儿童CT辐射剂量:在瑞士建立一项基于年龄诊断参考水平的研究

本研究的目的是评估瑞士儿科病人在脑部、胸部、腹部CT检查中受到的辐射剂量并建立一个不同年龄组的诊断参考水平。将表格送至10个儿童CT扫描中心,表格     

Establishment of CT diagnostic reference levels (DRLs) for a Singapore healthcare cluster

IntroductionThe use of computed tomography (CT) in healthcare institutions has increased rapidly in recent years. The Singapore Health Services (SingHealth) cluster of healthcare institutions has taken the first step in establishing a local cluster-wide CT Diagnostic Reference Levels (DRL) in Singapore. CT dose data from each institution were collected through two primary dosimetry metrics: volume CT dose index (CTDI_vol measured in mGy) and dose-length product (DLP measured in mGy.cm).MethodsData from 19 CT scanners in seven institutions under one of Singapore healthcare cluster were retrospectively collected and analysed. The five common adult CT examinations analysed were CT Brain (non-contrast enhanced), CT Chest (IV contrast enhanced), CT Kidney-Ureter-Bladder (CT KUB, non-contrast enhanced), CT Pulmonary Angiogram (CT PA, IV contrast enhanced) and CT Abdomen-Pelvis (CT AP, IV contrast enhanced, single phase). Median CTDI_vol and DLP values for the five CT examinations from each institution were derived, with the cluster DRLs determined as the 75th percentile of the distribution of the institution median dose values.ResultsA total of 2413 dose data points were collected over a six-month period from June to November 2020. The cluster CT DRLs for the five CT examinations were determined to be 47 mGy and 820 mGy.cm for CT Brain, 5.4 mGy and 225 mGy.cm for CT Chest, 6.7 mGy and 248 mGy.cm for CT PA, 4.6 mGy and 190 mGy.cm for CT KUB and 6.9 mGy and 349 mGy.cm for CT AP.ConclusionThe establishment of the cluster CT DRLs provided individual institutions with a better understanding if their CT doses are unusually high or low, while emphasising that these DRLs are not meant as hard dose limits or constraints to follow strictly.     

Clinical indication-based diagnostic reference levels for paediatric head computed tomography examinations in Kano Metropolis,northwestern Nigeria

IntroductionPaediatric patients are recognised to be at higher risk of developing radiation-induced cancer than adults because of rapidly growing organs and tissues which are vulnerable to cellular damage. The aim of the study was to determine indication based Diagnostic Reference Levels (DRL_CI) for paediatric head computed tomography (CT) examinations within Kano metropolis, Nigeria.MethodsCT dose index (CTDI_vol), dose length product (DLP) and other scan parameters were recorded for 113 paediatric undergoing CT head examinations. Different clinical indications were recorded and categorised in addition to patient age. Third quartile values (75th percentile) of the median dose were considered as DRL_CI. Analysis of Variance (ANOVA) was used to test for differences between DRL_CI, for different age groups, and variations among institutions. The Statistical Package for Social Sciences version 23.0 was used for analysis. Statistical significance was set at p < 0.05.ResultsDRL_CI for Hydrocephalus for <5 years and 5–10 years was 28.10 mGy and 28.11 mGy with DLP of 1623.20 mGy cm and 1623.21 mGy cm, respectively. The 11–15 year group recorded 29.10 mGy and 1625.20 mGy cm. Indications of haemorrhage/trauma and post-seizure imaging all had same values for <5 years and 5–10 years (28.10 mGy and 1623.20 mGy cm) while the 11 to 15-year group recorded 39.60 mGy and 1626 mGy cm. Intracranial Space Occupying lesion had the same DRL_CI value for < 5years and 5–10 years (29.0 mGy and 1600 mGy cm, respectively) the 11 to 15-year group recorded values of 46.20 mGy and 1663.4 mGy cm. There was no statistically significant difference between DRL_CI for <5 years and 5 to 10-year age groups (p = 0.199), while different centres showed some statistically significant relationships (p = 0.02).ConclusionThe study noted dose differences between age groups less than 10 years and above ten years, there were some statistically significant relationship with DRL_CI. Dose optimisation techniques for paediatric examinations together with selection of the right protocol for paediatric head CT are necessary.Implications for practiceThe study has provided DRL_CI for paediatric head CT examinations. These values can be used for future comparisons and as a potential dose optimisation tool. Such data can also guide radiographers when selecting appropriate parameters for indication-based CT examination to help achieve a low dose with acceptable image quality.     

