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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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Objective:To calculate the typical values of diagnostic reference levels (DRLs) for CT examinations of head, chest and abdomen-pelvis in children using the volumetric CT dose index (CTDI vol), the size-specific dose estimation value (SSDE WD) based on the water equivalent diameter (WD) and the dose length product (DLP) as indicators to measure the radiation dose level of CT examinations in Department of Radiology, Children′s Hospital of Nanjing Medical University. Methods:The CT examination images of patients admitted to the Hospital from January 2021 to December 2021 were retrospectively collected, encompassing 1 391 for head, 1 386 for chest and 1 035 for abdomen-pelvis. Their age, CTDI vol and DLP were recorded and the anterior-posterior diameter (AP), lateral diameter (LAT), area (A ROI) and CT value within area (CT ROI) of the middlemost scanned image were measured manually. The effective diameter ( d), WD, conversion factor ( f16/32X SIZE) and SSDE WD were calculated in accordance with the American Academy of Physicists in Medicine (AAPM) reported method . Patients were divided into 5 groups in terms of their examined site. age and body size: <1, 1-, 5-, 10-, and 15- years old. The number of patients in each group was 252, 320, 400, 380 and 39 for the head, 188, 320, 399, 398 and 81 for the chest, and 75, 310, 310, 300 and 40 for the abdomen-pelvis region. The patients for head examination was divided into five groups of <12.5, 12.5-, 14-, 15-, 16-cm based on LAT, with 151, 222, 319, 399 and 300 cases in each group, respectively. The chest and abdomen-pelvis were divided into five groups of <15, 15-, 20-, 25-, 30- cm based on d, with 275, 527, 400, 165 and 19 cases in each chest group, respectively; the abdomen-pelvis 403, 410, 184, 34 and 4 cases. The 75th percentile of CTDI vol, SSDE WDand DLP were counted in each group as typical DRL values, and the differences between CTDI vol and SSDE WD in measuring radiation dose were compared. Results:The typical values of DRL in the head, chest and abdomen-pelvis areas as measured by CTDI vol were 14.9-24.1, 1.8-4.5, and 2.0-7.5 mGy, respectively, by age grouping; the typical values of DRL as measured by SSDE WD were 14.7-18.9, 4.2-6.9, and 4.7-11.8 mGy, respectively; the typical values of DRL as measured by DLP were 260-505, 40-185 and 64-435 mGy·cm. The typical values of DRL measured by CTDI vol were 1.8-6.8 and 2.2-9.2 mGy for the chest and abdomen-pelvis region, respectively, by d grouping; the typical values of DRL measured by SSDE WD were 4.2-9.1 and 4.9-13.0 mGy; typical values of DRL as measured by DLP were 40-255 mGy·cm and 85-545 mGy·cm, respectively. The typical values of DRL measured by CTDI vol were 14.1-23.1 mGy for head grouping by LAT; the typical values of DRL measured by SSDE WD were 14.3-18.5 mGy. The typical values of DRL measured by DLP were 240-475 mGy·cm. The CTDI vol was larger than SSDE WD in the head except for the (<1 year and <12.5 cm) subgroup, and the CTDI vol in head was (18.63±3.24) mGy and SSDE WD was (16.38±1.81) mGy, the difference was statistically significant ( t= 48.78, P < 0.001). The CTDI vol was smaller than SSDE WD within each subgroup in chest and abdomen-pelvis, the CTDI vol of chest was (2.77±1.02) mGy, and SSDE WD was (5.22±1.26) mGy with a statistically significant difference ( t=-210.89, P < 0.001); the CTDI vol of abdomen-pelvis was ( 3.36 ± 1.82) mGy and SSDE WD was (6.27 ± 2.44) mGy. The difference was also statistically significant ( t = -115.16, P < 0.001). Conclusions:The typical values of DRLs in the hospital are at a reasonable and low level compared with those in other countries, and SSDE WD reflects radiation dose more accurately than CTDI vol.Therefore there is an urgent need to establish DRLs based on SSDE WD.
