Investigation of breast dose in five screening mammography centres in Greece

The objectives of this study were to investigate the techniques currently used for screening mammography in Greece, to estimate the mean glandular dose (MGD) for establishing a baseline radiation dose database, to analyse the effects of various factors on MGD, and to compare the results with others in the literature. Five mammographic facilities and 250 women having as a routine screening mammogram one craniocaudal (CC) and one mediolateral oblique (MLO) projection in each breast were included in the study. The parameters recorded were age, weight, compressed breast thickness (CBT), tube potential (kV), tube loading (mA s) and MLO projection angle. Large differences were observed among the different mammography facilities, mainly in terms of the tube potential setting and the MLO angle used. The average MGD per exposure was 1.4 +/- 0.6 mGy while the respective averages separately for the CC and MLO projections were 1.2 +/- 0.5 and 1.5 +/- 0.7 mGy, respectively. The average MGD values recorded in this study were below the limit of 2 mGy established for the reference medium-sized breast of 4.5 cm CBT. However, the variety of techniques observed revealed the need for a nationwide survey concerning screening mammography in Greece.     

Bone marrow dose estimates from work-related medical x-ray examinations given between 1943 and 1966 for personnel from five U.S. nuclear facilities

Inclusion of dose from work-related medical x-ray examinations with occupational external dose in an epidemiological study may reduce misclassification of exposures and provide more accurate assessment of leukemia risk from occupational exposure to ionizing radiation. In a multi-site leukemia case-control study, annual bone marrow doses due to work-related x-ray examinations given between 1943 and 1966 were estimated for cases and controls employed at five nuclear facilities. Only active bone marrow dose from photofluorographic chest and routine lumbar spine x rays were included. Bone marrow dose assigned for a single exposure ranged from 1.0 to 1.4 mGy. Mean and median cumulative bone marrow doses for each of the five sites from work-related x-ray examinations ranged from 2.0 to 14 mGy and 2.1 to 8.8 mGy, respectively. Results suggest that bone marrow dose from work-related photofluorographic and lumbar spine x-ray examinations given during the time period of this study may be significant compared to occupational bone marrow dose.     

江苏省乳腺X射线摄影医疗照射剂量调查

目的］ 通过调查和测量计算江苏省乳腺X射线摄影受检者乳房压缩厚度（compressed breast thickness,CBT）和腺体平均剂量（average glandular dose,AGD）,了解江苏省乳腺X射线摄影的AGD分布情况及影响因素。 ［方法］ 抽样调查来自5 城市17 个医疗机构中17 台次340 个乳腺X射线摄影的曝光参数,使用X线质量控制检测仪测量其入射体表空气比释动能（entrance surface air kerma,ESAK）。使用国际通用方法计算AGD,并分析其与CBT等因素的关系。［结果］ 在江苏省抽取的340 个乳腺X射线摄影参数中,AGD均数为1.66 mGy。CBT 服从正态分布,均数和标准差分别为4.22 cm和1.12 cm。两种不同体位的CBT 差异有统计学意义（t=-3.481,P 〈 0.05）,两种体位的AGD水平差异无统计学意义（t=-0.791,P 〉 0.05）。 ［结论］ CBT 可能通过不同机制影响AGD水平,可为建立适合我国乳腺X射线摄影受检者剂量指导水平提供依据。     

