Objective To construct a machine learning model for predicting benign and malignant pulmonary nodules based on CT features.Methods A total of 129 patients with single solid nodules on CT from January 2021 to January 2023 in Hai'an People's Hospital were selected.All of them underwent chest CT scan,and the quantitative parameters,morphological features and radiomics features were recorded.The differentiation of benign and malignant pulmonary nodules was carried out according to relevant diagnostic criteria.The cases were divided into the training set and the internal test set.The constructed models included radiomics labels,morphological model,CT model and combined model.Results There were 98 cases in the training set(27 malignance and 71 benign)and 31 cases in the internal test set(7 malignance and 24 benign).Univariate analysis showed that there were significant differences in age,lesion diameter,mean density,burr sign,pleural depression sign,vacuole sign and air bronchial sign between malignant group and benign group(P<0.05).Compared with benign group,malignant group had higher proportions of burr sign,pleural depression sign,vacuole sign,air bronchial sign,and larger lesion diameter and mean density(P<0.05).LinkDocAI intelligent diagnosis system for pulmonary nodules was used to outline regions of interest and from which 1 000 radiomics features were extracted.The feature selection was performed in 98 cases,and 20 features were screened out after standardized treatment and correlation testing,excluding missing features,low importance feature values and highly correlated features.Through LASSO regression and 10-fold cross validation,λ1se was selected as the optimal λ to construct radiomics labels,and the two most meaningful features(LBP_Glszm_ZoneEntropy and Gradient_Shape_MinorAxis)were enrolled.CT model was considered as the optimal model in this study,and it had an area under receiver operating characteristic curve of 0.912 and 0.889 in the training set and the internal testing set,respectively.Conclusion The machine learning model to predict benign and malignant lung nodules based on CT features has good predictive efficiency,and it can realize the differential diagnosis of benign and malignant pulmonary nodules.

We use a dense and fully connected convolutional network with good feature learning in small samples, to automatically pre-deline CTV of cervical cancer patients based on CT images and evaluate the effect. The CT data of stage IB and IIA postoperative cervical cancer with similar delineation scope were selected to be used to evaluate the pre-sketching accuracy from three aspects:sketching similarity, sketching offset and sketching volume difference. It has been proved that the 8 most representative parameters are superior to those with single network and reported internationally before. Dense V-Net can accurately predict CTV pre-delineation of cervical cancer patients, which can be used clinically after simple modification by doctors.
Automation ; Female ; Humans ; Machine Learning ; Patients ; Tomography, X-Ray Computed ; Uterine Cervical Neoplasms/diagnostic imaging*

Objective To explore the feasibility of the volume modulated arc therapy ( VMAT) auto-planning based on template library ( TL). Methods VMAT plans of 68 patients diagnosed with postoperative rectal cancer in Eclipse system were retrospectively selected. The prescription dose was 50 Gy/25F. In 19 patients, the feature values of target and organs at risk were extracted as the vectors. The final optimized restricted conditions were saved as the TL. Then, the plans of 15 rectal cancer patients (10 cases from TL and 5 outside TL) were automatically optimized. According to the multi-dimensional vector similarity principle, the similarity parameter αwas defined. The designed program automatically selected the optimal-object template in an in-house software developed with Matlab. The dosimetric parameters of the auto-optimized plans with the optimal-object template (ATP) and the clinical plan (CP) were compared by the paired t-test. The changes in the dosimetric parameters and similarity parameter α were statistically compared by Pearson′s correlation analysis. The linear fitting of the dosimetric parameters with α was used by least squares method to explore the tendency of the ATP dosimetric parameters relative to CP. Results The dosimetric parameters of ATP for 13 cases were slightly worse than those of CP. The conformal index (P=0. 004), heterogeneous index (P= 0. 015),V40(P= 0. 003) and mean dose (P= 0. 022) of the intestine significantly differed. The α values of these 13 cases were 2. 67,2. 60,2. 60,2. 49,2. 67,2. 74,2. 72,2. 48, 2. 53,2. 86,2. 68,2. 56 and 2. 63. The α value was significantly correlated with the V40 or mean dose of the bladder (r= 0. 649 and 0. 603,P= 0. 016 and 0. 029).Along with the increase of α value ,V40 and mean dose of the intestine for ATP were gradually deteriorated than those of CP . The remaining dosimetric para-meters of ATP were close to or superior to those of CP. Conclusions The results of ATP are slightly worse than those of CP, whereas can satisfy the clinical requirements. The TL, the quality of TL and ATP remain to be further optimized.

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.

