子宫肌瘤患者子宫动脉栓塞过程中的X线辐射研究

目的研究子宫肌瘤患者在子宫动脉栓塞(UAE)术中所经受的X射线照射及降低辐射的方法。方法回顾性分析早期90例和近期10例UAE辐射剂量资料,采用DSA机(AngiostarPlus)配置的穿透电离室型剂量监测系统(DiamentorKI和DiamentorED),在线读取面积剂量乘积(DAP)(cGy·cm2)和入射表面剂量(ESD)(mGy)。结果早期90例UAE透视时间(28.60±23.73)min,摄影(87±38)帧,DAP均值(6178±3802)cGy·cm2,ESD均值(378±245)mGy。近期10例UAE透视时间(19.80±7.18)min,摄影(83±13)帧,DAP均值(1722±342)cGy·cm2,ESD均值(121±32)mGy。透视剂量率均值约为早期的1/2,图像采集剂量率均值约为早期的1/4。结论缩短透视时间与减少透视剂量率、减少图像采集帧数与图像采集剂量率,是降低UAE治疗过程中患者X射线辐射的有效方法。     

急性冠状动脉综合征介入患者辐射剂量分析

目的分析200例急性动脉综合征介入治疗患者受照射剂量,探讨病变部位、狭窄程度、年龄和手术医生等因素对辐射剂量的影响。方法回顾分析我院200例急性动脉综合征行介入治疗(PCI)患者所记录的剂量资料,随机配置的剂量检测系统记录剂量面积乘积(DAP)和累计剂量(CD),根据DAP值估算有效剂量(ED)。根据血管病变受累程度分为单一病变和复杂病变以及患者年龄分组(小于40岁组,40~60岁组及大于60岁组)、左右侧冠状动脉和第一操作医生对患者受辐射剂量的影响。结果①本次收录200例行PCI术者累积剂量CD值191~5524 mGy,平均值(1157±781)mGy;剂量面积乘积DAP值(12714~417228)mGy·cm^2,平均值(100690±63896)mGy.cm^2;有效剂量ED范围1.119~58.411 mSv,平均值(14±9)mSv。②单一病变相比复杂病变辐射剂量少,CD值、DAP值、ED值差异有统计学意义(P<0.05)。③左侧冠状动脉大于右侧冠状动脉(P<0.05)。④3个年龄组间各个剂量值方差分析差异无统计学意义(P>0.05)。⑤2组不同年资操作医生患者所受剂量差异无统计学意义(P>0.05)。结论急性冠状动脉综合征PCI术患者接受辐射剂量差异较大,主要与病变本身(包括病变部位和累计范围及变异等)因素相关。     

主动脉瘤血管内治疗中影像学设备对于病人辐射剂量的影响

目的采用移动透视C臂、移动血管造影机和固定血管造影机等不同的影像学设备,比较病人在进行主动脉瘤血管内治疗(EVAR)中的辐射剂量。材料与方法回顾研究3.5年时间内147例病人所进行的153次EVAR操作的剂量面积乘积(DAP)。根据这些数据,计算入射表面剂量(ESD)和有效剂量(ED)。使用透视C臂、移动和固定血管造影机的例数分别为79、26和48例。结果所有设备所采用的透视时间基本上相同,为15～19min。不同系统间的临床转归没有显著差异。不同影像设备间,DAP[移动C臂:(32±20)Gy.cm2;移动血管机:(362±164)Gy.cm2;固定血管机:(464±274)Gy.cm2;P<10-6]、ESD(移动C臂:(0.18±0.11)Gy;移动血管机:(2.0±0.8)Gy;固定血管机:(2.5±1.5)Gy;P<10-6)和ED[移动C臂:(6.2±4.5)mSv;移动血管机:(64±26)mSv;固定血管机:(129±76)mSv;P<10-6]差异具有统计学意义。结论采用现代便携式C臂进行EVAR时的辐射剂量远小于专用的固定或移动血管造影机。     

