COPD identification using maximum intensity projection of lung field CT images and deep convolution neural network / 中华健康管理学杂志

Objective:To propose a model using the maximum intensity projection (MIP) of lung field computed tomography (CT) images and deep convolution neural network (CNN) and explore its value in identifying chronic obstructive pulmonary disease (COPD).Methods:A total of 201 subjects were selected from the Second Hospital of Dalian Medical University from January 2010 to May 2021. All subjects were included according to the inclusion criteria and were divided into COPD group (101 cases) and healthy controls group (100 cases). Each patient underwent a high-resolution CT scan of the chest and pulmonary function test. First, the lung field was extracted from CT images and the intrapulmonary MIP images were acquired. Second, with these MIP images as input, the model for identifying COPD was constructed based on a modified residual network (ResNet). Finally, the influence of the number of residual blocks on the performance of the models was investigated. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the identification efficiency.Results:The accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of ResNet26 was 76.1%, 76.2%, 76.0%, 76.2%, and 76.0%, respectively; and the AUC of the test was 0.855 (95% CI: 0.799-0.901). The accuracy, sensitivity, specificity, PPV, NPV of ResNet50 was 77.6%, 76.2%, 79.0%, 78.6%, and 76.7%, respectively; and the AUC of the test was 0.854 (95% CI: 0.797-0.900). The accuracy, sensitivity, specificity, PPV, NPV of ResNet26d was 82.1%, 83.2%, 81.0%, 81.6%, and 82.7%, respectively; and the AUC of the test was 0.885 (95% CI: 0.830-0.926). Conclusions:The COPD identification model via MIP images from CT images within the lung and deep CNN is successfully constructed and achieves accurate COPD identification. And it can provide an effective tool for COPD screening.

Dosimetric Analysis of Template-assisted 192Ir-source Hypofractionated Stereotactic Ablative Brachytherapy for Peripheral Lung Cancer / 肿瘤防治研究

Objective To explore the dose of template-assisted 192Ir source hypofractionated stereotactic brachytherapy (SABT) for peripheral lung cancer. Methods We retrospectively analyzed the dose parameters of GTV and OARs of 28 peripheral lung cancer patients treated with template-assisted 192Ir-source hypofractionated SABT, and compared the dose parameters between SABT with virtual SBRT. Results The Dmean and V150 for the GTV in the SABT plan were significantly higher than those in the SBRT plan (all P < 0.01). For OARs, all dosimetric parameters in the SABT plan were significantly lower than those in the SBRT plan (all P < 0.01), except for the D1000cm3 and D1500cm3 for the lung (P > 0.05). Conclusion Template-assisted 192Ir source hypofractionated SABT ensures high dose in the gross tumor volume and reduces the dose in organs at risk in the treatment of peripheral lung cancer.

Preliminary observation of the safety of template-assisted 192Ir source hypofractionated stereotactic ablative brachytherapy for locally advanced non-small cell lung cancer / 中华放射肿瘤学杂志

Objective@#To preliminarily evaluate the safety of the coplanar template-assisted 192Ir hypofractionated stereotactic ablative brachytherapy (SABT) in patients with locally advanced non-small cell lung cancer (LA-NSCLC), and assess the effect of template-assisted technology upon the accuracy of SABT by comparing the consistency of dosimetric parameters between preoperative and operative plans.@*Methods@#Fifteen patients histologically confirmed with LA-NSCLC (stage ⅡB-ⅢA) were recruited and received the template-assisted SABT delivered in a risk-adapted fractionation (30 Gy/1F). Preoperative planning, template-assisted needle implantation, operative planning and implementation were performed in all patients. Dosimetric results of preoperative and operative plans were statistically compared by assessing the dosimetric parameters of gross tumor volume (HI, CI, D90, V100 and V150) and organ at risk(V5, V20 and mean dose of bilateral lung, D2cc of spinal cord. The incidence of perioperative complications of SABT was recorded. The safety and feasibility of SABT were evaluated.@*Results@#Slight changes were noted in terms of target dose and irradiated dose to the lung between preoperative and operative plans without statistical significance (both P>0.05). No severe adverse events, such as severe pneumothorax, hemothorax and hemoptysis were observed.@*Conclusions@#Application of the template-assisted SABT can enhance the accuracy of implantation, maintain the consistency of the dosimetric parameters between the preoperative and operative plans and guarantee the clinical efficacy.