Medical x-ray exposure doses as contaminants of atomic bomb doses

Since 1967 at the times of their biennial ABCC/RERF radiological examinations, all Adult Health Study (AHS) subjects have been interviewed to determine the exposures to medical x-rays they experienced in institutions other than RERF in order to estimate the numbers of examinations and corresponding doses which they received. These data have been stored on computer tapes together with the doses these subjects received during their radiological examinations in the ABCC/RERF Department of Radiology. Thus, their medical x-ray doses are available along with their atomic bomb doses (tentative 1965 doses revised, T65DR) for assessment of the role of ionizing radiation in the development of diseases. The medical x-ray doses incurred at RERF were assessed by means of phantom dosimetry. Those at other institutions were determined using phantom dosimetry data and results of surveys for trends in radiological examinations in Hiroshima and Nagasaki. By the end of 1982, the average medical x-ray doses to the active bone marrow were 12.04 mGy for A-bomb exposed groups and 8.92 mGy for control groups (not-in-cities); to the male gonads, 2.26 mGy and 1.89 mGy, respectively; and to the female gonads, 17.45 mGy and 12.58 mGy, respectively. Results for Hiroshima and Nagasaki were similar. The main impact of medical x-ray doses was in the lowest T65DR group. Medical x-ray active bone marrow doses ranged from 0.05-500% (mean, 35%) of A-bomb doses in the 10-99 mGy T65DR group. In the 100-999 mGy T65DR group, medical x-ray active bone marrow doses ranged from 0.005-50% (mean, 5%) of their T65DR. In the greater than 1,000-mGy T65DR group, medical x-ray exposures were proportionally less. Female active bone marrow and gonad doses were similar in magnitude to the male active bone marrow doses. Medical x-ray exposures produced smaller doses to the gonads of males than to those of the females. The use of medical x-rays is steadily increasing. Careful consideration of doses from medical sources is essential for reliable assessments of the effects from exposures to the atomic bombs.     

上海市2007年X射线诊断的医疗照射剂量水平

[目的]掌握当前上海市各主要类型x射线诊断检查的剂量水平。[方法]根据x射线诊断设备种类、应用发展趋势及医院级别的差异,分别抽查约3％的普通x射线机和约25％的计算机X射线摄影、数字化X射线摄影以及x射线计算机断层扫描（x—cT）机,通过布放热释光剂量计测量成年人在不同检查方式和体位的入射体表剂量;利用标准的X—CT剂量模体和电离室测量不同扫描条件下的CT剂量指数,进而估算受检者的有效剂量。[结果]X射线摄影所致受检者的入射体表剂量平均值的变化范围为0．13～4．35mGy,其中手部摄影最低、腰椎侧位摄影最高。胸部透视时胸部表面的平均剂量为3．79mGy。胆囊和尿路造影以及上消化道钡餐和钡灌肠检查的受检者上腹部体表的平均剂量最大,分别为30．24、30．97、25．28、23．02mGy;消化道钡餐检查时胸部体表的平均剂量为24．27mGy,钡灌肠检查时下腹部体表的平均剂量为21．62mGy。头部X-CT扫描时受检者的平均有效剂量为（0．58±0．22）mSv,体部x—CT扫描时受检者的平均有效剂量为（5．18±1．92）mSv。[结论]较全面地得到了当前上海市主要类型x射线诊断所致受检者的剂量水平,可为推动进一步完善x射线诊断的医疗照射指导（参考）水平和加强受检者防护提供重要资料。     

我国乳腺X射线摄影受检者乳腺剂量水平调查研究

目的 通过调查全国15个省市不同级别医疗机构乳腺X射线摄影曝光参数并测量计算受检者乳腺平均剂量,分析我国乳腺X射线摄影中受检者压迫后乳房厚度分布及乳腺受照剂量水平,为建立适合我国成年女性受检者乳腺X射线摄影的剂量指导水平提供依据。方法 按照《医用辐射危害评价与控制技术研究》实施方案的要求,调查临床实际乳腺摄影受检者的年龄、乳房压迫厚度、曝光参数、摄影体位等相关信息,通过手动曝光测量该条件下乳房压迫厚度处的入射空气比释动能(K_a,i),计算受检者的乳腺平均剂量(AGD)。结果 共在全国15个省的149家医院调查了4372例乳腺X射线摄影体位,273台不同类型乳腺X射线摄影设备,包括屏片乳腺X射线摄影、计算机乳腺X射线摄影(乳腺CR)和直接数字乳腺X射线摄影(乳腺DR)设备,对于这三种类型的设备,头尾(CC)位投照时受检者AGD的平均值分别为1.21,1.77,1.61 mGy,AGD的75%位分别为1.36,2.22,1.81 mGy;斜侧(MLO)位时受检者AGD平均值分别为1.02,1.78,1.66 mGy,AGD的75%位分别为1.23,2.46,1.81 mGy。CC位和MLO位时乳房压迫厚度的中位数分别为4.2和4.5 cm。结论 不同类型乳腺X射线摄影设备中,屏片乳腺X射线摄影设备致受检者的乳腺平均剂量最低,其次是乳腺DR设备,乳腺CR设备致患者剂量最高。     