野战方舱内冠状动脉造影投照体位对辐射剂量和影像质量的影响

目的 探讨野战综合手术救治方舱内施行冠状动脉(冠脉)造影中不同的投照体位对患者辐射剂量和影像质量的影响,为剂量优化提出建议.方法 用标准体模测定冠脉造影9个不同投照体位下图像清晰时剂量面积乘积(DAP)和入射表面剂量(ESD)透视和摄影的辐射剂量值;并在方舱内对6只实验动物施行9个不同投照体位下的冠脉造影,观察比较不同体位的影像质量.结果 不同投照体位下,透视时DAP剂量范围值为12.96 ～ 31.28 μGym2/s,ESD透视范围为21 403.33～71 106.67 μGy/S;摄影时DAP剂量范围值为39.55～87.59 μGy/s(10帧),ESD剂量范围值为67 647.25～ 212 498.54 μGy(10帧).正位剂量值最小,脾位最大,其他体位与正位相比差异均有统计学意义(P＜ 0.05);不同体位影像质量平均评分值范围为3.55 ～ 3.85,正位影像质量最好,脾位最差,其他体位与正位相比差异均有统计学意义(P＜0.05).结论 不同投照体位,辐射剂量、影像质量不同.手术过程中应根据手术需要,合理选择投照体位以期既能保证图像质量又能减少患者受照剂量.     

107例数字减影血管造影受检者所受辐射剂量分析

目的 统计血管造影受检者每次检查所受辐射剂量值及影响辐射剂量的相关因素,为分析、评估放射诊疗风险提供数据参考。方法 收集107例受检者检查时在线记录的全部辐射剂量值及其与剂量相关的技术参数值,按照检查区域头部、腹部和心脏进行分类,统计每例受检者的总透视时间、透视累积剂量面积乘积(DAP)、透视累积皮肤入射剂量(ESD),计算透视剂量率;统计每例受检者的造影曝光次数、造影曝光时间、采集帧频率,以及造影累积剂量面积乘积和造影累积皮肤入射剂量;统计每例受检者的透视加造影的总累积剂量面积乘积和总累积皮肤入射剂量。对所有数据分门别类进行相应的对比分析。结果 冠状动脉造影+介入,ESD为(22 285.5±18 682.7)μGy·m²,DAP为(2 942.1±2 557.3)mGy;头部血管造影DAP为(25 929.6±8 302.7)μGy ·m²,DAP为(1 288.8±682.3)mGy;腹部血管造影,DAP为(12 129.7±10 646.1)μGy·m²,ESD为(730.1±584.7)mGy。结论 血管造影受检者所受总累积剂量,冠状动脉造影相对最高,其次是头部血管造影,腹部血管造影相对较低。     

心血管介入手术中透视时间作为辐射剂量警示指标的可行性研究

目的以心血管介入术后采集空气比释动能(reference air kerma,AK)值和剂量面积乘积(dose-area product,DAP)值数据为依据,分析术中透视时间报警设置作为心血管介入手术辐射剂量的监测和警示工具的可行性。方法回顾性分析2016年11月至2018年1月上海长海医院736例冠状动脉造影术(CAG)和经皮冠状动脉治疗术(PCI)病例,收集术中透视时间、AK和DAP数据资料。德国西门子成像设备分组(Ceiling系统和Biplane系统)和手术类型分组(CAG和PCI),对辐射剂量数据进行比较,以及对心血管介入手术AK和DAP值与透视时间数据采用Spearman检验解析相关性。结果Ceiling和Biplane成像系统中手术透视时间为(8.9±7.8)和(8.6±7.3)min,透视AK均值和DAP均值分别为(472±474)、(510±509)mGy、(4548±4085)和(4255±3781)μGy·m^2,术中总(透视+造影)AK和DAP均值为(703±595)、(733±614)mGy、(6253±4938)和(5681±4432)μGy·m^2。CAG与PCI术中透视时间均值分别为(2.4±0.9)和(15.7±4.9)min。PCI透视辐射剂量(AK和DAP)与术中总辐射剂量比值分别为74%和78%。心血管介入手术中透视时间与AK值(r=0.822)和DAP值(r=0.844)都呈高度相关性(P<0.001)。结论透视采集辐射剂量是心血管介入手术中辐射剂量的主要来源,辐射剂量随透视时间延长而增加,透视时间监测和报警设置在心血管介入临床应用中作为术中辐射防护工具有一定的参考和警示价值。     

