1.Expert consensus on the diagnosis and treatment of cemental tear.
Ye LIANG ; Hongrui LIU ; Chengjia XIE ; Yang YU ; Jinlong SHAO ; Chunxu LV ; Wenyan KANG ; Fuhua YAN ; Yaping PAN ; Faming CHEN ; Yan XU ; Zuomin WANG ; Yao SUN ; Ang LI ; Lili CHEN ; Qingxian LUAN ; Chuanjiang ZHAO ; Zhengguo CAO ; Yi LIU ; Jiang SUN ; Zhongchen SONG ; Lei ZHAO ; Li LIN ; Peihui DING ; Weilian SUN ; Jun WANG ; Jiang LIN ; Guangxun ZHU ; Qi ZHANG ; Lijun LUO ; Jiayin DENG ; Yihuai PAN ; Jin ZHAO ; Aimei SONG ; Hongmei GUO ; Jin ZHANG ; Pingping CUI ; Song GE ; Rui ZHANG ; Xiuyun REN ; Shengbin HUANG ; Xi WEI ; Lihong QIU ; Jing DENG ; Keqing PAN ; Dandan MA ; Hongyu ZHAO ; Dong CHEN ; Liangjun ZHONG ; Gang DING ; Wu CHEN ; Quanchen XU ; Xiaoyu SUN ; Lingqian DU ; Ling LI ; Yijia WANG ; Xiaoyuan LI ; Qiang CHEN ; Hui WANG ; Zheng ZHANG ; Mengmeng LIU ; Chengfei ZHANG ; Xuedong ZHOU ; Shaohua GE
International Journal of Oral Science 2025;17(1):61-61
Cemental tear is a rare and indetectable condition unless obvious clinical signs present with the involvement of surrounding periodontal and periapical tissues. Due to its clinical manifestations similar to common dental issues, such as vertical root fracture, primary endodontic diseases, and periodontal diseases, as well as the low awareness of cemental tear for clinicians, misdiagnosis often occurs. The critical principle for cemental tear treatment is to remove torn fragments, and overlooking fragments leads to futile therapy, which could deteriorate the conditions of the affected teeth. Therefore, accurate diagnosis and subsequent appropriate interventions are vital for managing cemental tear. Novel diagnostic tools, including cone-beam computed tomography (CBCT), microscopes, and enamel matrix derivatives, have improved early detection and management, enhancing tooth retention. The implementation of standardized diagnostic criteria and treatment protocols, combined with improved clinical awareness among dental professionals, serves to mitigate risks of diagnostic errors and suboptimal therapeutic interventions. This expert consensus reviewed the epidemiology, pathogenesis, potential predisposing factors, clinical manifestations, diagnosis, differential diagnosis, treatment, and prognosis of cemental tear, aiming to provide a clinical guideline and facilitate clinicians to have a better understanding of cemental tear.
Humans
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Dental Cementum/injuries*
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Consensus
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Diagnosis, Differential
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Cone-Beam Computed Tomography
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Tooth Fractures/therapy*
2.Effects of Sishen Pills on the Expression of TREK-1 Signaling Pathway in Rats of Irritable Bowel Syndrome with Diarrhea
Xiaoyuan LIN ; Shuangyang LUO ; Na DENG ; Xuting XIA ; Jiemin LIU ; Yujie LI
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(10):94-99
Objective To observe the effect of Sishen Pills on the expression of TREK-1 signaling pathway in rats of irritable bowel syndrome with diarrhea(IBS-D);To explore its mechanism in treating IBS-D.Methods Ten SPF-grade SD rats were randomly selected as the normal group,and the remaining 30 rats were used to prepare the IBS-D rat model by senna gavage combined with water stress avoidance method,and then the modeled rats were randomly divided into the model group,Western medicine group(15.23 mg/kg pivoxyl bromide)and Chinese medicine group(7.32 g/kg Sishen Pills).The medication groups were gavaged by corresponding drugs,and the normal group and model group were given equal volume of pure water,once a day,for consecutive 14 d.The general state of the rats was observed,the contents of serum cyclic adenosine monophosphate(cAMP),protein kinase A(PKA)and phosphorylated extracellular signal-regulated kinase(p-ERK)were detected by ELISA,the positive expressions of biportal potassium channel TREK-1 and p-ERK in colonic tissue were detected by immunofluorescence,the expressions of cAMP,PKA and p-ERK protein were detected by Western blot.Results Compared with the normal group,the body mass of rats in the model group was significantly reduced,and loose stool rate significantly increased(P<0.01);the contents of cAMP,PKA and p-ERK in serum were significantly increased(P<0.05,P<0.01);the positive expression and protein expression of TREK-1 in colonic tissue were significantly reduced,while the positive expression of p-ERK significantly increased(P<0.01),and the expressions of cAMP and PKA proteins significantly increased(P<0.01).Compared with the model group,the body mass of rats in Chinese medince group significantly increased,and loose stool rate significantly decreased(P<0.01);the contents of cAMP,PKA and p-ERK in serum were significantly reduced(P<0.05,P<0.01);the positive expression and protein expression of TREK-1 in colonic tissue significantly increased(P<0.01),while the positive expression of p-ERK significantly decreased(P<0.05),and the expressions of cAMP and PKA proteins significantly decreased(P<0.01).Conclusion Sishen Pills may regulate intestinal motility by affecting the expression of the TREK-1 signaling pathway,thereby treating IBS-D.
