1.Research progress on the toxic effects and mechanisms of perfluorobutyric acid
Lin ZHONG ; Yiru QIN ; Zuofei XIE ; Banghua WU ; Lihua XIA
China Occupational Medicine 2025;52(6):709-712
Perfluorobutyric acid (PFBA) is a representative short-chain compound of per- and polyfluoroalkyl substances (PFAS), which is widely used in fluorochemical manufacturing, food packaging, and outdoor textile processing industries. PFBA primarily enters into the human body via oral intake, inhalation, and dermal exposure and can be efficiently metabolized. PFBA exhibits cytotoxicity by disrupting cell proliferation, inducing oxidative stress, and disturbing lipid metabolism, thereby impairing cellular homeostasis. In addition, PFBA can induce abnormal activation of peroxisome proliferator-activated receptor α-dependent and/or independent pathways, leading to lipid metabolism disorders and subsequent liver injury. Animal studies have demonstrated that PFBA exposure alters renal biochemical parameters and induces epidermal inflammation, abnormal keratinization, and even necrosis, suggesting potential nephrotoxicity and dermal toxicity. PFBA is capable of crossing the placental barrier, and PFBA levels in umbilical cord blood have been negatively correlated with insulin and insulin-like growth factor 1. Moreover, plasma PFBA levels in patients infected with coronavirus disease 2019 have been associated with infection severity, indicating potential reproductive, developmental, and immunotoxic effects. At present, systematic occupational and environmental exposure monitoring data for PFBA remain limited, the toxic mechanisms in certain target organs have not been fully elucidated, and the molecular regulatory networks underlying reproductive and immune toxicity remain unclear. Future research should focus on improving PFBA monitoring strategies, strengthening studies on PFBA occupational exposure detection methods, toxic effects and mechanisms, and refining occupational risk assessment systems, to provide a scientific basis for establishing occupational exposure limits, optimizing risk management strategies, and safeguarding public health.
2.Metabolic profiling analysis of acute renal toxicity in mice exposed to perfluorobutanoic acid
Lin ZHONG ; Yiru QIN ; Zhiming HU ; Zuofei XIE ; Jingjing QIU ; Banghua WU ; LiHua XIA
China Occupational Medicine 2025;52(4):368-375
Objective To explore the nephrotoxic effects of exposure to perfluorobutanoic acid (PFBA) and its mechanism in mice, with a particular focus on analyzing the changes in kidney metabolism and their potential implications. Methods The specific pathogen free C57BL/6 mice were randomly divided into control group, low-dose group, and high-dose group, with 10 mice in each group. Mice in the three groups received intragastric administration of PFBA solution at doses of 0, 35 and 350 mg/kg body weight, once per day for seven consecutive days. The histopathological changes of kidneys of mice in these three groups were evaluated. Metabolomic profiling of mouse kidneys was performed using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Differentially accumulated metabolites (DAMs) were identified based on the Human Metabolome Database, and related metabolic pathways were analyzed through MetaboAnalyst 6.0 and Kyoto Encyclopedia of Genes and Genomes (KEGG). Results Histopathological analysis of kidneys showed that the renal pelvis mucosa of mice in the low-dose group presented focal mild inflammatory changes without marked structural damage, whereas mice in the high-dose group showed severe inflammation and partial destruction of renal structure. The kidney coefficient of mice in both low-dose group and the high-dose group decreased (both P<0.05), and the Paller scores of renal tissues increased (both P<0.05) compared with that in the control group. The Paller score of mouse renal tissue in the high-dose group was higher than that in the low-dose group (P<0.05). Metabolomic profiling identified 46 DAMs (26 upregulated, 20 downregulated) in the low-dose group and 104 DAMs (54 upregulated, 50 downregulated) in the high-dose group, with 26 shared DAMs between the two dose groups. KEGG pathway analysis revealed that DAMs were mainly involved in metabolic pathways such as glycerophospholipid metabolism, glycerolipid metabolism, sphingolipid and steroid hormone synthesis. Conclusion Acute exposure to PFBA can cause kidney injury in mice. Lipid metabolism pathways such as glycerophospholipid and sphingolipid metabolism is involved in the development of acute renal toxicity of PFBA.
