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Objective:To study the risk of malignant tumor in medical X-ray workers in Shanghai and provide scientific data for the study on occupationally exposed population.Methods:A retrospective cohort study was conducted to investigate the risk of cancer. Totally, 715 physicians in radiology departments during 1950-1980 in Shanghai were selected as exposure group, while 738 with non-radiology departments in the same hospital in the same time period as control group. The basic information on the selected physicians and associated cancer incidence were collected. The comulative number of individuals with cancer from 1980 to 2021 was calculated. The relative risk ( RR) of cancer was analyzed using logistic regression model in terms of gender, birth year, and work starting year. As well, stratified analysis based on confounding factors was conducted. Results:A total of 1 369 individuals were followed up, including 668 in exposure group and 701 in control group. The cumulative person-year of observed individuals was 52 980. As of 31 December 2021, a total of 199 patients with various malignant tumors were identified. The results of the logistic regression analysis showed that the risk of malignant tumors in exposure group was significantly higher than that in control group. The adjusted RR of solid cancer and total cancer was 1.49 (95% CI: 1.08-2.05, P=0.015) and 1.40 (95% CI: 1.02-1.92, P=0.036), respectively. In addition, the risk of thyroid cancer in exposure group was significantly higher than that in control group ( RR=10.06, 95% CI: 2.05-49.62, P=0.005). Stratified analysis showed that the exposure group had a higher risk of total cancer both for femals and workers taking their jobs at age of 21-25. Conclusions:The risk of thyroid cancer, solid cancer and total cancer in the medical X-ray workers was significantly higher than that in control group. It is suggested that radiation protection in medical practice should be strengthened for the occupationally exposed workers, especially for femals and workers taking their jobs at low age.
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Objective:To study the distribution of CT doses to paediatric patients in Shanghai by investigating the CT dose parameters availiable in Shanghai′s children′s hospticals, and to provide the basis for establishing the diagnostic reference level for the paediatic patients subjected to CT scanning in Shanghai.Methods:In 2021, a general survey was carried out of the CT doses to the head, chest and abdomen of the scanned paediatric patients in four children′s hospitals in the municipality. The scanned paediatic patients were divided into four age groups of 0-, 1-, 5- and 10-15 years old, each with 30 subjects. The basic information were collected on the subjects, CT scanning parameters, volume CT dose index (CTDI vol) and dose length product (DLP). SPSS 16.0 was used to carry out statistical analysis of the differences in CTDI vol and DLP between different age groups at the same site and between different hospitals for the same age group at the same site. Results:The 75 th percentile values of CTDI vol and DLP for 0-, 1-, 5- and 10-15 age groups were 25, 25, 28, 43 mGy and 402, 477, 504, 752 mGy·cm, respectively, for head scanning; 2.7, 2.2, 2.8, 5.4 mGy and 40, 48, 75 and 176 mGy·cm for chest; and 4.9, 4.4, 8.2, 12 mGy and 106, 131, 273, 471 mGy·cm for abdomen. There were significant differences in CTDI vol and DLP between different age groups at the same site and between different hospitals for the same age group at the same site (head, chest and abdomen CTDI vol:χ2=221.68, 167.27, 127.07, DLP: χ2=220.63, 261.46, 216.61; for four age groups, CTDI vol: head χ2=30.46, 38.39, 25.21, 73.04, chest χ2=30.46, 35.69, 58.92, and 48.03, abdomen χ2=66.58, 41.62, 48.93, and 67.38; DLP: head χ2=28.82, 72.49, 47.72, 52.34, chest χ2=28.82, 35.95, 50.66, 41.64, abdomen χ2=45.53, 26.02 39.34, 44.24, P <0.05 ). Conclusions:The 75 th percentile values of CTDI vol and DLP for head, chest and abdomen in 4 children′s hospitals in Shanghai are lower or close to the values given in the relevant national standards and the diagnostic reference levels in some European countries, with higher DLP values on some scanning sites. The CT scanning procedures for paediatric patients needs to be further optimized.
