Research Progress and Forensic Application of Human Vascular Finite Element Modeling and Biomechanics / 法医学杂志

The finite element method (FEM) is a mathematical method for obtaining approximate solutions to a wide variety of engineering problems. With the development of computer technology, it is gradually applied to the study of biomechanics of human body. The application of the combination of FEM and biomechanics in exploring the relationship between vascular injury and disease, and pathological mechanisms will be a technological innovation for traditional forensic medicine. This paper reviews the construction and development of human vascular FEM modeling, and its research progress on the vascular biomechanics. This paper also looks to the application prospects of FEM modeling in forensic pathology.

Survey on the Construction Status of Forensic Virtual Autopsy Laboratory and the Applicability of Laboratory Accreditation / 法医学杂志

OBJECTIVES@#To survey the development status and actual needs of virtual autopsy technology in China and to clarify the applicability of forensic virtual autopsy laboratory accreditation.@*METHODS@#The questionnaire was set up included three aspects：(1) the current status of virtual autopsy technology development; (2) the accreditation elements such as personnel, equipment, entrustment and acceptance, methods, environmental facilities; (3) the needs and suggestions of practicing institutions. A total of 130 forensic pathology institutions were surveyed by online participation through the Questionnaire Star platform.@*RESULTS@#Among the 130 institutions, 43.08% were familiar with the characteristics of virtual autopsy technology, 35.38% conducted or received training in virtual autopsy, and 70.77% have establishment needs (including maintenance). Relevant elements were suitable for laboratory accreditation.@*CONCLUSIONS@#Virtual autopsy identification has gained social recognition. There is a demand for accreditation of forensic virtual autopsy laboratory. After the preliminary assessment, considering the characteristics and current situation of this technology, China National Accreditation Service for Conformity Assessment (CNAS) can first carry out the accreditation pilot of virtual autopsy project at large comprehensive forensic institutions with higher identification capability, and then CNAS can popularize the accreditation in a wide range when the conditions are suitable.

Effects of long working hours exposure on occupational stress and depression symptoms in couriers in Zhejiang Province / 中华劳动卫生职业病杂志

Objective: To understand the current situation of long working hours exposure of couriers in Zhejiang Province, and to analyze the influence of long working hours exposure levels on their occupational stress and depression symptoms, and provide a basis for promoting the physical and mental health of couriers. Methods: From September to December 2021 , 1159 couriers from Zhejiang Express Transport Companies were selected as respondents by cluster sampling, and their basic information were collected. The occupational stress and depression symptoms of the couriers were assessed using the Core Occupational Stress Scale (COSS) and the Patient Health Questionnaire-9 (PHQ-9). The effects of long work hours (>48 h per week) on the occupational stress and depression symptoms of the couriers were analyzed. Results: The average age of 1159 courier in Zhejiang Province was (33.24±8.42) years, the average weekly working hours were (63.21±18.77) h, and 75.15% (871/1159) were long-term workers. The detection rates of occupational stress and depression symptoms in courier were 32.44% (376/1159) and 32.53% (377/1159), respectively. There were significant differences in the detection rates of occupational stress and depression symptoms among couriers with different ages, educational background, marital status, monthly average income, length of service, position or post, shift status, drinking status, and average weekly working hours (P <0.05). The adjusted logistic regression analysis showed that, after adjusting for the influence of confounding factors such as age, educational background, marital status, monthly average income, length of service, position or post, shift status and drinking status, compared with the weekly working hours ≤48 h, weekly working hours of 63-77 h, 78-92 h, ≥93 h were the risk factors for occupational stress (OR=1.547, 95%CI: 1.019-2.350; OR=1.886, 95%CI: 1.184-3.006; OR=2.338, 95%CI: 1.188-4.062) and depression symptoms (OR=1.897, 95%CI: 1.258-2.860; OR=2.041, 95%CI: 1.290-3.230; OR=4.978, 95%CI: 2.551-9.715) of couriers (P<0.05) . Conclusion: Long working hours could increase the risk of occupational stress and depression symptoms among couriers. It is necessary to arrange working hours reasonably to reduce the occurrence of occupational stress and depression symptoms of couriers.

