Paediatric dose measurements for chest X-ray examinations at Maternity and Children Hospital in Najran - Saudi Arabia

The entrance skin dose (ESD) of chest X-ray examinations for AP and PA projections of paediatric patients at Maternity and Children Hospital in Najran, Saudi Arabia have been obtained using DoseCal software. The majority of the results obtained show low measured ESD for chest X-ray examinations. The mean of ESD for the AP projection was found to be 37.5, 40.5, 41.3, and 52.3 μ Gy for age groups 0-1, >1-5, >5-10, and >10-15 years respectively. However, the ESD for PA projection was found to be 50.7 and 56.7 μ Gy for age groups >5-10, and >10-15 years respectively.     

Use of the VIP-Man model to calculate energy imparted and effective dose for x-ray examinations

A male human tomographic model was used to calculate values of energy imparted (epsilon) and effective dose (E) for monoenergetic photons (30-150 keV) in radiographic examinations. Energy deposition in the organs and tissues of the human phantom were obtained using Monte Carlo simulations. Values of E/epsilon were obtained for three common projections [anterior-posterior (AP), posterior-anterior (PA), and lateral (LAT)] of the head, cervical spine, chest, and abdomen, respectively. For head radiographs, all three projections yielded similar E/epsilon values. At 30 keV, the value of E/epsilon was approximately 1.6 mSv J(-1), which is increased to approximately 7 mSv J(-1) for 150 keV photons. The AP cervical spine was the only projection investigated where the value of E/epsilon decreased with increasing photon energy. Above 70 keV, cervical spine E/epsilon values showed little energy dependence and ranged between approximately 8.5 mSv J(-1) for PA projections and approximately 17 mSv J(-1) for AP projections. The values of E/epsilon for AP chest examinations showed very little variation with photon energy, and had values of approximately 23 mSv J(-1). Values of E/epsilon for PA and LAT chest projections were substantially lower than the AP projections and increased with increasing photon energy. For abdominal radiographs, differences between the PA and LAT projections were very small. All abdomen projections showed an increase in the E/epsilon ratio with increasing photon energy, and reached a maximum value of approximately 13.5 mSv J(-1) for AP projections, and approximately 9.5 mSv J(-1) for PA/lateral projections. These monoenergetic E/epsilon values can generate values of E/epsilon for any x-ray spectrum, and can be used to convert values of energy imparted into effective dose for patients undergoing common head and body radiological examinations.     

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。     

Direct measurement of a patient's entrance skin dose during pediatric cardiac catheterization

Children with complex congenital heart diseases often require repeated cardiac catheterization; however, children are more radiosensitive than adults. Therefore, radiation-induced carcinogenesis is an important consideration for children who undergo those procedures. We measured entrance skin doses (ESDs) using radio-photoluminescence dosimeter (RPLD) chips during cardiac catheterization for 15 pediatric patients (median age, 1.92 years; males, n = 9; females, n = 6) with cardiac diseases. Four RPLD chips were placed on the patient''s posterior and right side of the chest. Correlations between maximum ESD and dose–area products (DAP), total number of frames, total fluoroscopic time, number of cine runs, cumulative dose at the interventional reference point (IRP), body weight, chest thickness, and height were analyzed. The maximum ESD was 80 ± 59 (mean ± standard deviation) mGy. Maximum ESD closely correlated with both DAP (r = 0.78) and cumulative dose at the IRP (r = 0.82). Maximum ESD for coiling and ballooning tended to be higher than that for ablation, balloon atrial septostomy, and diagnostic procedures. In conclusion, we directly measured ESD using RPLD chips and found that maximum ESD could be estimated in real-time using angiographic parameters, such as DAP and cumulative dose at the IRP. Children requiring repeated catheterizations would be exposed to high radiation levels throughout their lives, although treatment influences radiation dose. Therefore, the radiation dose associated with individual cardiac catheterizations should be analyzed, and the effects of radiation throughout the lives of such patients should be followed.     

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.     

Absorbed dose to very low birth weight infants from 18F-fluorodeoxyglucose

The radiation absorbed dose to very low birth weight infants from 18F-fluorodeoxyglucose was investigated. Ten newborns undergoing clinical positron tomography lung imaging were included in this study. Two consecutive 45-min dynamic scans immediately following intravenous injection of fluorodeoxyglucose were acquired; the first was over the head, and the second was over the chest. Time-activity curves were generated for the brain, heart wall, lungs, and, when visible, the kidneys. The cumulated activity measurements obtained were for the entire organ masses; these masses were much smaller than the corresponding organ masses for the newborn mathematical model. Patient-specific dosimetry yielded average doses of 2.5 x 10(-1) mGy MBq(-1) for the brain, 6.8 x 10(-1) mGy MBq(-1) for the heart wall, 2.2 x 10(-1) mGy MBq(-1) for the kidneys, and 4.4 x 10(-1) mGy MBq(-1) for the lungs. The effective dose was estimated to be 2.1 x 10(-1) mSv MBq(-1), which is half that previously published for newborns but still an order of magnitude higher than that for adults.     