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@#<b>Objective</b> To investigate the quality control and protection level of medical electron linear accelerators in Shanghai, China. <b>Methods</b> The startified random sampling method was used to cover tertiary, secondary and ungraded hospitals, and a total of 30 medical electron linear accelerators in 15 hospitals were tested for quality control and protection level according to relevant standards. <b>Results</b> Five medical electron linear accelerators failed the quality control test, with an overall inspection pass rate of 83.3% and a re-inspection pass rate of 100%. The pass rate of flatness of square X-ray irradiation field (5 cm × 5 cm)-(30 cm × 30 cm) was 83.3%, the pass rate of symmetry of square X-ray irradiation field was 96.7%, and other indices were qualified. All medical electron linear accelerator rooms passed the protection test. <b>Conclusion</b> The protection of medical electron linear accelerator rooms in Shanghai meets the requirements of national standards, and some indices do not meet the requirements of national standards in the preliminary inspection. The quality control of medical electron linear accelerators should be further strengthened to ensure the treatment effect of patients.
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Background Individual monitoring of occupational external exposure is an essential part of the occupational health management of radiation workers, and is an important basis for the evaluation of individual absorbed dose and the diagnosis of occupational radiation diseases. Continuous participation of monitoring service providers in intercomparison is a fundamental quality assurance for routine monitoring, which can identify problems and improve them in time. Objective Taking the Laboratory of Radiation Protection in Shanghai Institute of Preventive Medicine as an example, to evaluate the performance of an individual occupational external dose monitoring system in the laboratory, identify influencing factors of the monitoring results, and provide a basis for improving the quality of daily monitoring by analyzing the process and results of a national intercomparison of individual dose monitoring. Methods According to the Testing criteria of personnel dosimetry performance for external exposure (GBZ 207-2016), and the relevant requirements of Class II (photon) inspection, a total of 20 groups of blind sample dosimeters were measured for four consecutive years from 2018 to 2021. The radiation energy source of each group was identified, and related personal dose equivalent Hp(10), the uncertainty of measurement results, and the deviation between the reported value and the reference value were calculated. The national intercomparison process and results of individual dose monitoring were also analyzed. Results The energy sources of the blind samples in the tested laboratory for four years were N100 or Cs-137. The reported dose values of the blind samples were 0.57-4.61 mSv, the combined uncertainties were 0.043-0.365 mSv, the expanded uncertainties (k=2) were 0.09-0.73 mSv, and the relative expanded uncertainties (k=2) were 13.8%-16.4%. The single-group performance ∣Pi∣ of 20 sets of blind samples in the four years was ≤0.10, the yearly comprehensive performance of 5 sets of blind samples was ≤0.10, and the yearly Q score of the test report was >15 points. The laboratory achieved excellent results in the national intercomparison of individual dose monitoring in four consecutive years, except the Q value not reaching full score. Conclusion The laboratory exhibits standardized data processing of individual dose monitoring, generates accurate and reliable results, and meets the requirements of relevant national standards; but it should continue to participate in the national intercomparison of individual dose monitoring, strengthen the angular response research of energy identified dosimeter, improve the monitoring ability of low-dose X-rays, analyze the key points of reducing the uncertainty of measurement results, and continuously improve the monitoring ability.
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Background Based on numerous epidemiological studies, radionuclide 131I can result in thyroid disease. Objective To study the contamination level of thyroid 131I in 131I treatment associated radiation workers in nuclear medicine departments in Shanghai. Methods Based on a general survey on basic situation of nuclear medicine in Shanghai, the level of internal exposure of radiation workers involved in 131I treatment was assessed with questionnaires and on-site monitoring. A portable γ spectrometer was used for on-site detection, the intake and annual effective dose were estimated according to the measurement results. Physical examination reports were collected for radionuclide positive workers, and chromosome testing was performed. Results There were 579 nuclear medicine workers and 175 were engaged in 131I treatment in Shanghai. 131I was detected in thyroid of 18 workers, with a detection rate of 10.3%. Among them, the detection rates of thyroid 131I in nurses and cleaners were 23% and 25% respectively. The mean measured activity of thyroid 131I was 306.1 Bq and the maximum measured activity was 3716.9 Bq (nurse). The maximum intake was estimated at 37544 Bq and the median was 786.4 Bq. The average annual committed effective dose was 1.22 mSv and the maximum value was 14.87mSv. The chromosomal aberration rates of all detected workers were negative, and all blood indicators were normal except one with low hemoglobin. Conclusion The annual dose of nuclear medical staff engaged in 131I treatment does not exceed the national standard limit, but the internal exposure of nurses and cleaners should not be ignored. On the basis of strengthening protection and decontamination, routine internal exposure monitoring should be carried out.