3.Liuwei Dihuang Pills improve chemotherapy-induced ovarian injury in mice by promoting the proliferation of female germline stem cells.
Bo JIANG ; Wen-Yan ZHANG ; Guang-di LIN ; Xiao-Qing MA ; Guo-Xia LAN ; Jia-Wen ZHONG ; Ling QIN ; Jia-Li MAI ; Xiao-Rong LI
China Journal of Chinese Materia Medica 2025;50(9):2495-2504
This study primarily investigates the effect of Liuwei Dihuang Pills on the activation and proliferation of female germline stem cells(FGSCs) in the ovaries and cortex of mice with premature ovarian failure(POF), and how it improves ovarian function. ICR mice were randomly divided into the control group, model group, Liuwei Dihuang Pills group, Liuwei Dihuang Pills double-dose group, and estradiol valerate group. A mouse model of POF was established by intraperitoneal injection of cyclophosphamide. After successful modeling, the mice were treated with Liuwei Dihuang Pills or estradiol valerate for 28 days. Vaginal smears were prepared to observe the estrous cycle and body weight. After the last administration, mice were sacrificed and sampled. Serum levels of estradiol(E_2), follicle-stimulating hormone(FSH), luteinizing hormone(LH), and anti-Müllerian hormone(AMH) were measured by enzyme-linked immunosorbent assay(ELISA). Hematoxylin-eosin(HE) staining was used to observe ovarian morphology and to count follicles at all stages to evaluate ovarian function. Immunohistochemistry was used to detect the expression of mouse vasa homolog(MVH), a marker of ovarian FGSCs. Immunofluorescence staining, using co-labeling of MVH and proliferating cell nuclear antigen(PCNA), was used to detect the expression and localization of specific markers of FGSCs. Western blot was employed to assess the protein expression of MVH, octamer-binding transcription factor 4(Oct4), and PCNA in the ovaries. The results showed that compared with the control group, the model group exhibited disordered estrous cycles, decreased ovarian index, increased atretic follicles, and a reduced number of follicles at all stages. FSH and LH levels were significantly elevated, while AMH and E_2 levels were significantly reduced, indicating the success of the model. After treatment with Liuwei Dihuang Pills or estradiol valerate, hormone levels improved, the number of atretic follicles decreased, and the number of follicles at all stages increased. MVH marker protein and PCNA proliferative protein expression in ovarian tissue also increased. These results suggest that Liuwei Dihuang Pills regulate estrous cycles and hormone disorders in POF mice, promote the proliferation of FGSCs, improve follicular development in POF mice, and enhance ovarian function.
Animals
;
Female
;
Drugs, Chinese Herbal/administration & dosage*
;
Mice
;
Cell Proliferation/drug effects*
;
Mice, Inbred ICR
;
Ovary/cytology*
;
Primary Ovarian Insufficiency/genetics*
;
Follicle Stimulating Hormone/metabolism*
;
Humans
;
Anti-Mullerian Hormone/blood*
;
Antineoplastic Agents/adverse effects*
;
Luteinizing Hormone/metabolism*
;
Cyclophosphamide/adverse effects*
4.Application of motor behavior evaluation method of zebrafish model in traditional Chinese medicine research.