CT低剂量联合迭代算法在输尿管结石诊断中的应用

目的 探讨CT低剂量联合迭代算法在输尿管结石诊断中的应用价值.方法 90例输尿管结石患者在首次检查均应用常规剂量扫描(120 kV,400 mAs),采用滤波反投影算法(FBP)薄层重组,保守治疗后结石未排出.复查CT应用低剂量扫描随机分为3组(A组:120 kV,200 mAs;B组:120 kV,150 mAs;C组:120 kV,100 mAs)后分别行6级迭代算法薄层重组.由2名放射医师采用双盲法读片并对图像质量做主观评分,记录CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP),计算辐射有效剂量(ED);测量图像的客观噪声值,计算信噪比,测量结石CT值及最大长径,记录结石检出数.结果 常规组:CTDIvol(23.51±0.79) mGy,DLP(1166.38±52.78)mGy·cm,ED(17.50±0.79)mSv;A组:CTDIvol(11.78±0.38) mGy,DLP(584.68±25.47) mGy· cm,ED(8.77±0.38) mSv;B组:CTDIvol(8.34±0.13)mGy,DLP(462.87±24.76) mGy· em,ED(6.94±0.37)mSv;C组:CTDIvol(5.47±0.21) mGy,DLP(268.20±19.03)mGy·cm,ED(4.02±0.29) mSv;各组低剂量迭代算法重组的iDose l ～6图像结石检出数、结石CT值及大小与常规剂量比较差异无统计学意义(P＞0.05);A组低剂量迭代算法重组的iDose4图像噪声(SD)、信噪比(SNR)及iDose 4—6图像质量主观评分与常规剂量比较差异无统计学意义(P＞0.05);B组低剂量迭代算法重建的iDose6图像噪声、信噪比及图像质量主观评分与常规剂量比较差异无统计学意义(P＞0.05);C组低剂量迭代算法重建的iDose l～6各组图像噪声、信噪比及图像质量主观评分与常规剂量比较差异有统计学意义(P＜0.05).结论 CT低剂量扫描联合迭代算法诊断输尿管结石是可行的,可以在不影响图像质量的前提下明显减低辐射剂量.管电压120 kV情况下,在iDose6水平管电流150mAs为最低临界扫描参数.     

心脏介入患者受照剂量研究

目的 调查我院心脏介入诊疗过程中患者受照剂量分布和剂量参考水平,并分析各种剂量参数如皮肤峰值剂量(PSD)和剂量面积乘积(DAP)之间的相关性.方法 对135例患者的剂量数据进行分析研究,其中接受冠状动脉造影(CAG)患者84例,接受经皮心脏介入(PCI)患者51例.记录每例患者DAP值、参考点累计剂量值(CD)以及透视时间,总采集图像幅数.采用热释光剂量片(TLD)矩阵测量患者皮肤剂量.TLD矩阵大小为10行9列,行间隔5 cm,列间隔4 cm.结果 对于PCI,DAP均值为7946.91μGym2;CD均值为1395.3 mGy,平均透视时间10.9 min,平均采集945幅.PSD范围为38.91～184.79mGy.DAP与PSD的相关性为0.54,PSD与CD的相关性为0.53.对于CAG,DAP均值为2690.84 μGym2;CD均值为431.6 mGy,平均透视时间为2.9 min,平均采集544幅.PSD范围26.18～120.37 mGy.DAP与PSD的相关性为0.52,PSD与CD的相关性为0.45.结论 患者所受皮肤剂量峰值低于所致皮肤损伤辐射阈值(2 Gy).各种辐射剂量参数(如DAP,CD和透视时间等)的结果与其他学者的研究结果相仿.从结果可以看出PSD与DAP、CD等参数相关性较差,因此基于这些数据对个体皮肤峰值剂量进行估算的方法较不科学,需要对其进一步研究.     