3.Effect of Simo decoction in improving low-grade inflammation of duodenum and protecting mucosal barrier in functional dyspepsia rats
Haiyue ZHANG ; Qian LUO ; Qin LIU ; Xingxu WEI ; Longbiao CHEN ; Yunzong HAN ; Siqing CHEN ; Shu ZHOU ; Xiaoyuan LIN ; Sainan ZHOU
Chinese Journal of Immunology 2025;41(7):1737-1742,1751
Objective:To explore the effect of Simo decoction improving the low duodenal inflammation and protecting the du-odenal mucosal barrier in rats with functional dyspepsia(FD).Methods:Sixty SD rats were randomly divided into control group(10 rats)and model group(50 rats),and the modeling rats were prepared by multivariate intervention method.After successful modeling,the modeling rats were randomly divided into model group,Simo decoction high-dose,medium-dose,low-dose group and mosapride group,with 10 rats in each group.The high-dose,medium-dose,and low-dose groups of Simo decoction were ga-vage given 5.62 g/kg,2.81 g/kg,and 1.40 g/kg,respectively,and the mosapride group was gavage given 0.305 mg/kg of mosapride,and the control group and model group were gavage given the same amount of distilled water for 14 days.The body weight of rats was observed;gastric emptying rate and small bowel propulsion rate were measured;transmission electron microscopy was used to observe the morphology of duodenal epithelial cells;ELISA detected serum levels of IL-17A and IL-22;Western blot and immunohistochemis-try were used to detect the expressions of protease-activated receptor 2(PAR-2)and tight junction protein(ZO-1,claudin-1)in the duodenum.Results:Compared with the control group,the body weight,gastric emptying rate and small intestinal propulsion rate of the model group were significantly reduced(P<0.01),transmission electron microscopy showed widening of the duodenal epithelial cell space,serum IL-17A and IL-22 levels were significantly increased(P<0.01),the expression of PAR-2 in duodenal tissue was in-creased,and the expressions of ZO-1 and claudin-1 were downregulated(P<0.01).Compared with model group,the gastric emptying rate and small intestinal propulsion rate in Simo decoction high-dose,medium-dose and mosapride group were increased(P<0.05,P<0.01),the contents of IL-17A and IL-22 in serum decreased(P<0.05,P<0.01),and the expression of PAR-2 in duodenal tissues was down-regulated,the expressions of ZO-1 and claudin-1 was significantly increased(P<0.01).The low-dose group of Simo soup could improve weight loss(P<0.01),reduce IL-17A content and PAR-2 expression,and increase ZO-1 and claudin-1 expression(P<0.05,P<0.01),while the effect on other indexes was not obvious.Conclusion:Simo decoction may reduce low-grade duodenal in-flammation to repair the mucosal barrier by down-regulating the levels of IL-17A and IL-22 and the expression of PAR-2,and up-regu-lating the expression of ZO-1 and claudin-1,so as to exert the effect of FD treatment.
