影响数字乳腺X线摄影辐射剂量因素研究

目的 对影响数字乳腺X线摄影辐射剂量的不同靶面/滤过组合以及不同曝光模式进行研究.方法 采用西门子MAMMOMAT NovationDR型数字乳腺摄影机,应用不同靶面/滤过组合和不同曝光模式对乳腺体模和X射线用矩形波测试卡进行照射,记录其辐射剂量并观察测试卡显示的线对数,再对临床病例进行对比研究,记录其辐射剂量并观察照片质量有无差别.结果 同等X线片质量下,三种不同靶面/滤过组合和两种不同曝光模式的辐射剂量差别较大,在体模试验中,钼靶/钼滤过组合达到2.2 mGy,钼靶/铑滤过组合达到1.5 mGy,而钨靶/铑滤过组合最小,只有1.0mGy；与自动曝光模式的辐射剂量3.0 mGy相比,手动曝光控制模式的辐射剂量可下降到1.5mGy.同时,临床病例测试结果与体模测试结果完全相符.结论 在实际工作中,应尽量选择手动曝光控制模式和钨靶/铑滤过组合进行摄影,以尽量减少患者的辐射剂量.     

不同附加滤过组合对球管负荷和辐射剂量的影响

【摘要】目的：探讨不同附加滤过组合对球管负荷和辐射剂量的影响,旨在合理选择附加滤过组合,既能有效减少辐射剂量又不过分损耗X线球管。方法：以设备自带设定膝关节正位、腰椎正位和胸部正位摄影曝光模式,分别进行不同附加滤过组合［无附加滤过（A组）、2mm铝（B组）、0.1mm铜+2mm铝（C组）、0.2mm铜+2mm铝（D组）］对自制模体进行三组曝光,每组模式的曝光因子（除滤过组合外）相同,每个滤过组合进行5次曝光,记录每次曝光的曝光量（mAs）和剂量面积乘积（DAP）值,并进行统计学分析。结果：随着附加滤过厚度的增加,球管负荷随之增大;辐射剂量（DAP）随之减小;两两比较显示,球馆负荷（mAs值）D组>C组>B组>A组(P<0.001),辐射剂量（DAP值）D组相似文献   

冠心病介入诊疗中透视与电影辐射剂量率对比分析

目的：研究冠心病患者介入诊疗中DSA设备显示的实时辐射剂量率,为医务人员合理控制辐射剂量提供依据。方法随机抽取2014年9月采用美国通用公司DSA机介入诊疗的冠心病患者30例,对术中DSA机由透视模式转换为电影模式时各自序列显示的辐射剂量率进行对比分析。结果透视辐射剂量率为18．5～212．0 mGy/min,均值为（114．7±42．1） mGy/min;电影辐射剂量率为216～1691 mGy/min,均值为（970．1±298．4） mGy/min。透视与电影辐射剂量率总体均值之比为1︰8．5。数字平板探测器面积越大,辐射剂量率均值越大,电影辐射剂量率均值较透视辐射剂量率均值增高趋势越明显;透视辐射剂量率均值较电影辐射剂量率均值低,差异显著。结论医务人员在冠心病介入诊疗中应合理选择 DSA 设备类型,密切观察动态实时显示的辐射剂量率,及时调整检查模式及可控参数,即刻评估可能致患者放射损伤的剂量水平,合理控制辐射剂量,以降低电离辐射对人体健康产生的辐射效应。     

电子束CT辐射测定

常用三个不同指标描述CT检查辐射剂量:辐射剂量峰值(PRD),多次扫描平均剂量(MSAD)、和CT剂量标准(CTDI)。利用以往报道的胶片条剂量测量技术测量层面辐射剂量和PRD、MSAD、和CTDI。将预先裁成的直接曝光X线胶片条放置在不透光的支架上,用于在空气中和常规CTDI体模内测量曝光。利用与作者采用的电子束CT匹配的常规X线球管的光谱特征对胶片校正。曝光后,用自     

64层螺旋CT颈椎采集模式放射剂量的分析

目的 探讨64层螺旋CT 3种颈椎采集模式的放射剂量.方法选用同一水模进行64层螺旋CT检查扫描,扫描范围30 cm,根据采集方式不同,分为3组:分别采用64×0.6 mm(A组)、24×1.2 mm(B组)、20×0.6 mm(C组)采集方式,每组扫描30次.记录每次扫描的平均容积剂量指数、扫描时间和有效球管电流数值,并计算出剂量长度和平均有效剂量.结果 3组平均容积剂量A组>B组>C组;C组平均容积剂量比A组和B组平均容积剂量分别降低21.922%和18.58%.结论 64层螺旋CT 20×0.6 mm采集模式进行颈椎扫描放射剂量最小.     