Comparison of CT Values between Thrombus and Postmortem Clot Based on Cadaveric Pulmonary Angiography / 法医学杂志

OBJECTIVES@#To explore the difference in CT values between pulmonary thromboembolism and postmortem clot in postmortem CT pulmonary angiography (CTPA) to further improve the application value of virtual autopsy.@*METHODS@#Postmortem CTPA data with the definite cause of death from 2016 to 2019 were collected and divided into pulmonary thromboembolism group (n=4), postmortem clot group (n=5), and control group (n=5). CT values of pulmonary trunk and left and right pulmonary artery contents in each group were measured and analyzed statistically.@*RESULTS@#The average CT value in the pulmonary thromboembolism group and postmortem clot group were (168.4±53.8) Hu and (282.7±78.0) Hu, respectively, which were lower than those of the control group (1 193.0±82.9) Hu (P<0.05). The average CT value of the postmortem clot group was higher than that of the pulmonary thromboembolism group (P<0.05).@*CONCLUSIONS@#CT value is reliable and feasible as a relatively objective quantitative index to distinguish pulmonary thromboembolism and postmortem clot in postmortem CTPA. At the same time, it can provide a scientific basis to a certain extent for ruling out pulmonary thromboembolism deaths.

Investigation on 90Sr and 137Cs activity concentrations in water in Hangzhou urban area from 2012 to 2020 / 中华放射医学与防护杂志

Objective:To investigate the activity concentrations of 90Sr and 137Cs in water in Hangzhou urban area. Methods:From 2012 to 2020, Qiantang River water as an important drinking water source, tap water as direct drinking water for residents, and West Lake water in tourists crowded area were selected forwater quality monitoring with respect to conctnts of 90Sr and 137Cs. The activity concentrations of 90Sr and 137Cs in water samples, as collected in wet and dry seasons resepectively, were determined by radiochemical analysis, with the 137Cs to 90Sr activity ratios obtained. Results:From 2012 to 2020, the activity concentrations of 90Sr and 137Cs in tap water were (2.0±1.1) - (7.4±0.4) mBq/L and (0.45±0.06) - (7.1±0.6) mBq/L, respectively. The 137Cs to 90Sr activity ratios ranged from 0.07 to 2.40. The activity concentrations of 90Sr and 137Cs in Qiantang River were (3.7±1.1) - (17.0±4.4) mBq/L and (0.28±0.01) - (15.0±4.5) mBq/L, respectively. The 137Cs to 90Sr activity ratios ranged from 0.03 to 0.90. The activity concentrations of 90Sr and 137Cs in West Lake water were (2.2±0.5) - (11.0±2.0) mBq/L and (0.32±0.04) - (7.9±1.9) mBq/L, respectively. The 137Cs to 90Sr activity ratios ranged from 0.05 to 1.20. Conclusions:The activity concentrations of 90Sr and 137Cs in water in Hangzhou urban area were at the background levels, lower than the concentration limits, 10 Bq/L both for 90Sr and 137Cs recommended by WHO in the 4 th edition of Guidelines for Drinking Water Quality.

Research progress on the protective effect and mechanism of puerarin on diabetic retinopathy / 国际眼科杂志(Guoji Yanke Zazhi)