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Objective:To investigate the level of radiation doses to adults caused by CT examination in Huai′an, and explore the local CT diagnostic reference levels (DRLs).Methods:Totally 45 CT scaners were selected to investigate the information on hospitals, equipment, scanning parameters, and radiation doses. Empirical formula were used to estimate the effective dose to adults. Nonparametric rank sum tests were used to analyze differences in radiation dose level between CT service age and hospital grade.Results:A total of 3 483 patients were collected, including 890 for head examinations, 890 for chest, 846 for abdomen, and 857 for lumbar spine. The 75% percentile values of CTDI vol to adult patients from CT scanning for head, chest, abdomen, lumbar spine examinations were 63.0, 12.4, 20.0 and 24.0 mGy, respectively. The 75% percentile values of DLP were 858.6, 416.0, 620.7 and 559.2 mGy·cm, respectively. The 75% percentile values of DLP for males was higher than those for females. There were significant statistical differences in radiation doses dependent on equipment service (head: U =10 326.00, P<0.05; chest: U=36 094.50, P<0.05; abdomen: U= 7 859.00, P<0.05; lumbar spine: U=42 408.00, P<0.05), and hospital grade (head: H=14.280, P<0.05; chest: H=17.85, P<0.05; abdomen: H=97.18, P<0.05; lumbar spine: H=138.94, P<0.05). Conclusions:The CT radiation dose levels in Huai′an city is basically consistent with standard-reommended values, which is in line with the current status of CT equipment dose levels in the country. It is necessary to strengthen the quality control and maintenance of CT equipment.
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Objective To investigate radiation doses to examinees undergoing computed tomography (CT) scanning of different body parts (the head, chest, and abdomen) in medical institutions of Shijiazhuang, China, and to provide a reference for optimizing radiation protection for examinees in medical institutions. Methods March 2021 to March 2022, eleven medical institutions of radiation monitoring in Shijiazhuang were surveyed for the basic information, scanning parameters, and dosimetric data of a total of 930 adults and children who received CT examinations. The dosimetric data of the subjects were analyzed and compared with the domestic and international diagnostic reference levels and the results of other cities in China. Results In the above hospitals, the CTDIvol(P50) of CT subjects in children's group were 17.42-50.45 mGy, 2.13-14.01 mGy and 3.58-28.20 mGy, respectively. DLP(P50) ranges from 228.87 to 966.97 mGy·cm, 33.20 to 296.03 mGy·cm, and 74.90 to 926.53 mGy·cm, respectively. In the adult group, the CTDIvol(P50) in the head, chest and abdomen of CT subjects were 37.28-54.05 mGy, 6.43-14.99 mGy and 8.28-18.75 mGy, respectively. DLP(P50) ranges from 372.81 to 630.56 mGy·cm, from 219.77 to 467.93 mGy·cm, and from 313.86 to 689.87 mGy·cm, respectively. The distribution of radiation doses in different-grade hospitals varied greatly. The abdomen dose of the children's hospital was higher than other hospitals. Especially the primary hospitals were significantly higher than the recommended diagnostic reference level (DRL). Conclusion In some secondary and primary hospitals, the setting of CT scanning parameters was simplified, not specific to the subjects’ age and body types. They should strictly comply with the principal of optimizing radiation protection to strengthen radiation dose optimization and supervision, reducing the radiation dose of examinees in future examinations .
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During interventional procedures,subjects are exposed to direct and scattered X-rays.Establishing diagnostic reference levels is an ideal way to optimize the radiation dose and reduce radiation hazard.In recent years,diagnostic reference levels in interventional radiology have been established in different countries.However,because of the too many indicators for characterizing the radiation dose,the indicators used to establish diagnostic reference levels vary in different countries.The research achievements in this field remain to be reviewed.We carried out a retrospective analysis of the definition,establishment method,application,and main factors influencing the dose difference of the diagnostic reference level,aiming to provide a basis for establishing the diagnostic reference level for interventional procedures in China.