X线乳腺摄影受检者腺体平均剂量水平调查

目的调查河北省内部分医院乳腺x线机受检者腺体平均剂量水平,比较普通增感屏／胶片机,计算机x线摄影（CR）,数字放射线摄影（DR）及不同压迫厚度乳腺腺体平均剂量水平的差异。方法乳腺腺体平均剂量测量采用VictoreenNEROTMmax系统主机（美国Cardinal Health公司）及Victoreen6000—529乳腺电离室（美国FLUKE公司）。结果3种乳腺X线机在实际诊断工作中,钼靶屏／片机剂量平均值为（0．74±0．23）mGy,CR与DR剂量平均值分别为（1．60±1．02）与（1．69±0．80）mGy,受检者腺体平均剂量水平钼靶屏／片机低于CR及DR,其差异有统计学意义（P〈0．05）。对CR与DR受检者腺体平均剂量进行。检验,P值为0．35,差异无统计学意义。随着乳房压迫厚度的增加,腺体平均剂量水平有所增加,但差异无统计学意义（P〉0．05）。结论在医师操作熟练、设备保养得当的情况下,乳腺X线钼靶屏／片机可以满足一般患者诊断要求,中小型医院或经济欠发达地区医院可以使用钼靶屏／片X线     

Comparison of dose from radiological examination for scoliosis in children among two pediatric hospitals by Monte Carlo simulation

The radiation exposures of children undergoing full spine radiography were investigated in two pediatric hospitals in Greece. Entrance surface kerma (Ka,e) was assessed by thermoluminescence dosimetry and patient's effective dose (E) was estimated by Monte Carlo simulation. All required information regarding patient age and sex, the irradiation geometry, the x-ray spectra, and other exposure parameters (tube voltage and current) were registered as well. Values of Ka,e were measured to range from 0.22 mGy to 2.12 mGy, while E was estimated to range from 0.03 mSv to 0.47 mSv. In general, all values were greater in one of the two hospitals, as higher tube currents and exposure times were used in the examinations because of the difference in radiographers' training and practice. Moreover, dose to red bone marrow was found to be between 0.01 to 0.23 mSv and dose to breast ranged between 0.02 and 1.05 mSv depending on the age, projection, and hospital. These values are comparable with literature sources.     

妊娠期患者腹部CT检查所致胎儿辐射风险分析

目的：对妊娠患者进行常规腹部螺旋CT扫描所致胎儿辐射风险进行评估。方法：曝光条件由临床CT检查选择病例的统计数据确定。CT扫描仪包括3个生产厂商的双排、16排和64排CT。胎儿受照剂量由患者子宫的器官剂量代替。子宫器官剂量由SR250软件估算。结果：对于所有机型的常规腹部螺旋CT扫描,胎儿受照剂量范围为14～26mGy,平均值和方差为（18.5±4.7）mGy。结论：根据ICRP建议书,分别从3个角度评价胎儿辐射效应：①常规腹部螺旋CT扫描不会引起胎儿组织损伤及功能障碍;②不会造成胎儿智力发育障碍;③胎儿时期的X射线照射会提高幼儿时期癌症的发生率。然而,由于实际情况的复杂性,很难确定这个癌症发生率提高的程度有多大。因此,根据本次实验所估计的胎儿受照剂量,妊娠患者进行常规腹部螺旋CT扫描导致胎儿发生辐射效应的概率极低。     