普通单源CT与双源CT检查中食管癌患者有效剂量的研究

目的 采用仿真人体模型,探讨单源螺旋CT和双源螺旋CT在不同扫描模式下食管癌患者有效剂量的差异。方法 根据ICRP推荐的组织及器官,对仿真人体模型38个组织器官进行打孔并布置剂量计。在相同扫描条件下,分别采用双源64层螺旋CT双能扫描模式、双源64层螺旋CT单能扫描模式与普通单源64层螺旋CT扫描模式,对仿真人体模型进行扫描,测量不同器官、组织的吸收剂量,进而估算患者的有效剂量。结果 双源64层螺旋CT双能扫描模式组、双源64层螺旋CT单能扫描模式组与普通单源64层螺旋CT扫描模式组不同器官、组织吸收剂量范围分别：0.126~329.7 mGy,0.114~317.8 mGy,0.123~321.2 mGy,各组中吸收剂量最低者均为性腺,最高者均为骨组织。三个模式组中患者的有效剂量分别为26.9 mSv,26.1 mSv,26.8 mSv。结论 双源CT双能扫描模式,双源CT单能扫描模式与普通单源CT扫描模式下,患者的有效剂量基本一致,相差不大,因此在临床应用时,可以不考虑患者剂量的因素,而是根据临床需要选择恰当的扫描模式。同时,对于扫描野外的性腺等敏感器官应当采用物理防护,降低患者的器官受照辐射剂量。     

若干常规放射诊断典型投照条件下成年受检者器官剂量与有效剂量的估算

目的 利用剂量面积积分仪DOSEGUARD100所带软件WINODS提供的计算程序,估算典型投照条件下,中国参考人(男、女)的器官剂量和有效剂量分布情况,检验改变投照参数对受检者剂量的影响并检验WINODS软件的适用性。方法 将用剂量面积积分仪DOSEGUARD100所带软件WINODS提供的计算程序估算的结果和课题组实际测量的结果相比较。结果 在所推荐的医疗照射指导水平下中国参考人(男、女)有效剂量分别为:腰椎AP 0.301 mGy,0.743 mGy;骨盆AP0.23 mGy,0.639 mGy;胸片AP 0.021 mGy,0.029 mGy;腹部0.303 mGy,0.414 mGy,对胸片AP若投照电压从68 kV提高到120 kV,在保持出射剂量不变的情况下,入射体表剂量下降,有效剂量下降,对于上述投照(120 kV或68 kV)若将总滤过由1.5 mmAl提高到3.0 mmAl,则入射体表剂量下降,有效剂量下降,与本课题组用仿真人体模进行的模拟试验结果基本一致。结论 表明WINODS计算程序可用于估算受检者器官剂量和有效剂量情况,以推进放射诊断投照参数优化工作的进展。     

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.     

仿真人体模型测量腹部CT受检者受照剂量研究

目的 通过仿真人体模型实验,针对现在所使用的腹部扫描条件,对患者的受照情况进行全面了解。方法 选择常规扫描参数和低剂量扫描参数,利用仿真人体模型,在相应体表位置和预定孔中插入剂量计,测量体表剂量和器官或组织的吸收剂量,并计算有效剂量。结果 常规剂量组和低剂量组的器官或组织的受照剂量范围分别为0.014~96.7 mGy,0.00148~5.56 mGy,有效剂量结果分别为14.5 mSv和1.52 mSv。结论 合理减少CT检查所致受检者剂量,需要建立科学实用的放射诊断的医疗照射参考(指导)水平。     

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。     

Estimation of entrance surface air kerma due to diagnostic X-ray examinations of adult patients in Uttarakhand,India and establishment of local diagnostic reference levels

It is well established that diagnostic X-ray practices must be optimised to keep patient radiation dose as low as compatible with providing the diagnostic information required. For effective optimisation of diagnostic exposures, the International Commission on Radiological Protection (ICRP) introduced the concept of diagnostic reference levels (DRLs) in 1996. The present study aimed to carry out an extensive dose survey of diagnostic radiography installations in the Uttarakhand region of India to establish local DRL Values for the different diagnostic practices. During the survey, air kerma values were measured for 297 diagnostic X-ray machines installed at 270 medical centres in the region and the entrance surface air kerma (K _a,e) was estimated for ten commonly performed radiographic projections. These included chest posterior-anterior (PA), cervical spine anterior-posterior (AP), skull PA, abdomen AP, KUB (kidney, ureter and bladder), lumbar spine AP, lumbar spine lateral (LAT), pelvis AP, thoracic spine AP, and thoracic spine LAT. Wide variations were observed in the estimated values of K _a,e for individual projections. The third quartile of the distribution of the median values of the estimated K _a,e for a given projection was calculated to establish local DRL Values. The majority of the acquired dose data were found to be comparable to or less than the proposed national and international DRLs. The local DRL Values reported in this study may be used to improve radiological practice by reducing patient doses during radiography examinations. The obtained data may also contribute to a national patient dose database for establishing future national DRLs.     

