Objective To develop a convolutional neural network based model for predicting the dose distribution of intensity-modulated radiotherapy(IMRT)in cervical cancer,and to evaluate its potential applications in automated treatment planning.Methods The pelvic IMRT plans for 100 female patients were collected,with 80 cases in the training set,10 in the validation set,and 10 in the test set.A dose prediction model was built based on the three-dimensional(3D)residual network for forecasting 3D dose distribution.Masks for organs-at-risk and planning target areas were extracted from CT images and RT Structure files.Density values were assigned to different structures according to a density map,and the resulting CT maps were used as input images for model training.The optimal model was used to predict the 3D dose distribution,and the predicted results were compared with the dose distribution from manual treatment planning in terms of dosimetric parameters.Results The experimental results on the 10-case test set demonstrated that dosimetric parameter differences were insignificant and within clinically acceptable ranges.The mean absolute error,average Dice similarity coefficient,and 95%Hausdorff distance for 10 cases in test set were(0.58±0.16)Gy,0.90±0.03,and(10.61±7.17)mm,respectively.Compared with manual planning,prediction model showed slightly decreased rectal V45,small bowel D2cc,and the V20 of bilateral femoral heads was reduced.The predicted D95 of planning target area was lower than manual planning,but the differences in D90,homogeneity index,and conformity index were trivial.There were minor differences in 3D dose distributions between the two,and the dose distribution generated by prediction model met clinical requirements.Conclusion The convolutional neural network based dose prediction model can accurately forecast the dose distribution for cervical cancer IMRT,exhibiting the potential to be used in automated treatment planning and quality evaluation.

Objective To develop a convolutional neural network based model for predicting the dose distribution of intensity-modulated radiotherapy(IMRT)in cervical cancer,and to evaluate its potential applications in automated treatment planning.Methods The pelvic IMRT plans for 100 female patients were collected,with 80 cases in the training set,10 in the validation set,and 10 in the test set.A dose prediction model was built based on the three-dimensional(3D)residual network for forecasting 3D dose distribution.Masks for organs-at-risk and planning target areas were extracted from CT images and RT Structure files.Density values were assigned to different structures according to a density map,and the resulting CT maps were used as input images for model training.The optimal model was used to predict the 3D dose distribution,and the predicted results were compared with the dose distribution from manual treatment planning in terms of dosimetric parameters.Results The experimental results on the 10-case test set demonstrated that dosimetric parameter differences were insignificant and within clinically acceptable ranges.The mean absolute error,average Dice similarity coefficient,and 95%Hausdorff distance for 10 cases in test set were(0.58±0.16)Gy,0.90±0.03,and(10.61±7.17)mm,respectively.Compared with manual planning,prediction model showed slightly decreased rectal V45,small bowel D2cc,and the V20 of bilateral femoral heads was reduced.The predicted D95 of planning target area was lower than manual planning,but the differences in D90,homogeneity index,and conformity index were trivial.There were minor differences in 3D dose distributions between the two,and the dose distribution generated by prediction model met clinical requirements.Conclusion The convolutional neural network based dose prediction model can accurately forecast the dose distribution for cervical cancer IMRT,exhibiting the potential to be used in automated treatment planning and quality evaluation.

Care dependence refers to a complex and comprehensive state of being dependent on others due to the limita-tion of physical functions caused by the disease.Elderly stroke patients are high risk group for care dependence due to decrease in self-care ability caused by their disease characteristics.Therefore,this paper reviews the current research status,influencing factors,and interventions of care dependence,in order to provide reference for increasing attention to the care needs of elderly stroke patients,reducing their dependence,and improving their quality of life.

Adult ; Humans ; Retrospective Studies ; Pneumonia ; Community-Acquired Infections/epidemiology* ; Hospitalization

Objective:To evaluate the 3-year survival outcomes and late injury between the self-designed patent single-channel applicator, which was modified from the traditional tandem applicator and wrapped with a oval-shield alloy around the source channel and standard Fletcher-type applicator in the high-dose-rate brachytherapy for cervical cancer.Methods:Patients initially diagnosed with cervical cancer in the Affiliated Hospital of Southwest Medical University from December 2011 to April 2017 were enrolled and randomly assigned into the external beam radiotherapy (EBRT)+ single-channel intracavitary applicator group (the patent single-channel group) and EBRT+ the Fletcher applicator group. The whole pelvis irradiation was delivered with 6-MV photons via a four-field box variant or anterior and posterior parallel fields. Five to six fractions of intracavitary brachytherapy were performed at a dose of 7 Gy at point A once a week after 30 Gy (Equivalent Dose in 2 Gy at point A: 80-90 Gy). Chemotherapy was given with intravenous injection of cisplatin at a dose of 40 mg/m 2 once weekly during EBRT. Clinical efficacy and safety were evaluated after corresponding treatment. Results:In total, 150 eligible cases were assigned into the Fletcher applicator group and 149 cases into the patent single-channel group. Up to December 2020, all patients had been followed up for 3 years, and the median duration of follow-up was 61 months. In the Fletcher group, the 3-year overall survival, progression-free survival and locoregional failure-free survival was 76.3%, 78.1% and 75.4%, and 83.8%, 80.3% and 85.5% in the single-channel group, respectively. In the Fletcher group, the cumulative rate of grade 3-4 late rectal complications was 3.3% and 6.7% in the single-channel group ( P=0.122). The cumulative rate of grade 3-4 bladder complications was 1.3% in the Fletcher group and 0.7% in the single-channel group ( P=1.000). Conclusion:The self-designed patent single-channel intracavitary applicator yields equivalent long-term clinical efficacy and safety to the standard Fletcher-type three-channel applicator in the HDR brachytherapy for uterine cervical cancer.

Objective: To evaluate whether the self-designed single-channel intracavitary applicator yields equivalent clinical efficacy and safety to the standard Fletcher-type three-channel applicator in the high-dose-rate (HDR) brachytherapy for uterine cervical cancer. Methods: From December 2011 to April 2017, patients initially diagnosed with cervical cancer were randomly assigned into the external beam radiotherapy (EBRT)+ single-channel intracavitary applicator group (the patent single-channel group) and EBRT+ the Fletcher applicator group. Whole pelvis irradiation was delivered with 6-MV photons via a four-field box variant or anterior and posterior parallel fields. Five to six fractions of intracavitary brachytherapy were performed at a dose of 7 Gy at point A once a week after 30 Gy (BED at point A: 80-90 Gy). Chemotherapy was given with intravenous injection of cisplatin at a dose of 40 mg/m² once weekly during EBRT.Clinical efficacy and safety were evaluated after the treatment. Results: In total, 150 eligible cases were assigned into the Fletcher applicator group and 149 cases into the patent single-channel group. The short-term clinical efficacy and acute toxicity did not significantly differ between two groups. The response rate was 94.0% in the Fletcher group, and 94.7% in the patent single-channel group. In the Fletcher applicator group, 76(50.7%) patients developed ≥ grade 3 hematologic toxicity and 61(40.9%) in the patent group (P=0.195). Conclusions: The self-designed patent single-channel intracavitary applicator yields equivalent clinical efficacy and safety (acute toxicity) to the standard Fletcher-type three-channel applicator in the HDR brachytherapy for uterine cervical cancer. Clincal Trial Registration Chinese Clinical Trial Registry (ChiCTR-TRC-12002321).