National CT use and radiation exposure: United States 1983

Data from two sources provide an estimate that in 1983, 5-5.5 million computed tomographic (CT) procedures were performed in the U.S. Of those, 63% were head scans, 27% body, and 10% spine. Ten percent or fewer were high-resolution studies, primarily spine CT. The surface dose varies widely but ranges between 1 and 7 rad (10-70 mGy) for most examinations. It is estimated that CT scanning contributes 7%-8% of the adult active bone marrow dose that is received from diagnostic radiology.     

Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P Thermoluminescent Dosemeter and its applications in diagnostic radiology—a review

This study investigated the dosimetric properties of the high sensitivity TLD (Thermoluminescent Dosemeter) of LiF:Mg,Cu,P and its applications in diagnostic radiology. A reproducible readout and annealing regime for this high sensitivity TLD was developed in the initial part of this study with the newly installed automatic TLD Reader system. Basic dosimetric characteristics of this T.L. dosemeter were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom. The applications studied in radiological procedures included: dose reduction in lumbar spine radiography utilizing the “anode heel effect”; gonad dose variation with kV_p in chest radiography; foetal dose comparison between computed tomography (CT) and computed radiography (CR) in X-ray pelvimetry; lens dose reduction with bismuth eye-shields in CT brain studies; foetal dose assessment of early pregnancy in common high risk radiological examinations. It is anticipated that the unique and favourable dosimetric performance of LiF:Mg,Cu,P T.L. phosphor will be exploited further in measurements of low level dose received by patients and staff in diagnostic radiological procedures such as paediatric X-ray examinations.     

Diagnostic radiology usage in ambulatory and hospital care

Data from a nationwide survey of physicians show that there were a total of 214 million medical radiologic examinations performed in the United States in 1977, or just under one for each member of the resident population. Approximately 58% of these procedures were performed in ambulatory patients (including those in hospital outpatient departments) and 42% were in hospitalized patients. Data for the number of visits with (single or multiple) radiologic examinations produced an estimate of 184 million annual visits with one or more diagnostic radiographs. These estimates provide a comprehensive measure of national use of diagnostic radiology at the time the data were collected, as well as a basis of comparison for analyses of contemporary patterns of utilization of radiologic procedures.     

内蒙古自治区常规X射线诊断患者剂量调查结果分析

目的 分析内蒙古地区常规X射线诊断患者入射体表剂量水平。方法 根据全国医疗照射剂量及频度调查项目方案的要求,完成内蒙古地区30%数量医疗机构常规X射线诊断应用现状调查,按照医疗机构年接诊人数比例抽取内蒙古地区12个盟市24家医疗机构开展普通X射线诊断患者入射体表剂量调查。将不同设备、不同级别医院、不同照射部位间受检者入射体表剂量结果进行比较。结果 在各类诊断设备中,以数字X射线摄影系统（DR）为主。在各类常规X射线诊断检查过程中,腰椎摄影所致患者平均入射体表剂量为3.39 mGy/人,骨盆及髋关节摄影检查所致患者平均入射体表剂量为1.65 mGy/人,颈椎、四肢和胸部摄影所致患者平均入射体表剂量分别为0.90、0.38、0.37 mGy/人。在胸部、腰椎、颈椎3种部位的诊断检查中,使用屏片摄影设备所致受检者入射体表剂量高于DR测量结果,差异具有统计学意义（Z=-3.229、-4.820、-5.265,P<0.05）。结论 屏片摄影设备所致患者的入射体表剂量大于DR,操作人员的操作行为是影响患者入射体表剂量的重要因素。     

Collective irradiation caused by radio-diagnostic procedures in France in 1982. Results (2)

This paper gives the most important results of the collective dose received by patients who undergoing diagnostic radiology examinations in France in 1982. It details, per each X-ray examination type, the collective organ dose associated with, and highlights the importance of the radiological procedures (number of X-ray films, fluoroscopy screening time) on the received patient doses. If one takes into account organs for which dosimetric measurements have been carried out, the collective effective dose equivalent per 10(6) inhabitants is 442 man-Sievert; the genetically significant dose reaches 0.295 mSv and finally the collective red bone marrow dose due to 45 million X-ray exams practiced in France (1982) is 40,300 man-Sievert i.e. 0.742 mSv. per inhabitant.     