Increasing prevalence and incidence of diabetes mellitus(DM)-the most common chronic consumptive disease worldwide-has a devastating impact on people's daily lives, particularly through the deterioration or complete loss of vision brought on by diabetic retinopathy(DR). Therefore, it is imperative to investigate the pathogenesis and effective treatment of DR. Meanwhile, Pueraria lobata is the extensively used dried root of kudzu or dried kudzu, also known as Pueraria flavonoids. Moreover, its roots are primarily composed of isoflavones, Pueroside ABC, triterpenes, and alkaloids, which can calm cardio-cerebrovascular smooth muscle and enhance microcirculation. Currently, it is widely employed for the treatment of cardio-cerebrovascular diseases, osteonecrosis, DM and its complications, neurodegenerative disorders, endometriosis and tumor diseases. Inhibiting retinal neovascularization, alleviating ischemia and hypoxia, decreasing advanced glycation end products in diabetes, raising insulin-like growth factor(IGF)expression while decreasing tumor necrosis factor-α(TNF-a)expression, decreasing vascular endothelial growth factor(VEGF)expression, reducing retinal nerve cell death, inhibiting the NOD-like receptor protein 3(NLRP3)inflammatory pathway and inhibiting ferroptosis are all mechanisms by which puerarin(Pue)has been found to protect the retina in recent studies. Thus, this article summarizes the current comprehension of the mechanism and protective effect of Pue on diabetic retina, serving as a guidepost for its future development and application.

Thoughts on improving comprehensive risk assessment method of occupational disease hazards of employers / 环境与职业医学

The National Disease Control and Prevention Bureau and the National Health Commission jointly issued an announcement on Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement, which presented a method of comprehensive risk assessment method of occupational disease hazards of employers. This method embraces relevant factors at full scale and is simple in operation, but its applicability and accuracy of assessment results need further practical study. Based on the steps of occupational health risk assessment and proven occupational health risk assessment methods available at home and abroad, this paper proposed improvements and discussed the comprehensive risk assessment method of occupational disease hazards of employers, so as to provide a technical basis to implement the occupational disease hazard classification management of employers for relevant government supervision departments.

Development and present situation of occupational health grading and classification supervision methods of employers in China / 环境与职业医学

In the face of a serious occupational disease prevention and control situation, the lack of efficient supervision and regulation methods has become a prominent contradiction. This paper reviewed the progress and application of occupational health grading and classification supervision methods for employers in China in recent years, and analyzed the characteristics and limitations of selected methods. The grading and classification supervision methods have gradually developed from considering only inherent health risk of occupational disease hazards, to considering both inherent attributes of occupational disease hazards and exposure duration. Some regional authorities introduced trial measures for grading and classification of occupational health supervision by embracing exposure level of an occupational disease hazard of interest, associated outcome severity, and occupational health management situation of targeted employers. In October 2022, the National Disease Control and Prevention Bureau issued the Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement, which further promoted the establishment of a differentiated occupational health supervision model. Grading and classification of occupational health supervision can improve the supervision efficiency of public health administration departments and promote employers to fulfill the main responsibility of occupational disease prevention and control.

Research progress on health effects associated with exposure to long working hours / 环境与职业医学

The phenomenon of workers working beyond standard working hours is called long working hours. In recent years, more and more relevant studies at home and abroad have shown the association between long working hours and adverse health effects of occupational populations, such as increased risks of cardiovascular diseases, diabetes, and various psychological conditions such as depression and occupational stress. However, the current research has not yet reached a consistent conclusion. The main reason is that the physiological and psychological effects of exposure to long working hours need to be explored in depth. Therefore, based on the relevant research progress at home and abroad, this article introduced the health effects of long working hours from both physical and psychological aspects, including hypertension, cardiovascular diseases, diabetes, depression, and job burnout, expounded related mechanisms involved, and indicated deficiencies in current research on long working hours and the next research directions.