Objective To study the difference of the constructed doses between electronic portal imaging device (EPID) and dynalogs files of linac for in vivo phantom dosimetry.Methods Twelve pelvic patients treated with volumetric modulated arc therapy (VMAT) plans were selected and the information of each plan was copied to theCheese phantom to recalculate the doses before delivered on Varian RapidArc Linac.TheCheese phantom was placed on the isocenter and the electronic portal image (EPI) formed by the EPID was sent to EPIgray software to reconstruct the actual delivered doses.Meanwhile,dynalogs files were respectively imported to the Mobius software to reconstruct the actual delivered doses too.The point dose in the center of each VMAT plan (the center of the effective sensitive volume of ionization chamber) was measured by the A1SL ionization chamber.At the same time,the dose of sensitive volume of ionization chamber from treatment planning systcm (TPS) was recorded.Results The relative deviation between the dose from TPS and the measurement results by the ionization chamber was 1.13％.The difference between the reconstructed doses of EPID-based or the dynalogs file-based with the measurement results by the ionization chamber was not statistically significant (P ＞ 0.05).Conclusions The two methods of dose reconstruction can provide reference for in vivo dosimetry of VMAT.

Objective To investigate the dosimetric feasibility of volumetric modulated arc therapy (VMAT)with a simultaneous integrated boost(SIB-VMAT58.75 Gy)for preoperative chemoradiotherapy in patients with locally advanced rectal cancer(LARC),and to provide a basis for clinical practice.Methods Nine patients with stage Ⅱ-Ⅲ rectal cancer who underwent preoperative concurrent chemoradiotherapy were involved in the study,and two plans were performed for each patient:SIB-VMAT58.75 Gy and VMAT50.00 Gy. For the SIB-VMAT58.75 Gy plan,the prescribed dose was 58.75 Gy(2.35 Gy/fraction)for the local rectal tumor and positive lymph nodes(GTV 58.75 Gy),and 50 Gy(2 Gy/fraction)for the regions at high risk of harboring microscopic disease(pelvic lymphatic drainage area)(PTV 50Gy).For the VMAT50.00 Gy plan,the prescribed dose was 50 Gy(2 Gy/fraction)for the regions at high risk of harboring microscopic disease(pelvic lymphatic drainage area)without a boost. The conformity index(CI),homogeneity index (HI),and dose for target areas and organs at risk(OAR)were assessed according to the dose-volume histogram. The paired t-test or nonparametric rank test was used to compare the differences between the two plans. Results Both plans met the prescription goal for PTV dose coverage. There was no significant difference in CI for the PTV between the two plans(1.0±0.0 vs. 1.0±0.0,P>0.05).The SIB-VMAT58.75 Gy plan had a worse HI than the VMAT50.00 Gy plan(0.2± 0.2 vs. 0.1± 0.0,P<0.05).There was no significant difference in V10-V50of the small intestine,bladder,femoral heads,and pelvis between the two plans(P>0.05),but D 2 cm3of the small intestine was significantly higher in the SIB-VMAT58.75 Gy plan than in the VMAT50.00 Gy plan(P=0.038). Conclusions The SIB-VMAT58.75 Gy plan for LARC achieves required target volume dose coverage and OAR dose constraints,which is safe and feasible in terms of dosimetry,and its clinical efficacy and adverse effects need further evaluation.

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 evaluate the cone beam CT (CBCT) image quality and its long-term stability for HUs under different scanning conditions.Methods With the OBI system, Catphan 504 phantom using the different modes was scanned through one year. Analysis of variance (ANOVA) was used to evaluate the CBCT images.Results The results of contrast resolution under different scanning conditions met the requirements of acceptance test procedure. Spatial contrast resolution(≥5 lp/cm) of half-fan scanning conditions were inferior to those (≥7 lp/cm) of ful-fan mode. The accuracies of spatial linear distance and angle were within±1%. HUs in air density plug were constant, but HUs of other plugs with different conditions had the signifi cant difference (F=660.84,P=0). Under different conditions in a year, the mean HUs showed a good agreement.Conclusions HUs of CBCT image under different scanning conditions exist a little difference, but there is a good consistency for the long term stability analysis. It is helpful for CBCT images directly used for dose re-calculation in adaptive radiation therapy (ART).

Objective Evaluation of intensity-modulated radiation therapy(IMRT) delivery quality assurance(DQA) using EDOSE software based on accelerator electronic portal imaging device (EPID).Methods Analysed the dose response uniformity correction of EPID imaging plate in different fields and the gamma pass rates about the fields; And compared the calculated parameters of the EDOSE and the Pinnacle planning station.Results The uniformities on the homogeneous region of thefi elds are good after who corrected by EDOSE. The gamma(γ, 3mm/3%) pass rates are in the ideal range. The volume of the organs at risk(OAR) have no statistical signifi cance except the right lung; A part of the parameters have statistical signifi cance.Conclusions The results of the calculation and analysis of EDOSE has a high agreement with the planning system.

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.