先心病患者在介入诊疗中辐射剂量控制分析

【摘要】 目的 探讨如何控制先心病（CHD）患者在介入诊疗中辐射剂量。方法 利用SIEMENS DSA设备连续观察介入诊疗的CHD患者273例。按年龄和疾病分组统计总辐射时间（T）、累积剂量（CD）、剂量面积乘积（DAP）、峰值皮肤剂量（PSD）和有效剂量（ED）,分段统计CD和PSD,结合CHD介入诊疗实际进行分析,为控制辐射剂量提供依据。结果 总体T、CD、PSD（1/2CD）、PSD（4/5CD）、DAP、ED中位数达到3.05 min、113 mGy、56.5 mGy、90.4 mGy、11.62 Gy?cm2,、1.98 mSv,参数范围差异显著;CHD介入诊疗以未成年为主分布于各年龄段、各病种,年龄分组以少年中位数突出,疾病分组以室内隔缺损（VSD）中位数较大,各分组参数范围均差异显著;辐射剂量分段统计以＜100 mGy为主,＞500 mGy较少。结论 提高术者及介入放射技师辐射剂量控制意识及技能,采用多种措施减少或避免辐射暴露,通过数据库建立辐射剂量参照值,有助于控制CHD患者介入诊疗辐射剂量。     

多层螺旋CT低剂量扫描技术在甲状腺增强扫描中的临床应用

目的：探讨多层螺旋 CT 低剂量扫描技术在甲状腺增强扫描中的临床应用价值。方法80例患者随机分为4组(每组各20例),4组分别为：A 组,120 kV、180 mA;B 组,120 kV、100 mA;C 组,100 kV、180 mA;D 组,100 kV、100 mA。主观评价图像质量并评分,统计甲状腺 CT 值、图像背景噪声(N)、图像信噪比(SNR)、CT 剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效辐射剂量(ED)并进行对比分析。结果4组图像主观评分为3.90±0.31、3.75±0.44、3.70±0.47、3.60±0.60,SNR 为26.34±3.13、25.08±1.87、25.86±2.38、24.87±2.20,四者无统计学差异(P >0.05);甲状腺 CT 值为(168.55±13.39)HU、(170.70±11.34)HU、(185.20±22.35)HU、(190.55±21.38)HU,N 为(6.48±0.84)HU、(6.83±0.45)HU、(7.19±0.86)HU、(7.66±1.01)HU, CTDIvol 为(10.95±0.00)mGy、(6.08±0.00)mGy、(6.59±0.00)mGy、(3.66±0.00)mGy,DLP 为(145.67±8.79)mGy·cm、(84.58±4.94)mGy·cm、(89.86±3.26)mGy·cm、(50.20±1.89)mGy·cm,ED 为(0.73±0.04)mSv、(0.42±0.03)mSv、(0.45±0.03)mSv、(0.25±0.01)mSv,四者有统计学差异(P <0.05)。结论多层螺旋 CT 低剂量扫描技术既能保证图像质量又能有效降低甲状腺增强 CT 检查的辐射剂量。     

Patient radiation dose during lithotripsy.

Measurements were made of the radiation dose to patients undergoing lithotripsy. Two groups were studied; patients undergoing ultrasound localization of calculi, and patients undergoing fluoroscopic localization. Dose area product (DAP) measurements were obtained using a Diamentor ionization chamber. Ultrasound localization produced a mean DAP of 137 cGy cm2 equivalent to a mean effective dose of 0.24 mSv. Fluoroscopy localization produced a mean DAP of 552 cGy cm2 equivalent to a mean effective dose of 1.2 mSv. There was no correlation between stone size and fluoroscopy time. We recommend the use of ultrasound localization as a first option whilst restricting the use of fluoroscopy (preferably pulsed) for ureteric and difficult renal calculi.     