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Objective:To investigate the characteristics of diagnostic radiology and the situation of repeated examinations at medical institutions of Jinshan district, and put forward strategies and suggestions for the correct guidance on and reasonable applications of various medical exposures.Methods:The cases data on radiological examinations at medical institutions in Jinshan district, obtained in 2017 from Shanghai Municipal Health Commission Information Center Platform, was used to describe the characteristics of population distribution of patients, examination types, examination areas, diagnosed diseases, number of repeated examinations and the result of radiological examinations.Results:The main types of radiological examinations in Jinshan district were the CT scans and the conventional X-ray diagnosis, accounted respectively for 53.2% and 44.7% of the total radiological examinations. The radiological examinations were mainly performed on household registration (77.3%). The number of radiological examinations on males was close to on females, with examination frequency of 49.4% for males and 50.1% for females. The greatest frequency of radiological examinations was found in the age group older than 41 years, accounting for 77.1% of CT scans and 65.2% of the conventional X-ray diagnosis. The main examination sites of the CT scans at Jinshan medical institutions were chest (32.8%), abdomen (19.4%), brain (16.1%) and spine (11.4%), and for the conventional X-ray diagnosis were chest (43.2%) and limbs (39.6%). The main departments applying for radiological examinations are surgery (39.7%) and medicine (27.1%). The numbers of radiological examinations are, respectively, diseases of the respiratory system (19.8%), the injury, poisoning and some other consequences of external causes (15.8%), and the diseases of musculoskeletal system and connective tissue (15.8%). The positive rate of the conventional X-ray diagnosis was 53.1%, and the positive rate of CT scans was 73.5%. The conventional X-ray diagnosis and CT scans contributed higher specific rates of repeated examinations, accounting for 9.3% and 7.9% of the total of such type examination, respectively.Conclusions:CT scans in Jinshan district accounted for more than half of the total frequency of radiological examinations, therefore, interventions should be imposed on certain types of phycians and patients types.
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Objective:To construct back propagation (BP) neural network model to predict the dose required for 131I therapy for hyperthyroidism and to calculate the personalized dose plan for patients. Methods:A complete set of data of patients treated for hyperthyroidism radioaiodine was collected from the nuclear medicine departments of several medical colleges in Shanghai, including history, examination result, treatment course, etc. As a result, a prediction model was established. The predicated result for BP neural network, radial basis function (RBF) neural network and Support Vector Machine (SVM) were compared by means of small sample data. The optimal model was selected to predict administrated dose and to finally test the accuracy of the model.Results:The average errors in BP neural network, RBF neural network and SVM model based on small samples were 5.53%, 7.09% and 9.64%, respectively. After comparison, BP neural network was selected to build the prediction model. 30 cases of data were selected by random sampling to verify the BP neural network. The mean error, mean square error, minimum error and maximum error of the prediction result were 7.22%, 0.053, 0.57% and 13.78%, respectively.Conclusions:In this study, a neural network prediction method was proposed to provide a more accurate dose for patients in need of radioiodine therap for hyperthyroidism, and to reduce the possibility of radiation damage or the unsatisfactory therapeutic effect caused by insufficient dose. It has clinical practical significance in providing the reference for clinicians to evaluate the administrated dose.