Effective and organ doses using helical 4DCT for thoracic and abdominal therapies

The capacity of 4DCT to quantify organ motion is beyond conventional 3DCT capability. Local control could be improved. However we are unaware of any reports of organ dose measurements for helical 4DCT imaging. We therefore quantified the radiation doses for helical 4DCT imaging. Organ and tissue dose was measured for thoracic and abdominal 4DCT in helical mode using an adult anthropomorphic phantom. Radiation doses were measured with thermoluminescence dosimeter chips inserted at various anatomical sites on the phantom. For the helical thoracic 4DCT, organ doses were 57.2 mGy for the lung, 76.7 mGy for the thyroids, 48.1 mGy for the breasts, and 10.86 mGy for the colon. The effective doses for male and female phantoms were very similar, with a mean value of 33.1 mSv. For abdominal 4DCT imaging, organ doses were 14.4 mGy for the lung, 0.78 mGy for the thyroids, 9.83 mGy for breasts, and 58.2 mGy for the colon (all obtained by using ICRP 103). We quantified the radiation exposure for thoracic and abdominal helical 4DCT. The doses for helical 4DCT were approximately 1.5 times higher than those for cine 4DCT, however the stepwise image artifact was reduced. 4DCT imaging should be performed with care in order to minimize radiation exposure, but the advantages of 4DCT imaging mandates its incorporation into routine treatment protocols.     

脑血管介入放射诊治中患者的X射线辐射评价

目的 研究DSA方式介入性脑血管造影诊断与脑血管栓塞治疗过程中患者所受X射线辐射。方法 100例脑部病变患者,脑血管造影诊断68例、脑血管栓塞治疗32例。Siemens公司DSA机Angiostar-Plus随机配置剂量监测系统(Diamentor K1 and Diamentor ED),在线测量面积剂量乘积DAP(cGycm²)和入射表面剂量ESD(mGy)、采用Monte-Carlo转换因子估算有效剂量ED(mSv)。结果 本组病例一次IVNR的DAP、ESD、ED值分别为(11 916±7 499)cGycm²、(973±682)mGy、(12.59±9.12)mSv。其中造影诊断组的剂量分别为(9 264±3 777)cGycm²、(741±321)mGy、(10.01±6.85)mSv,血管栓塞治疗组的剂量分别为(17 553±10 027)cGycm²、(1 496±952)mGy、(18.06±10.90)mSv,两组的差异具有显著性意义。摄影剂量[DAP(mSv)、mGy]/透视[DAP(mSv)、mGy]的比值,分别为7.52±6.44、6.14±4.72。结论 在IVNR诊治过程中,患者受到大剂量X射线辐射,其摄影剂量均值数倍于透视剂量,减少摄影总帧数是降低患者辐射最有效的方法。     

Retrospective patient dose analysis of Ghana's first direct digital radiography system

ABSTRACT: The log file generated in the flat panel detector of a direct digital x-ray machine (General Electric, Haulun Medical Systems, Serial Number 8M0392) after x-ray exposure was used to acquire data regarding the entrance surface air kerma (ESAK) for some routine x-ray examinations. The data were collected for a minimum of 10 standard adult patients undergoing each examination considered. The mean ESAK were found to be 0.25, 0.33, 0.14, 7.33, 9.76, 7.38, and 6.86 mGy for skull AP and LAT, chest AP, lumbar spine AP and LAT, pelvis AP and abdomen AP series, respectively. The mean ESAK values recorded from this study show wide variations but were below diagnostic reference levels (DRLs) of the Commission of European Communities and also compare with other recommendations. The comparisons of this study's dose levels with DRLs were undertaken as an approach to dose optimization. The study revealed that a dose audit of digital radiography systems is necessary because of the potential high doses one is likely to receive. Continuous dose evaluation in digital radiography is therefore encouraged in order to optimize doses to patients.     

Absorbed dose estimates in positron emission tomography studies based on the administration of 18F-labeled radiopharmaceuticals.