颅骨与腰椎骨髓转化的MR定量研究及临床应用

目的 :从定量角度探讨MRI上颅骨与腰椎骨髓转化特点并评估骨髓相对信号强度 (RSI)的诊断价值。方法 :正常组 2 5 7例 ,其中颅骨 10 1例 ,腰椎 15 6例 ;异常组 6例 ,白血病 5例 ,多发性骨髓瘤 1例。MR扫描仪为 0 .5TPhilipsGyroscan。成像序列为TSET1 WI ,测定颅骨和腰椎骨髓的RSI并进行F检验、相关分析及动态分析。结果 :腰椎和颅骨骨髓RSI与年龄呈明显正相关 (P <0 .0 1)。颅骨骨髓RSI的净增量及平均增长速度大于腰椎。正常组颅骨骨髓与腰椎骨髓RSI在不同年龄段之间差异有显著性意义。异常组骨髓RSI值明显低于相应年龄段正常均值。结论 :骨髓RSI在不同年龄段间存在显著性差异 ,颅骨骨髓转化程度、速度均较腰椎显著。RSI对弥漫性骨髓浸润性疾病有较高的敏感性 ,但缺乏特异性。     

天津市X射线诊断设备医疗照射频度调查

目的 掌握天津市X射线诊断设备医疗照射频度,为规范医疗照射管理,合理配置和使用医疗卫生资源提供建议。方法 采用普查的方式,以行政文件形式下发调查表格,对天津市687家医院（部队和武警医院除外）的X射线诊断设备基本情况和医疗照射诊疗情况进行调查,了解天津市2018年X射线诊断设备的基本情况和诊疗人次。将调查的各类型放射诊疗人次数除以2018年全市常住人口数,得出不同X射线诊断设备的应用频度,并对结果加以分析。结果 2018年天津市共有X射线诊断设备（含介入放射学）1 562台,平均每万人拥有1.00台。天津市从事X射线诊断工作（含介入放射学）的放射工作人员共4 782人,操作每台设备的放射工作人员数为3.06人/台,其中三级医院最高,为5.25人/台、未定级医院最低,为1.18人/台。全市X射线诊断医疗照射8 905 970人次,其中三级医院占54.81%、二级医院占18.00%、一级医院占16.21%、未定级医院占10.98%;X射线摄影检查占71.30%,年频度为407.84人次/千人口、CT检查占21.81%,年频度为124.74人次/千人口、介入放射学占1.04%,年频度为5.98人次/千人口,其他X射线检查占5.85%,年频度为33.47人次/千人口。结论 天津市X射线诊断设备配置基本合理,X射线诊断医疗照射频度呈上升趋势,各X射线诊断检查类别分布的合理性还需进一步提高,做好医疗照射防护,降低群体剂量水平,保护广大公众的健康和安全,是今后放射防护工作的重要课题。     

MR study of bone marrow changes of the spine following radiotherapy

MR examinations of bone marrow variations in the spine after radiotherapy were performed on 24 patients in the thoracic and lumbar vertebral column. The actinically affected bone marrow showed a characteristic increase of signal intensity in T1-weighted sequences in the sagittal plane, due to conversion of red marrow to fatty marrow. The dose in the well-defined radiation areas was between 28 and 70 Gray (Gy). The lowest dose, applied to the bone-marrow bordering on the defined radiation areas, where we still could find an increase of signal intensity, was below 2.6 to 5 Gy. MR imaging was performed between 6 and 9 month after radiotherapy.     

Normal age-related patterns of cellular and fatty bone marrow distribution in the axial skeleton: MR imaging study

Knowledge of age-related distribution patterns of cellular and fatty marrow is critical to the interpretation of magnetic resonance (MR) imaging studies. To determine such patterns, the authors retrospectively evaluated 70 examinations each of the skull, cervical spine, thoracic spine, lumbar spine, pelvis, and proximal femur (420 examinations) in patients without known bone marrow abnormality who ranged in age from 6 months to older than 70 years. Two to four distinct patterns were identified in each anatomic area on spin-echo images obtained with a short repetition time and a short echo time. The relative frequency of the patterns for different age groups is consistent with the known physiologic conversion from cellular to fatty marrow with advancing age. Knowledge of these patterns should help in the interpretation of MR images of the axial skeleton.     