4.Efficacy analysis of a model for predicting axillary lymph node metastasis in breast cancer using Ki67, molecular subtyping, and ultrasonographic parameters
Qiaocong LUO ; Zhimei LI ; Yuling YAO ; Qiuming WANG ; Xiaoyuan LI ; Sirong LAN
Chinese Journal of Endocrine Surgery 2025;19(2):198-202
Objective:To explore the diagnostic value of combining Ki67, molecular subtyping, and ultrasonographic parameters in predicting axillary lymph node metastasis in breast cancer.Methods:200 breast cancer patients who were admitted to Meizhou People’s Hospital from Jan. 2020 to Dec. 2022 were collected. Based on the presence or absence of axillary lymph node metastasis in breast cancer, the patients were divided into an axillary lymph node metastasis group and a non-axillary lymph node metastasis group. Age, clinical stage, tumor location, tumor size, degree of differentiation, boundary, blood flow, echo, calcification, morphology, vascular invasion, Ki67, molecular typing, resistance index (RI) , shear wave velocity were collected. Multivariate Logistic regression analysis was used to screen the risk factors for axillary lymph node metastasis of breast cancer, and receiver operating characteristic curve (ROC) was used to evaluate the clinical value of ki67, molecular typing combined with ultrasound parameters in the diagnosis of axillary lymph node metastasis of breast cancer.Results:There were no statistically significant differences in age, clinical stage, tumor location, tumor size, differentiation degree, boundary, blood flow, echo or calcification between the axillary lymph node metastasis group and the non-axillary lymph node metastasis group ( t=0.80, χ20.13, χ2=0.14, χ2=0.90, χ2=0.64, χ2=1.03, χ2=0.04, χ2=0.34, χ2=1.2, P>0.05) , while there were statistically significant differences in morphology, vascular invasion, Ki67, molecular classification, RI and shear wave velocity between the two groups ( χ2=12.01, χ2=8.75, χ2=11.36, χ2=11.43, t=6.34, t=7.25, P<0.05) . Multivariate Logistic regression analysis showed that vascular invasion, Ki67 high expression, triple negative breast cancer, RI and shear wave velocity were all risk factors for axillary lymph node metastasis ( OR=5.572,4.026,3.632,107.639,1.936, P<0.05) . ROC curve analysis results showed that the AUC of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was 0.620, 0.594, 0.744 and 0.792, respectively, and the AUC of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was 0.846. The AUC of the combination of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was higher than that of Ki67, molecular typing, RI and shear wave velocity alone ( Z=5.55,7.10,3.44,2.45, P<0.05) . Conclusions:High Ki67 expression, triple-negative breast cancer, lymphovascular invasion,RI, and shear wave velocity are all risk factors for axillary lymph node metastasis in breast cancer. The combined use of Ki67, molecular subtype, RI, and shear wave velocity can improve the diagnostic accuracy for axillary lymph node metastasis in breast cancer.
5.Efficacy analysis of a model for predicting axillary lymph node metastasis in breast cancer using Ki67, molecular subtyping, and ultrasonographic parameters
Qiaocong LUO ; Zhimei LI ; Yuling YAO ; Qiuming WANG ; Xiaoyuan LI ; Sirong LAN
Chinese Journal of Endocrine Surgery 2025;19(2):198-202
Objective:To explore the diagnostic value of combining Ki67, molecular subtyping, and ultrasonographic parameters in predicting axillary lymph node metastasis in breast cancer.Methods:200 breast cancer patients who were admitted to Meizhou People’s Hospital from Jan. 2020 to Dec. 2022 were collected. Based on the presence or absence of axillary lymph node metastasis in breast cancer, the patients were divided into an axillary lymph node metastasis group and a non-axillary lymph node metastasis group. Age, clinical stage, tumor location, tumor size, degree of differentiation, boundary, blood flow, echo, calcification, morphology, vascular invasion, Ki67, molecular typing, resistance index (RI) , shear wave velocity were collected. Multivariate Logistic regression analysis was used to screen the risk factors for axillary lymph node metastasis of breast cancer, and receiver operating characteristic curve (ROC) was used to evaluate the clinical value of ki67, molecular typing combined with ultrasound parameters in the diagnosis of axillary lymph node metastasis of breast cancer.Results:There were no statistically significant differences in age, clinical stage, tumor location, tumor size, differentiation degree, boundary, blood flow, echo or calcification between the axillary lymph node metastasis group and the non-axillary lymph node metastasis group ( t=0.80, χ20.13, χ2=0.14, χ2=0.90, χ2=0.64, χ2=1.03, χ2=0.04, χ2=0.34, χ2=1.2, P>0.05) , while there were statistically significant differences in morphology, vascular invasion, Ki67, molecular classification, RI and shear wave velocity between the two groups ( χ2=12.01, χ2=8.75, χ2=11.36, χ2=11.43, t=6.34, t=7.25, P<0.05) . Multivariate Logistic regression analysis showed that vascular invasion, Ki67 high expression, triple negative breast cancer, RI and shear wave velocity were all risk factors for axillary lymph node metastasis ( OR=5.572,4.026,3.632,107.639,1.936, P<0.05) . ROC curve analysis results showed that the AUC of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was 0.620, 0.594, 0.744 and 0.792, respectively, and the AUC of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was 0.846. The AUC of the combination of Ki67, molecular typing, RI and shear wave velocity in the diagnosis of axillary lymph node metastasis of breast cancer was higher than that of Ki67, molecular typing, RI and shear wave velocity alone ( Z=5.55,7.10,3.44,2.45, P<0.05) . Conclusions:High Ki67 expression, triple-negative breast cancer, lymphovascular invasion,RI, and shear wave velocity are all risk factors for axillary lymph node metastasis in breast cancer. The combined use of Ki67, molecular subtype, RI, and shear wave velocity can improve the diagnostic accuracy for axillary lymph node metastasis in breast cancer.
