1.Assessing High-density Y-SNP Panels for Paternal Haplogroup Assignment in Forensic Practice
De-Qin ZHANG ; Chun-Nian WANG ; Lin-Lin LOU ; Meng NI ; Jing GAO ; Jiang HUANG ; Li JIANG
Progress in Biochemistry and Biophysics 2026;53(2):458-469
ObjectiveThe accuracy of Y-chromosome haplogroup assignment is crucial for tracing paternal lineage in male samples. With the advancement of high-throughput sequencing technologies, high-density Y-SNP genotyping from whole-genome or array-based data has become a standard method for determiningY-chromosome haplogroups. This study systematically evaluated the performance of 4 commonly used high-density SNP genotyping systems—namely, the Global Screening Array (GSA), Chinese Genotyping Array (CGA), Affymetrix array, and the 1240K capture panel—for haplogroup assignment. This work provides a reference for data comparison across different systems. MethodsWe extracted genotype data for the 4 Y-SNP panels from 30× whole-genome sequencing (WGS) data of 1 590 male samples from the 1000 Genomes Project. Additionally, GSA array genotype data from 384 relative pairs (spanning 1st- to 12th-degree relationships) from 109 Chinese Han families were collected. Haplogroup assignment was performed using Y-LineageTracker v1.3.0 software. We assessed the concordance and resolution of haplogroup assignments between the four Y-SNP panels and the WGS data. The consistency and resolution of haplogroup assignments were also evaluated for both the 1000 Genomes Project samples and the 109 family samples collected in this study. Furthermore, the impact of varying numbers of Y-SNPs on haplogroup assignment was examined. ResultsThe GSA and CGA panels demonstrated superior resolution and discrimination of haplogroup subclades compared with the other two panels. The haplogroup assignments from the GSA, CGA, and 1240K panels showed high concordance with WGS data, with consistency rates exceeding 88.70%, whereas the Affymetrix platform exhibited a significantly lower consistency rate of 61.89%. Specifically, the GSA and CGA panels consistently demonstrated superior performance compared with the other two panels in the assignment of haplogroups O-M175 and H-L901, achieving complete concordance (100%) for both haplogroups. In contrast, the Affymetrix panel erroneously assigned all individuals belonging to haplogroup O-M175 to haplogroup K2-M526. Furthermore, its accuracy for haplogroup H-L901 was exceedingly low, at merely 1.41%. This poor performance was characterized by the misassignment of 98.59% of H-L901 samples—specifically, 1.41% to J-M304 and a predominant 97.18% to F-M89. For haplogroup R-M207, all four panels exhibited uniformly high levels of consistency, with concordance values exceeding 94.00%. Notably, for haplogroup E-M96, the 1240K and Affymetrix panels outperformed the GSA and CGA panels in terms of concordance, representing the first instance in which these two panels surpassed the latter. Conversely, for haplogroups J-M304, Q-M242, and I-M170, all 4 panels showed relatively elevated misclassification rates, with the Affymetrix array demonstrating the poorest overall performance. None of the four panels showed any discordant haplogroup assignments among the familial relative pairs analyzed. A positive correlation was observed between the number of Y-SNPs (ranging from 1 000 to 10 000) and classification consistency; however, classification consistency plateaued when the number of Y-SNPs exceeded 10 000. Furthermore, a random sampling analysis conducted on the GSA and CGA panels demonstrated that the haplogroup misclassification rate exhibited negligible fluctuation across the Y-SNP range of 500 to 1 000. Conversely, a marked enhancement in classification consistency was observed as the number of markers increased from 1 000 to 5 000, ultimately reaching a plateau within the interval of 5 000 to 8 000 markers. ConclusionThese findings indicate that the GSA and CGA panels provide high resolution and concordance, delivering reliable Y-haplogroup assignment for forensic investigations.