Establishing diagnostic reference levels for interventional procedures in Kenya

PurposeTo quantify ionizing radiation exposure to patients during interventional procedures and establish national diagnostic reference levels (NDRLs) for clinical radiation exposure management.MethodsThe cumulative reference point air kerma, kerma area product, fluoroscopy time and other operational parameters were monitored for 50 children and 261 adult patient procedures in five catheterization medical laboratories in Kenya. To estimate the risk associated with the exposure, effective doses were derived from the kerma area product using conversion factors from Monte Carlo models.ResultsAbout 3% of the measured cumulative reference point air kerma for the interventional procedures approached the threshold dose limit with the potential to cause deterministic effects such as skin injuries. In interventional cardiology, the results obtained for both children and adults indicated 33% were below the diagnostic reference levels (DRLs). In adult interventional radiology, 29% for cumulative reference point air kerma, and 43% for kerma area product and fluoroscopy time respectively were below the diagnostic reference levels. NDRLs were proposed for routine use in the procedures considered and for the non-existent DRLs situations in paediatric interventional cardiology.ConclusionThe measured patient doses were above the DRLs available in the literature indicating a need for radiation optimization through, continuous monitoring and recording of patient dose. To promote radiation safety, facilities performing interventional procedures need to establish a radiation monitoring notification threshold for possible deterministic effects, in addition to the use of the newly established national diagnostic reference levels, as a quality assurance measure.     

成年人CT扫描中辐射剂量和诊断参考水平的探讨

目的 通过全国范围内CT辐射剂量的调查,了解成年人辐射剂量的现状,进而探讨成年人CT的诊断参考水平不符,需要根据我国的实际建立自己的DRL。方法 2015年9月至2016年3月在全国30个省、自治区、直辖市调查168家医院,其中三级和二级医院各约占一半。随机调查年度状态检测合格的168台CT,包括了临床应用中普遍使用的品牌和型号。每台CT收集头颅、鼻窦、颈部、胸部、腹部、盆腔、腰椎、尿路造影、冠状动脉CT血管造影（CTA）、颅脑CTA、颈部CTA和胸腹CTA共12个检查项目、每个项目10个随机病例。以容积CT剂量指数（CTDI_vol）和剂量长度乘积（DLP）作为剂量参量,每个检查项目的所有数据按照大小排序,取25%、50%和75%位数,其中75%位数为参考水平。所得剂量数值与国际相关放射防护组织发布的DRL进行比较。结果 共收集16 244个标准体型成年病例的剂量数据,经逐一检查剔除274个无效数据,剩余15 970个病例数据。全国范围内不同的CT使用单位,同一检查项目的CTDI_vol、DLP和扫描期项都有很大差异。与国际放射防护组织发布的数据相比,不同检查项目的诊断参考水平的差异程度各不相同,颅脑诊断水平与参考值相当、胸部腹部较低。剂量指数值最大的几种检查项目为头颅、冠状动脉CTA、颅脑CTA和鼻窦。尿路造影的CTDI_vol虽然仅为20 mGy,但DLP却高达2 620 mGy·cm。结论 我国现有的CT剂量水平与国际相关组织发布的诊断标准水平（DRL）不符,需要根据我国的实际建立自己的DRL。     

基于辐射剂量结构化报告的CT辐射剂量分析

目的：应用医学数字成像和通信（ DICOM ）标准定义的辐射剂量结构化报告（ RDSR）,实现CT检查的辐射剂量统计分析。方法利用自行设计的软件,通过检索影像归档和通信系统（ PACS）,获取1230份CT检查的RDSR文件。将相关信息提取后,结合扫描部位建立患者剂量数据库。根据年龄将患者分为成年组（10岁以上）及儿童组（0～1岁,1～5岁,5～10岁）,分别统计各扫描部位的平均容积CT剂量指数（ CTDIvol ）、剂量长度乘积（ DLP）,估算有效剂量（ E）;并计算75％分位DLP值,与诊断学参考水平（ DRL）相比较。结果成年患者组,CTDIvol与DLP值呈中度正相关（r＝0?41）,上腹部增强扫描的E最高,其75％分位DLP值超过DRL60％;儿童5～10岁组的CTDIvol高于0～1岁与1～5岁组（t＝2?42、2?04,P＜0?05）, DLP值与年龄呈低度正相关（r＝0?16）,E与年龄呈中度负相关（r＝-0?48）。结论应用RDSR获得患者辐射剂量是一种简单、高效的方法。随着新设备的普及与区域化医疗平台的应用,RDSR将成为剂量学水平调查及个人剂量记录的主要工具。     