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Humans , Diagnostic Reference Levels , Radiology, Interventional/methods , Radiation Dosage , Retrospective Studies , RadiographyABSTRACT
Objective:To understand the current situation of CT radiation dose in children all over our country, and to explore the diagnostic reference level (DRL) of CT in children.Methods:The radiation dose reports of pediatric CT examination were collected end to November 30, 2021 and divided into five age groups: 0-1 month,>1 month-4 years,>4-10 years,>10-14 years and >14-18 years. There were 9 scanning item such as head, nasal sinus, temporal bone, neck, chest, abdomen, head enhanced CT, chest enhanced CT and abdomen enhanced CT. In each item, volume CT dose index (CTDI vol) and dose length product (DLP) were selected as radiation dose parameters, the 75% percentile were selected for DRL. The DRL results of head, chest and abdomen were compared with the DRL published by Chinese Society of Radiology and European Commission. Results:From March 2019 to November 2021, a total of 33 hospitals in 23 provinces were collected, including 20 children′s specialized hospitals, 11 women′s and children′s hospitals and 2 general hospitals, including 19 135 children′s CT scans. The DRL of 45 subgroups according to 5 age groups and 9 scanning items were obtained. The DRL results showed that the CTDI vol in five age groups was 26.9-42.8 mGy, and the DLP was 347-694 mGy·cm for head; 3.5-8.0 mGy, 54-293 mGy·cm for chest; and 6.3-13.2 mGy, 155-564 mGy·cm for abdomen. The DRL of the age group >4-10 years group in this investigation was agreed to the DRL of Chinese Society of Radiology. Compared with the European guidelines, there was little difference in the radiation dose of head scan, while the radiation dose of chest and abdomen in the young age group increased significantly. Conclusion:This survey reveals the radiation dose level distribution of children CT in our country. The radiation dose level of some items was inconsistent with the DRL of relevant international organizations. So our own DRL is needed to be set up according to the actual clinical reality of our country as a guideline.
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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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Objective@#To investigate the reference level of surface radiation dose of digital radiography (DR) among adult examinees in Beilun District, Ningbo City, so as to provide insights into the optimization of the parameters of DR systems and rational management of the radiation dose.@*Methods@#Based on the cloud imaging system covering 14 DR systems in 11 public hospitals in Beilun District, the diagnosis of adults receiving DR and DR systems check were collected from May 2020 to April 2021. The air kerma-area product ( PKA ) was selected as a measure, and the local diagnostic reference level ( LDRL ), the regional median dose ( RMD ), the regional lowest dose predicted level ( LDPL ) and the typical dose in the DR imaging room were defined using the quartile method according to the examination site, projection direction and radiography positions. The PKA value was transformed into incident air kerma ( Ka, e ), and compared with the recommended value in the Requirements for Radiological Protection in Diagnostic Radiology ( GBZ 130-2020 ).@*Results@#DR was performed among 133 065 person-times from May 2020 through April 2021 in Beilun District. The greatest RMD was found on abdomen AP DR in the supine position ( 120 μGy·m2 ), and the lowest RMD was seen on chest PA DR in the standing position ( 17 μGy·m2 ). The maximums of typical dose in the DR imaging room on chest PA ( 33 vs. 30 μGy·m2 ), abdomen AP ( 161 vs. 153 μGy·m2 ) and pelvis AP DR ( 164 vs. 162 μGy·m2 ) were greater than LDRL in the supine position, and the minimums of typical dose on chest PA ( 10 vs. 11 μGy·m2 ) and chest LAT DR ( 33 vs. 34 μGy·m2 ) were lower than LDPL in the standing position. Following transformation into Ka, e, the LDRL ranged from 0.27 to 3.80 mGy, and the maximums of typical dose ranged from 0.25 to 3.55 mGy, which was much lower than the recommended dose proposed in the national criteria.@*Conclusions@#The reference level of surface radiation dose of DR is established among adults in Beilun District, which is lower than the recommended dose in the national criteria of China. Such a reference level may be employed by medical institutions for optimization of the parameters of DR systems. Key words： digital radiography radiation dose diagnostic reference level air kerma-area product