Preliminary observation of the safety of template-assisted 192Ir source hypofractionated stereotactic ablative brachytherapy for locally advanced non-small cell lung cancer / 中华放射肿瘤学杂志

Objective To preliminarily evaluate the safety of the coplanar template-assisted 192Ir hypofractionated stereotactic ablative brachytherapy (SABT) in patients with locally advanced non-small cell lung cancer (LA-NSCLC),and assess the effect of template-assisted technology upon the accuracy of SABT by comparing the consistency of dosimetric parameters between preoperative and operative plans.Methods Fifteen patients histologically confirmed with LA-NSCLC (stage ⅡB-ⅢA) were recruited and received the template-assisted SABT delivered in a risk-adapted fractionation (30 Gy/1F).Preoperative planning,template-assisted needle implantation,operative planning and implementation were performed in all patients.Dosimetric results of preoperative and operative plans were statistically compared by assessing the dosimetric parameters of gross tumor volume (HI,CI,D90,V100 and V150) and organ at risk (V5,V20 and mean dose of bilateral lung,D2cc of spinal cord.The incidence of perioperative complications of SABT was recorded.The safety and feasibility of SABT were evaluated.Results Slight changes were noted in terms of target dose and irradiated dose to the lung between preoperative and operative plans without statistical significance (both P＞0.05).No severe adverse events,such as severe pneumothorax,hemothorax and hemoptysis were observed.Conclusions Application of the template-assisted SABT can enhance the accuracy of implantation,maintain the consistency of the dosimetric parameters between the preoperative and operative plans and guarantee the clinical efficacy.

Relationship between the overlap volume of organ at risk and target and the dose to organ at risk in intensity-modulated radiotherapy / 中华放射肿瘤学杂志

Objective To explore the relationship between the overlap volume of organ at risk (OAR) and target (Voverlap) and the mean dose to OAR (DmOAR) in intensity-modulated radiotherapy (IMRT).Methods Fifty randomly selected patients undergoing IMRT for nasopharyngeal carcinoma (NPC) and an equal number of patients undergoing radical IMRT for cervical cancer in our hospital were enrolled as subjects.The relationship between Voverlap and DmoAR in IMRT was analyzed.The Matlab software was used to generate function to fit the relationship between Voverlap and DmOAR for different OARs.Results The Voverlap varied among patients with NPC or cervical cancer.The ratio of Voverlap to the volume of OAR (VOAR) was positively correlated with the ratio of DmOAR to the prescribed dose (Dp) (all P=0.01).A function was generated to fit the correlation between Voverlap/VOAR ratio and DmOAR/Dp ratio.Conclusions In IMRT,patients have different Voverlap/VoAR ratios due to varicd target volume,disease stages,OAR filling status,and OAR volume.As criteria for plan verification,a specific DmOAR value for each OAR should be calculated before radiotherapy planning based on the corresponding correlation function and the Voverlap/VoAR ratio with a fixed dose prescription.It can be used to reduce the subjective influence on the optimization of radiotherapy planning.