Radiation Exposure in Vascular Angiographic Procedures

PurposeTo evaluate dose reduction in vascular angiographic procedures by using fluoroscopy capture instead of digital subtraction angiography frames for documentation.Materials and MethodsA total of 764 consecutive vascular interventional procedures performed over a period of 1 year were retrospectively analyzed with respect to the fluoroscopy time and the resulting dose–area product (DAP), the DAP of the radiographic frames, and the overall DAP.ResultsA total of 70% of the total DAP was a result of the acquisition of radiographic frames, leaving only 30% being applied by fluoroscopy.ConclusionsFluoroscopy capture should be used for documentation whenever possible. A registry of radiation exposure should not only comprise a sufficiently large number of interventions but also different intervention types to allow the development of interventional reference levels.     

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software

PurposeTo evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software.Materials and MethodsIn this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed.ResultsBilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm² ± 69.5 (range, 44.7–410.9 Gy ⋅ cm²). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm² ± 21.3 (range, 8.6–148.6 Gy ⋅ cm²) or 26.4% (percentage of total DAP), 58.2 Gy ⋅ cm² ± 48.3 (range, 10.3–309.3 Gy ⋅ cm²) or 43.3%, and 40.7 Gy ⋅ cm² ± 14.5 (range, 15.9–86.3 Gy ⋅ cm²) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes.ConclusionsIntraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.     

心血管病介入操作时患者受照剂量研究

目的 对心血管介入手术中患者所受辐射剂量及与辐射剂量相关的指标进行采集和分析,为改善患者的辐射防护提供依据.方法 对在省属三级甲等医院进行的26例完整的心血管介入手术的患者进行临床数据采集,按手术类别分成冠状动脉血管造影术(CA)及行冠状动脉血管造影术(CA)后继续行经皮穿刺腔内冠状动脉成形术(PTCA)两组,采用TLD个人剂量计照射野矩阵测量法,检测患者荧光照射时间、入射皮肤剂量(ESD)、最高皮肤剂量(PSD)、剂量-面积乘积(DAP)等指标,用TLD测量在模拟心血管手术条件下体模器官剂量.结果 荧光透视时间为(17.7±15.6)min,范围为0.80～42.4 min;ESD范围为(159±138)mGy,4.40～459 mGy;PSD范围为(769±705)mGy,22.6～2.43×103mGy.CA+PTCA组的荧光照射时间、ESD、PSD均大于CA组,差异有统计学意义.最大皮肤受照剂量与透视时间有较好的相关性(r=0.84,P＜0.01).结论 心血管病放射性介入操作时,可通过透视时间来估算最大皮肤受照剂量.

Abstract：

Objective To collect and analyze the radiation dose to patients in cardiovascular interventional procedures and the radiation dose-related indicators,in order to provide a basis for improving radiation protection of patients.MethodsThe clinical data of 26 cases of complete cardiovascular interventional procedures was collected in the municipal Grade A Class Three hospitals,including coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA),and the patient-received radiation doses and other related factors was studied.TLD personal dosimeter radiation field matrix method was used to measure fluorescence time,the entrance skin dose (ESD),the peak skin dose (PSD),dosearea product (DAP) and other indicators.TLD was used to measure the organ dose of the phantom under the cardiovascular interventional procedure condition.ResultsThe fluoroscopy time was (17.7 ±15.6) min during the range of 0.80-42.4 min.The average entrance skin dose (ESD) was (159 ± 138)mGy during the range of 4.40-459 mGy.The peak skin dose (PSD) was (769 ± 705) mGy during the range of 22.6 - 2.43 × 103mGy.The fluorescence time,entrance skin dose (ESD) ,peak skin dose (PSD) of the group CA + PTCA are greater than the group CA and the difference has statistical significan.The peak skin dose and the fluoroscopy time have good linear correlation (r = 0.84,P ＜ 0.01 ).Conclusion The peak skin dose the patient received in cardiovascular interventional radiological operation can be estimated through the fluoroscopy time.     