2.Assessing High-density Y-SNP Panels for Paternal Haplogroup Assignment in Forensic Practice
De-Qin ZHANG ; Chun-Nian WANG ; Lin-Lin LOU ; Meng NI ; Jing GAO ; Jiang HUANG ; Li JIANG
Progress in Biochemistry and Biophysics 2026;53(2):458-469
ObjectiveThe accuracy of Y-chromosome haplogroup assignment is crucial for tracing paternal lineage in male samples. With the advancement of high-throughput sequencing technologies, high-density Y-SNP genotyping from whole-genome or array-based data has become a standard method for determiningY-chromosome haplogroups. This study systematically evaluated the performance of 4 commonly used high-density SNP genotyping systems—namely, the Global Screening Array (GSA), Chinese Genotyping Array (CGA), Affymetrix array, and the 1240K capture panel—for haplogroup assignment. This work provides a reference for data comparison across different systems. MethodsWe extracted genotype data for the 4 Y-SNP panels from 30× whole-genome sequencing (WGS) data of 1 590 male samples from the 1000 Genomes Project. Additionally, GSA array genotype data from 384 relative pairs (spanning 1st- to 12th-degree relationships) from 109 Chinese Han families were collected. Haplogroup assignment was performed using Y-LineageTracker v1.3.0 software. We assessed the concordance and resolution of haplogroup assignments between the four Y-SNP panels and the WGS data. The consistency and resolution of haplogroup assignments were also evaluated for both the 1000 Genomes Project samples and the 109 family samples collected in this study. Furthermore, the impact of varying numbers of Y-SNPs on haplogroup assignment was examined. ResultsThe GSA and CGA panels demonstrated superior resolution and discrimination of haplogroup subclades compared with the other two panels. The haplogroup assignments from the GSA, CGA, and 1240K panels showed high concordance with WGS data, with consistency rates exceeding 88.70%, whereas the Affymetrix platform exhibited a significantly lower consistency rate of 61.89%. Specifically, the GSA and CGA panels consistently demonstrated superior performance compared with the other two panels in the assignment of haplogroups O-M175 and H-L901, achieving complete concordance (100%) for both haplogroups. In contrast, the Affymetrix panel erroneously assigned all individuals belonging to haplogroup O-M175 to haplogroup K2-M526. Furthermore, its accuracy for haplogroup H-L901 was exceedingly low, at merely 1.41%. This poor performance was characterized by the misassignment of 98.59% of H-L901 samples—specifically, 1.41% to J-M304 and a predominant 97.18% to F-M89. For haplogroup R-M207, all four panels exhibited uniformly high levels of consistency, with concordance values exceeding 94.00%. Notably, for haplogroup E-M96, the 1240K and Affymetrix panels outperformed the GSA and CGA panels in terms of concordance, representing the first instance in which these two panels surpassed the latter. Conversely, for haplogroups J-M304, Q-M242, and I-M170, all 4 panels showed relatively elevated misclassification rates, with the Affymetrix array demonstrating the poorest overall performance. None of the four panels showed any discordant haplogroup assignments among the familial relative pairs analyzed. A positive correlation was observed between the number of Y-SNPs (ranging from 1 000 to 10 000) and classification consistency; however, classification consistency plateaued when the number of Y-SNPs exceeded 10 000. Furthermore, a random sampling analysis conducted on the GSA and CGA panels demonstrated that the haplogroup misclassification rate exhibited negligible fluctuation across the Y-SNP range of 500 to 1 000. Conversely, a marked enhancement in classification consistency was observed as the number of markers increased from 1 000 to 5 000, ultimately reaching a plateau within the interval of 5 000 to 8 000 markers. ConclusionThese findings indicate that the GSA and CGA panels provide high resolution and concordance, delivering reliable Y-haplogroup assignment for forensic investigations.
3.Development and Validation of a High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for Detecting Adrenocortical Hormones and Establishment of Age-Stratified Reference Intervals in Reproductive-Aged Women from Guangxi, China
Yixuan LIU ; Tingwei JIN ; Yushuang WEI ; Xuelian QIN ; Siyu DENG ; Jie ZHENG ; Boteng YAN ; Yuanyuan NONG ; Yu YE ; Shengzhu HUANG ; Yu LONG ; Jianmin LI ; Ganqin WANG ; Pei HUANG ; Jinghang JIANG ; Fan WU ; Zengnan MO ; Yonghua JIANG
Annals of Laboratory Medicine 2026;46(2):146-154
Background:
Adrenocortical hormones, particularly 11-oxygenated androgens, are pivotal in female reproductive health and fertility. Standardized detection kits and population-specific reference intervals are lacking in China, hindering related clinical applications.
Methods:
A HPLC-tandem mass spectrometry (HPLC-MS/MS) pipeline was developed, rigorously validated, and applied to simultaneously quantify corticosterone, cortisone, cortisol, 18-OH cortisol, androstenedione (A4), 11β-hydroxyandrostenedione (11-OH A4), dehydroepiandrosterone, and dehydroepiandrosterone sulfate in serum samples from 455 reproductive-aged women (18–45 yrs) in Guangxi, China. Age-dependent concentration trends were analyzed, and reference intervals stratified by age (2.5th to 97.5th percentiles) were established. Correlations with body-composition metrics, ethnicity, and the menstrual cycle were investigated.