Lumbar spine radiology: analysis of the posteroanterior projection

The use of the posteroanterior (PA) technique as a means of dose reduction has been used effectively in radiology departments for chest and abdominal examinations. The aim of this investigation was to establish if the PA lumbar spine projection offers any advantages over the traditional anteroposterior (AP) view in terms of radiation dose and image quality. The contribution of tissue displacement to any dose reduction was also evaluated. The first part of the study involved the use of an anthropological phantom where entrance surface and an internal dose were measured for both the PA and AP projections. Entrance surface doses for both projections were then measured on randomly allocated female patients. Resultant image quality was assessed using CEC quality criteria. Anterior to posterior patient diameter was also recorded. The results demonstrated that with the PA compared with the AP projection, reductions of 38.6 % (p = 0.016) and 38.9 % (p = 0.02) in patient entrance surface dose and internal phantom dose, respectively. No significant differences in image quality were noted between the two projections. Patient diameter decreased by 1.8 cm with the PA view. The authors conclude that tissue displacement is the main factor for the patient dose reduction and recommend employment of the PA procedure for routine lumbar spine examinations. Received: 3 August 1999; Revised: 5 November 1999; Accepted: 9 November 1999     

直接摄影检查患者的照射剂量分析

目的 通过对不同部位直接摄影(DR)检查的医学数字成像和传输(DICOM)文件信息中的患者剂量信息的统计,调查不同投照部位DR摄片的照射剂量分布范围,分析影响DR检查照射剂量的因素。方法 随机选取浙江省某三甲医院2009年1月至4月5160次DR摄片,包括胸部、胸椎及腰椎正、侧位、腹部前后位及骨盆正位。应用软件自动提取每例患者检查中DICOM信息文件中的剂量面积乘积(DAP),并结合照射野的范围,计算各部位DR检查的入射表面剂量(ESD)。结果 腹部前后位、腰椎侧位、胸椎正侧位的变异系数在60%以下;胸部正侧位、腰椎正位、骨盆正位的变异系数为60%~80%。各个部位的DAP最大值与最小值比值,除腹部前后位较小为3倍,其余部位差异较大。其中,腰椎正位最大差别为46倍、腰椎侧位30倍,胸椎侧位、胸部正位、侧位、骨盆正位、胸椎正位分别为23、23、18、16、11倍。通过计算得到ESD值选择75%分位点与现行普通摄片诊断参考水平(DRL)比较后发现,胸部正、侧位分别下降75%和73%;腰椎正侧位下降66%和77%;胸椎正侧位下降85%和84%;骨盆正位下降88%;腹部前后位下降88%。结论 DR检查中各个部位的DAP与ESD值存在较大变动,ESD值与现行的常规摄片的DRL相比有较大下降;有必要回顾分析DR摄片的患者照射剂量,对患者照射剂量与图像质量进行质量管理。     

Some indicative parameters on diagnostic radiology in Spain: first dose estimations

The Medical Physics Group at the Complutense University of Madrid has been co-ordinating, for approximately 1 year, a project on optimization of radiation protection in diagnostic radiology, in co-operation with the other states of the European Community. Exhaustive data on the subject, which offer accurate results on patient dosimetry for the different types of examination, are the final aim of the project. So far, it has been possible to analyse in detail the data from the National Institute of Health (NIH), which manages the care of about 96% of the Spanish population, plus the findings from several hospitals, outpatient centres and private clinics of the community of Madrid, which allowed us to perform the first dose estimations and to extrapolate them to the rest of Spain. The following estimations are presented: annual frequency of different examinations, their variation from 1985 to 1986, number of diagnostic rooms used for a given minimum of annual examinations, organ doses for different examinations, effective dose-equivalent, genetically significant dose for some examinations, as well as the collective dose.     

Evidence against the use of lumbar spine radiography for low back pain

AIM: To review abnormalities reported on plain radiographic examination of the lumbar spine in patients referred with low back pain by general practitioners. Additionally, we evaluated and stratified the prevalence of these abnormalities by age. Finally, the diagnostic impact of lumbar spine radiography for the diagnosis of degenerative change, fracture, infection and possible tumour, was modelled. MATERIALS AND METHODS: A retrospective review of 2007 radiographic reports of patients referred with low back pain for lumbar spine radiography to a large radiology department was performed. The reports were classified into different diagnostic groups and subsequently stratified according to age. The potential diagnostic impact of lumbar spine radiography was modelled by using the prevalence of conditions studied as pre-test probabilities of disease. RESULTS: The prevalence of reported lumbar spine degeneration increased with age to 71% in patients aged 65-74 years. The overall prevalence of fracture, possible infection, possible tumour was low in our study population: 4, 0.8 and 0.7%, respectively. Fracture and possible infection showed no association with age. Possible tumour was only reported in patients older than 55 years of age. CONCLUSION: Although the prevalence of degenerative changes was high in older patients, the therapeutic consequences of diagnosing this abnormality are minor. The prevalence of possible serious conditions was very low in all age categories, which implies radiation exposure in many patients with no significant lesions.     