宁夏儿童头颅、胸部CT辐射剂量状况分析

目的 评估宁夏地区儿童头颅、胸部CT检查的辐射剂量水平,为不同年龄段儿童的CT辐射剂量优化提供基础。方法 采用分层整群抽样的方法,实地采集宁夏地区不同市、县、区不同规模医院1~2周内儿童（≤15岁）头颅、胸部CT的扫描参数、容积CT剂量指数（CTDI_vol）及剂量长度乘积（DLP）,计算患者有效剂量（E）值;并将CTDI_vol、DLP的第75百分位数（P₇₅）与其他国家推荐的DRL值进行比较;所有儿童分4个年龄组：<1岁、1~5岁、6~10岁、11~15岁。结果 走访调查39家医院,调查CT设备47台,采集头颅断层扫描1 134例,胸部平扫636例。头颅CTDI_vol、DLP的P₇₅分别为：<1岁：44.2 mGy、456.2 mGy·cm;1~5岁：57.2 mGy、659.6 mGy·cm;6~10岁：61.1 mGy、668.7 mGy·cm;11~15岁：63.6 mGy、849.3 mGy·cm。胸部CTDI_vol、DLP的P₇₅分别为：<1岁：5.0 mGy、89.2 mGy·cm;1~5岁：5.9 mGy、124.8 mGy·cm;6~10岁：6.0 mGy、167.9 mGy·cm;11~15岁：7.1 mGy、235.0 mGy·cm。结论 宁夏地区儿童胸部CT的辐射剂量与其他报道相近,但头颅CT的辐射剂量相对偏高,且各年龄段均存在偏高现象,尤以婴儿患者较著;应加强宁夏地区儿童头颅CT的辐射剂量优化与监管,增强儿科医生、放射科医生的剂量控制意识,提高对辐射相关风险的认识。     

儿童CT检查诊断参考水平典型值的初步探讨

目的统计以容积CT剂量指数(CTDI_(vol))、基于水当量直径(WD)的体型特异性剂量估算值(SSDEWD)及剂量长度乘积(DLP)为衡量指标的儿童头颅、胸部及腹盆部CT检查诊断参考水平(DRL)典型值,衡量本医疗机构CT检查辐射水平。方法回顾性收集2021年1月至2021年12月间南京医科大学附属儿童医院收治的头颅1391例,胸部1386例及腹盆部1035例患者CT影像资料,分别记录其年龄、CTDI_(vol)、DLP,手动测量最中间扫描图像的前后径(AP)、左右径(LAT)、兴趣区面积(AROI)及面积内CT值(CTROI),按照美国医学物理学家学会(AAPM)报告方法,计算有效直径(d)、WD、转换因子(f16/32XSIZE)及SSDEWD;将各检查部位分别按照年龄及体型进行分组:按照年龄分为<1、1~、5~、10~、15~岁5组,各分组患儿数分别为:头颅252、320、400、380及39例;胸部188、320、399、398及81例;腹盆部75、310、310、300及40例。头颅基于LAT分为<12.5、12.5~、14~、15~、16~cm 5组,每组患儿分别为151、222、319、399及300例;胸部、腹盆部基于d分为<15、15~、20~、25~、30~cm 5组,每组患儿分别为胸部275、527、400、165及19例;腹盆部403、410、184、34及4例。统计各分组内CTDI_(vol)、SSDEWD和DLP的第75百分位数,将其作为DRL典型值;并比较CTDI_(vol)和SSDEWD在衡量辐射剂量上的差异。结果按年龄分组,以CTDI_(vol)为衡量指标的头颅、胸部、腹盆部DRL典型值分别为14.9~24.1、1.8~4.5和2.0~7.5 mGy;以SSDEWD为衡量指标的DRL典型值分别为14.7~18.9、4.2~6.9和4.7~11.8 mGy;以DLP为衡量指标的DRL典型值分别为260~505、40~185和65~435 mGy·cm。按d分组,以CTDI_(vol)为衡量指标的胸部、腹盆部DRL典型值分别为1.8~6.8和2.2~9.2 mGy;以SSDEWD为衡量指标的DRL典型值分别为4.2~9.1和4.9~13.0 mGy;以DLP为衡量指标的DRL典型值分别为40~255和85~545 mGy·cm。头颅按LAT分组,以CTDI_(vol)为衡量指标的DRL典型值为14.1~23.1 mGy;以SSDEWD为衡量指标的DRL典型值为14.3~18.5 mGy;以DLP为衡量指标的DRL典型值为240~475 mGy·cm。头颅除年龄<1岁、LAT<12.5 cm分组外,CTDI_(vol)均大于SSDEWD,头颅CTDI_(vol)为(18.63±3.24)mGy,SSDEWD为(16.38±1.81)mGy,差异有统计学意义(t=48.78,P<0.001);胸部、腹盆部各分组CTDI_(vol)均小于SSDEWD,胸部CTDI_(vol)为(2.77±1.02)mGy,SSDEWD为(5.22±1.26)mGy,差异有统计学意义(t=-210.89,P<0.001);腹盆部CTDI_(vol)为(3.36±1.82)mGy,SSDEWD为(6.27±2.44)mGy,差异亦有统计学意义(t=-115.16,P<0.001)。结论本医疗机构DRL典型值与其他国家相比处于合理且较低水平,SSDEWD较CTDI_(vol)能更准确反映辐射剂量,亟需建立基于SSDEWD的DRLs。     