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Objective@#To investigate the current status of CT radiation dose to adults in Ningxia, and provide basic data for developing the first diagnostic reference level of adults from CT scanning.@*Methods@#Stratified cluster sampling method was used to investigate the in-service status of CT scanners with various brands and different models in different grades of hospital in Ningxia. Interval sampling method was used to obtain everyday′s scanning parameters and radiation dose values from different types of scanning examinations in surveyed hostipitals. Basic information was collected include hospitals, CT scanner, scanning types and patients. CT scanning parameters, CTDIvol and DLP values were recorded, with effective dose values calculated. The data were statistically analyzed by examination types and comparation was made with the DRL values recommended by other countries.@*Results@#Finally, there were 45 medical institutions in this study, including 10 public tertiary A hospitals, 5 public tertiary B hospitals, 23 public secondary A hospitals, 5 private hospitals and 2 physical examination centers. 58 CT scanners from 6 manufacturers and 4 952 adult patients were investigated. The 75th percentile (P75) of CTDIvol, DLP, and E values of common scanning examinations were listed as follows: 65.67 mGy, 860.74 mGy·cm, and 1.64 mSv in skull scanning; 29.32 mGy, 490.00 mGy·cm, and 2.83 mSv in neck scanning; 36.92 mGy, 954.42 mGy·cm, and 4.87 mSv in neck enhanced scanning; 11.50 mGy, 382.06 mGy·cm , and 5.68 mSv in chest scanning; 45.80 mGy, 1 713.22 mGy·cm, and 25.01 mSv in chest enhanced scanning; 20.10 mGy, 506.59 mGy·cm, and 7.75 mSv in upper abdominal scanning; 50.07 mGy, 1 434.19 mGy·cm, and 21.94 mSv in upper abdominal enhanced scanning; 14.33 mGy, 670.78 mGy·cm, and 10.26 mSv in abdominal-pelvic scanning; 48.00 mGy, 2 294.00 mGy·cm, and 35.10 mSv in abdominal-pelvic enhanced scanning; 16.10 mGy, 471.58 mGy·cm, and 6.08 mSv in pelvic scanning; 31.04 mGy, 1 138.78 mGy·cm, and 14.69 mSv in pelvic enhanced scanning.@*Conclusions@#The CT scanning radiation doses to skull, neck, chest and pelvis in Ningxia are slightly lower than, or similar to, in other countries, but the abdominal scanning dose is significantly higher than that in other countries. It is necessary to optimize the abdominal CT scanning protocol.
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PURPOSE: There is substantial need for optimizing radiation protection in nuclear medicine imaging studies. However, the diagnostic reference levels (DRLs) have not yet been established for nuclear medicine imaging studies in Korea.MATERIALS AND METHODS: The data of administered activity in 32 nuclear medicine imaging studies were collected from the Korean Society of Nuclear Medicine (KSNM) dose survey database from 2013 and 2014. Through the expert discussions and statistical analyses, the 75th quartile value (Q3) was suggested as the preliminary DRL values. Preliminary DRLs were subjected to approval process by the KSNM Board of Directors and KSNM Council, followed by clinical applications and performance rating by domestic institutes.RESULTS: DRLs were determined through 32 nuclear medicine imaging studies. The Q3 value was considered as appropriate selection as it was generally consistent with the most commonly administered activity. In the present study, the final version of initial DRL values for nuclear medicine imaging in Korean adults is described including various protocols of the brain and myocardial perfusion imaging.CONCLUSION: The first DRLs for nuclear medicine imaging in Korean adults were confirmed. The DRLs will enable optimized radiation protection in the field of nuclear medicine imaging in Korea.
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Adult , Humans , Academies and Institutes , Brain , Korea , Myocardial Perfusion Imaging , Nuclear Medicine , Radiation ProtectionABSTRACT
Objective To investigate the CT scanning parameters in hospitals at different levels in 15 provinces and cities in China and the doses to patients undergoing CT examination,in order to provide the basis for establishing CT diagnostic reference level suitable for our country.Methods As required in the implementation program for Technical Study on Medical Radiation Hazard Assessment and Control,the information on the patients examined and the CT scanning parameters in clinical practices were investigated.The CT dose index (CTDI100,CTDIW,CTDIVOL) of CT scanner was measured by using the CT ionization chamber.The dose length product (DLP) was calculated on the basis of the scan length of the patients examined.Results A total of 6 524 CT scanning procedures and 483 different types of CT scanning equipment were surveyed in 166 hospitals in 15 provinces in China.For head,chest,abdomen,and lumbar vertebrae,the average weighted CTDIW were 43,15,19 and 25 mGy,respectively,and the third quartile of CTDIw were 50,19,23 and 32 mGy,respectively.The average DLP were 540,397,503 and 376 mGy· cm,respectively.The third quartile of DLP were 659,525,632 and 479 mGy· cm respectively.Conclusions Through this survey,the doses to CT-examined patients in some provinces were basicly ascertained.The third quartile of doses to four body parts of the examined patients are different from the diagnostic reference level given in publications in other countries and regions.It is important to establish the CT diagnostic reference level suitable for our CT-examined patients according to Chinese national physical characteristics and therefor to promote the optimization of medical radiation protection in CT examination.