MRI of spinal bone marrow: part 2, T1-weighted imaging-based differential diagnosis

OBJECTIVE: The purpose of this article is to review the structure of bone marrow and the differential diagnosis of bone marrow pathology on the basis of T1-weighted MRI patterns. CONCLUSION: Bone marrow is an organ that is evaluated routinely during MRI of the spine, particularly lumbar spine evaluation. Thus, it is one of the most commonly performed MRI examinations. T1-weighted MRI is a fundamental sequence in evaluating spinal marrow, and an understanding of T1-weighted MR signal abnormalities is important for the practicing radiologist.     

Radiation exposure in dental radiology: a 1998 nationwide survey in Switzerland

OBJECTIVES: To measure the frequencies of dental radiological examinations in Switzerland and to determine the associated collective radiation doses. METHODS: To evaluate the frequencies, a sample of 376 dental practitioners and other institutions performing dental radiology were requested to fill in questionnaires designed to measure, amongst others, frequencies of dental radiodiagnoses according to type of examination, patient age and gender, dental specialty and type of surgery. The associated collective radiation doses were determined by multiplying the relevant frequencies with dose estimates obtained from recent measurements and calculations. RESULTS: The total number of dental examinations performed in Switzerland in 1998 was 4.1 million (581 per 1000 population). Periapical, bitewing and panoramic radiographs were the most frequent types of dental examinations. The collective dose associated with dental radiology was 71 person.Sv. This amounts to an annual average effective dose to the population of 10 muSv per caput, which is in agreement with the figures reported for countries of similar healthcare level. Various features such as the age distribution of the radiographed patients, the forms of collimators used, film consumption and the use of digital imaging systems are presented. CONCLUSIONS: Several recommendations for dose reduction are made. These include the re-evaluation of the patterns and justification for prescribing some particular types of dental examinations as well as the avoidance of unnecessary irradiation by the use of rectangular collimation and high sensitivity F-speed films.     

Quality criteria implementation for brain and lumbar spine CT examinations

A study was undertaken to implement the quality criteria proposed by the European Commission for brain general and lumbar spine (disc herniation) CT examinations. The proposed criteria were evaluated for samples including 93 brain and 86 lumbar spine CT examinations, with special emphasis on the diagnostic and radiation dose requirements. The extent to which the image criteria had been achieved was evaluated after two independent observers had each read the images twice. Dose measurements were conducted in parallel to estimate the proposed dose quantities needed to obtain the images. For brain examinations, we found that a group of image criteria were largely met, and met uniformly in all sites. One criterion (1.2.5) was frequently fulfilled but had intermediate values for two sites; the remaining criteria were fulfilled to different extents, although for criteria 1.2.1 and 1.2.2, scores were lower than 50% and 70%, respectively. The mean percentage image quality score had values between 57% and 78%, with variation coefficients in the range 30-68%. Mean values of the dose quantities were in the ranges 44-74 mGy for weighted CT dose index (CTDIw), 497-1018 mGy cm for dose-length product (DLP) and 1.1-2.2 mSv for effective dose (E). CTDIw and DLP were not correlated because of significant variations in the scanned length, whereas DLP and E were strongly correlated. A weak relationship between image quality score and DLP was found for the sample as a whole. For lumbar spine examinations, none of the critical reproduction image criteria was systematically achieved. One group of criteria (1.2.7, 1.2.8 and 1.2.9) was fulfilled to a large extent in many departments, but fulfilment of the remainder varied widely. The mean score fluctuated in the range 39-88%, with three groups of differences: low (39-51%), intermediate (67-71%) and high (85-88%). Mean values of the CTDIw varied between sites in the range 27-48 mGy. Mean DLP values varied between 188 mGy cm and 333 mGy cm, and the mean effective dose ranged between 3 mSv and 5 mSv. There were significant differences in effective dose between men and women. By sites, there was no relationship between DLP and mean score, with the highest image score associated with intermediate dose values. The percentage disagreement among the observers about a given criterion ranged between 2% and 22% for brain, and between 3% and 46% for lumbar spine.     