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@#<b>Objective</b> To investigate dose parameters in computed tomography (CT) scanning of common body parts inall public medical institutions in Shanghai, China, and analyze the dose distribution of CT scanning among adult subjects in Shanghai, and to provide a basis for establishing the diagnostic reference levels of CT scanning in Shanghai. <b>Methods</b> We selected at least one medical institution with CT services each from all 16 districts of Shanghai. In each medical institution, a piece of CT equipment with qualified annual inspection was sampled to investigate the doses to subjects in head, chest, abdomen, and lumbar spine scanning. We collected the basic information of the subjects, CT scanning parameters, volumetric CT dose index (CTDI<sub>vol</sub>), and dose length product (DLP). <b>Results</b> The scanning data of 1475 subjects were obtained. The 75th percentiles of the CTDI<sub>vol</sub> of the head, chest, abdomen, and lumbar spine were 57 mGy, 11 mGy, 16 mGy, and 23 mGy, respectively. The 75th percentiles of the DLP were 862 mGy·cm, 361 mGy·cm, 593 mGy·cm, and 550 mGy·cm, respectively. <b>Conclusion</b> CTDI<sub>vol</sub> and DLP differed significantly at different body parts, and also differed greatly at the same body parts. The DLP of men was slightly higher than that of women.
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ObjectiveTo determine the individual dose level and changing trend in the occupational external exposure of radiation workers in Shanghai， and provide scientific evidence for health risk assessment for radiation workers. MethodsIn the Occupational Health Management System for Radiation Workers of the National Health Commission-External Exposure Personal Monitoring and Management Subsystem， we retrieved the monitoring data of 38 077 external exposure individual dose of all medical radiation workers in Shanghai from 2015 to 2019. Using clustered sampling method， a total of 11 370 radiation workers in medical institutions （including tertiary， secondary， and primary hospitals） were selected in the study. Statistical analyses were conducted using SPSS 22.0. ResultsThe collective annual effective dose of 11 370 radiation workers was determined to be 4.340 person Sv， including 2.270 man·mSv in diagnostic radiology， 1.112 man·mSv in interventional radiology， and <0.5 man·mSv in other categories. The average annual effective dose was 0.382 mSv， which was 0.482 mSv in nuclear medicine， 0.431 mSv in radiotherapy， and <0.5 mSv in other categories. Moreover， the average annual effective dose of 6 workers （0.05%） was higher than 5 mSv， whereas that of 10 453 workers （92%） were less than 1 mSv； in addition， the annual dose of 911 workers （8.0%） was between 1‒5 mSv. All workers had average annual effctive dose lower than 20 mSv. The annual effective dose differed significantly by years （F=161.1， P<0.01）， by occupational groups （F=13.5， P<0.01）， and by hospital levels （F=264.5， P<0.01）. ConclusionThe average annual effective dose of radiation workers in medical institutions in Shanghai is lower than the national standard limit， suggesting proper and adequate radiation protection system and measures in medical institutions.
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Intersphincteric resection (ISR) is a limited sphincter preserving surgery for low rectal cancer. The 4K laparoscopic system has the advantage of enhancing the accurate recognition of anatomical structures for operators. The authors investigate the imaging evaluation and technical standard of 4K laparoscopic ISR of low rectal cancer through surgical examples.
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Objective@#To study the the application characteristics of paediatric CT examination by investigating four main children′s hospital of Shanghai.@*Methods@#All the CT scan cases of paediatric patients in this work were obtained from the radiology information system (RIS) database in four hospitals between 2011 and 2014. The distribution of using CT scans was analysed according to the age, gender, anatomical regions and the duplicated cases of the patient, then estimated the paediatric CT scan rates of four hospitals in Shanghai.@*Results@#Retrospective review of RIS showed 249 350 CT examinations from 175 672 young patients were performed between 2011 and 2014 in the surveyed hospitals. More males (62%) were scanned than females (38%). The majority of children receiving the examinations were 1 to 5 years old, which amounted to 40.3% in all. Cardiac CT accounted for 14.5% among all children of ≤1 year old CTs and accounted for 63.0% among all cardiac CT scans. There were 33 634 (19.1%) individuals who had received 2 or more CT scans during the four years. The estimated paediatric CT scan frequencies of four hospitals in Shanghai from 2011 to 2014 were 37.9 examinations per 1 000 population in 2011, 43.3 examinations per 1 000 population in 2012, 43.3 examinations per 1 000 population in 2013 and 39.0 examinations per 1 000 population in 2014.@*Conclusions@#The CT scan frequencies of four hospitals in children and young adults was almost keeping stable in Shanghai.