Contemporary Interventional Radiology Dosimetry: Analysis of 4,784 Discrete Procedures at a Single Institution

PurposeTo report dosimetry of commonly performed interventional radiology procedures and compare dose analogues to known reference levels.Materials and MethodsDemographic and dosimetry data were collected for gastrostomy, nephrostomy, peripherally inserted central catheter placement, visceral arteriography, hepatic chemoembolization, tunneled catheter placement, inferior vena cava filter placement, vascular embolization, transjugular liver biopsy, adrenal vein sampling, transjugular intrahepatic portosystemic shunt (TIPS) creation, and biliary drainage between June 12, 2014, and April 26, 2018, using integrated dosimetry software. In all, 4,784 procedures were analyzed. The study included 2,691 (56.2%) male subjects and 2,093 (43.8%) female subjects with mean age 55 ± 21 years (range: 0-104 years) and with mean weight of 76.9 ± 29.4 kg (range: 0.9-268.1 kg). Fluoroscopy time, dose area product (DAP), and reference dose were evaluated.ResultsTIPS had the highest mean fluoroscopy time (49.1 ± 16.0 min) followed by vascular embolization (25.2 ± 11.4 min), hepatic chemoembolization (18.8 ± 12.5 min), and visceral arteriography (17.7 ± 3.2 min). TIPS had the highest mean DAP (429.2 ± 244.8 grays per square centimeter [Gy·· cm²]) followed by hepatic chemoembolization (354.6 ± 78.6 Gy·· cm²), visceral arteriography (309.5 ± 39.0 Gy·· cm²), and vascular embolization (298.5 ± 29 Gy·· cm²). TIPS was associated with the highest mean reference dose (2.002 ± 1.420 Gy) followed by hepatic chemoembolization (1.746 ± 0.435 Gy), vascular embolization (1.615 ± 0.381 Gy), and visceral arteriography (1.558 ± 1.720 Gy). Of the six procedures available for comparison with the reference levels, the mean fluoroscopy time, DAP, and reference dose for each procedure were below the proposed reference levels.ConclusionAdvances in image acquisition technology and radiation safety protocols have significantly reduced the radiation exposure for a variety of interventional radiology procedures.     

Radiation Exposure in Nonvascular Fluoroscopy-Guided Interventional Procedures

Purpose

To investigate the radiation exposure in non-vascular fluoroscopy guided interventions and to search strategies for dose reduction.

Materials and Methods

Dose area product (DAP) of 638 consecutive non-vascular interventional procedures of one year were analyzed with respect to different types of interventions; gastrointestinal tract, biliary interventions, embolizations of tumors and hemorrhage. Data was analyzed with special focus on the fluoroscopy doses and frame doses. The third quartiles (Q3) of fluoroscopy dose values were defined in order to set a reference value for our in-hospital practice.

Results

Mean fluoroscopy times of gastrostomy, jejunostomy, right and left sided percutaneous biliary drainage, chemoembolization of the liver and embolization due to various hemorrhages were 5.9, 8.6, 13.5, 16.6, 17.4 and 25.2 min, respectively. The respective Q3 total DAP were 52.9, 73.3, 155.1, 308.4, 428.6 and 529.3 Gy*cm². Overall, around 66% of the total DAP originated from the radiographic frames with only 34% of the total DAP applied by fluoroscopy (P < 0.001). The investigators experience had no significant impact on the total DAP applied, most likely since there was no stratification to intervention-complexity.

Conclusion

To establish Diagnostic Reference Levels (DRLs), there is a need to establish a registry of radiation dose data for the most commonly performed procedures. Documentation of interventional procedures by fluoroscopy “grabbing” has the potential to considerably reduce radiation dose applied and should be used instead of radiographic frames whenever possible.     