Results:
The HPLC-MS/MS method demonstrated high precision (intra- and inter-assay CVs < 15%), accuracy, and sensitivity. All eight hormones exhibited significant age-related declines (P < 0.001 for seven hormones; P = 0.001 for 11-OH A4). Notably, 11-OH A4 levels were significantly lower in the 35–45-yr (3.05 nmol/L) and 25–34-yr (3.09 nmol/L) age groups than in the 18–24-yr (3.57 nmol/L) age group, whereas no significant difference was observed between the 35–45-yr and 25–34-yr age groups. Weak negative correlations were observed between the body mass index and corticosterone and cortisone levels, whereas ethnicity and the menstrual cycle showed no significant associations with hormone levels.
Conclusions
We developed an HPLC-MS/MS-based method for simultaneously quantifying eight adrenocortical hormones, including 11-OH A4, and defined age-specific reference intervals for reproductive-aged Chinese women. These findings advance the clinical utility of adrenocortical hormones in diagnosing and managing reproductive disorders.
4.Consistent Detection of Aquaporin-4 Antibodies:A Comparative Analysis Between Fixed and Live Cell-Based Assays
Jing WANG ; Linge WANG ; Xiaolin YANG ; Zhizhong LI ; Jinyu JIANG ; Qiao XU ; Siyuan HUANG ; Qing FU ; Yang YANG ; Rongrong ZHANG ; Lin YANG ; Ai CHEN ; Xiaopeng ZENG ; Ke XU ; Peng ZHENG ; Xinyue QIN ; Jinzhou FENG
Journal of Clinical Neurology 2026;22(2):212-220
Background:
and Purpose Live cell-based assays (LCBA) are increasingly used for serological antibody detection due to their ability to preserve antigen conformation, offering moderately higher sensitivity than fixed cell-based assays. However, the clinical necessity of prioritizing LCBA for the detection of aquaporin-4 immunoglobulin G (AQP4-IgG) in neuromyelitis optica spectrum disorder (NMOSD) remains unclear, especially when compared to its established role in diagnosing myelin oligodendrocyte glycoprotein antibody-associated disease.
Methods:
We compared the performance of live cell-based assays using immunofluorescence (LCBA-IF) and fixed cell-based assays using immunofluorescence (FCBA-IF) in detecting AQP4-IgG in 90 cases of NMOSD meeting 2015 International Panel for Neuromyelitis Optica Diagnosis criteria, alongside 40 controls. Additionally, we further investigated the relationship between AQP4-IgG titers as measured by LCBA-IF and FCBA-IF and clinical parameters in NMOSD patients.
Results:
Results showed 96.9% agreement between LCBA-IF and FCBA-IF (Cohen’s κ=0.935), with a strong Spearman correlation (0.977, p<0.001). Both methods demonstrated 100% specificity, with LCBA-IF showing slightly higher sensitivity compared to FCBA-IF. Within LCBAIF-tested groups, statistically significant differences in annualized relapse rates were observed across all pairwise comparisons (low-titer vs. moderate-titer, low-titer vs. high-titer, and moderate-titer vs. high-titer; all p<0.050). However, this association reached statistical significance in some FCBA-IF-tested groups.
Conclusions
Overall, there is a strong concordance between LCBA-IF and FCBA-IF in detecting AQP4-IgG, where LCBA-IF shows slightly higher sensitivity. Furthermore, there is a potential link between elevated AQP4-IgG titers and an increased risk of relapse, and this correlation may appear more pronounced when using LCBA-IF.