6.Effect of Simo decoction in improving low-grade inflammation of duodenum and protecting mucosal barrier in functional dyspepsia rats
Haiyue ZHANG ; Qian LUO ; Qin LIU ; Xingxu WEI ; Longbiao CHEN ; Yunzong HAN ; Siqing CHEN ; Shu ZHOU ; Xiaoyuan LIN ; Sainan ZHOU
Chinese Journal of Immunology 2025;41(7):1737-1742,1751
Objective:To explore the effect of Simo decoction improving the low duodenal inflammation and protecting the du-odenal mucosal barrier in rats with functional dyspepsia(FD).Methods:Sixty SD rats were randomly divided into control group(10 rats)and model group(50 rats),and the modeling rats were prepared by multivariate intervention method.After successful modeling,the modeling rats were randomly divided into model group,Simo decoction high-dose,medium-dose,low-dose group and mosapride group,with 10 rats in each group.The high-dose,medium-dose,and low-dose groups of Simo decoction were ga-vage given 5.62 g/kg,2.81 g/kg,and 1.40 g/kg,respectively,and the mosapride group was gavage given 0.305 mg/kg of mosapride,and the control group and model group were gavage given the same amount of distilled water for 14 days.The body weight of rats was observed;gastric emptying rate and small bowel propulsion rate were measured;transmission electron microscopy was used to observe the morphology of duodenal epithelial cells;ELISA detected serum levels of IL-17A and IL-22;Western blot and immunohistochemis-try were used to detect the expressions of protease-activated receptor 2(PAR-2)and tight junction protein(ZO-1,claudin-1)in the duodenum.Results:Compared with the control group,the body weight,gastric emptying rate and small intestinal propulsion rate of the model group were significantly reduced(P<0.01),transmission electron microscopy showed widening of the duodenal epithelial cell space,serum IL-17A and IL-22 levels were significantly increased(P<0.01),the expression of PAR-2 in duodenal tissue was in-creased,and the expressions of ZO-1 and claudin-1 were downregulated(P<0.01).Compared with model group,the gastric emptying rate and small intestinal propulsion rate in Simo decoction high-dose,medium-dose and mosapride group were increased(P<0.05,P<0.01),the contents of IL-17A and IL-22 in serum decreased(P<0.05,P<0.01),and the expression of PAR-2 in duodenal tissues was down-regulated,the expressions of ZO-1 and claudin-1 was significantly increased(P<0.01).The low-dose group of Simo soup could improve weight loss(P<0.01),reduce IL-17A content and PAR-2 expression,and increase ZO-1 and claudin-1 expression(P<0.05,P<0.01),while the effect on other indexes was not obvious.Conclusion:Simo decoction may reduce low-grade duodenal in-flammation to repair the mucosal barrier by down-regulating the levels of IL-17A and IL-22 and the expression of PAR-2,and up-regu-lating the expression of ZO-1 and claudin-1,so as to exert the effect of FD treatment.