低剂量数字化平板探测器在子宫输卵管造影中的辐射剂量研究

目的 探讨低剂量数字化平板探测器应用于HSG检查的低辐射剂量价值.方法 分别对3组HSG检查患者应用普通数字化X线装置、数字化平板探测器及其低剂量模式进行检查,均采用自动曝光控制技术,应用RTI DoseGuard剂量面积乘积仪和RTI WinODS剂量软件检测并计算出每位患者的剂量面积乘积与有效剂量.采用配对t检验比较普通数字化X线装置与数字化平板探测器及其低剂量模式有效剂量的差异性.结果 普通数字化X线装置、数字化平板探测器及其低剂量模式的有效剂量分别为3.52mSv、1.26mSv与0.39mSv.数字化平板探测器HSG检查中的辐射剂量约为普通数字化X线装置的1/3,且差异有统计学意义（t=10.85,P＜0.01）;低剂量模式数字化平板探测器的辐射剂量约为普通数字化X线装置的1/9,且差异有统计学意义（t=17.86,P＜0.01）.结论 低剂量数字化平板探测器应用于HSG检查具有显著的低辐射剂量优势,能够降低接受HSG检查患者受孕后的出生缺陷率.     

床旁防护屏在冠状动脉介入诊疗过程中对不同操作者的防护作用

目的 探讨床旁防护屏对冠状动脉介入诊疗过程中,第一及第二术者位置辐射剂量的屏蔽效果。方法 采用冠状动脉造影过程中常用的足位、右足位、左足位、头位、左头位、左侧位、右侧位7个体位,桡动脉途径,对标准仿真人模体进行曝光采集。测量高度125 cm,在不同采集体位时,测量有无床旁防护屏情况下的入射体表剂量率,采用t检验比较体表入射剂量率是否存在差异,并分别计算辐射剂量的屏蔽效果。结果 在无床旁防护屏情况下,各采集体位第一术者位置的剂量率高于第二术者(t=97.1~2 263.0,P<0.05);在有床旁防护屏情况下各采集体位(除左足位外)第一术者的剂量率低于第二术者(t=-80.9~275.1,P<0.05);床旁防护屏对第一、第二术者位置的辐射剂量屏蔽率范围分别为92.26%~99.36%、27.83%~97.90%。结论 采用床旁防护屏可有效降低操作者位置的辐射剂量,并改变了操作者站立区域的剂量分布,冠状动脉介入诊疗过程中应充分利用床旁防护屏,同时重点关注第二术者的防护。     

不同曝光模式对数字乳腺X线摄影影像质量和辐射剂量的影响

目的探讨数字乳腺X线摄影中不同曝光模式对影像质量及辐射剂量的影响,便于实际工作中在保证影像质量的前提下,通过对曝光模式及曝光条件选择有效降低病人的辐射损伤。方法先采用自动曝光模式(28kV、60mAs)对乳腺模体进行曝光,然后采用相同的压迫厚度和压力,根据自动曝光模式的摄影条件,在手动曝光模式下,分别固定管电压和管电流量,依次改变相应的管电流量及管电压对模体进行曝光,记录各曝光条件下入射剂量(ESD)、平均腺体剂量(AGD)和美国放射学会(ACR)标准的影像评分值。采用SPSS17.0软件中KruskalWallis检验对自动和手动曝光模式产生的各值进行统计学处理。结果手动曝光模式下,当管电压固定为28kV,管电流量由60mAs升至70mAs时,ESD和AGD分别增加了15.4%;当管电流量降至45mAs时,ESD和AGD分别降低了26.1%。当管电流量固定为60mAs,管电压由28kV升至32kV时,ESD和AGD分别增加了47.0%和62.7%;当管电压降至26kV时,ESD和AGD分别降低了22.6%和28.2%。不同曝光模式下影像的整体质量均无明显差别(P>0.05)。结论自动曝光模式下所得到的ESD与AGD均不是最低剂量。以自动曝光模式为基础,分别固定管电压或管电流量,在一定范围内分别手动降低管电流量或管电压值,在不影响影像质量的前提下,可降低辐射剂量。同时,影像质量达到一定水平后,不再随摄影条件增加而提高。     