Characteristics of occupational hearing loss in Zhejiang Province from 2006 to 2020 / 环境与职业医学

Background Occupational hearing loss associated with noise is becoming more and more serious, and occupational noise-induced deafness has become the second most frequently reported occupational disease in China. Objective To characterize occupational hearing loss in Zhejiang Province so as to provide a basis for the formulation of hearing protection strategies and measures. Methods Through the occupational diseases reporting system, the data of new cases of occupational noise-induced deafness in Zhejiang Province from 2006 to 2020 and the audiometry results of laborers who were exposed to occupational noise and participated in physical examinations from 2015 to 2020 were collected. The distribution of new cases of occupational noise-induced deafness were described in categories of region, year, industry, enterprise scale, age, onset age, and length of work, as well as the detection of increased high-frequency hearing threshold of workers who ordered occupational health examination in each year. Results A total of 575 cases of occupational noise-induced deafness were reported in Zhejiang Province from 2006 to 2020, of which 526 cases were male and 49 were female. The mean onset age of patients with noise-induced deafness was (44.8±8.0) years. There was a significant difference in mean onset age between male and female (t=3.420, Ρ=0.001). The median length of work [M (P25, P75)] at the time of onset was 9.0 (5.5, 13.2) years. The number of cases of noise-induced deafness and its proportion to the total number of occupational diseases in a year showed an increasing trend from 2006 to 2020 and the average annual growth rate was 22.11%. The patients were mainly distributed in the Hangzhou, Ningbo, and Jiaxing, and the number of cases were 194, 140, and 112, respectively, accounting for 77.5% of the total cases in Zhejiang Province. Manufacturing industry was dominant one in terms of the number of cases, which accounted for 89.6% (515 cases). Private economic enterprise, in terms of economic type, accounted for 57.4% (330 cases). There were significant differences in the length of work at the time of onset among different economic types of enterprises (H=29.081, Ρ<0.001). There were 215 cases in the medium-sized enterprises and 265 in the small- and micro-sized enterprises, respectively, accounting for 83.5% of the the total number of cases. Conclusions From 2006 to 2020, the cases of occupational noise-induced deafness in Zhejiang Province present an increasing trend, with a relatively short length of work at the time of onset, and regional and industrial agglomeration.

Impact of water supply from Qiandao Lake on gross radioactivity level in drinking water in downtown Hangzhou / 中华放射医学与防护杂志

Objective:To investigate the levels of gross radioactivity in drinking water in Hangzhou city before and after Qiandao Lake as the water source to the main urban area of Hangzhou.Methods:Since 2012, water samples were collected from water source, factory water and peripheral water in rainy and dry seasons, respectively, to determine their gross α and β activity concentrations for comparison and analysis.Results:The gross radioactivity levels in drinking water in Hangzhou are lower than the limits specified in the national standard "Standards for drinking water quality" (GB 5749-2006), without statistically significant difference for these water sources between the rainy and dry season ( P>0.05). The gross α(0.008±0.000)and gross β(0.034±0.013)levels in Qiandao lake were both less than those in Qiantang river ( Z=-3.235, -4.058, P<0.05), with significant difference ( Z=-2.181, -4.577, P<0.05). There was no significant difference in gross α and gross β in factory water and peripheral water before and after the operation of Qiandao Lake water supply project ( P>0.05). Conclusions:The gross radioactivity in drinking water in downtown Hangzhou are low from 2012 to 2020. The gross radioactivity levels in Qiandao Lake are lower than in the lower reaches of Qiantang river and Dongtiao steam. No impact was generated on radioactivity levels in drinking water after Qiandao lake supplied water to Hangzhou.

Automatic Identification of Brain Injury Mechanism Based on Deep Learning / 法医学杂志

OBJECTIVES@#To apply the convolutional neural network (CNN) Inception_v3 model in automatic identification of acceleration and deceleration injury based on CT images of brain, and to explore the application prospect of deep learning technology in forensic brain injury mechanism inference.@*METHODS@#CT images from 190 cases with acceleration and deceleration brain injury were selected as the experimental group, and CT images from 130 normal brain cases were used as the control group. The above-mentioned 320 imaging data were divided into training validation dataset and testing dataset according to random sampling method. The model classification performance was evaluated by the accuracy rate, precision rate, recall rate, F1-value and AUC value.@*RESULTS@#In the training process and validation process, the accuracy rate of the model to classify acceleration injury, deceleration injury and normal brain was 99.00% and 87.21%, which met the requirements. The optimized model was used to test the data of the testing dataset, the result showed that the accuracy rate of the model in the test set was 87.18%, and the precision rate, recall rate, F1-score and AUC of the model to recognize acceleration injury were 84.38%, 90.00%, 87.10% and 0.98, respectively, to recognize deceleration injury were 86.67%, 72.22%, 78.79% and 0.92, respectively, to recognize normal brain were 88.57%, 89.86%, 89.21% and 0.93, respectively.@*CONCLUSIONS@#Inception_v3 model has potential application value in distinguishing acceleration and deceleration injury based on brain CT images, and is expected to become an auxiliary tool to infer the mechanism of head injury.

