1.Optimization of radiation source arrangement in brachytherapy for linear keloids
Siyu XIN ; Liangang GE ; Qiuchi CHEN ; Jizeng MENG ; Jian ZHANG ; Fulin GAO
Chinese Journal of Medical Physics 2025;42(11):1414-1419
Objective To optimize the dose distribution of postoperative brachytherapy for linear keloids,and to investigate the effects of the number of radiation sources n,source-to-skin distance d,and source spacing a on dose distribution,thereby providing a reasonable radiation source arrangement scheme for radiotherapy in narrow and elongated wound areas.Methods A one-dimensional idealized model was established.Based on the inverse-square law,dose distributions were calculated under combinations of differentn(4,6,8,10)and d(from 0.3 to 2.0 cm).The proportions of dose-effective areas(90%-110%of the prescribed dose)and penumbra areas(20%-80%of the prescribed dose)were analyzed to evaluate the rationality of dose distribution.Results When d/a slightly exceeded 0.5,the proportion of the effective area reached its peak,and the proportion of the penumbra area was relatively low.An excessively small d/a led to cold spots in the irradiated area,while an excessively large d/a expanded the penumbra area.Increasing n significantly reduced the penumbra range and improved dose homogeneity.Conclusion The dose distribution is most reasonable when d/a is slightly greater than 0.5,and a multi-source arrangement(n≥6)is preferred to enhance dose homogeneity.This study provides guidance for parameter optimization in brachytherapy for keloids.
2.Optimization of radiation source arrangement in brachytherapy for linear keloids
Siyu XIN ; Liangang GE ; Qiuchi CHEN ; Jizeng MENG ; Jian ZHANG ; Fulin GAO
Chinese Journal of Medical Physics 2025;42(11):1414-1419
Objective To optimize the dose distribution of postoperative brachytherapy for linear keloids,and to investigate the effects of the number of radiation sources n,source-to-skin distance d,and source spacing a on dose distribution,thereby providing a reasonable radiation source arrangement scheme for radiotherapy in narrow and elongated wound areas.Methods A one-dimensional idealized model was established.Based on the inverse-square law,dose distributions were calculated under combinations of differentn(4,6,8,10)and d(from 0.3 to 2.0 cm).The proportions of dose-effective areas(90%-110%of the prescribed dose)and penumbra areas(20%-80%of the prescribed dose)were analyzed to evaluate the rationality of dose distribution.Results When d/a slightly exceeded 0.5,the proportion of the effective area reached its peak,and the proportion of the penumbra area was relatively low.An excessively small d/a led to cold spots in the irradiated area,while an excessively large d/a expanded the penumbra area.Increasing n significantly reduced the penumbra range and improved dose homogeneity.Conclusion The dose distribution is most reasonable when d/a is slightly greater than 0.5,and a multi-source arrangement(n≥6)is preferred to enhance dose homogeneity.This study provides guidance for parameter optimization in brachytherapy for keloids.
3.Gonadotropin-inhibitory hormone in regulation of reproduction and behavior in mammalians.
Fansen MENG ; Xuequn CHEN ; Jizeng DU
Journal of Zhejiang University. Medical sciences 2013;42(2):224-231
RF-amide related peptide (RFRP) is the orthologue of gonadotropin-inhibitory hormone (GnIH) in mammals. The bodies of RFRP cell are located in the dorsomedial nucleus of the hypothalamus (DMH) and the fibers project to preoptic area (POA) and median eminence of the hypothalamus. Its receptor mainly distributes in hypothalamus. RFRP fibers project to GnRH cells to regulate mammalian reproduction axis. This paper reviews the progress of current researches on RFRP in regulation of animal behaviors, including reproduction, food intake, anxiety and stress response.
Animals
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Behavior, Animal
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physiology
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Mammals
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physiology
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Neuropeptides
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physiology
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Reproduction
;
physiology

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