5.Visualization Analysis of Research Hotspots and Development Trends of Immune Cells in Radiotherapy for Rectal Cancer
Lingzhen JIANG ; Feiyu QIN ; Yuna LI ; Yan QIN ; Junhui TANG ; Liang MING ; Xiaowei QI ; Zhaohui HUANG ; Yuan YIN
Cancer Research on Prevention and Treatment 2026;53(7):523-533
Objective To analyze the overall characteristics, research hotspots, and development trends of immune cell-related studies in radiotherapy for rectal cancer. Methods A systematic search was conducted by using Web of Science Core Collection to retrieve articles related to radiation therapy and immune cells in rectal cancer published from 1991 to 2024. Advanced bibliometric tools, such as VOSviewer and CiteSpace, were utilized to facilitate analysis and describe publication trends, geographic contributions, institutional affiliations, journal prominence, author collaboration, and prominent keywords. Results The annual number of relevant publications has increased steadily, showing remarkable growth over the past five years. Studies focusing on adaptive immune cells (T and B cells) account for the largest proportion of works and form the most extensive collaboration networks, reflecting the central role of T cell–mediated antitumor immunity in radiotherapy. Meanwhile, innate immune cells, including myeloid-derived suppressor cells, macrophages, monocytes, and neutrophils, are increasingly investigated for their regulatory roles in shaping the tumor immune microenvironment and influencing therapeutic responses. Among countries, China and the United States have contributed the highest number of publications and demonstrated strong academic influence. While several stable research groups have been formed, intergroup collaboration remains limited. Keyword analysis revealed that radiotherapy-induced immune modulation, tumor immune microenvironment remodeling, and treatment response have emerged as major research hotspots. Conclusion Research on immune cells in rectal cancer radiotherapy has progressed rapidly in recent years. The emphasis of this field has gradually shifted from single-treatment approaches to mechanistic studies investigating the interaction between radiotherapy and the tumor immune microenvironment. The field still demonstrates considerable potential for future research and clinical translational applications.
6.Latent profile analysis of non-suicidal self-injury behaviors in adolescent outpatients
Liqiong LIN ; Qianle LEI ; Huang feng LIN ; Qin JIANG
Sichuan Mental Health 2025;38(5):427-433
BackgroundPrevious studies on subgroups of adolescent non-suicidal self-injury (NSSI) behaviors have predominantly focused on community and school-based samples, with limited research on clinical samples. The precise identification of clinically distinct NSSI subgroups in adolescents is critical for optimizing medical resource allocation. ObjectiveTo explore the subgroups of NSSI in adolescent outpatients, and to provide references for intervening of NSSI behaviors. MethodsFrom May 2021 to April 2022, 192 adolescents who met the NSSI diagnostic criteria as outlined in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) were recruited from psychiatry or psychology clinics at 6 hospitals in Fujian Province. Participants were assessed using the Adolescent Non-suicidal Self-injury Assessment Questionnaire (ANSAQ), the Childhood Trauma Questionnaire (CTQ), the Depression Anxiety Stress Scale-21 item(DASS-21) and the Difficulties in Emotion Regulation Scale (DERS). Latent profile analysis was conducted using Mplus 8.0. ResultsA total of 192 adolescents with NSSI behaviors completed the study, and the analysis yielded three subgroups of self-injurers: the mild self-injury group (50 cases, 26.04%), the emotional disorder group (81 cases, 42.19%), and the severe self-injury group (61 cases, 31.77%). There were significant differences in the total scores of CTQ, DASS-21 and DERS among the three groups (F=8.058, 51.414, 48.742, P<0.01). The severe self-injury group exhibited significantly higher scores in CTQ, DASS-21 and DERS when compared to both the mild self-injury group and the emotional disorder group (P<0.05). Moreover, the emotional disorder group also reported notably higher DASS-21 and DERS scores in comparison to the mild self-injury group (P<0.05). ConclusionClinical studies on adolescent outpatients engaging in NSSI behaviors reveal three distinct typological profiles, mild self-injury, emotional disorder-related self-injury, and severe self-injury. [Funded by Fujian Social Science Planning Project (number, FJ2019B173)]
7.Analysis of the status and related factors of hyperopic reserve among non-myopia children aged 5-12 years in Guangdong Province
JIANG Jing, LI Meng, SUN Yi, LIN Rong, HUANG Zhenhui, LIU Rong, QIN Ran, GUO Xin, QU Yabin
Chinese Journal of School Health 2025;46(12):1787-1791
Objective:
To explore the current status of hyperopic reserve and its related factors among non-myopia preschool and primary school students aged 5 to 12 years in Guangdong Province, so as to provide a basis for formulating intervention strategies for the pre myopia stage of children.
Methods:
From October to December 2023, by using stratified cluster random sampling method, a survey on hyperopic reserve among preschool children and primary school students in Guangdong were conducted. And a total of 10 567 children from the senior class of kindergarten to the sixth grade of primary school who completed autorefraction measurements with and without cycloplegia and the questionnaire survey were included in the study. The prevalence characteristics of low hyperopic reserve among non-myopia children were analyzed, and multivariable Logistic regression was used to analyze the related factors.