Xin LI ; Qin-Qin LIANG ; Bing-Yue ZHANG ; Zhong-Shang XIA ; Gang BAI ; Zheng-Cai DU ; Er-Wei HAO ; Jia-Gang DENG ; Xiao-Tao HOU
China Journal of Chinese Materia Medica 2025;50(10):2631-2639
The zebrafish model has attracted much attention due to its strong reproductive ability, short research cycle, and ease of maintenance. It has always been an important vertebrate model system, often used to carry out human disease research. Its motor behavior features have the advantages of being simpler, more intuitive, and quantifiable. In recent years, it has received widespread attention in the study of traditional Chinese medicine(TCM)for the treatment of sleep disorders, neurodegenerative diseases, fatigue, epilepsy, and other diseases. This paper reviews the characteristics of zebrafish motor behavior and its applications in the pharmacodynamic verification and mechanism research of TCM extracts, active ingredients, and TCM compounds, as well as in active ingredient screening and safety evaluation. The paper also analyzes its advantages and disadvantages, with the aim of improving the breadth and depth of zebrafish and its motor behavior applications in the field of TCM research.
Zebrafish/physiology*
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Medicine, Chinese Traditional
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Drugs, Chinese Herbal/therapeutic use*
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Disease Models, Animal
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Drug Evaluation, Preclinical/methods*
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Animals
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Sleep Wake Disorders/physiopathology*
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Epilepsy/physiopathology*
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Neurodegenerative Diseases/physiopathology*
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Fatigue/physiopathology*
;
Behavior, Animal/physiology*
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Motor Activity/physiology*
5.Effects of combined use of active ingredients in Buyang Huanwu Decoction on oxygen-glucose deprivation/reglucose-reoxygenation-induced inflammation and oxidative stress of BV2 cells.
Tian-Qing XIA ; Ying CHEN ; Jian-Lin HUA ; Qin SU ; Cun-Yan DAN ; Meng-Wei RONG ; Shi-Ning GE ; Hong GUO ; Bao-Guo XIAO ; Jie-Zhong YU ; Cun-Gen MA ; Li-Juan SONG
China Journal of Chinese Materia Medica 2025;50(14):3835-3846
This study aims to explore the effects and action mechanisms of the active ingredients in Buyang Huanwu Decoction(BYHWD), namely tetramethylpyrazine(TMP) and hydroxy-safflor yellow A(HSYA), on oxygen-glucose deprivation/reglucose-reoxygenation(OGD/R)-induced inflammation and oxidative stress of microglia(MG). Network pharmacology was used to screen the effective monomer ingredients of BYHWD and determine the safe concentration range for each component. Inflammation and oxidative stress models were established to further screen the best ingredient combination and optimal concentration ratio with the most effective anti-inflammatory and antioxidant effects. OGD/R BV2 cell models were constructed, and BV2 cells in the logarithmic growth phase were divided into a normal group, a model group, an HSYA group, a TMP group, and an HSYA + TMP group. Enzyme-linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory cytokines such as interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and interleukin-6(IL-6). Oxidative stress markers, including superoxide dismutase(SOD), nitric oxide(NO), and malondialdehyde(MDA), were also measured. Western blot was used to analyze the protein expression of both inflammation-related pathway [Toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)] and oxidative stress-related pathway [nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)]. Immunofluorescence was used to assess the expression of proteins such as inducible nitric oxide synthase(iNOS) and arginase-1(Arg-1). The most effective ingredients for anti-inflammatory and antioxidant effects in BYHWD were TMP and HSYA. Compared to the normal group, the model group showed significantly increased levels of IL-1β, TNF-α, IL-6, NO, and MDA, along with significantly higher protein expression of NF-κB, TLR4, Nrf2, and HO-1 and significantly lower SOD levels. The differences between the two groups were statistically significant. Compared to the model group, both the HSYA group and the TMP group showed significantly reduced levels of IL-1β, TNF-α, IL-6, NO, and MDA, lower expression of NF-κB and TLR4 proteins, higher levels of SOD, and significantly increased protein expression of Nrf2 and HO-1. Additionally, the expression of the M1-type MG marker iNOS was significantly reduced, while the expression of the M2-type MG marker Arg-1 was significantly increased. The results of the HSYA group and the TMP group had statistically significant differences from those of the model group. Compared to the HSYA group and the TMP group, the HSYA + TMP group showed further significant reductions in IL-1β, TNF-α, IL-6, NO, and MDA levels, along with significant reductions in NF-κB and TLR4 protein expression, an increase in SOD levels, and elevated Nrf2 and HO-1 protein expression. Additionally, the expression of the M1-type MG marker iNOS was reduced, while the M2-type MG marker Arg-1 expression increased significantly in the HSYA + TMP group compared to the TMP or HSYA group. The differences in the results were statistically significant between the HSYA + TMP group and the TMP or HSYA group. The findings indicated that the combined use of HSYA and TMP, the active ingredients of BYHWD, can effectively inhibit OGD/R-induced inflammation and oxidative stress of MG, showing superior effects compared to the individual use of either component.