Compensation examination of the cervical and lumbar spines: critical disagreement in radiographic interpretation

Radiographic interpretation is often the major factor in the decision to award compensation for job-related complaints, especially in the Veterans Administration system. Three board-certified radiologists reviewed 200 consecutive lumbar and cervical spine examinations and assigned each case to one of three categories: normal, normal for age (not compensable), or degenerative disease (compensable). A critical disagreement, in which at least one radiologist considered the examination compensable and another not compensable, occurred in interpretation of 31% of the cervical and 46% of the lumbar spine examinations. Although the overall detection of radiographic findings was similar among all three radiologists, diagnostic interpretation of the findings varied greatly. Although most radiologists and orthopedists agree that the use of plain radiography of the spine as a deciding factor in awarding compensation is unjustified and inappropriate, until the regulations are changed there is a pressing need for strict, objective, radiographic criteria for determining "normal aging" of the cervical and lumbar spines so that interpreatations can be more uniform.     

Bone marrow immunoscintigraphy for the detection of skeletal metastases in patients with breast cancer

In this study, we evaluated the efficacy of bone marrow immunoscintigraphy (BMIS) for the detection of skeletal metastases in 23 patients with histologically confirmed breast cancer. All patients underwent whole-body BMIS 3-6 h after the intravenous injection of 0.20-0.33 mg of the intact anti-NCA 95 MAb BW 250/183 labelled with 259-555 MBq 99Tcm and a whole-body 99Tcm-MDP bone scan. In four patients, BMIS SPET of the lumbar spine was also performed. Serum alkaline phosphatase was determined in all patients and the level of human anti-mouse antibody (HAMA) in 16. Final diagnosis was confirmed by radiology and 2 years follow-up. Compared with the 99Tcm-MDP bone scan, BMIS demonstrated better specificity (88% vs 75%) and a better positive predictive value (92% vs 85%). There were no significant differences between BMIS and the bone scan in the detection of skeletal metastases (P > 0.05). In one patient with normal planar BMIS of the lumbar spine, SPET disclosed a metastatic lesion in the bone marrow. The correlation coefficient between BMIS and bone scan and between BMIS and serum alkaline phosphatase was r = 0.688 and r = 0.483 respectively. One patient developed a minor HAMA response after BMIS. Patients with diffuse increased activity of the skull on the bone scan had a significantly higher skull to whole body ratio on BMIS (P < 0.01). Thus BMIS can improve the specificity and positive predictive value of bone scanning in the detection of skeletal metastases, with a low HAMA response. Diffuse increased activity of the skull on bone scans could be explained by bone marrow extension. SPET scanning of the spine may improve the sensitivity of BMIS.     

Comparison of In-111 granulocytes and Tc-99m albumin colloid for bone marrow scintigraphy by the use of quantitative SPECT imaging

A comparison of In-111 oxinate labeled autologous granulocytes and Tc-99m albumin colloid for bone marrow scintigraphy is reported. The aim of this report was to determine if the intense uptake in the liver and spleen with nano-sized colloids, which hampers the evaluation of the skeletal parts surrounding the liver, is reduced by the use of radiolabeled granulocytes. This study is based on a retrospective analysis of 19 abdominal tomographic examinations with In-111 granulocytes performed to detect septic foci. After correction for attenuation and scattering of photons was performed, the uptake in the bone marrow of the lumbar spine was seen to be related to the liver, spleen, and tissue background activity. The results in this study were compared with corresponding data from 20 normal liver/spleen tomographic examinations performed with Tc-99m nanocolloid, which is routinely used for bone marrow scintigraphy. The bone marrow/liver activity ratio for granulocytes varied, but it exceeded the corresponding mean ratio for colloid in all examinations. The mean values for granulocyte uptake 3 and 20 hours after injection was, respectively, about 6 and almost 10 times higher than were those for colloid. The activity ratios between bone marrow and spleen as well as between bone marrow and tissue background was not improved and or may even have been reduced by the use of granulocytes. It is suggested that granulocytes labeled in vitro by Tc-99m hexamethylpropylene amineoxime (HMPAO) or in vivo by monoclonal antigranulocyte antibodies may provide techniques for improved bone marrow imaging.