Population exposure to diagnostic use of ionizing radiation in The Netherlands

The use of ionizing radiation for diagnostic medical procedures and the exposure of the Dutch population to this radiation were assessed for 1998. The annual average effective dose from diagnostic medical exposures has increased by 26% to 0.59 mSv per capita since the last inventory of medical radiation exposure in the Netherlands a decade ago. The population-averaged effective dose comprises x-ray procedures in hospitals (87%), nuclear medicine examinations (11%), mammography screening (1.5%), and extramural dentistry (0.2%). The rise has resulted mainly from an increase in frequency and patient dose for CT examinations and from vascular radiology. The increase in the number of CT examinations leveled off in the mid-1990's. Medically exposed people were found to be significantly older than the general population. Based on age distribution alone, an "age reduction factor" for the risk coefficient of 0.64 was found to apply to the medically exposed group. More information on patient dose for the complete set of procedures should, according to this study, become available.     

Towards establishment of the national reference dose levels from computed tomography examinations in Tanzania.

Without the knowledge of reference dose levels (RDLs) from computed tomography (CT) examinations, the optimal dose to patients undergoing CT examinations cannot be realised. The aim of this study was therefore to assess the radiation dose levels from CT examinations according to reference dose quantities proposed by the European Commission (EC) guidelines. The dosimetric quantities proposed in the EC for CT are weighted CT dose index (CTDI(w)) for a single slice and dose-length product (DLP) for a complete examination. The RDLs from five common CT examinations were obtained from eight hospitals. The RDLs in terms of CTDI(w) and DLP were estimated from measurements of CTDI in standard phantoms using typical exposure parameters. Mean values of CTDI(w) for head and lumbar spine had a range of 25-77 and 18-47 mGy, respectively, while those for chest, abdomen and pelvis had a range of about 11-25 mGy, respectively. Mean values of DLP for head, chest and abdomen had a range of 610-1684, 496-992 and 717-1428 mGy cm, respectively, while those for lumbar spine and pelvis had a range of 200-382 and 526-1302 mGy cm, respectively. Wide variations of mean CTDI(w) and DLP values among hospitals observed for similar CT examinations were mainly attributed to the variations of CT scanning protocols and scanner types. The mean CTDI(w) values per examination for almost all hospitals were below proposed RDLs, while the mean DLP values per examination were almost all above the proposed RDLs for all except one hospital. These were mainly influenced by the large scan length used in Tanzanian hospitals. In order to achieve the required level of dose for establishment of the national RDLs, it was concluded that further investigation of optimization of scanning protocols is needed.     

Absorbed dose to the adult male and female brain from 18F-fluorodeoxyglucose

The absorbed doses to adult male and female brains from 18F-fluorodeoxyglucose were investigated. A total of eight male and six female patients undergoing clinical positron tomography brain scans were included in this study. This patient population allowed for a comparison of the absorbed dose to the brain in men and women. For each patient, time-activity curves for the brain were generated, yielding cumulated activity measurements for the entire organ. From these cumulated activities the average residence times for both male and female subjects were calculated and then multiplied by the S-values from the MIRDOSE 3.1 software program for absorbed dose estimates. The average absorbed dose per administered activity to the adult male brain was found to be 4.2 x 10(-2) mGy MBq(-1), which is lower than that found for the adult female brain of 5.3 x 10(-2) mGy MBq(-1). Six of the male and all six female subjects were each studied on two separate occasions, allowing for an analysis of within-subject variability. The average variation in the self-dose for all 12 patients was found to be within 14%, suggesting that in most cases this method of obtaining a single dose estimate is precise.     

A survey of fluoroscopic equipment in Victoria

A survey of fluoroscopic units in the state of Victoria has been carried out. For fixed fluoroscopy equipment, routine quality assurance tests were carried out on the x-ray tube used for conventional radiographs, and factors relating to image quality and patient dose were measured for the screening tube. For the mobile image intensifiers, quality assurance tests were carried out and factors relating to image quality and patient dose were measured. There was a ratio of about 20 in the dose rates between the units with the highest and lowest screening dose rates with the same size phantom. Guidance levels based on the third quartile values of the entrance dose rates and spot film doses are recommended. The recommended guidance doses are: mobile image intensifier: dose rate: 30 mGy/min; fixed screening unit: dose rate: 42 mGy/min and spot film: 5 mGy.     

