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Objective:Utilizing multi-criterion optimization (MCO) technology to improve plan design quality based on knowledge-based planning (KBP) model.Methods:Fifty-five patients with nasopharyngeal carcinoma (NPC) who had completed radiotherapy were selected, and fixed-field intensity-modulated radiotherapy (IMRT) technology was used in each case. Among them, 40 cases were randomly selected as training set 1. Then, IMRT plans in training set 1 were preprocessed by MCO technology to construct a new training set 2. With the initial training set 1 and the processed training set 2 as training samples, the traditional KBP model and the MCO-KBP model refined by MCO technology were trained, respectively. Among the remaining 15 cases, 5 cases were randomly selected as the validation set, and the remaining 10 cases were used as the test set. After verification, the test set was used to statistically analyze the plan quality of the initial manual plan and the automatic plan generated by the traditional KBP model and the MCO-KBP model.Results:The target dose (D 95%) of plans generated by the traditional KBP model and the MCO-KBP model met the clinical requirements. Conformity index (CI) and homogeneity index (HI) were almost the same ( P>0.05), and the doses of organ at risk (OAR) of the automatic plans generated by the MCO-KBP model were lower than those of the traditional KBP model. For example, compared with the traditional KBP model, the average D max of the brainstem in the automatic plans generated by the MCO-KBP model was lower by 2.13 Gy, the average D mean of the left parotid gland was lower by 1.39 Gy, the average D mean of the right parotid gland was lower by 1.59 Gy, and the average D max of the left optic nerve was lower by 1.42 Gy, the average D max of the right optic nerve was lower by 1.16 Gy, and the average D max of the pituitary gland was lower by 1.88 Gy. All of the above-mentioned dosimetry indexes were statistically significant. Conclusion:Compared with the traditional KBP model, the IMRT plans designed by the refined MCO-KBP model have obvious advantages in the protection of OAR, which proves the feasibility of utilizing MCO technology to improve the plan design quality of the KBP model.
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Speaking lesson is an effective way and teaching skill to prepare lessons for the teaching of anatomy. Taking the speaking lesson design of lecture teaching of the neck as an example, this article shows the teaching of topographic anatomy for "5+3" integrated clinical medical students. Adhering to the teaching concept of "student-centered", we have launched the theoretical teaching of "problem-centered discussion" and the experimental teaching of "operator responsibility system" in groups, with the "thanksgiving" humanistic education running through the whole process of theoretical and experimental courses. The teaching is a good way to cultivate the students' gratitude consciousness and humanistic quality, self-learning ability, critical thinking ability, communication and expression ability, hands-on operation ability and teamwork spirit, which has laid a solid foundation for training medical professionals in the new era.
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Pancreas arises from dorsal and ventral anlagens on an embryological basis,with a difference in histocytology.Immunohistochemical staining for an anti-pancreatic polypeptide can be performed to discriminate between the dorsal and ventral pancreas because of the difference in the amount of pancreatic polypeptide contained by the dorsal and ventral pancreas.Differences of survival in patients were approved due to the difference in histocytology between the dorsal and ventral pancreas,including the ability of local invasion,lymph node metastases,and nerve plexus invasion.
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Pancreas arises from dorsal and ventral anlagens on an embryological basis,with a difference in histocytology.Immunohistochemical staining for an anti-pancreatic polypeptide can be performed to discriminate between the dorsal and ventral pancreas because of the difference in the amount of pancreatic polypeptide contained by the dorsal and ventral pancreas.Differences of survival in patients were approved due to the difference in histocytology between the dorsal and ventral pancreas,including the ability of local invasion,lymph node metastases,and nerve plexus invasion.
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Aging changes of somatostatin (SS) mRNA-positive neurons in the dorsal hippocampus of old rats were studied by in situ hybridization histochemistry and image analysis. In the young rats,SS mRNA-positive cell bodies were mainly located in the pyramidal and polymorphic cell layers of the CA1 and CA2 regions, and in the strata radiatum and polymorphic cell layer of the CA3 region, and in the polymorphic cell layer of dentate gyrus. In the old rats,SS mRNA-positive cell bodies were concentrated in the polymorphic cell layer and denate gyrus. A marked decrease of number of SS mRNA-positive cell bodies and a significant increase of gray value of SS mRNA-positive cell bodies were found in the dorsal hippocampus and dentate gyrus of the old rats as compared with the young rats. No significant age difference in the sectional area of SS mRNA-positive cell bodies was observed in the dorsal hippocampus. The results showed that there were apparent changes with aging of the SS mRNA-positive cell bodies in the dorsal hippocampus of the rats. The significance of the changes remains to be studied further.