Investigation into patient doses for intravenous urography and proposed Irish diagnostic reference levels

With the introduction of Council Directive 97/43/Euratom, all member states should establish relevant diagnostic reference levels for X-ray examinations. Diagnostic reference levels help to facilitate standardisation and optimisation within departments and attempt to reduce dose variations between hospitals. High variation of individual patient doses for plain-film examinations by up to a factor of 75 was demonstrated by a previous Irish study, which highlighted the necessity for further investigation into other examinations in Ireland. The current work aimed to establish reference values for intravenous urography (IVU) examinations, an important contributor to collective dose. Eleven Irish hospitals were randomly selected, representing 30% of the total number of hospitals. Dose-area product (DAP) readings for IVUs were recorded along with technical and procedural details. Resultant data demonstrated mean hospital and individual patient DAP variations of a factor of 4 and 58, respectively. Stepwise regression analysis demonstrated that number of images taken, method of image acquisition and patient weight were the main causal agents for dose variations recorded. A proposed diagnostic reference level of 12 Gy cm² was established at the level of the third-quartile value of the mean hospital DAP values. This article provides evidence of large variations in DAP values for IVU examinations. It is hoped that application of the proposed DRL of 12 Gy cm² will reduce the size of these variations.     

Diagnostic reference levels in plain radiography for paediatric imaging: A Portuguese study

ObjectiveTo determine diagnostic reference levels (DRLs) for the most frequent paediatric plain radiography examinations in Portugal (chest, pelvis and abdomen) and to characterise a standard paediatric patient for each age group used in literature.MethodsAnthropometric data was collected from 9935 patients. Each age group (<1, 1–<5, 5–<10, 10–<16, ≥16) was categorised by the median values of weight, height and BMI, to define a standard patient. Exposure parameters, kerma-area product (KAP-mGy cm²) and entrance surface air kerma (ESAK-μGy) were collected. DRLs for KAP and ESAK were defined as the 75th percentile (P75) of dose values and presented by age and weight.ResultsIn each age group the P75 of KAP varied from 11 to 77 mGy cm² for chest; 23–816 mGy cm² for pelvis; 25–979 mGy cm² for abdomen. The P75 of ESAK varied from 49 to 67 μGy for chest; 98–1129 μGy for pelvis and 70–1060 μGy for abdomen.ConclusionThe P75 of dose values determined in this study were lower than those published in literature. When available, weight is the preferred parameter to categorise paediatric patients. The large ranges of dose values found in this study, demonstrates a clear need for the optimisation and harmonisation of practice.     