Results:
The prevalence rate of low hyperopic reserve among 8 790 non-myopia children was 62.4%. The average spherical equivalent (SE) for children aged 5 to 12 years was 0.88 (0.25, 1.25)D, decreasing from 1.13 ( 0.75 , 1.50)D in senior kindergarten to -1.00 (-2.50, 0.38)D in sixth grade, with the difference was statistically significant ( H=2 475.3, P <0.01). Multivariable Logistic regression analysis, after adjusting for confounders including gender, urban and rural, and grade, revealed that parental myopia was a risk factor for low hyperopic reserve in the preschool stage (one parent with myopia: OR=1.62, 95%CI =1.35-1.93; both parents with myopia: OR=2.05, 95%CI = 1.66 -2.55); in the lower primary school stage, parental myopia (one parent with myopia: OR=1.46, 95%CI =1.27-1.68; both parents with myopia: OR=1.58, 95%CI =1.33-1.89), frequently or always reading or using electronic screens while lying down or on one s stomach ( OR=1.43, 95%CI =1.13-1.81), and never or occasionally maintaining a viewing distance of over 3 meters when watching TV/playing video games ( OR=1.34, 95%CI =1.04-1.72) were risk factors; in the higher primary school stage, failing to take a break every hour during near work ( OR=1.79, 95%CI =1.16-2.75) was a risk factor (all P <0.05).
Conclusions
The emmetropization of children aged 5-12 years in Guangdong Province is accelerated, and non-myopia children generally exhibit insufficient hyperopic reserve. The contributing factors for insufficient hyperopia reserve in non-myopia children vary across different educational stages, necessitating targeted precision interventions.
8.Correlation analysis of central venous oxygen saturation-related indexes at different time points with low cardiac output syndrome in children after congenital heart disease correction surgery
Jingxiao LI ; Yunkai CAI ; Binfeng LEI ; Wei LU ; Liqin MO ; Weifeng HUANG ; Chaohai LYV ; Liuying QIN ; Jingwei JIANG ; Ting ZHOU
Chongqing Medicine 2025;54(5):1155-1160
Objective To explore the correlation between central venous oxygen saturation(ScvO2)-re-lated indexes at different time points and the occurrence of low cardiac output syndrome(LCOS)after con-genital heart disease(CHD)correction surgery.Methods A total of 73 children who underwent CHD correc-tion surgery in this hospital from July 1st,2021 to July 1st,2024 were selected as the research subjects.The clinical data,preoperative conditions,and postoperative conditions of the children were collected.The ScvO2 and arterial lactate(Lac)levels of the children at different time points(the 1st,6th,12th,and 24th hours after surgery)were monitored,and the ScvO2/Lac at different time points and the change rate of ScvO2 in different time periods were calculated.The correlation between ScvO2-related indexes and LCOS after CHD correction surgery was analyzed.Results ScvO2 at the 6th hour after surgery,ScvO2 at the 12th hour after surgery,Sc-vO2/Lac at the 12th hour after surgery,the change rate of ScvO2 from the 1st to the 24th hour after surgery,the change rate of ScvO2 from the 6th to the 12th hour after surgery,and the change rate of ScvO2 from the 12th to the 24th hour after surgery were independent influencing factors of LCOS occurrence after CHD cor-rection surgery(P<0.05).There was a negative correlation between ScvO2 at the 12th hour after surgery,ScvO2/Lac and LCOS occurrence after CHD correction surgery(r=-0.543,-0.523,P<0.05).The area under the curve(AUC)of ScvO2 at the 12th hour after surgery for predicting LCOS occurrence after CHD correction surgery was 0.938(95%CI:0.865-1.000);the AUC of ScvO2/Lac at the 12th hour after surgery for predicting LCOS occurrence after CHD correction surgery was 0.922(95%CI:0.851-0.994).Conclusion ScvO2 and ScvO2/Lac at the 12th hour after surgery have good predictive potential for LCOS occurrence af-ter CHD correction surgery.