DR床边胸部摄影辐射剂量优化的实验研究

目的 探讨数字化移动DR床边机在胸部正位摄影中的条件最优化.资料与方法 采用岛津MobileDaRt床旁机分别用固定管电流、增加管电压和固定管电压、增加管电流两种方法对人体胸部模型进行曝光,同时测量距阴极1 m处的辐射剂量,辐射测量仪离地高80 cm.每组获得的图像请2名有经验的放射科医师采用双盲法进行评分.对计数资料进行t检验,计量资料进行卡方检验.结果 固定管电流,管电压从70 kU增加到85 kU,每组得到的图像质量所对应的受试者操作特性曲线(ROC)曲线下的而积(Az值)分别为0.383,0.733,0.675,0.250.固定管电压,管电流从0.5 mAs增加到1.8 mAs,每组得到的图像质量所对应的Az值分别为0.650,0.683,0.817,0.725.kV和mAs分别与图像质量R×C卡方检验P=0.012,P=0.001.结论 管电压和管电流的改变都会影响到辐射剂量,并且两者都与辐射剂量呈正相关.在实际的临床运用中应该选取合理的曝光条件.     

胸部摄影附加滤过对辐射剂量的影响

目的 探讨不同附加滤过对成人胸部高电压X射线摄影的图像质量、辐射剂量和X射线管负荷的影响,筛选合适附加滤过厚度,优化临床摄影参数.资料与方法 分析心脏手术前后进行检查的32例患者采用0、0.1、0.2、0.3mm铜附加滤过胸部摄影图像的质量,并进行患者皮肤入射剂量和散射线剂量率标准水模实验测试.结果 随着附加滤过板厚度的增加,患者皮肤入射剂量下降约30％,管负荷增加,室内散射线剂量率明显减少.32例患者不同厚度滤过板的各图像质量均具有一致性(P＜ 0.01).结论 摄影时选用一定厚度的附加滤过板可以减少患者表面剂量,同时不会造成X射线图像质量下降.进行成人胸部高仟伏摄影时,宜添加0.1～0.2mm的铜附加滤过,以达到防护最优化要求.     

Reduction of Operator Radiation Dose by an Extended Lower Body Shield

PurposeTo quantify the reduction in operator exposure to scatter radiation by using an extension component in addition to a commonly used lower body radiation shield attached to an interventional radiology procedure table.Materials and MethodsAn anthropomorphic pelvis phantom was exposed to fluoroscopy at varying C-arm angles to simulate a standard interventional procedure. A MAVIG UT60 lower body shield (MAVIG, Munich, Germany) (48 cm × 78 cm, 0.5 mm lead equivalent), with an attachable extension component (48 cm × 36 cm), was suspended from the edge of the table adjacent to the pelvic phantom. Using a handheld Geiger counter, scatter radiation exposure rates were measured at the level of an operator’s eye, chest, waist, and knee, with various C-arm angles both with and without the attachable extension component. Mean exposure rates for each experimental setup were calculated and compared.ResultsOverall, scatter radiation exposures were lower with the addition of the extension component, with the largest reductions (> 80%) measured at the operator’s waist and knee levels, for all C-arm angles. The highest reduction in scatter radiation exposure was measured at knee level, at 0 degrees left posterior oblique projection, where the use of the lower body shield extension component reduced the exposure rate from 4.80 mR/h to 0.44 mR/h (90.8% reduction, P < .001). Reductions in scatter radiation were less at eye and chest levels.ConclusionsThe use of the additional extension component to the lower body radiation shield can result in large (> 80%) reductions in operator scatter radiation exposure, particularly to the lower body.     