我国CT检查成年人辐射剂量诊断参考水平的建立历程及解读

经过放射诊断专家、影像技术专家、辐射防护专家和专业技术人员10多年的探索,一项基于大规模国内调查数据而建立的CT检查成年人辐射剂量诊断参考水平(diagnostic reference level,DRL)以国家卫生行业标准(WS/T 637-2018)形式发布。其制定原则和方法符合国际惯例和我国的实际情况,基本上涵盖了我国成年人常见CT检查项目,与国外的DRL比较,整体处于一个合理或较低的剂量水平。给出的50%分位数(可能达到水平)和25%分位数(异常低剂量的提示水平)作为辐射剂量优化指导的额外工具。在日常放射诊断活动中,使辐射剂量与图像质量、临床诊断任务相匹配,降低非正当过高或过低剂量的发生频率。     

Establishment of Local Diagnostic Reference Levels of Pediatric Abdominopelvic and Chest CT Examinations Based on the Body Weight and Size in Korea

ObjectiveThe purposes of this study were to analyze the radiation doses for pediatric abdominopelvic and chest CT examinations from university hospitals in Korea and to establish the local diagnostic reference levels (DRLs) based on the body weight and size.Materials and MethodsAt seven university hospitals in Korea, 2494 CT examinations of patients aged 15 years or younger (1625 abdominopelvic and 869 chest CT examinations) between January and December 2017 were analyzed in this study. CT scans were transferred to commercial automated dose management software for the analysis after being de-identified. DRLs were calculated after grouping the patients according to the body weight and effective diameter. DRLs were set at the 75th percentile of the distribution of each institution''s typical values.ResultsFor body weights of 5, 15, 30, 50, and 80 kg, DRLs (volume CT dose index [CTDI_vol]) were 1.4, 2.2, 2.7, 4.0, and 4.7 mGy, respectively, for abdominopelvic CT and 1.2, 1.5, 2.3, 3.7, and 5.8 mGy, respectively, for chest CT. For effective diameters of < 13 cm, 14–16 cm, 17–20 cm, 21–24 cm, and > 24 cm, DRLs (size-specific dose estimates [SSDE]) were 4.1, 5.0, 5.7, 7.1, and 7.2 mGy, respectively, for abdominopelvic CT and 2.8, 4.6, 4.3, 5.3, and 7.5 mGy, respectively, for chest CT. SSDE was greater than CTDI_vol in all age groups. Overall, the local DRL was lower than DRLs in previously conducted dose surveys and other countries.ConclusionOur study set local DRLs in pediatric abdominopelvic and chest CT examinations for the body weight and size. Further research involving more facilities and CT examinations is required to develop national DRLs and update the current DRLs.     

Paediatric computed tomography radiation dose: A review of the global dilemma简

Computed tomography (CT) has earned a well-deserved role in diagnostic radiology, producing cross-sectional and three-dimensional images which permit enhanced diagnosis of many pathogenic processes. The speed, versatility, accuracy, and non-invasiveness of this procedure have resulted in a rapid increase in its use. CT imaging, however, delivers a substantially higher radiation dose than alternative imaging methodologies, particularly in children due to their smaller body dimensions. In addition, CT use in children produces an increased lifetime risk of cancer, as children’s developing organs and tissues are inherently more vulnerable to cellular damage than those of adults. Though individual risks are small, the increasing use of CT scans in children make this an important public health problem. Various organizations have recommended measures to minimize unnecessary exposures to radiation through CT scanning. These include elimination of multiple or medically unnecessary scans, development of patient-specific dosing guidelines, and use of alternative radiographic methodology wherever possible. Another important factor in excessive CT exposures, however, is a documented lack of awareness among medical practitioners of the doses involved in CT usage as well as its significant potential dangers. This review examines the effects of paediatric CT radiation, discusses the level of medical practitioner awareness of these effects, and offers recommendations on alternative diagnostic methods and practitioner education.     

Estimation of the radiation dose for dental spectral cone-beam CT

Objectives:The purpose of this study was to estimate the radiation dose for a dental spectral cone-beam CT (SCBCT) unit at different scanning parameters.Methods:Radiation dose measurements were performed for a commercially available dental SCBCT. Scans were obtained at different exposure times and fields of view (FOV), both for non-spectral (25×18 cm, 14×18 cm, 14×12 cm, 9×9 cm, 6×6 cm) and spectral modes (14×18 cm, 14×12 cm, 9×9 cm, 6×6 cm) with the tube voltage alternating between 80 and 110 kV for spectral mode, and fixed at 110 kV for non-spectral mode. An ion chamber was used for air kerma and dose area product (DAP) measurements. The effective dose was estimated based on the mAs using previously published logarithmic curves for CBCT units with a similar X-ray spectrum.Results:The adult effective dose, in non-spectral mode, was 44-269 µSv for small FOVs, 131-336 µSv for the medium FOV, and 163-476 µSv for the large FOV. In spectral mode, the estimated adult effective doses were 96-206 µSv for small, 299 µSv for medium and 372 µSv for large FOV protocols. Paediatric effective doses were estimated to be 75% higher than corresponding adult doses.Conclusion:SCBCT showed comparable doses with other CBCT devices, but DAP values were generally above currently published DRLs. Spectral imaging might allow for artefact reduction at comparable dose levels, which should be assessed in further image quality studies at both a technical and diagnostic levels.     