Main clinical, therapeutic and technical factors related to patient's maximum skin dose in interventional cardiology procedures

Objective: The study aimed to characterise the factors related to the X-ray dose delivered to the patient's skin during interventional cardiology procedures. Methods: We studied 177 coronary angiographies (CAs) and/or percutaneous transluminal coronary angioplasties (PTCAs) carried out in a French clinic on the same radiography table. The clinical and therapeutic characteristics, and the technical parameters of the procedures, were collected. The dose area product (DAP) and the maximum skin dose (MSD) were measured by an ionisation chamber (Diamentor; Philips, Amsterdam, The Netherlands) and radiosensitive film (Gafchromic; International Specialty Products Advanced Materials Group, Wayne, NJ). Multivariate analyses were used to assess the effects of the factors of interest on dose. Results: The mean MSD and DAP were respectively 389 mGy and 65 Gy cm(-2) for CAs, and 916 mGy and 69 Gy cm(-2) for PTCAs. For 8% of the procedures, the MSD exceeded 2 Gy. Although a linear relationship between the MSD and the DAP was observed for CAs (r=0.93), a simple extrapolation of such a model to PTCAs would lead to an inadequate assessment of the risk, especially for the highest dose values. For PTCAs, the body mass index, the therapeutic complexity, the fluoroscopy time and the number of cine frames were independent explanatory factors of the MSD, whoever the practitioner was. Moreover, the effect of technical factors such as collimation, cinematography settings and X-ray tube orientations on the DAP was shown. Conclusion: Optimising the technical options for interventional procedures and training staff on radiation protection might notably reduce the dose and ultimately avoid patient skin lesions.     

Evaluation of exposure dose to patients undergoing catheter ablation procedures—a phantom study

The aim of this study was to evaluate entrance skin dose (ESD), organ dose and effective dose to patients undergoing catheter ablation for cardiac arrhythmias, based on the dosimetry in an anthropomorphic phantom. ESD values associated with mean fluoroscopy time and digital cine frames were in a range of 0.12–0.30 Gy in right anterior oblique (RAO) and 0.05–0.40 Gy in left anterior oblique (LAO) projection, the values which were less than a threshold dose of 2 Gy for the onset of skin injury. Organs that received high doses in ablation procedures were lung, followed by bone surface, esophagus, liver and red bone marrow. Doses for lung were 24.8–122.7 mGy, and effective doses were 7.9–34.8 mSv for mean fluoroscopy time of 23.4–92.3 min and digital cine frames of 263–511. Conversion coefficients of dose-area product (DAP) to ESD were 8.7 mGy/(Gy·cm²) in RAO and 7.4 mGy/(Gy·cm²) in LAO projection. The coefficients of DAP to the effective dose were 0.37 mSv/(Gy·cm²) in RAO, and 0.41 mSv/(Gy·cm²) in LAO projection. These coefficients enabled us to estimate patient exposure in real time by using monitored values of DAP.     

髋关节数字化断层融合摄影的低剂量研究

目的 探讨髋关节数字化断层融合(DTS)摄影中最佳剂量比的设定,以最大程度地减少患者接受的辐射剂量.方法 90例行髋关节数字化断层融合摄影的患者,以随机数字表法,分别以6、7、8倍的剂量比组进行DTS检查,使用单因素方差分析比较不同剂量比设定下所得的图像质量和辐射剂量.结果 3组的表面吸收剂量(ESD)、剂量面积乘积(DAP)、图像质量评分分别为[(3.76±1.89)mGy、(18.41±11.71)dGy ·cm²、3.03±0.24]、[(5.24±2.76)mGy、(26.99±13.34)dGy ·cm²)、3.60±0.11]、[(6.39±1.75)mGy、(36.96±22.49)dGy ·cm²、3.64±0.09],各组间差异有统计学意义(F=10.94、9.45、139.26, P<0.05),通过3组间两两比较,ESD值和DAP值均是6倍剂量比组<7倍剂量比组<8倍剂量比组.6倍剂量比组的图像质量评分低于其他两组,7倍剂量比组和8倍剂量比组的图像质量评分差异无统计学意义.结论 剂量比是决定DTS检查辐射剂量的重要参数,髋关节DTS检查的剂量比设置为7时,可实现低曝光剂量和高图像质量的平衡,以最大限度地保护患者免受不必要的辐射损害.