Logistic Regression Analysis of the Mechanism of Blunt Brain Injury Inference Based on CT Images / 法医学杂志

OBJECTIVES@#To study the correlation between CT imaging features of acceleration and deceleration brain injury and injury degree.@*METHODS@#A total of 299 cases with acceleration and deceleration brain injury were collected and divided into acceleration brain injury group and deceleration brain injury group according to the injury mechanism. Subarachnoid hemorrhage (SAH) and Glasgow coma scale (GCS), combined with skull fracture, epidural hematoma (EDH), subdural hematoma (SDH) and brain contusion on the same and opposite sides of the stress point were selected as the screening indexes. χ2 test was used for primary screening, and binary logistic regression analysis was used for secondary screening. The indexes with the strongest correlation in acceleration and deceleration injury mechanism were selected.@*RESULTS@#χ2 test showed that skull fracture and EDH on the same side of the stress point; EDH, SDH and brain contusion on the opposite of the stress point; SAH, GCS were correlated with acceleration and deceleration injury (P<0.05). According to binary logistic regression analysis, the odds ratio (OR) of EDH on the same side of the stress point was 2.697, the OR of brain contusion on the opposite of the stress point was 0.043 and the OR of GCS was 0.238, suggesting there was statistically significant (P<0.05).@*CONCLUSIONS@#EDH on the same side of the stress point, brain contusion on the opposite of the stress point and GCS can be used as key indicators to distinguish acceleration and deceleration injury mechanism. In addition, skull fracture on the same side of the stress point, EDH and SDH on the opposite of the stress point and SAH were relatively weak indicators in distinguishing acceleration and deceleration injury mechanism.

Virtual Autopsy Morphological Features of Drowning / 法医学杂志

OBJECTIVES@#To explore the application value of virtual autopsy to obtain key evidence information on drowned corpses and its application value of virtual autopsy in the diagnosis of drowning.@*METHODS@#In this study, 7 corpses were selected as the research objects. The image data of corpses were collected by computed tomography (CT) before conventional autopsy. The characteristics of corpses were observed through image reading, combined with virtual measurement indexes, and compared with 15 non-drowned corpses.@*RESULTS@#The postmortem CT of drowning showed the more fluid in respiratory tract than the non-drowning, and ground-glass opacities in the lung. The statistical volume of fluid in the sinus (maxillary sinus and sphenoid sinus) was (10.24±4.70) mL in drowning cases and (2.02±2.45) mL in non-drowning cases. The average CT value of fluid in the sinus, left atrial blood and gastric contents in drowning cases were (15.91±17.20), (52.57±9.24) and (10.33±12.81) HU, respectively, which were lower than those in non-drowning cases (P<0.05).@*CONCLUSIONS@#The comprehensive consideration of multiple characteristic image manifestations and the virtual measurement indexes are helpful to the forensic pathological diagnosis of drowning. Virtual autopsy can be used as an auxiliary method in the forensic diagnosis of drowning.

