of EPID.For the dose reconstructed by EPID,the average γ passing rates of Primus were 98.86%and 91.39%under the criteria of 3%/3 mm,10%threshold and 2%/2 mm,10%threshold,respectively.The average γ passing rates of VenusX were 98.49%and 91.11%,respectively.Conclusion The EPID-based accelerator quality control system can improve the efficiency of accelerator quality control and reduce the workload of physicists.