Cervical spine tomography with an angiographic C-arm.

Phantom studies were performed to develop a technique for linear tomography of the craniocervical junction with a digital fluoroscopic angiographic C-arm unit. Section thicknesses were similar to those used at conventional tomography, and the radiation dose was lower. C-arm tomography was possible with a 6-second exposure and a 40 degrees arc. C-arm tomography is a practical method for decreasing patient turnaround time.     

C形臂X线机与CT联合导向在经皮椎体成形术中的应用

目的探讨在移动式C形臂X线机与16排CT联合导向下,经皮椎体成形术中在治疗骨质疏松性椎体压缩骨折的操作方法及优势。方法将移动式C形臂X线机与16排CT置于同一机房,组成组合机。16排CT扫描病变椎体及相邻椎体,确定穿刺点及穿刺路径,评价术后椎体情况;移动式C形臂X线机实时透视监视注射聚乙烯吡咯烷酮(骨水泥)。结果在组合机引导下对12例单椎体压缩骨折的患者行经皮椎体成形术成功率100%,无并发症发生。结论移动式C形臂X线机与16排CT联合导向在经皮椎体成形术中的操作简便、定位准确、监视实时、导向安全,特别提高了L4椎体平面以上各椎体行椎体成形术的安全性。     

C形臂X线机辅助下L形解剖锁定钢板微创治疗Rüedi-AllgöwerⅡ、Ⅲ型闭合性Pilon骨折的疗效

 

目的 探讨C形臂X线机辅助下L形解剖锁定钢板微创治疗Rüedi-AllgöwerⅡ、Ⅲ型闭合性Pilon骨折的临床疗效。方法 在2013-01至2018-12武警第二机动总队医院采用术中分次C形臂X线机透视骨折部位,有限切开组织,骨折复位满意,L形锁定钢板固定良好,微创治疗Rüedi-AllgöwerⅡ、Ⅲ型闭合性Pilon骨折24例患者。结果 24例均获得随访,时间6～24个月,平均(15±3.25)个月,骨折愈合佳,无切口感染、血管损伤及踝关节僵硬等并发症;仅有1例出现创伤性关节炎,后经康复治疗1年后恢复正常。根据Mazur踝关节功能评分以及骨折的复位愈合程度评定:优16例,良5例,可3例,优良率为87.5%。结论 C形臂X线机辅助下L形锁定钢板微创治疗Rüedi-AllgöwerⅡ、Ⅲ型闭合性Pilon骨折,临床观察,疗效满意。

     

C-Bogen-CT-unterstützte 3D-Navigation perkutaner Interventionen

So far C-arm CT images were predominantly used for a precise guidance of an endovascular or intra-arterial therapy. A novel combined 3D-navigation C-arm system now also allows cross-sectional and fluoroscopy controlled interventions. Studies have reported about successful CT-image guided navigation with C-arm systems in vertebroplasty. Insertion of the radiofrequency ablation probe is also conceivable for lung and liver tumors that had been labelled with lipiodol. In the future C-arm CT based navigation systems will probably allow simplified and safer complex interventions and simultaneously reduce radiation exposure.     

Imaging guidance with C-arm CT: prospective evaluation of its impact on patient radiation exposure during transhepatic arterial chemoembolization

Purpose

To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization.

Materials and Methods

Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured.

Results

The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively.

Conclusions

Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.     