Construction of healthy enterprises in coal industry / 中国职业医学

@#Promoting the construction of healthy enterprises in the China's coal industry will help coal enterprises to fulfill their ， ， legal and social responsibilities contribute to the construction of healthy cities and protect the health of occupational ， ， individuals from various aspects. In recent years the patriotic health campaign the health promotion project of industrial and ， ， ， mining enterprises the construction of standardized management system of coal mine safety the construction of green mines and the construction project of staff quality have laid the foundation for the construction of healthy enterprises in China's coal ， industry. However the development of coal industry in China is unbalanced and insufficient. There are many problems such as a ， general lack of professional talents the exist of a large number of small coal mines and the underprivileged technology of coal ， ， ， mining poor working environment in underground coal mines many occupational hazards in workplace and relatively few special incentive measures for the construction of healthy enterprises in the coal industry. It is recommended that coal ， enterprises with advanced productivity take the lead to demonstrate coal mine industry construction actively promote advanced ， ， and applicable technology and equipment steadily improve the professional level of coal industry workers comprehensively ， ， improve the environment of mining areas strengthen the monitoring and treatment of occupational hazards improve and ， - implement special incentive measures for healthy enterprises and comprehensively promote the high quality development of coal industry and the construction of healthy enterprises. So as to effectively protect the health occupational rights and interests of workers and provide assistance for occupational health work in the new era.

Parameterized Analysis of Craniocerebral Injury Caused by Fist / 法医学杂志

Objective Based on the theory of biomechanics, the finite element method was used to study the injury characteristics of different parts of brain hit by fist with different force and to predict the risk of craniocerebral injury, in order to provide reference for actual medical protection and forensic identification. Methods The finite element model of fist was constructed by using DICOM data modeling method and related software, and the effective mass and speed of fist were used to represent the kinetic energy of fist, and combined with human finite element model THUMS 4.02, the characteristics of craniocerebral injury caused by frontal and lateral blows were parametrically simulated. Results The probability of direct death from a blow to the head was low, but as fist power increased, so did the risk of craniocerebral injury. The characteristics of craniocerebral injury were also significantly different with the different fist hitting head locations. When the frontal area was attacked, the maximum equivalent stress of skull was 122.40 MPa, while that of brain tissue was 4.31 kPa. When the temporal area was attacked, the maximum equivalent stress of skull was 71.53 MPa, while that of brain tissue was 7.09 kPa. Conclusion The characteristics and risks of skull fracture and brain tissue injury are different when different parts of the brain are hit by fist. When the frontal area is hit, the risk of skull fracture is significantly higher than when the temporal area is hit. The risk of brain tissue injury is the opposite. The position with the highest probability of skull fracture is generally the place where the skull is directly impacted, and with the conduction of stress waves, it will spread to other parts of the skull, while the position with the highest risk of brain tissue injury is not the place where the brain is directly impacted.

Investigation on 90Sr level in offshore seawater and seafood therein around Sanmen nuclear power plant site and assessment of committed effective dose from 2015 to 2019 / 中华放射医学与防护杂志

Objective:To investigate and analyze the radioactivity level of 90Sr in offshore seawater and seafood therein around Sanmen nuclear power plant (NPP) and to estimate the annual committed effective dose to local population from ingestion of 90Sr in seafood from 2015 to 2019. Methods:From 2015 to 2019, the offshore seawater and 3 kinds of marine products grown locally in Sanmen and consumed by local residents were collected for measurement of the level of 90Sr radioactivity. The committed effective doses to the local population were estimated based on monitoring result and consumption data on seafood in Zhejiang offshore. Results:The radioactivity concentrations of 90Sr ranged from 2.4 to 4.1 mBq/L in the seawater, close to the natural radioacrive background level and from 6.7×10 -2 to 1.3 Bq/kg in seafood, lower than the standard values specified in the "Limited concentrations of radioactive materials in foods" (GB 14882-94). Annual committed effective dose to the local population from 90Sr attributable to consumption of seafood in Sanmen County from 2015 to 2019 were 2.2×10 -4-4.2×10 -4mSv, respectively, far lower than the worldwide committed effective dose result ing from internal exposure. Conclusions:From 2015 to 2019, the radioactivity concentration of 90Sr in seawater and seafood are stable, with neglectable dose burden to the local population.