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Objective To investigate the current status of CT radiation dose to adults in Ningxia, and provide basic data for developing the first diagnostic reference level of adults from CT scanning. Methods Stratified cluster sampling method was used to investigate the in-service status of CT scanners with various brands and different models in different grades of hospital in Ningxia. Interval sampling method was used to obtain everyday' s scanning parameters and radiation dose values from different types of scanning examinations in surveyed hostipitals. Basic information was collected include hospitals, CT scanner, scanning types and patients. CT scanning parameters, CTDIvol and DLP values were recorded, with effective dose values calculated. The data were statistically analyzed by examination types and comparation was made with the DRL values recommended by other countries. Results Finally, there were 45 medical institutions in this study, including 10 public tertiary A hospitals, 5 public tertiary B hospitals, 23 public secondary A hospitals, 5 private hospitals and 2 physical examination centers. 58 CT scanners from 6 manufacturers and 4952 adult patients were investigated. The 75th percentile (P75) of CTDIvol, DLP, and E values of common scanning examinations were listed as follows: 65.67 mGy, 860.74 mGy·cm, and 1.64 mSv in skull scanning;29.32 mGy, 490. 00 mGy·cm, and 2.83 mSv in neck scanning;36. 92 mGy, 954. 42 mGy·cm, and 4. 87 mSv in neck enhanced scanning; 11. 50 mGy, 382.06 mGy·cm , and 5.68 mSv in chest scanning; 45.80 mGy, 1713.22 mGy·cm, and 25.01 mSv in chest enhanced scanning; 20. 10 mGy, 506. 59 mGy·cm, and 7. 75 mSv in upper abdominal scanning;50. 07 mGy, 1434. 19 mGy·cm, and 21. 94 mSv in upper abdominal enhanced scanning; 14. 33 mGy, 670.78 mGy·cm, and 10. 26 mSv in abdominal-pelvic scanning; 48. 00 mGy, 2294. 00 mGy·cm, and 35.10 mSv in abdominal-pelvic enhanced scanning;16.10 mGy, 471.58 mGy·cm, and 6.08 mSv in pelvic scanning;31.04 mGy, 1138. 78 mGy·cm, and 14. 69 mSv in pelvic enhanced scanning. Conclusions The CT scanning radiation doses to skull, neck, chest and pelvis in Ningxia are slightly lower than, or similar to, in other countries, but the abdominal scanning dose is significantly higher than that in other countries. It is necessary to optimize the abdominal CT scanning protocol.