9.Exploring aspirin discontinuation timing based on third-trimester risk reassessment in women with first-trimester high risk of pre-eclampsia
Xiaoyan HUANG ; Meiqin JIANG ; Qianqian LIN ; Wenjing MENG ; Qin XUE
Chinese Journal of Obstetrics and Gynecology 2025;60(9):709-715
Objective:To investigate whether continued low-dose aspirin (LDA) intervention affects the incidence of pre-eclampsia (PE) and adverse pregnancy outcomes in pregnant women with high-risk PE screening in the first trimester and reassessed as low risk at 28 weeks of gestation.Methods:This study was a prospective observational cohort study. From April 2022 to April 2024, a total of 106 pregnant women who underwent prenatal examination in the Affiliated Jiangyin Hospital of Nantong University were enrolled. They were assessed as high risk of PE by multiple indicators combined screening at 11-13 +6 weeks of gestation, received LDA intervention, and were reassessed as low risk of PE at 28 weeks of gestation. The patients were divided into withdrawal group (49 cases) and continuation group (57 cases). The incidence of PE and adverse pregnancy outcomes were compared between the two groups. Results:(1) There were no statistically significant differences in general conditions and the incidence of pregnancy complications between the two groups (all P>0.05). During the PE risk screening at 11-13 +6 weeks of gestation, there were no statistically significant differences in mean arterial pressure (MAP) and ultrasound uterine artery pulsation index (UtPI) between the two groups (all P>0.05), but the placental growth factor (PlGF) level in the withdrawal group was significantly lower than that in the continuation group ( P=0.023). There was no significant difference in the proportion of pregnant women with high risk of PE before 32 weeks and 34 weeks of pregnancy between the two groups (all P>0.05). (2) There were 7 cases (14%, 7/49) of PE in the withdrawal group, including 1 case (2%, 1/49) of early-onset PE and 3 cases (6%, 3/49) of PE before 37 weeks of pregnancy. There were 11 cases (19%, 11/57) of PE in the continuation group, including 2 cases (4%, 2/57) of early-onset PE and 4 cases (7%, 4/57) of PE before 37 weeks of pregnancy. There were no significant differences in the incidence of PE (including early-onset PE and PE before 37 weeks of pregnancy), gestational hypertension, severe PE, chronic hypertension complicated with PE and chronic hypertension complicated with pregnancy between the two groups (all P>0.05). (3) There were no significant differences in cesarean section rate, preterm birth rate, placental abruption, postpartum hemorrhage, fetal growth restriction, fetal distress rate, neonatal birth weight, neonatal asphyxia, and 1-minute and 5-minute Apgar scores between the two groups (all P>0.05). No stillbirth occurred in the two groups. Conclusion:For pregnant women with high risk of PE screening in the first trimester and taking LDA intervention, there is no difference in the incidence of PE and adverse pregnancy outcomes whether to continue LDA or not after being reassessed as low risk at 28 weeks of gestation.
10.A study and application of rapid and precise dose measurement based on Gafchromic EBT4 film in FLASH radiotherapy
Yi ZHANG ; Yiwei YANG ; Yinghong TANG ; Shilan WANG ; Peng WU ; Qin YANG ; Xufan HUANG ; Yin LUO ; Yu JIANG ; Wenjun LUO ; Guiqiang ZOU ; Hua FENG ; Yinxiang HU
Chinese Journal of Radiological Medicine and Protection 2025;45(11):1144-1151
Objective:To establish a rapid and precise dose measurement method with EBT4 film and ensure its measurement accuracy to be within the required range through strict operational procedures for the purpose of addressing the two essential issues of poor measurement accuracy and timeliness of EBT film under FLASH conditions.Methods:After storing under different humidity conditions for a certain period of time, the film was exposed to radiation for analyzing the influence of air humidity on the intrinsic performance of EBT film. By means of repeated scanning operations and the film angle rotation, the influences of repeated scanning and film placement angle were analuzed. Parabolic correction method was used to reduce the spatial position influence during the scanning process. By analying the relationship between net optical density (netOD) and absorbed dose through the comparison of three fitting method, the optimal fitting curve was selected. After irradiation of the same batch of films for 5 min and 24 h, the film doses were calibrated and then compared with ionization chamber-measured result. The rapid and precise film dosimetry method was used to measure both the percentage depth dose from X-rays at ultra-high dose rate and the dose distribution at a depth of 2 cm in water.Results:Air humidity had the greatest influence on the intrinsic performance of EBT film (approximately 20%). The average deviation of repeated scans is within 0.5%. The angle at which the film is placed significantly affected the readouts of the film with the maximum influence approximately 70%. The net optical density combined with polynomial fitting can control the fitting residuals of 1-16 Gy within 3%. The change rate of light channels at 5 min already mostly met the requirements of the rapid mode (< 0.5%). Compared with the measurement result obtained using the reference ionization chamber, the deviations of the 5 min or 24 h dose calibration curves were all within 2%.Conclusions:The EBT4 film can be employed as a precise dosimeter to quickly measure the FLASH radiation dose. Rapid and precise FLASH dose measurements can meet the stringent requirements of both preclinical and clinical FLASH research.


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