Radiation exposure in stent-grafting of abdominal aortic aneurysms

In recent years, endovascular stent-grafting of abdominal aortic aneurysms has become more and more common. The radiation dose associated with these procedures is not well documented however. The aim of the present study was to estimate the radiation exposure and to simulate the effects of a switch from C-arm radiographic equipment to a dedicated angiographic suite. Dose-area product (DAP) was recorded for 24 aortic stent-grafting procedures. Based on these data, entrance surface dose (ESD) and effective dose were calculated. A simulation of doses at various settings was also performed using a humanoid Alderson phantom. The image quality was evaluated with a CDRAD contrast-detail phantom. The mean DAP was 72.3 Gy cm(2) at 28 min fluoroscopy time with a mean ESD of 0.39 Gy and a mean effective dose of 10.5 mSv. If the procedures had been performed in an angiographic suite, all dose values would be much higher with a mean ESD of 2.9 Gy with 16 patients exceeding 2 Gy, which is considered to be a threshold for possible skin injury. The image quality for fluoroscopy was superior for the C-arm whilst the angiographic unit gave better acquisition images. Using a C-arm unit resulted in doses similar to percutaneous coronary intervention (PCI). If the same patients had been treated using dedicated angiographic equipment, the risk of skin injury would be much higher. It is thus important to be aware of the dose output of the equipment that is used.     

无C臂X光机条件下射频消融室上性心动过速27例

目的　探讨在无C臂X光机条件下射频消融室上性心动过速的可行性。方法　 2 7例室上性心动过速患者按常规电生理检查方法和射频消融术方法进行操作 ,冠状窦电极经颈内静脉放置。结果　 2 7例患者均射频消融成功 ,随访 2～11月无 1例复发。结论　基层医院无C臂X光机条件下 ,只要熟练掌握阵发性室上性心动过速的心内电生理和靶点图特征 ,以及X线心脏影像 ,根据体表心电图选择适当的病人 ,也可成功地对室上性心动过速病人行射频消融术。     

Radiation exposure of the interventional radiologist during percutaneous biopsy using a multiaxis interventional C-arm CT system with 3D laser guidance: a phantom study

Objective:

Evaluation of absolute radiation exposure values for interventional radiologists (IRs) using a multiaxis interventional flat-panel C-arm cone beam CT (CBCT) system with three-dimensional laser guidance for biopsy in a triple-modality, abdominal phantom.

Methods:

In the phantom, eight lesions were punctured in two different angles (in- and out-of-plane) using CBCT. One C-arm CT scan was performed to plan the intervention and one for post-procedural evaluation. Thermoluminescent dosemeters (TLDs) were used for dose measurement at the level of the eye lens, umbilicus and ankles on a pole representing the IRs. All measurements were performed without any lead protection. In addition, the dose–area product (DAP) and air kerma at the skin entrance point was documented.

Results:

Mean radiation values of all TLDs were 190 µSv for CBCT (eye lens: 180 µS, umbilicus: 230 µSv, ankle: 150 µSv) without a significant difference (p > 0.005) between in- and out-of-plane biopsies. In terms of radiation exposure of the phantom, the mean DAP was not statistically significantly different (p > 0.05) for in- and out-of-plane biopsies. Fluoroscopy showed a mean DAP of 7 or 6 μGym², respectively. C-arm CT showed a mean DAP of 5150 or 5130 μGym², respectively.

Conclusion:

In our setting, the radiation dose to the IR was distinctly high using CBCT. For dose reduction, it is advisable to pay attention to lead shielding, to increase the distance to the X-ray source and to leave the intervention suite for C-arm CT scans.

Advances in knowledge:

The results indicate that using modern navigation tools and CBCT can be accompanied with a relative high radiation dose for the IRs since detector angulation can make the use of proper lead shielding difficult.     

Technical considerations on the usage of a general-purpose flatbed image scanner when making a dose-density table

The DD-System is a dose-distribution system for analyzing the film method with a general-purpose flatbed image scanner. By analyzing the analogue digital conversion(ADC)value of each pixel acquired by the DD-system, we examined the technical problems of measurement with the scanner when making a dose-density table. When film of uniform density was measured, the ADC values distributed normally. Deviation of the values at the same pixel point on another time was about one-ten thousandth of the average. Deviation of the values from the time the scanner was turned on was in the same range. Although it may be negligible, the values measured at a peripheral area on the flatbed deviated about 2SD from the average measured at the central area. Further, deviation of the value obtained with a shade covering the outside of the irradiation field from that taken without the shade was about one thousandth. These deviations are not negligible. In the case of making a dose-density table with a DD-System and a general-purpose flatbed image scanner, the film should be set in the center of the flatbed, and the sampling area should be selected from those areas where the ADC values are distributed normally. Then proper data can be obtained and more accurate tables can be made.