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Objective To investigate the entrance surface dose to the examined patients in radiography using digital and screen-film system in hospitals at different levels in 15 provinces and municipalities in China,in order to provide data for developing diagnostic reference level of radiography suitable for our national physical characteristics.Methods According to the requirements of the Technical Study on Medical Radiation Hazard Assessment and Control,the examined patients aged 20-70 years were selected,with body weight ranging from 55 to 80 kg for male and 50 to 70 kg for female.TLDs were used to measure the entrance surface dose to adult patients in radiography.No less than 10 examined patients were required at each body position,with examined locations including head (PA,LAT),chest (PA,LAT),abdomen (AP),pelvis (AP),lumbar (AP,LAT),and thoracic vertebra (AP,LAT).Results A total of 19 975 individuals undergoing radiography and 1 813 radiographic equipment of different types including screen-film radiography,computed radiography (CR) and digital radiography (DR),were investigated in 342 hospitals in 15 provinces and municipalities throughout the country.For these three types of equipment,the average entrance surface dose to the examined were 1.75,1.9,and 1.15 mGy in head (PA),1.69,1.46and 1.03 mGy in head (LAT),0.75,0.65 and 0.36 mGy in chest (PA),1.81,1.26 and 0.88 mGy in chest (LAT),4.37,3.77 and 2.15 mGy in abdomen (AP),3.73,3.56 and 2.75 mGy in pelvis (AP),5.49,5.84 and 4.17 mGy in lumbar (AP),12.01,9.37 and 6.82 mGy in lumbar (LAT),4.53,3.65 and 2.49 mGy in thoracic vertebra (AP),and 6.91,6.43 and 4.15 Gy in thoracic vertebra (LAT).Conclusions Entrance surface dose caused by radiography examination varies dependent on different exposure locations.Entrance surface doses caused by digital radiography are all lower than by screen-film radiography;those caused by digital radiography are lower than by computed radiography,except for thoracic vertebra (AP).In all examinations,no difference of statistical significance is found between CR and screen-film radiography in entrance surface dose.
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Since the nuclear disaster at the Fukushima Daiichi Nuclear Power Plant in 2011, radiation safety has become an important issue in nuclear medicine. Many structured guidelines or recommendations of various academic societies or international campaigns demonstrate important issues of radiation safety in nuclear medicine procedures. There are ongoing efforts to fulfill the basic principles of radiation protection in daily nuclear medicine practice. This article reviews important principles of radiation protection in nuclear medicine procedures. Useful references, important issues, future perspectives of the optimization of nuclear medicine procedures, and diagnostic reference level are also discussed.
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Disasters , Nuclear Medicine , Nuclear Power Plants , Radiation ProtectionABSTRACT
After the rapid development of medical equipment including CT or PET-CT, radiation doses from medical exposure are now the largest source of man-made radiation exposure. General principles of radiation protection from the hazard of ionizing radiation are summarized as three key words; justification, optimization, and dose limit. Because medical exposure of radiation has unique considerations, diagnostic reference level is generally used as a reference value, instead of dose limits. In Korea, medical radiation exposure has increased rapidly. For medical radiation exposure control, Korea has two separate control systems. Regulation is essential to control medical radiation exposure. Physicians and radiologists must be aware of the radiation risks and benefits associated with medical exposure, and understand and implement the principles of radiation protection for patients. The education of the referring physicians and radiologists is also important.
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Humans , Guidelines as Topic , International Agencies , Occupational Exposure , Positron-Emission Tomography , Radiation Injuries/etiology , Radiation Protection , Radiation, Ionizing , Radiotherapy Dosage/standards , Reference Values , Tomography, X-Ray ComputedABSTRACT
Objective To analyse the CT radiation dose statistically using the standardized radiation-dose-structured report (RDSR) of digital imaging and communications in medicine (DICOM). Methods Using the self-designed software, 1230 RDSR files about CT examination were obtained searching on the picture archiving and communication system ( PACS ) . The patient dose database was established by combination of the extracted relevant information with the scanned sites. The patients were divided into adult group (over 10 years) and child groups (0-1 year, 1-5 years, 5-10 years) according to the age. The average volume CT dose index ( CTDIvol ) and dose length product ( DLP) of all scans were recorded respectively, and then the effective dose ( E) was estimated. The DLP value at 75% quantile was calculated and compared with the diagnostic reference level ( DRL) . Results In adult group, CTDIvol and DLP values were moderately and positively correlated ( r=0?41 ) , the highest E was observed in upper abdominal enhanced scan, and the DLP value at 75% quantile was 60% higher than DRL. In child group, their CTDIvol in group of 5-10 years was greater than that in groups of 0-1 and 1-5 years ( t=2?42, 2?04, P<0?05);the DLP value was slightly and positively correlated with the age (r=0?16), while E was moderately and negatively correlated with the age ( r = -0?48 ) . Conclusions It is a simple and efficient method to use RDSR to obtain the radiation doses of patients. With the popularization of the new equipment and the application of regionalized medical platform, RDSR would become the main tool for the dosimetric level surveying and individual dose recording.