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Objective@#To build a comprehensive information system of radiological health in Shanghai and provide basic data for prevention and control of radiation hazards factors.@*Methods@#A management information platform of radiological health suitable for Shanghai was constructed by sorting out the historical archives and records, combining with content of current work, and using the information platform in China for reference. All Institutions are responsible for the collection and input of the data generated in the work, and the system judges the nature of the data according to the rules, and then completes the interactive analysis of the data with the municipal platform according to the standards, which forms the three-level platform management mode of the city, districts and medical institutions.@*Results@#Data module platform covering health records, environmental monitoring, business warning and statistical reports was built in one year since its preliminary inception in 2014. In the beginning there were only 468 usersof institutions, and by the end of 2018, about 1 241 users were active. Nearly 300 000 pieces of data were collected.@*Conclusions@#The construction of comprehensive management information platform of radiological health in Shanghai promotes the standardization and effectiveness of radiological health information management, provides a monitoring model for sustainable long-term development, and provides basic data for further policy management or decision-making.
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Objective To study the the application characteristics of paediatric CT examination by investigating four main children′s hospital of Shanghai. Methods All the CT scan cases of paediatric patients in this work were obtained from the radiology information system (RIS) database in four hospitals between 2011 and 2014. The distribution of using CT scans was analysed according to the age, gender, anatomical regions and the duplicated cases of the patient, then estimated the paediatric CT scan rates of four hospitals in Shanghai. Results Retrospective review of RIS showed 249350 CT examinations from 175672 young patients were performed between 2011 and 2014 in the surveyed hospitals. More males (62％) were scanned than females (38％) . The majority of children receiving the examinations were 1 to 5 years old, which amounted to 40. 3％ in all. Cardiac CT accounted for 14. 5％ among all children of≤1 year old CTs and accounted for 63. 0％ among all cardiac CT scans. There were 33634 (19. 1％) individuals who had received 2 or more CT scans during the four years. The estimated paediatric CT scan frequencies of four hospitals in Shanghai from 2011 to 2014 were 37. 9 examinations per 1000 population in 2011, 43. 3 examinations per 1000 population in 2012, 43. 3 examinations per 1000 population in 2013 and 39. 0 examinations per 1000 population in 2014. Conclusions The CT scan frequencies of four hospitals in children and young adults was almost keeping stable in Shanghai.
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Objective To build a comprehensive information system of radiological health in Shanghai and provide basic data for prevention and control of radiation hazards factors. Methods A management information platform of radiological health suitable for Shanghai was constructed by sorting out the historical archives and records, combining with content of current work, and using the information platform in China for reference. All Institutions are responsible for the collection and input of the data generated in the work, and the system judges the nature of the data according to the rules, and then completes the interactive analysis of the data with the municipal platform according to the standards, which forms the three-level platform management mode of the city, districts and medical institutions. Results Data module platform covering health records, environmental monitoring, business warning and statistical reports was built in one year since its preliminary inception in 2014. In the beginning there were only 468 usersof institutions, and by the end of 2018, about 1241 users were active. Nearly 300000 pieces of data were collected. Conclusions The construction of comprehensive management information platform of radiological health in Shanghai promotes the standardization and effectiveness of radiological health information management, provides a monitoring model for sustainable long-term development, and provides basic data for further policy management or decision-making.