Changing radiation dose from diagnostic computed tomography examinations in Saskatchewan

Purpose

Follow-up study to observe if provincial mean effective radiation dose for head, chest, and abdomen-pelvis (AP) computed tomographies (CTs) remained stable or changed since the initial 2006 survey.

Methods

Data were collected in July 2008 from Saskatchewan's 13 diagnostic CT scanners of 3358 CT examinations. These data included the number of scan phases and projected dose length product (DLP). Technologists compared projected DLP with 2006 reference data before scanning. Projected DLP was converted to effective dose (ED) for each head, chest, and AP CT. The total dose that the patients received with scans of multiple body parts at the same visit also was determined.

Results

The mean (± SD) provincial ED was 3.4 ± 1.6 mSv for 1023 head scans (2.7 ± 1.6 mSv in 2006), 9.6 ± 4.8 mSv for 588 chest scans (11.3 ± 8.9 mSv in 2006), and 16.1 ± 9.9 mSv for 983 AP scans (15.5 ± 10.0 mSv in 2006). Single-phase multidetector row CT ED decreased by 31% for chest scans (9.5 ± 3.9 mSv vs 13.7 ± 9.7 mSv in 2006) and 17% for AP scans (13.9 ± 6.0 mSv vs 16.8 ± 10.6 mSv in 2006) and increased by 19% for head scans (3.2 ± 1.2 mSv vs 2.7 ± 1.5 mSv in 2006). The total patient dose was highest (33.8 ± 10.1 mSv) for the 20 patients who received head, neck, chest, and AP scans during a single visit. Because of increased utilisation and the increased CT head dose, Saskatchewan per capital radiation dose from CT increased by 21% between 2006 and 2008 (1.14 vs 1.38 mSv/person per year).

Conclusion

Significant dose and variation reduction was seen for single-phase CT chest and AP examinations between 2006 and 2008, whereas CT head dose increased over the same interval. These changes, combined with increased utilisation, resulted in per capita increase in radiation dose from CT between the 2 studies.     

宁夏成年人常见CT检查项目的辐射剂量状况调查研究

目的 调查宁夏地区成年人常见CT检查项目的辐射剂量现状,为建立宁夏成年人患者CT检查的第一个诊断参考水平提供依据。方法 采用分层整群抽样的方法,对宁夏地区不同规模医疗机构的不同品牌及型号CT扫描设备的使用情况及辐射状况进行调查,采用间隔抽样,获取被调查单位每日不同检查项目的扫描参数及辐射剂量值。登记医院、CT设备、检查项目、检查类型及患者的基本信息,记录各检查项目的CT扫描参数、CT剂量指数（CTDI_vol）和剂量长度乘积（DLP）值,计算患者的有效剂量E值;对所得数据按检查项目分组统计分析,并与其他国家推荐的诊断参考水平（DRL）值和辐射剂量状况进行比较。结果 调查宁夏地区45家医疗机构（公立三甲10家、公立三乙5家、公立二甲23家、民营医院5家、体检中心2家）6个生产品牌的58台CT设备,成年人患者4 952名。常见检查项目的CTDI_vol、DLP值及患者E值的第75百分位数值（P₇₅）为：头颅65.67 mGy、860.74 mGy ·cm、1.64 mSv;颈部29.32 mGy、490.00 mGy ·cm、2.83 mSv,颈部增强36.92 mGy、954.42 mGy ·cm、4.87 mSv;胸部11.50 mGy、382.06 mGy ·cm、5.68 mSv,胸部增强45.8 mGy、1 713.22 mGy ·cm、25.01 mSv;上腹部20.1 mGy、506.59 mGy ·cm、7.75 mSv,上腹部增强50.07 mGy、1 434.19 mGy ·cm、21.94 mSv;腹盆部14.33 mGy、670.78 mGy ·cm、10.26 mSv,腹盆部增强48 mGy、2 294 mGy ·cm、35.10 mSv;盆腔16.1 mGy、471.58 mGy ·cm、6.08 mSv,盆腔增强31.04 mGy、1 138.78 mGy ·cm、14.69 mSv。结论 宁夏地区头颅、颈部、胸部及盆腔CT辐射剂量较其他国家偏低或相差不大,而腹部CT辐射剂量明显高于其他国家,迫切需要对宁夏腹部CT扫描方案进行优化。     

