Objective The aim of this study was to explore the effectiveness of self-made oral humidity detection device to assist in evaluating the degree of parotid gland damage in radiotherapy for nasopharyngeal carcinoma,so as to guide doctors to change the radiotherapy plan in time,reduce the radiation dose to parotid gland,and reduce the incidence of xerostomia after radiotherapy.Methods A retrospective analysis was conducted on the relationship between oral humidity and parotid gland dose of radiotherapy in 60 patients with nasopharyngeal carcinoma using oral detection devices in the Department of Oncology of Southwest Medical University Affiliated Hospital from January 1,2022 to December 31,2022.According to the method of changing the radiotherapy plan,patients were divided into experimental group(n=30)and control group(n=30).The patients in the experimental group used a self-made oral humidity detection device to detect oral humidity,when 30 patients with oral relative humidity below 65%underwent CT simulation positioning and changed the radiotherapy plan to reduce the dose of parotid gland;The control group patients collected oral humidity but did not interfere in the radiotherapy plan,and only underwent CT positioning during the mid-term radiotherapy.The average oral humidity,parotid gland,and target area dose parameters of patients were analyzed after radiotherapy.The follow-up questionnaire was conducted to evaluate the life quality of patients in terms of dry mouth,decreased taste,difficulty opening mouth,and dental caries in two groups.Results The average oral humidity(t=2.938,P<0.05),the Dmean of average dose of bilateral parotid glands(tleft=-2.076,tright=-2.094,P<0.05),the D50 for dose of 50%volume of bilateral parotid glands(tleft=-2.123,tright=-2.230,P<0.05),and the volume percentage V30 of bilateral parotid gland dose(tleft=-2.505,tright=-2.491,P<0.05)in patients were significantly re-duced in the experimental group compared to the control group,while there was no statistically significant differences in target area do-simetric parameters(P>0.05).The dry mouth and taste loss in the experimental group were lower than those of the control group(P<0.05),and the difficulty in opening the mouth and caries scores were lower than those of the control group,but the difference was not statistically significant(P>0.05).Conclusion The oral humidity detection device can detect the oral humidity of radiotherapy pa-tients in time,objectively evaluate the impact of radiation on patient's parotid gland,guide doctors to change the radiotherapy treatment plan in a timely manner,minimize the degree of parotid gland damage,and improve their quality of life in nasopharyngeal carcinoma radiotherapy patients.At the same time,the device is easy to operate,time-consuming,and non-invasive,which improves the effec-tiveness and safety of radiotherapy technology and is worth promoting this device.

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.

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 D_mean 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 D_1000cm³ and D_1500cm³ 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.

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 Ⅱ_B-Ⅲ_A) 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, D_2cc 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.

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.

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.

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.

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.

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.
Algorithms ; Cone-Beam Computed Tomography ; Humans ; Image Interpretation, Computer-Assisted ; Imaging, Three-Dimensional ; Software

BACKGROUND:To date, there are few domestic reports about the influence of bone marrow mesenchymal stem cel s on T cel s proliferation in patients with aplastic anemia. And no study addresses the topic that if bone marrow mesenchymal stem cel s achieve immune regulation in aplastic anemia patients through inhibiting T cel s proliferation.
OBJECTIVE:To explore the effects of human bone marrow mesenchymal stem cel s on T cel s immune regulation in patients with aplastic anemia.
METHODS:Human bone marrow mesenchymal stem cel s were isolated, cultured and subcultivated in vitro. The morphological appearance of bone marrow mesenchymal stem cel s was observed and surface markers were measured by flow cyometry. The bone marrow mesenchymal stem cel s were co-cultured with T cel s extracted from peripheral blood of healthy volunteers and aplastic anemia patients for 7 days. The expressions of interferon-γ, interleukin-4 and interleukin-10 in the supernatants were detected with enzyme linked immunosorbent assay.
RESULTS AND CONCLUSION:The levels of interleukin-2 and interferon-γin the supernatant of aplastic anemia patients were significantly higher (P<0.05), while levels of interleukin-4 and interleukin-10 were significantly lower than that in healthy controls (P<0.05). Bone marrow mesenchymal stem cel s suppressed the elevated levels of interleukin-2 and interferon-γ, and enhanced the decreased levels of interleukin-4 and interleukin-10, thus regulating the immune dysfunction of aplastic anemia patients.