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Objective To explore the distribution and application of diagnostic X-ray procedures in Shanghai through investigating the 49 sample medical institutions,to provide the theoretical basis of protective strategies for medical exposure.Methods According to the grade of medical institutions,stratified random samplings were used to select 49 medical institutions.The basic information of the surveyed medical institutions and person-times of various types of X-ray diagnostic procedures were gathered by radiology information system and manual recording.Results In the sampled medical institutions,393 sets of X-ray equipment were engaged in X-ray diagnostic radiology,and the total number of X-ray diagnostic imaging was 4 442 662.The gender ratio of male and female was 1 ∶0.99.The total frequency of diagnostic X-ray procedures was 1 228 examinations per thousand population,including 304 examinations per thousand population of CT scan,105 examinations per thousand population of dental radiography.Conclusions The frequency of diagnostic X-ray procedures in 2016 increased compared with the data surveyed during the period of the " 11th Five-year Plan",in which the frequency of CT procedures increased significantly.
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Objective To establish an accuracy test method for MDCT dose assessment based on information in DICOM images.Methods The type of MDCT studied in this paper was widely used in clinical practice.A software package developed by java language was used to automatically read doserelated information from DICOM files of MDCT.The CTDIvol and DLP of each pectoral or abdominal scan was calculated based on these information and the basic scan parameters such as collimation,mAs and pitch.The calculated values were compared with the displayed values.Results For pectoral scans,the difference between the calculated and displayed values was between-2％-8％ for CTDIvol,and-2％-5％ for DLP.For abdominal scan,the difference between the calculated and displayed values was 0-2％ for CTDIvol,and-2％-3％ for DLP.Conclusions This method is useful for MDCT dose assessment and is worth disseminating its application for general use.
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Objective To survey the current dose level for adults undergoing posteroanterior (PA) chest X-ray photography in Shanghai,and to analyze the main factors affecting the dose level.Methods The thermoluminescence dosimeters (TLDs) were deployed to measure entrance surface dose (ESD) in the center of radiated fields.According to the numbers of three types of X-ray equipment and their distribution among different grade hospitals in Shanghai,the ESDs were surveyed for 1032 adults undergoing examination of PA chest X-ray photography from 2008 to 2010,and the relevant information was also recorded.The differences of the mean ESDs among different grade hospitals,equipment types and photographic parameters were statistically analyzed.Results The arithmetic mean of the ESDs for adults undergoing examination of PA chest X-ray photography in Shanghai was 0.23 mGy,and the 75th percentile value was 0.29 mGy,which were all below the current China diagnostic reference level (0.40 mGy).The averaged ESDs were significantly correlated with the grade of hospital,the equipment types and the photographic parameters.Conclusions Compared with the value in the last century,the ESD for adults undergoing PA chest X-ray photography in Shanghai obviously decreases,and there are the potentials for further reduction.
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Objective To study the effect on the environmental radioactivity level and the health of the residents in Shanghai when Qinshan Nuclear Power Station(QNPS) has been in normal operational condition for 17 years. Methods The field monitoring and the sampling analytical method were used for monitoring the radioactivity level in outdoor environment, drinking water, food and soil. Results The outdoor natural radiation level and the radioactivity level in the sample of the environmental media were on the normal background level. There was no distinct change in the environmental radiation level of Jinshan Area when QNPS was in normal operational condition. The radioactivity level in the environmental media was far lower than the limit values specified by the national standard GB. The effective dose of the outdoor natural external exposure for the residents is about 0.102 mSv/a and the effective dose of the internal exposure from the artificial radionuclides 90Sr and 137Cs in food for the residents is about 0.488 μSv/a. Conclusions There is no effect of the radioactive contamination on the environmental radioactivity level and the health of the residents in Shanghai when QNPS has been in normal operational condition for 17 years.
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Objective To study the age-related changes of rat bone histomorphometry and its correlation to other parameters of bone metabolism. Methods Ten female SD rats at the age of 3 months old,9 months old and 15 months old were labeled with tetracycline(30 mg/kg) via abdomen on fourteen and four days before executing. Histomorphometry were performed on L4 and right tibiae. Physical density of left femur and L2 were measured. Anti-compression property of L3 was assayed. Serum levels of calcium and phosphorus and 1,25(OH)_ 2 D_ 3 were determined. Results Compared with the 3-month-old rats,the trabecular bone volume(TBV) of L4 and right tibiae decreased 43.3%( P