Oxidative Stress/drug effects*
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Drugs, Chinese Herbal/pharmacology*
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Animals
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Mice
;
Glucose/metabolism*
;
Cell Line
;
Inflammation/genetics*
;
Oxygen/metabolism*
;
Pyrazines/pharmacology*
;
Microglia/metabolism*
;
NF-E2-Related Factor 2/immunology*
;
NF-kappa B/immunology*
;
Toll-Like Receptor 4/immunology*
;
Anti-Inflammatory Agents/pharmacology*
;
Humans
6.Heart-sparing strategy for breast cancer radiotherapy based on nnU-Net: regional optimization and automatic segmentation
Jinghan HUANG ; Maidina BATUER ; Chuanghui ZHOU ; Zhi ZHANG ; Limei DENG ; Yuan XU ; Junyuan ZHONG ; Linghong ZHOU ; Xia LI ; Genggeng QIN
Chinese Journal of Radiation Oncology 2025;34(4):355-362
Objective:To investigate the feasibility and optimal expansion width of replacing the left anterior descending coronary artery (LADCA) with the region of heart sparing (RHS) to reduce cardiac radiation dose during breast cancer radiotherapy.Methods:Retrospective analysis was conducted on data from 88 patients with left-sided breast cancer who underwent radiotherapy at 2 centers: Nanfang Hospital of Southern Medical University (50 cases for the training set, 15 cases for the internal test set) and Ganzhou Hospital of Nanfang Hospital (23 cases for the external test set) from March 2022 to January 2024. All patients had left-sided invasive ductal carcinoma with axillary lymph node metastasis, and had undergone modified radical mastectomy and chemotherapy. Based on simulation CT images, 2 radiation oncologists delineated the LADCA and 8 RHSs. The RHSs were delineated by expanding the LADCA contour by 0.5 cm increments, totaling 8 expansions. The RHS widths were defined as 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 cm. The nnU-Net model was trained for 3D automatic segmentation of the LADCA and RHSs. Model performance was evaluated using the Dice similarity coefficient (DSC), relative volume error (RVE), sensitivity, specificity, and 95% Hausdorff distance (HD95). Additionally, the minimum, maximum, and average relative dose variations (RDV) as well as V5% and V20% indicators were calculated for the LADCA and each RHS. Correlation analysis was performed using the least squares regression, with the slope and coefficient of determination ( R2) employed to evaluate the accuracy of the model fitting, the relationship between the LADCA and RHS, and the degree of their correlation, thereby assessing the substitutive effect of the RHS for the LADCA. Results:The DSC for the LADCA was 0.415, while the DSCs for RHS widths of 0.5 cm and 4.0 cm were 0.718 and 0.835, respectively. Overall, the automatic segmentation performance improved with increasing RHS width. The DSC, RVE, sensitivity, specificity, and HD95 for the external test set were largely consistent with those of the internal test set, demonstrating the model's good robustness across different datasets. All RDVmin values were negative, while RDVmax and RDVmean showed a positive correlation with RHS width. RDVmean increased from 39.01% to 75.89% as the RHS width increased. In the correlation analysis, the slopes for RHS widths of 1.5 cm and 2.0 cm were 0.95 and 1.05, respectively, with R2 values and coefficients of variation of 0.79 and 0.73, and 21.11% and 24.03%, respectively. Conclusions:The automatic segmentation model trained on nnU-Net can accurately segment RHSs. Based on geometric and dosimetric indicators, a 1.5 cm-wide RHS is the most suitable substitute for the LADCA, effectively limiting the radiation dose to the LADCA without compromising target dose coverage.