Effect of needle arrangement on the lung dose in interstitial brachytherapy for lung cancer / 中华放射肿瘤学杂志

Objective To analyze the effect of needle arrangement on the lung dose in interstitial brachytherapy for lung cancer. Methods For 15 patients undergoing interstitial brachytherapy for lung cancer, a virtual radiotherapy plan in which needle arrangement was not restricted by the ribs was designed and compared with the original plan. For the two plans, V5, V20, V30, and mean lung dose(MLD)of the whole lung were determined when the prescribed doses were 10,30, 60, and 120 Gy, respectively. The data were analyzed by Wilcoxon signed-rank test. Results The lung V5,V20, V30, and MLD were significantly smaller in the virtual plan than in the actual plan(all P<0.05). Conclusions Irregular needle arrangement prevents a further reduction in the lung dose in interstitial brachytherapy for lung cancer. In the implantation surgery, therefore, the needles should be arranged as regularly as possible.

Level set motion-based elastic registration of 3D CT images in radiotherapy / 中国医学装备

Objective: To apply level set motion-based elastic registration method to radiotherapy CT image, then to provide technical support for the accurate evaluation of tumor and changing process of patients with endanger organ and its accumulative dose. Methods: Based on Vemuri’s level set motion method, we wrote the algorithm program using Matlab software and applied on two sets of 3D CT images from patients with cervical cancer and NPC for fully automatic elastic registration. Results: Comparing CT images before and after registration, for the cervical cancer patient, the minimum mean square error (MSE) decreased by 55.1%and correlation coefficient (CC) increased by 5.3%. For the NPC patient, MSE decreased by 32.1%and CC increased by 4.6%. Conclusion: From the image difference and evaluation parameters, the efficacy of level set motion-based elastic registration method was preliminarily demonstrated. In order to apply this method to clinical radiotherapy, dit needs to find a more accurate mathematical algorithm further in order to compute human anatomy deformation through image motion.

A study of the iso-center point coincidence between accelerator and radiotherapy planning system / 中华放射肿瘤学杂志

Objective To study the iso-center point coincidence of two accelerators with treatment planning system (TPS) based on γ passing rates of intensity-modulated radiotherapy (IMRT) plan verification.Methods Twenty-one IMRT plans were verified by Varian accelerator and twenty by Elekta accelerator with a gamma criterion of 3 mm/3％.The passing rates were measured when the iso-center point of TPS had-2,-1,0,1,and 2 mm shift in the x or y direction.A binomial curve of γwas fit to figure out the values of the two accelerators on the x and y axes when γ value reached the maximum.The γ pass rate difference was analysed by x2 test.Results The mean values of γ-2,γ-1,γ0,γ1,and γ2 in the x direction were (92.56±3.27) ％,(96.53± 1.82) ％,(96.13± 1.41) ％,(90.14± 2.87) ％,and (82.28± 4.69) ％ for Varian accelerator,and (94.82± 2.04) ％,(97.05± 2.02) ％,(98.38± 1.33) ％,(97.96± 1.44) ％,and (94.49±2.34)％ for Elekta accelerator.There was no significant difference in the mean value of γ0between the two accelerators (P=0.332).When γvalue reached the maximum,the values on the x and y axes were0.65 and-0.30 mm for Varian accelerator and 0.01 and 0.30 mm for Elekta accelerator,respectively.Conclusions In the same TPS,different accelerators have different degrees of coincidence of the actual field center point with the iso-center point of TPS,to which more attention should be paid in clinical practice.

Application of elastic registration based on Demons algorithm in cone beam CT / 生物医学工程学杂志

We applied Demons and accelerated Demons elastic registration algorithm in radiotherapy cone beam CT (CBCT) images, We provided software support for real-time understanding of organ changes during radiotherapy. We wrote a 3D CBCT image elastic registration program using Matlab software, and we tested and verified the images of two patients with cervical cancer 3D CBCT images for elastic registration, based on the classic Demons algorithm, minimum mean square error (MSE) decreased 59.7%, correlation coefficient (CC) increased 11.0%. While for the accelerated Demons algorithm, MSE decreased 40.1%, CC increased 7.2%. The experimental verification with two methods of Demons algorithm obtained the desired results, but the small difference appeared to be lack of precision, and the total registration time was a little long. All these problems need to be further improved for accuracy and reducing of time.