Individual dose reconstruction among residents living in the vicinity of the Semipalatinsk nuclear test site using EPR spectroscopy of tooth enamel

Individual accumulated doses were determined by EPR spectroscopy of tooth enamel for 26 adult persons residing in territories adjacent to the Semipalatinsk Nuclear Test Site (SNTS). The absorbed dose values due to radiation from nuclear tests were obtained after subtracting the contribution of natural background radiation from the total accumulated dose. The determined dose values ranged up to 250 mGy, except for one person from Semipalatinsk city with a measured dose of 2.8 +/- 0.4 Gy. Increased dose values were determined for the individuals whose teeth were formed before 1962, the end of the atmospheric nuclear tests. These values were found to be significantly larger than those obtained for a group of younger residents of heavily exposed territories and the residents of territories not exposed to radioactive fallout. These increased dose values are consistent with those based on officially registered data for the Northeastern part of Kazakstan adjacent to SNTS, which was exposed to high levels of radioactive fallout from nuclear tests in period 1949-1962.     

Monte Carlo estimation of radiation doses in red bone marrow and breast in common pediatric x-ray examinations

Radiation exposure was investigated for children undergoing various common radiographies in three dedicated pediatric hospitals in Greece. Kerma in air at the entrance of the beam (Ka,e) was measured with thermoluminescent dosimeters. Ka,e values ranged from 0.09 mGy to 5.52 mGy and were found to be greater in Hospital C, because of the increased high voltage and time-current product used by the radiation technologists. Equivalent doses in red bone marrow and breast were estimated with Monte Carlo simulation by PCXMC code. Values ranged from 2 microSv to 204 microSv for red bone marrow and from 0 to 817 muSv for breast. Variation in doses occurred due to field size, high voltage setting, and Ka,e.     

Estimates of doses from global fallout

This paper summarizes information about external and internal doses resulting from global fallout and presents preliminary estimates of doses resulting from intermediate fallout in the contiguous United States. Most of the data on global fallout were extracted from the reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, in which the radiation exposures from fallout have been extensively reviewed at regular intervals. United Nations Scientific Committee on the Effects of Atomic Radiation estimated the average effective doses received by the world's population before 2000 to be about 0.4 mSv from external irradiation and 0.6 mSv from internal irradiation, the main radionuclide contributing to the effective dose being 137Cs. Effective doses received beyond 2000 result mainly from the environmentally mobile, long-lived 14C and amount to about 2.5 mSv summed over present and future generations. Specific information about the doses from fallout received by the United States population is based on the preliminary results of a study requested by the U.S. Congress and conducted jointly by the Centers for Disease Control and Prevention and the National Cancer Institute. Separate calculations were made for the tests conducted at the Nevada Test Site and for the high-yield tests conducted mainly by the United States and the former Soviet Union at sites far away from the contiguous United States (global tests). The estimated average doses from external irradiation received by the United States population were about 0.5 mGy for Nevada Test Site fallout and about 0.7 mGy for global fallout. These values vary little from one organ or tissue of the body to another. In contrast, the average doses from internal irradiation vary markedly from one organ or tissue to another; estimated average thyroid doses to children born in 1951 were about 30 mGy from Nevada Test Site fallout and about 2 mGy from global fallout.     

江西省X射线摄影受检者入射体表剂量调查

目的 调查2017年度江西省X射线摄影所致受检者的入射体表剂量水平,阐述江西省X射线诊断的医疗照射现状。方法 随机选取南昌市、上饶市、赣州市、萍乡市、宜春市和九江市共6个地级市不同级别的20家医院,利用热释光剂量计测定1 273人次受检者不同照射部位的ESD值。结果 2017年江西省CR和DR摄影所致受检者的ESD范围分别为0.08~17.81 mGy和0.04~30.91 mGy,胸部正位和侧位、腰椎正位和侧位、颈椎正位和侧位、骨盆及髋关节的X射线摄影检查所致受检者的ESD值的范围分别为0.07~2.40 mGy、0.13~7.27 mGy、0.33~23.29 mGy、0.62~30.91 mGy、0.09~1.69 mGy、0.10~1.79 mGy、0.29~23.46 mGy。结论 江西省胸部侧位X射线摄影所致受检者的入射体表剂量75%百分位值超过医疗照射指导水平,部分照射部位ESD值较全国"九五"期间调查值有显著下降,DR摄影所致受检者剂量比CR高,应采取措施降低DR摄影所致受检者的辐射剂量。     