7.Deep learning-based dynamic generation of uterine geometry for cervical cancer radiotherapy
Batuer MAIDINA ; Jinghan HUANG ; Chuanghui ZHOU ; Junyuan ZHONG ; Lei YANG ; Linghong ZHOU ; Xia LI ; Genggeng QIN
Chinese Journal of Radiation Oncology 2025;34(6):585-593
Objective:To propose a semi-supervised learning method for dynamic generation of organ geometric contours, leveraging bladder volume variations and its relative position to the uterus to accurately generate uterine contours in cervical cancer radiotherapy.Methods:A total of 120 sets of pelvic planning CT images (including both full and empty bladder scans) from 60 patients with cervical cancer treated at the Department of Radiation Oncology, Nanfang Hospital of Southern Medical University between January and December 2023 were retrospectively collected. A conditional generative adversarial network (CGAN) based on a squeeze-and-excitation channel attention mechanism was proposed to accurately generate uterine geometric contours under varying bladder filling states. By emphasizing the critical spatial relationships between the bladder and uterus, the model learned the relative anatomical positions of pelvic organs and their motion correlations. The generative performance was quantitatively evaluated using the average Dice similarity coefficient (DSC), intersection over union (IoU), and the 95 th percentile Hausdorff distance (HD95), and was compared with GAN model, CGAN model, and Pix2Pix model. Pairwise comparisons were perfomed by paired-sample t-test. Results:The proposed SE-CGAN model achieved the best performance on the test set, with DSC of 0.83±0.09, IoU of 0.71±0.05, HD95 of (6.74±1.23) mm, improving DSC by 7.5%, 4.9%, and 3.6% compared to the GAN, CGAN, and Pix2Pix models, respectively (all P<0.001), and reducing the mean HD95 by 32.9%-45.3%. Statistical analysis revealed significant differences between SE-CGAN model and the other 3 baseline models, whereas no significant difference was observed between CGAN model and Pix2Pix model. The visualization results further demonstrated that the GAN model produced uterine contours deviated greatly from the real shape, and the edge was fuzzy; CGAN and Pix2Pix model achieved better overlap but lacked of precision in boundary reconstruction. In contrast, the contours generated by SE-CGAN model closely matched the ground truth with clearly defined edges, indicating superior reconstruction accuracy. Conclusions:In this study, we propose a generative adversarial network method that establishes a dynamic modulation mechanism by which the bladder state influences the uterine geometric contour, enabling accurate generation of the uterine contours from the bladder contours of any given localization CT scan. This approach effectively addresses the uncertainty in radiotherapy target delineation caused by pelvic organ motion.