Changes of rectal volume and location and their influence on rectal dose during the course of intensity-modulated radiotherapy of cervical cancer / 中华放射肿瘤学杂志

ObjectiveTo investigate the anatomical changes and dose variation of rectum during radiotherapy in patients with cervical cancer.Methods Ten patients with cervical cancer underwent intensity-modulated radiotherapy using online cone beam computed tomography (CBCT) before each fraction.Rectum was contoured on each CBCT and projected onto the planning CT to analyze the changes of the rectal volume and position.The rectal volume receiving ≥ 45 Gy ( V45 ) was evaluated accordingly.Results227 CBCT images in 10 patients were collected.The rectal volume changed from ( 35.0 ± 7.3)cm3 to (97.7±14.7) cm3.The shift of rectal center was (0.14 ±0.06) cm in left and right direction,(0.24±0.10) cm in anterior and posterior direction,and (0.55±0.28) cm in superior and inferior direction.The V45 of rectum varied from (9.19±2.46)％ to (60.54 ±11.67)％.In7 of the 10 patients,rectal volume and V45 of the rectum had significant positive correlation (r =0.582 - 0.743,all P ＜ 0.01 ).Among the 227 images,the V45 of rectum was ≤50％ in 68 images (30.0％ ).ConclusionsSignificant changes in rectal volume and position occurred during fractionated radiotherapy in patients with cervical cancer,which resuhs in variations in the dose rectum received.For most patients,rectal volume and the V45of rectum had significant positive correlation.

A clinical study for radiotherapy positioning with references images on CT simulator / 中华放射肿瘤学杂志

Objective To explore a new method of comparing the references images first to enhance the precision of the central point of the radiation treatment planning(RTP), try to establish a reference standard for this method in the nasopharyngeal cancer(NPC)and carcinoma of utercin cervix in the work of position verification. Methods For 50 RTPs of NPC and 20 RTPs of carcinoma of utercin cervix, the reference-CT-images in set-up and in position verification were compared, and to measure the difference between the two images. Then, in the same way, compare and measure the difference in the central-pointimages. Results For NPC, there was over 90% RTPs in which every difference measured was less than 2 mm;for carcinoma of utercin cervix, over 80% RTPs meet the criterion:the value of △MU1 ' or △MU2' was less than 5 mm and the others are less than 3 mm. Conclusions By comparing the references-CT-images in set-up and in position verification, the precision of the central point of the RTP is enhanced. The marks on the skin become more credible. So, it is feasible to perform the criterions in the work of position verification:for NPC every difference measured is less than 2 mm;for carcinoma of utercin cervix the value of △MU1 ' or △MU2 ' is less than 5 mm and the others are less than 3 mm.

Bladder anatomical changes and dose variation during the course of intensity-modulated radiation therapy of cervical cancer / 中华放射肿瘤学杂志

Objective To investigate bladder anatomical changes and dose variation in patients with cervical cancer.Methods We analyzed 20 patients,undergoing external beam radiotherapy scanning cone beam CT(CBCT)before each fraction.Bladder was contoured on each CBCT,was projected onto the planning CT and assesses anatomical changes and dose variation.Results A total 451 CBCT images,for 20 patients were collected for analysis,show more change in bladder volume and position.In 15 cases bladder volume and V45 had no significant correlation(r=0.225 -0.473,all P>0.05),4 cases shows negative correlation(r=-0.564,P<0.05;r=-0.597,P<0.01;r=-0.942,P<0.01;r=-0.816,P<0.01),1 case shows positive correlation(r=0.662,P<0.01).Have more than the criteria(V45≤50%)number is 64/451(14.2%)in whole treatment.Conclusions For most patients by filling adequacy bladder,bladder dose variation is acceptable:CTV lager for individual patients should be closely observed its regression,implementation of the offline or online calibration.