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。     

悬吊防护屏对介入医师最佳防护方案的体模研究

目的：探讨悬吊防护屏规格及摆放位置对介入手术中第一及第二术者辐射防护效果,为选择悬吊防护屏最佳辐射防护方案提供科学依据。方法在第一及第二术者站位,从地面20 cm至180 cm处,每隔20 cm放置一个个人计量仪。投照体位选择正位与左侧位。悬吊防护屏为铅玻璃(简称玻璃式)与铅玻璃下接铅橡胶皮(简称混搭式)两种。防护屏摆位分别为靠近术者、远离术者、在术者左侧及贴近球管4种。测量2种投照体位下,不同防护屏规格与摆位在第一及第二术者位9个高度的实时辐射剂量率,计算剂量屏蔽率。结果两种防护屏防护效果接近,以玻璃式略优。对于第一术者,正位投照时以近术者摆位的防护效果最佳,侧位投照则以术者左侧摆位的防护效果最好;对于第二术者,正及侧位投照均以近术者摆位防护效果最优。在最佳摆位情况下：正位投照时第一术者在120 cm高度、侧位投照时第一及第二术者各高度仍可检测到较高的辐射剂量率;第一与第二术者总体接受的辐射剂量接近;第一术者的剂量屏蔽率除正位120 cm高度稍低(玻璃式为60.11%,混搭式为39.89%)外,其余各点均高达93%以上,第二术者剂量屏蔽率为57%~97%;侧位屏蔽率整体略高于正位屏蔽率。结论两种防护屏防护效果接近,均能取得较好的防护效果,但正位投照时第一术者的120 cm高度及侧位投照时2位术者的各高度辐射剂量率仍相对较高,需加强对120 cm高度的辐射防护,并尽量少用侧位投照。     

悬吊防护屏对介入医师最佳防护方案的体模研究

目的：探讨悬吊防护屏规格及摆放位置对介入手术中第一及第二术者辐射防护效果,为选择悬吊防护屏最佳辐射防护方案提供科学依据。方法在第一及第二术者站位,从地面20 cm至180 cm处,每隔20 cm放置一个个人计量仪。投照体位选择正位与左侧位。悬吊防护屏为铅玻璃（简称玻璃式）与铅玻璃下接铅橡胶皮（简称混搭式）两种。防护屏摆位分别为靠近术者、远离术者、在术者左侧及贴近球管4种。测量2种投照体位下,不同防护屏规格与摆位在第一及第二术者位9个高度的实时辐射剂量率,计算剂量屏蔽率。结果两种防护屏防护效果接近,以玻璃式略优。对于第一术者,正位投照时以近术者摆位的防护效果最佳,侧位投照则以术者左侧摆位的防护效果最好;对于第二术者,正及侧位投照均以近术者摆位防护效果最优。在最佳摆位情况下：正位投照时第一术者在120 cm高度、侧位投照时第一及第二术者各高度仍可检测到较高的辐射剂量率;第一与第二术者总体接受的辐射剂量接近;第一术者的剂量屏蔽率除正位120 cm高度稍低（玻璃式为60．11%,混搭式为39．89%）外,其余各点均高达93%以上,第二术者剂量屏蔽率为57%～97%;侧位屏蔽率整体略高于正位屏蔽率。结论两种防护屏防护效果接近,均能取得较好的防护效果,但正位投照时第一术者的120 cm高度及侧位投照时两位术者的各高度辐射剂量率仍相对较高,需加强对120 cm高度的辐射防护,并尽量少用侧位投照。     

一种新生儿床旁X射线摄影装置辐射防护的临床可靠性研究

目的 分析新生儿床旁摄影防护和体位固定装置在新生儿床旁X射线摄影中的临床价值。方法 使用移动式X射线诊断机对仿真儿童体模进行投照,实验分为A组常规床旁摄影模式;B组使用床旁X射线摄影防护装置。分别在投照部位和辐射敏感部位放置X射线诊断水平剂量仪。以胸部、骨盆、头颅3个部位为投照中心,采集并记录投照部位和辐射敏感部位的辐射剂量。结果 以胸部为投照中心时,B组较A组非投照部位眼晶状体、甲状腺、性腺辐射剂量显著降低94.4%、96.9%、96.7%(t=-152.55、-445.16、-129.07,P＜0.05);以骨盆为投照中心时,B组较A组非投照部位眼晶状体、甲状腺、胸腺辐射剂量降低85.5%、87.1%、94.9%(t=-50.68、-194.18、-535.94,P＜0.05);以头颅为投照中心时,B组较A组非投照部位甲状腺、胸腺、性腺辐射剂量降低99.3%、97.4%、94.3%(t=-1859.97、-542.08、-66.26,P＜0.05)。结论 新生儿床旁X射线摄影中使用新生儿床旁摄影防护和体位固定装置可以显著降低患儿非投照区域的辐射剂量,同时具有固定和保护患儿的功能,提升了检查成功率。     