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Objective To suggest a national value for the diagnostic reference level (DRL) in terms of activity in MBq.kg–1, for nuclear medicine procedures with fluorodeoxyglucose (18F-FDG) in whole body positron emission tomography (PET) scans of adult patients. Materials and Methods A survey on values of 18F-FDG activity administered in Brazilian clinics was undertaken by means of a questionnaire including questions about number and manufacturer of the installed equipment, model and detector type. The suggested DRL value was based on the calculation of the third quartile of the activity values distribution reported by the clinics. Results Among the surveyed Brazilian clinics, 58% responded completely or partially the questionnaire; and the results demonstrated variation of up to 100% in the reported radiopharmaceutical activity. The suggested DRL for 18F-FDG/PET activity was 5.54 MBq.kg–1 (0.149 mCi.kg–1). Conclusion The present study has demonstrated the lack of standardization in administered radiopharmaceutical activities for PET procedures in Brazil, corroborating the necessity of an official DRL value to be adopted in the country. The suggested DLR value demonstrates that there is room for optimization of the procedures and 18F-FDG/PET activities administered in Brazilian clinics to reduce the doses delivered to patients. It is important to highlight that this value should be continually revised and optimized at least every five years. .
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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 investigate radiation doses in pediatric chest radiography in a national survey and to analyze the factors that affect radiation doses. MATERIALS AND METHODS: The study was based on the results of 149 chest radiography machines in 135 hospitals nationwide. For each machine, a chest radiograph was obtained by using a phantom representing a 5-year-old child (ATOM(R) dosimetry phantom, model 705-D, CIRS, Norfolk, VA, USA) with each hospital's own protocol. Five glass dosimeters (M-GD352M, Asahi Techno Glass Corporation, Shizuoka, Japan) were horizontally installed at the center of the phantom to measure the dose. Other factors including machine's radiography system, presence of dedicated pediatric radiography machine, presence of an attending pediatric radiologist, and the use of automatic exposure control (AEC) were also evaluated. RESULTS: The average protocol for pediatric chest radiography examination in Korea was 94.9 peak kilovoltage and 4.30 milliampere second. The mean entrance surface dose (ESD) during a single examination was 140.4 microgray (microGy). The third quartile, median, minimum and maximum value of ESD were 160.8 microGy, 93.4 microGy, 18.8 microGy, and 2334.6 microGy, respectively. There was no significant dose difference between digital and non-digital radiography systems. The use of AEC significantly reduced radiation doses of pediatric chest radiographs (p < 0.001). CONCLUSION: Our nationwide survey shows that the third quartile, median, and mean ESD for pediatric chest radiograph is 160.8 microGy, 93.4 microGy, and 140.4 microGy, respectively. No significant dose difference is noticed between digital and non-digital radiography systems, and the use of AEC helps significantly reduce radiation doses.
Subject(s)
Child, Preschool , Humans , Phantoms, Imaging , Radiation Dosage , Radiography, Thoracic , Republic of Korea , Risk FactorsABSTRACT
The purpose of this study was to investigate the effect of various technical parameters for the dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE) including the scatter radiation from the object, the blur caused by the focal spot, geometric magnification and detector characteristics. For the tube voltages ranging from 40 to 90 kVp in 10 kVp increments at the FDD of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at the same effective dose. The results showed that the eDQE was largest at 60 kVp when compares the eDQE at different tube voltage. Especially, the eDQE was considerably higher without the use of an anti-scatter grid on equivalent effective dose. This indicates that the reducing the scatter radiation did not compensate for the loss of absorbed effective photons in the grid. When the grid is not used the eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF). However, most of major hospitals in Korea employed a short FDD of 100 cm with an anti-scatter grid for the chest radiological examination of a 15 month old infant. As a result, the entrance surface air kerma (ESAK) values for the hospitals of this survey exceeded the Korean DRL (diagnostic reference level) of 100 microGy. Therefore, appropriate technical parameters should be established to perform pediatric chest examinations on children of different ages. The results of this study may serve as a baseline to establish detailed reference level of pediatric dose for different ages.