Research Status of Postmortem MSCT Angiography in Forensic Science / 法医学杂志

Virtual autopsy is a new technique for investigating the morphological changes of cadaveric tissues and organs by medical imaging technology. It has been widely used in the identification of causes of death. Multislice spiral computed tomography （MSCT） has become a routine inspection method in some identification institutions, although it cannot completely replace traditional autopsy, it plays a key auxiliary or substitute role in the identification of certain abnormal causes of death. Plain MSCT scan cannot visualize cadaveric vessels, but can perform cadaveric angiography to determine vascular injury or disease. This technology has entered a rapid development period in recent years, and has made a considerable progress in contrast agent, perfusion methods and imaging methods. This article summarizes several common cadaveric MSCT angiography methods, such as systemic angiography, angiography through cardiopulmonary resuscitation, targeted angiography, and angiography by cardiac puncture, and analyzes and compares the application prospects.

Analysis of Influencing Factors of Single Camera Photogrammetry in Forensic Three-Dimensional Reconstruction / 法医学杂志

Objective To evaluate the influence of factors such as the selection of equipment, focal length and the selection of reconstruction quality in the reconstruction software on the reconstruction results of single camera photogrammetry and provide reference for the forensic application of single camera photogrammetry. Methods The 19 skulls were measured by traditional measurement method and single camera photogrammetry. The differences between the two measurement methods and within the group with same equipment but different focal length were analyzed. One skull and one corpse were selected as the research objects. According to the reconstruction quality selection conditions in the photogrammetric software, the experimental group was divided into five grades. The model reconstructed by optical scanner was defined as reference model, while the model reconstructed by single camera photogrammetry was defined as test model. The test model was aligned with the reference model, 3D deviation analysis was carried out and the mean error and root mean square （RMS） values were calculated. Results The differences between EOS 7D zoom group and traditional measurement, and within the group with same equipment had statistical significance （P<0.05）. The mean error value and minimum RMS value of the skull reconstructed by single camera photogrammetry and the three-dimensional model of the corpse existed in the medium quality group, and the trend was basically the same. Conclusion The equipment and focal length has no obvious influence on the results of single camera photogrammetry. Lower reconstruction quality can easily cause distortion, while higher reconstruction quality can easily generate noise, so medium quality is preferred.

Evaluation of 3D Measuring Methods for Body Surface Damage and Scars / 法医学杂志

Objective To assess the accuracy and reliability of the two 3D measuring methods, structured-light scanning and single-camera photogrammetry in forensic body surface damage and scar measurement. Methods The measuring results of 86 injuries by the ruler method, structured-light scanning and single-camera photogrammetry were compared and evaluated. The area measuring results of 13 simulated scars by the structured-light scanning, single-camera photogrammetry, Photoshop lasso pixel method and PDF reading software were compared and evaluated. The time consumed was recorded. The known specification information of the stickers was used as the standard value to compare the measuring accuracy of the ruler method, structural-light scanning and single-camera photogrammetry, and to calculate the root mean square error （RMSE）. The consistency evaluation of intraclass correlation coefficient （ICC） for the repeatability of 3 measuring results obtained by different operators and the same operator. Results The differences in results of the two 3D measuring methods and the ruler method had no statistical significance; the differences between measuring results made by the structured-light scanning, single-camera photogrammetry and PDF reading software and that of the Photoshop lasso pixel method had no statistical significance. The post-processing of the single-camera photogrammetry consumed more time than that of other methods. When the long-distance group （10-40 cm） was measured, the results obtained by the ruler method were shorter than the standard value. The RMSE value results were structured-light scanning < single-camera photogrammetry < ruler method. The ICC value intragroup and intergroup were greater than 0.99. Conclusion Both structured-light scanning and single-camera photogrammetry can be applied in recording and measuring forensic body surface damage. The former has better performance in measurement accuracy and stability, while the latter has better color performance but longer post-processing time.