8.Analysis of Clinical Features and Multi-Slice Spiral CT Image Features of Acute Appendicitis in Soldiers Who Have Been Living in Plateau for A Long Time
Li-na YUE ; Juan-qin NIU ; Gang CHEN ; Man-ping CHENG ; Ning-xia MU ; Jia FAN ; Kang LIU ; Yu-lan NIU ; Ya-ping HE ; Zhong-hua LI
Progress in Modern Biomedicine 2025;25(11):1869-1878
Objective:To investigate the clinical features and multi-slice spiral computed tomography(CT)imaging features of acute appendicitis in soldiers who have been living in plateau for a long time.Methods:The clinical features and imaging data of 56 cases of acute appendicitis in soldiers who have been living in plateau for a long time confirmed by surgery from February 2022 to August 2024 were retrospectively analyzed.Results:In 56 cases with acute appendicitis in soldiers who have been living in plateau for a long time,the appendectomy position results showed:anterior ileum 4 cases(7.14%),lower ileum 10 cases(17.86%),posterior cecum 16 cases(28.57%),lower cecum 9 cases(16.07%),lateral cecum 2 cases(3.58%),posterior ileum 6 cases(10.71%),high(subhepatic)9 cases(16.07%),and left lower abdominal 0 cases,retroperitoneal appendicitis 0 cases,which was suggested that the anatomical position variation of appendicitis in soldiers with acute appendicitis who have been living at high altitude for a long time was relatively large.The direct manifestations of multi-slice spiral CT showed:appendectomy enlarged diameter>6 mm in 49 cases(87.50%),appendicular wall thickening>2 mm in 42 cases(75.00%),ppendiceal dilation lumen and effusion in 29 cases(51.79%),appendix indistinctness in 3 cases(5.36%),lppendix fecalith:27 cases(48.21%),gas in the appendix in 16 cases(28.57%).Indirect findings of multi-slice spiral CT showed that,periappendiceal exudation with shadow in 32 cases(57.14%),appendiceal cellulitis with peripheral abscess in 9 cases(16.07%),peritonitis and ascites in 13 cases(23.21%),ileocecal intestinal wall thickening in 22 cases(39.29%),mesenteric lymph node enlargement in 16 cases(28.57%),reflexive intestinal stasis in ileocecal region was observed in 19 cases(33.93%).Conclusion:In the officers and soldiers with acute appendicitis who lived at high altitude for a long time,multi-slice spiral CT showed the direct manifestations of appendiceal thickening,tube wall thickening,lumen dilatation,fluid accumulation,etc.,and the indirect manifestations were periappendiceal exudation with shadow,appendiceal cellulitis with peripheral abscess,ileocecal intestinal wall thickening,reflexes of small intestine and mesenteric lymph node enlargement.Multi-slice spiral CT has the advantages of clear and intuitive,high safety,high resolution and simple operation in the diagnosis of acute appendicitis.
9.Analysis of Clinical Features and Multi-Slice Spiral CT Image Features of Acute Appendicitis in Soldiers Who Have Been Living in Plateau for A Long Time
Li-na YUE ; Juan-qin NIU ; Gang CHEN ; Man-ping CHENG ; Ning-xia MU ; Jia FAN ; Kang LIU ; Yu-lan NIU ; Ya-ping HE ; Zhong-hua LI
Progress in Modern Biomedicine 2025;25(11):1869-1878
Objective:To investigate the clinical features and multi-slice spiral computed tomography(CT)imaging features of acute appendicitis in soldiers who have been living in plateau for a long time.Methods:The clinical features and imaging data of 56 cases of acute appendicitis in soldiers who have been living in plateau for a long time confirmed by surgery from February 2022 to August 2024 were retrospectively analyzed.Results:In 56 cases with acute appendicitis in soldiers who have been living in plateau for a long time,the appendectomy position results showed:anterior ileum 4 cases(7.14%),lower ileum 10 cases(17.86%),posterior cecum 16 cases(28.57%),lower cecum 9 cases(16.07%),lateral cecum 2 cases(3.58%),posterior ileum 6 cases(10.71%),high(subhepatic)9 cases(16.07%),and left lower abdominal 0 cases,retroperitoneal appendicitis 0 cases,which was suggested that the anatomical position variation of appendicitis in soldiers with acute appendicitis who have been living at high altitude for a long time was relatively large.The direct manifestations of multi-slice spiral CT showed:appendectomy enlarged diameter>6 mm in 49 cases(87.50%),appendicular wall thickening>2 mm in 42 cases(75.00%),ppendiceal dilation lumen and effusion in 29 cases(51.79%),appendix indistinctness in 3 cases(5.36%),lppendix fecalith:27 cases(48.21%),gas in the appendix in 16 cases(28.57%).Indirect findings of multi-slice spiral CT showed that,periappendiceal exudation with shadow in 32 cases(57.14%),appendiceal cellulitis with peripheral abscess in 9 cases(16.07%),peritonitis and ascites in 13 cases(23.21%),ileocecal intestinal wall thickening in 22 cases(39.29%),mesenteric lymph node enlargement in 16 cases(28.57%),reflexive intestinal stasis in ileocecal region was observed in 19 cases(33.93%).Conclusion:In the officers and soldiers with acute appendicitis who lived at high altitude for a long time,multi-slice spiral CT showed the direct manifestations of appendiceal thickening,tube wall thickening,lumen dilatation,fluid accumulation,etc.,and the indirect manifestations were periappendiceal exudation with shadow,appendiceal cellulitis with peripheral abscess,ileocecal intestinal wall thickening,reflexes of small intestine and mesenteric lymph node enlargement.Multi-slice spiral CT has the advantages of clear and intuitive,high safety,high resolution and simple operation in the diagnosis of acute appendicitis.