Effective radiation dose from semicoronal CT of the sacroiliac joints in comparison with axial CT and conventional radiography

The aim of this study was to evaluate the radiation dose given by semicoronal CT of the sacroiliac joints (SIJs) in comparison with axial CT and conventional radiography. The total effective radiation doses given by serial contiguous semicoronal and axial CT, using 5-mm slices, 120 kV and 330 mAs, were determined by measurement of organ doses using an anthropomorphic Rando Alderson phantom paced with thermoluminescence dosimeters. The doses given by conventional antero-posterior (AP) and oblique projections of the SIJs were determined similarly. In a female the total effective dose by semicoronal CT was found to be more than six times lower than by axial CT and 2.5 times lower than the dose use to obtain a conventional AP radiograph, the values being 102, 678, and 255 μSv, respectively. The effective dose by semicoronal CT was only a little higher than the dose given to obtain two oblique radiographs. In a male with lead protection of the gonads the dose by semicoronal CT was four times lower than by axial CT, but higher than by conventional radiography. In conclusion, the effective dose by semicoronal CT of the SIJs is lower than by axial CT, and in females a semicoronal CT implies a lower effective radiation dose that used to obtain an AP radiograph. Electronic Publication     

心脏CT辐射剂量相关研究

本文对心脏CT检查带来辐射风险,以及减少心脏CT辐射剂量的方法加以综述。对CT检查的目标人群来说,心脏冠脉图像的直接可见性的需求要超过他们对辐射剂量所带来危害的顾忌,冠脉CT利大于弊,仍为可选择的检查。     

The contribution of the internal scatter to radiation dose during CT scan of the head

Summary An acrylic head phantom was irradiated during a computed tomographic scan with four commercial scanners. Measurements of the spatial distribution of the radiation dose on the surface and internal to the phantom were performed for the scan plane and the scattered beam at various distances from the scan plane. The surface scatter dose was found to be considerably smaller than that for internal scatter. A significant increase in radiation exposure within the head phantom due to internal radiation seatter, and an asymmetrical primary beam profile for dual slice scanners were also noted.     

59521例CT检查辐射剂量分析

目的:分析59521例CT检查的辐射剂量数据,建立医院水平的CT诊断剂量参考水平.方法:使用CT辐射剂量计算软件,回顾性分析本院2015年7月-2016年6月共59521例成人的CT检查数据.按照检查部位分别计算CT容积剂量指数(CTDIv.1)、体型特异性剂量估计(SSDE)、剂量长度乘积(DLP)和有效剂量(ED)的中位数及四分位数间距(IQR),取CTDIvol和DLP的第3个四分位数(Q3)为诊断剂量参考水平(DRL),其中胸部CT的数据分为低剂量、单期、多期和全部扫描分别计算,腹部CT的数据分为单期、多期和全部检查分别计算.结果:各部位CTDIvol的DRL:头部为45.2 mGy;胸部低剂量为1.3 mGy,单期扫描为11.5 mGy,多期扫描为11.4 mGy,总剂量为11.8 mGy;腹部单期扫描为20.6 mGy,多期扫描为20.2 mGy,总剂量为20.6 mGy;冠状动脉为12.9 mGy.各部位DLP的DRL:头部为569.8 mGy· cm;胸部低剂量为42.0 mGy·cm,单期扫描为399.0 mGy·cm,多期扫描为968.5 mGy·cm,总剂量为474.0 mGy·cm;腹部单期扫描为958.0 mGy·cm,多期扫描为2419.1 mGy·cm,总剂量为2045.1 mGy·cm;冠状动脉为328.0 mGy·cm.结论:对临床日常工作中CT检查辐射剂量数据的汇总分析有助于在医院水平评估CT辐射剂量.