Significance of radiation exposure from work-related chest X-rays for epidemiological studies of radiation workers

BACKGROUND: Previous epidemiologic studies of workers at nuclear weapons facilities have not included X-ray exposures as part of the occupational radiation exposure. The research objective was to determine the contribution of work-related chest X-ray (WRX) exposure relative to the cumulative occupational radiation exposure. METHODS: Cases and controls were identified from a cohort of workers whose employment began as early as 1943. Medical records for 297 subjects were used to determine the bone marrow dose from their X-ray examinations. Individual dose data, however, were only available for 45 workers. Bone marrow dose estimates were calculated by converting the entrance-skin-exposure (from X-ray procedures) and occupational exposure (from monitoring data) to dose. RESULTS: Stereoscopic photofluorography delivered a bone marrow dose nearly 100 times that delivered by today's chest X-ray technique. Photofluorography was the predominant radiation source during the 1940s and 1950s. The cumulative WRX dose was, on average, 50 times their occupational doses. No correlation between occupational and WRX dose was found, but may be due to the small study size and incomplete dose data. CONCLUSIONS: These findings illustrate the importance of including WRX doses in retrospective epidemiological studies of radiation workers, especially if photofluorographic chest X-rays were performed and occupational exposure to ionizing radiation is low.     

Estimation of adult patient doses for common diagnostic X-ray examinations in Wad-madani,Sudan: derivation of local diagnostic reference levels

The objectives of this study were to estimate patient dose in some common diagnostic X-ray examinations. Radiation doses were estimated for 307 patients in six public hospitals comprising 7 X-ray units in Wad-madani, Sudan. Entrance surface air kerma (ESAK) was estimated in a three step protocol: First, X-ray unit output Y(d) was measured at a distance, d for different peak tube voltages and tube loadings (mAs). Next, incident air kerma (K_i) was calculated from Y(d) using inverse square law combined with patient exposure factors. ESAK was calculated from K_i using backscatter factor, B. Mean ESAK values are comparable to those reported in other countries and are below reference dose levels. The estimated mean ESAK values are: 0.3, 2.2, 2.2, 2.9, 2.8, 3.1, and 7.5 mGy for chest PA, Skull AP/PA, Skull LAT, Abdomen, Pelvis AP, Lumbar Spine AP and Lumbar Spine LAT examinations, respectively. The results are used for dose optimization, and to propose local diagnostic reference levels.     

Estimation of the thyroid doses for ukrainian children exposed in utero after the chernobyl accident

This paper describes methods for estimating thyroid doses to Ukrainian children who were subjects of an epidemiological study of prenatal exposure and presents the calculated doses. Participants were 2,582 mother-child pairs in which the mother had been pregnant at the time of the Chernobyl accident on 26 April 1986 or in the 2-3 mo following when (131)I in fallout was still present. Among these, 1,494 were categorized as "exposed;" a comparison group of 1,088 was considered "relatively unexposed." Individual in utero thyroid dose estimates were found to range from less than 1 mGy to 3,200 mGy, with an arithmetic mean of 72 mGy. Thyroid doses varied primarily according to stage of pregnancy at the time of exposure and level of radioactive contamination at the location of residence. There was a marked difference between the dose distributions of the exposed and comparison groups, although nine children in the latter group had calculated doses in the range 100-200 mGy. For those children who were born after the accident and prior to the end of June 1986, postnatal thyroid doses were also estimated. About 7.7% (200) of the subjects received thyroid doses after birth that were at least 10% of their cumulative doses.