7.Effects of Sishen Pills on the Expression of TREK-1 Signaling Pathway in Rats of Irritable Bowel Syndrome with Diarrhea
Xiaoyuan LIN ; Shuangyang LUO ; Na DENG ; Xuting XIA ; Jiemin LIU ; Yujie LI
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(10):94-99
Objective To observe the effect of Sishen Pills on the expression of TREK-1 signaling pathway in rats of irritable bowel syndrome with diarrhea(IBS-D);To explore its mechanism in treating IBS-D.Methods Ten SPF-grade SD rats were randomly selected as the normal group,and the remaining 30 rats were used to prepare the IBS-D rat model by senna gavage combined with water stress avoidance method,and then the modeled rats were randomly divided into the model group,Western medicine group(15.23 mg/kg pivoxyl bromide)and Chinese medicine group(7.32 g/kg Sishen Pills).The medication groups were gavaged by corresponding drugs,and the normal group and model group were given equal volume of pure water,once a day,for consecutive 14 d.The general state of the rats was observed,the contents of serum cyclic adenosine monophosphate(cAMP),protein kinase A(PKA)and phosphorylated extracellular signal-regulated kinase(p-ERK)were detected by ELISA,the positive expressions of biportal potassium channel TREK-1 and p-ERK in colonic tissue were detected by immunofluorescence,the expressions of cAMP,PKA and p-ERK protein were detected by Western blot.Results Compared with the normal group,the body mass of rats in the model group was significantly reduced,and loose stool rate significantly increased(P<0.01);the contents of cAMP,PKA and p-ERK in serum were significantly increased(P<0.05,P<0.01);the positive expression and protein expression of TREK-1 in colonic tissue were significantly reduced,while the positive expression of p-ERK significantly increased(P<0.01),and the expressions of cAMP and PKA proteins significantly increased(P<0.01).Compared with the model group,the body mass of rats in Chinese medince group significantly increased,and loose stool rate significantly decreased(P<0.01);the contents of cAMP,PKA and p-ERK in serum were significantly reduced(P<0.05,P<0.01);the positive expression and protein expression of TREK-1 in colonic tissue significantly increased(P<0.01),while the positive expression of p-ERK significantly decreased(P<0.05),and the expressions of cAMP and PKA proteins significantly decreased(P<0.01).Conclusion Sishen Pills may regulate intestinal motility by affecting the expression of the TREK-1 signaling pathway,thereby treating IBS-D.
8.Effects of Simo Decoction on the Gastrointestinal Dynamics of Rats with Functional Dyspepsia of Liver and Spleen Stagnation Syndrome
Sainan ZHOU ; Qian LUO ; Qin LIU ; Haiyue ZHANG ; Xiaoyuan LIN
Chinese Journal of Information on Traditional Chinese Medicine 2024;31(6):117-122
Objective To observe the effects of Simo Decoction on the expressions of vasoactive intestinal peptide(VIP)and its receptor 2(VIPR2)in rats with functional dyspepsia(FD)of liver and spleen stagnation syndrome;To investigate its mechanism of action in regulating gastrointestinal motility.Methods Totally 60 SD rats were randomly divided into blank group,model group,mosapride group(0.305 mg/kg)and Simo Decoction high-,medium-and low-dosage groups(5.62,2.81,1.40 g/kg).The liver and spleen qi stagnation FD rat model was prepared by multifactorial modeling method,and the corresponding drugs were given by gavage for 14 days.The general conditions of rats in each group were observed,and body mass,gastric emptying rate and small intestine propulsion rate were measured;the histological structure of gastric antrum tissue and duodenal tissue were observed by HE staining;the positive expressions of VIP and VIPR2 in duodenal tissue were observed by immunohistochemistry;the protein and mRNA expressions of VIP and VIPR2 in duodenal tissue were detected by Western blot and RT-PCR,respectively.Results Compared with the blank group,the general condition of the rats in model group was poorer,body mass,gastric emptying rate and small intestine propulsion rate were significantly lower(P<0.01),and the protein and mRNA expressions of VIP and VIPR2 in duodenal tissue significantly increased(P<0.05,P<0.01).Compared with the model group,the body mass,gastric emptying rate and small intestine propulsion rate in Simo Decoction high-and medium-dosage groups and the mosapride group significantly increased(P<0.05,P<0.01),and the protein and mRNA expressions of VIP and VIPR2 in duodenal tissue significantly decreased(P<0.05,P<0.01).HE staining showed no significant changes in the morphology of gastric antrum and duodenum tissues.Conclusion Simo Decoction may promote gastrointestinal motility by inhibiting the expressions of VIP and VIPR2 in duodenal tissue of FD rats with liver and spleen qi stagnation,thereby improving FD.