10.Heart-sparing strategy for breast cancer radiotherapy based on nnU-Net: regional optimization and automatic segmentation
Jinghan HUANG ; Maidina BATUER ; Chuanghui ZHOU ; Zhi ZHANG ; Limei DENG ; Yuan XU ; Junyuan ZHONG ; Linghong ZHOU ; Xia LI ; Genggeng QIN
Chinese Journal of Radiation Oncology 2025;34(4):355-362
Objective:To investigate the feasibility and optimal expansion width of replacing the left anterior descending coronary artery (LADCA) with the region of heart sparing (RHS) to reduce cardiac radiation dose during breast cancer radiotherapy.Methods:Retrospective analysis was conducted on data from 88 patients with left-sided breast cancer who underwent radiotherapy at 2 centers: Nanfang Hospital of Southern Medical University (50 cases for the training set, 15 cases for the internal test set) and Ganzhou Hospital of Nanfang Hospital (23 cases for the external test set) from March 2022 to January 2024. All patients had left-sided invasive ductal carcinoma with axillary lymph node metastasis, and had undergone modified radical mastectomy and chemotherapy. Based on simulation CT images, 2 radiation oncologists delineated the LADCA and 8 RHSs. The RHSs were delineated by expanding the LADCA contour by 0.5 cm increments, totaling 8 expansions. The RHS widths were defined as 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 cm. The nnU-Net model was trained for 3D automatic segmentation of the LADCA and RHSs. Model performance was evaluated using the Dice similarity coefficient (DSC), relative volume error (RVE), sensitivity, specificity, and 95% Hausdorff distance (HD95). Additionally, the minimum, maximum, and average relative dose variations (RDV) as well as V5% and V20% indicators were calculated for the LADCA and each RHS. Correlation analysis was performed using the least squares regression, with the slope and coefficient of determination ( R2) employed to evaluate the accuracy of the model fitting, the relationship between the LADCA and RHS, and the degree of their correlation, thereby assessing the substitutive effect of the RHS for the LADCA. Results:The DSC for the LADCA was 0.415, while the DSCs for RHS widths of 0.5 cm and 4.0 cm were 0.718 and 0.835, respectively. Overall, the automatic segmentation performance improved with increasing RHS width. The DSC, RVE, sensitivity, specificity, and HD95 for the external test set were largely consistent with those of the internal test set, demonstrating the model's good robustness across different datasets. All RDVmin values were negative, while RDVmax and RDVmean showed a positive correlation with RHS width. RDVmean increased from 39.01% to 75.89% as the RHS width increased. In the correlation analysis, the slopes for RHS widths of 1.5 cm and 2.0 cm were 0.95 and 1.05, respectively, with R2 values and coefficients of variation of 0.79 and 0.73, and 21.11% and 24.03%, respectively. Conclusions:The automatic segmentation model trained on nnU-Net can accurately segment RHSs. Based on geometric and dosimetric indicators, a 1.5 cm-wide RHS is the most suitable substitute for the LADCA, effectively limiting the radiation dose to the LADCA without compromising target dose coverage.

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