Absorbed doses were estimated after intravenous administration of 18F-labeled radiopharmaceuticals in Positron Emission Tomography (PET) studies. These radiopharmaceuticals, [18F]-2-Fluoro-2-Deoxy-D-Glucose (FDG), 6-[18F]Fluoro-L-Dopa (FDOPA) and 18F-5-Fluorodeoxyuridine (FdUR), are used in clinical research at the Cyclotron and Radioisotope Center of Tohoku University. Radiopharmaceutical biokinetic values were measured in humans or extrapolated from animal experiments. Selective organ uptake and rapid clearance of activity from the blood were observed. High activity in the bladder contents of humans was found. Calculations were made by the MIRD method, modified to account for the differences in physique and organ mass between the Caucasian Reference Man and the Japanese one. The bladder wall receives the highest dose (more than 1.23 x 10(-1) mGy/MBq) when any of these compounds are administered. Other organs receiving high doses are the heart, brain and kidneys from FDG; the kidneys and pancreas from FDOPA, and the kidneys and small intestine from FdUR. These organs received absorbed doses of more than 2.7 x 10(-2) mGy/MBq. Effective dose equivalents of 2.4 x 10(-2), 2.6 x 10(-2) and 3.3 x 10(-2) mSv/MBq were estimated in the intravenous administration of 18F-FDG, 18F-FDOPA and 18F-FdUR, respectively.     

18F-FDG和18F-FET PET-CT检查致受检者辐射剂量研究

目的 估算接受¹⁸F-FDG(¹⁸F-2-deoxy-D-glucose)和¹⁸F-FET(O-2-¹⁸F-fluoroethyl-L-tyrosine)PET-CT全身检查受检者的有效剂量和器官剂量。方法 使用两种PET-CT扫描协议进行全身显像。PET部分的有效剂量和器官剂量利用基于医学内照射剂量(Medical Internal Radiation Dose, MIRD)计算模式的计算程序IDAC 2.1进行计算,CT部分的有效剂量和器官剂量利用VirtualDose软件计算,PET和CT剂量之和为受检者总的有效剂量。结果 在常规PET-CT扫描中,男性受检者受¹⁸F-FDG辐射所致的有效剂量为(4.81 ±1.04) mSv,女性受检者为(6.09 ±0.73) mSv;男性受检者受¹⁸F-FET辐射所致的有效剂量为(2.67 ±0.38) mSv,女性受检者为(3.21 ±0.38) mSv;CT部分男性受检者的有效剂量为(5.63 ±0.32) mSv,女性受检者为(5.51 ±0.29) mSv。¹⁸F-FDG PET-CT检查男性和女性受检者所受总有效剂量分别为(10.44 ±1.09) mSv和(11.60 ±0.79) mSv。¹⁸F-FET PET-CT检查总有效剂量分别为(8.30 ±0.50) mSv和(8.72 ±0.49) mSv。在诊断性CT扫描中,CT扫描致男性受检者的有效剂量为(16.28 ±1.01) mSv,女性受检者为(13.49 ±0.72) mSv;¹⁸F-FDG PET-CT检查男性和女性受检者总有效剂量分别为(21.09 ±1.45) mSv和(19.58 ±1.03) mSv。¹⁸F-FET PET-CT检查总有效剂量分别为(18.95 ±1.08) mSv和(16.70 ±0.81) mSv。结论 不同的PET-CT扫描参数致受检者受到不同大小的辐射剂量,在日常工作中应根据受检者的实际情况,优化PET和CT的采集参数,降低受检者剂量,实践辐射防护最优化。     

小儿肠套叠复位术受照剂量的测量与分析

目的 调查分析X射线引导下空气灌肠整复术中患儿的受照剂量,为降低患儿辐射损伤风险提供依据.方法 收集接受空气灌肠整复术治疗的肠套叠患儿的资料;筛选、整理出3个不同年龄段的高、中、低组实验的条件,利用仿真人体模型模拟手术现场,借助热释光系统对患儿受照剂量进行测量.结果 肠套叠患儿在X射线引导下行空气灌肠整复治疗,成功率为...     

模拟后装放射源卡源处置时放射工作人员受照剂量研究

目的 估算放疗技师在应急处理后装放射源卡源过程中的受照剂量。方法 使用仿真人体盆腔模型替代宫颈癌患者,填充石蜡的假人替代放疗技师,模拟放射源在患者的子宫口位置发生卡源事故的场景,采用热释光剂量仪测量假人的4个敏感器官（晶体、甲状腺、乳腺、睾丸）表面不同时长内的受照剂量,并计算穿戴0.35 mm铅当量的防护用品的防护效果。结果 按¹⁹²Ir源强370 GBq计,无防护情况下各敏感器官在不同处理时间的受照剂量均小于0.12 mGy。在穿戴防护用品之后,各敏感器官的受照剂量减少1.7%~19.8%。结论 放疗技师在没有穿戴防护用品,¹⁹²Ir源强为370 GBq,应急处理时间35 s内的入射体表剂量不超过0.12 mGy,只相当于做一次X线摄影检查的受照剂量。     

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.