9.Effect of Jianpi Yichang Powder on the Expression of NLRP3 Inflammasome Signaling Pathway of Dendritic Cells Induced by TNF-α
Xiaoyuan LIN ; Longbiao CHEN ; Peiwen LUO ; Sainan ZHOU ; Jiemin LIU
Chinese Journal of Information on Traditional Chinese Medicine 2024;31(10):109-114
Objective To investigate the effects of Jianpi Yichang Powder on regulating the NLRP3 inflammasome signaling pathway to inhibit dendritic cells(DCs)inflammatory injury induced by TNF-α;To explore its mechanism in the treatment of ulcerative colitis.Methods C57BL/6 mice DCs were primitively isolated and cultured.The cultured DCs were randomly divided into the normal group,model group,negative control group,positive drug group and TCM group.DCs inflammatory microenvironment model was established by TNF-α induction.After corresponding treatments were given to each group,CCK-8 method was used to detect cell proliferation ability,immunofluorescence and Western blot were used to detect the protein expressions of NLRP3,ASC and Caspase-1 in DCs respectively,Western blot and RT-PCR were used to detect the protein and mRNA expressions of IL-1β and IL-18 in DCs.Results Compared with the normal group,the proliferation ability in DCs of model group significantly decreased(P<0.01),the positive expressions of NLRP3,ASC and Caspase-1 significantly increased,the expressions of NLRP3,ASC,Caspase-1,IL-18,IL-1β protein and IL-18,IL-1β mRNA in DCs significantly increased(P<0.01).Compared with the model group and negative control group,the proliferation ability of DCs significantly increased in positive drug group and TCM group(P<0.01),the positive expressions of NLRP3,ASC,and Caspase-1 significantly decreased(P<0.01),the protein expressions of NLRP3,ASC,Caspase-1,IL-1β and IL-18 significantly decreased(P<0.05,P<0.01),and the mRNA expressions of IL-1β and IL-18 significantly decreased(P<0.01).The cell proliferation ability,Caspase-1 positive expression,and IL-18 mRNA expression of TCM group were significantly higher than those of the positive drug group(P<0.05),while the mRNA expression of IL-1β was lower than that of the positive drug group(P<0.05).Conclusion Jianpi Yichang Powder can inhibit the inflammatory response of DCs induced by TNF-α,and its mechanism in the treatment of ulcerative colitis may be related to regulating the expressions of the NLRP3 inflammasome signaling pathway,including the expressions of NLRP3,ASC,Caspase-1,IL-18 and IL-1β.
10.Experimental study of the magnetic field correction factor of ionization chambers in MR-Linac
Yaping QI ; Jiahao LUO ; Yuan TIAN ; Zhipeng WANG ; Sunjun JIN ; Ji HUANG ; Xiaoyuan YANG ; Xin WANG ; Kun WANG
Chinese Journal of Radiation Oncology 2024;33(12):1119-1124
Objective:To measure the magnetic field correction factor of reference ionization chamber in a 1.5 T magnetic field and to explore the response of the ionization chamber among different angles between magnetic field and ionization chamber axis.Methods:A home-made magnetic compatible one-dimensional water tank was used to measure the response of PTW30013 and IBA FC65-G in 7 MV photon beam of Elekta Unity with and without magnetic field. The ionizing current was collected by PTW UNIDOS Tango electrometer. The effective measurement point of ionization chamber was positioned to the isocenter of MR-linac using electronic portal image device. The influence on water absorbed dose of reference point was obtained by Monte Carlo calculations.Results:The response of ionization chambers in strong magnetic field was related to the angle between chamber axis and magnetic field. The response of ionization chamber was significantly affected in perpendicular magnetic field with a deviation up to 4.54% compared to parallel magnetic field. The deviation between the magnetic field correction factors measured for parallel or reverse-parallel was 0.03%-0.24%. The magnetic field correction factors for PTW30013 and FC65-G measured in parallel magnetic field were 0.9934±0.0077 and 0.9990±0.0076, respectively.Conclusions:This study experimentally verifies that positioning the ionization chamber axis parallel to the magnetic field direction in MR-linac reference dosimetry can minimize the magnetic field impact. The determined magnetic field correction factor and uncertainty in 1.5 T magnetic field can provide necessary data for establishing an MR-linac reference dosimetry protocol.

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