冠状动脉介入术者上肢辐射的影响因素及防护

【摘要】 目的 探讨冠脉介入诊疗中术者上肢暴露部位射线剂量与部位高度、术者站位、造影体位及物理防护强度之间的关系。方法 通过对仿真人体模型进行造影曝光,采集桡动脉途径时2位模拟术者左手、左上臂在不同防护条件、不同造影体位下的体表入射剂量率。采用T检验比较仅穿无袖铅衣时左手和左上臂间的体表入射剂量率及同一部位在两位术者间的体表入射剂量率,比较左手在床旁防护前后的体表入射剂量率;采用单因素方差分析比较仅穿无袖铅衣时同一部位在各体位间的体表入射剂量率,比较左上臂在不同防护条件间的体表入射剂量率;并计算左手、左上臂在不同防护措施下的射线屏蔽率。结果 仅穿无袖铅衣时,第一术者上肢的体表入射剂量率均高于第二术者（左手t=38.9～86.5,左上臂t=13.0～83.8,P＜0.05）;两位术者左上臂大多数体位的体表入射剂量率高于左手（第一术者t=7.1～55.3,第二术者t=9.2～78.8,P＜0.05）。左手给予床旁防护后体表入射剂量率明显较低（第一术者左手t=49.4～181.6,第二术者左手t=5.1～47.3,P＜0.05）;左上臂给予的防护越强,体表入射剂量率越低（第一术者左上臂F=84.6～531.3,第二术者左上臂F=7.0～326.3,P＜0.05）。单纯床旁防护时,第一术者左手、左上臂的射线屏蔽率分别为22.46%～52.93%、23.83%～72.12%,第二术者左手、左上臂的射线屏蔽率分别为2.28%～17.39%、3.45%～50.62%,第一术者上肢的射线屏蔽率均高于第二术者,左上臂的射线屏蔽率在多数体位高于左手。半袖铅衣+床旁防护时第一、第二术者左上臂的射线屏蔽率升至73.32%～89.48%、63.97%～89.55%,两术者之间及各体位之间的射线屏蔽率差值较单纯床旁防护时明显缩小。结论 经桡动脉冠脉介入诊疗中,术者上肢暴露部位的射线剂量受部位高度、术者站位、造影体位、物理防护强度等多种因素综合影响,单纯床旁防护对第一术者上肢尤其上臂的防护效果更好,而半袖铅衣弥补了单纯床旁防护的不足,应充分利用床旁防护及穿戴强化的射线防护用品以减少介入术者的辐射危害。     

冠状动脉介入诊疗过程中不同悬吊防护屏位置对操作者所受剂量的影响

目的 探讨冠状动脉介入诊疗过程中悬吊防护屏位置的变化对第1及第2术者位置辐射剂量的影响。方法 采用冠状动脉造影过程中常用的足位、右足位、头位、左足位、左侧位、左头位、右侧位7个体位,经桡动脉途径对标准仿真人模体进行曝光采集。测量高度取125及155 cm,在不同采集体位时,用剂量仪测量不同悬吊防护屏位置时第1及第2术者位置的体表入射剂量率,并比较其是否存在差异。结果 对于第1术者只在左足位测得有效剂量率值,且悬吊防护屏靠近患者时的体表入射剂量率高于靠近术者时（t₁₂₅=46.9,t₁₅₅=4.1,P<0.05）;第2术者在足位、右足位、左侧位、右侧位悬吊防护屏靠近术者时的体表入射剂量率高于靠近患者时（t₁₂₅=11.9、24.4、11.2、2.7,t₁₅₅=16.1、2.8、14.4、28.8,P<0.05）;在头位、左足位、左头位时吊防护屏靠近术者时的体表入射剂量率低于靠近患者时（t₁₂₅=-4.3、-2.4、-80.4,t₁₅₅=-10.2、-6.7、-152.6,P<0.05）。结论 冠状动脉介入诊疗过程中悬吊防护屏位置的变化能引起操作者所受剂量的改变,但是不同体位时悬吊防护屏位置变化所引起的操作者所受剂量的变化趋势也不同,因此在实际操作过程中应针对不同投照体位合理应用悬吊防护屏,以有效减少操作者所受剂量。     

经皮冠状动脉介入术者不同体位所受辐射剂量特征分析

【摘要】　目的?探讨经皮冠状动脉介入诊疗过程中不同防护屏和操作者不同体位时所受辐射剂量的构成特点。 方法?采用冠状动脉介入诊疗常用7个体位,取桡动脉入路,对标准仿真人模体进行射线曝光,采集测量不同体位无床旁防护、只有悬吊防护屏、只有床旁固定铅裙时第1、第2操作者入射体表剂量。重复测量20次。采用t检验比较不同情况下体表入射剂量值差异,分别计算不同体位不同防护屏屏蔽率。 结果?第1、第2操作者体表入射剂量在只有床旁固定铅裙时均高于只有悬吊防护屏时（t值1 =926.0、376.5、75.8、1 329.0、668.0、1 148.0、419.5,t值2 =102.6、41.1、82.8、539.4、541.8、204.0、43.1）,差异均有统计学意义（P＜0.05）。不同体位悬吊防护屏对第1操作者体表入射剂量屏蔽率分别为98.31%、93.67%、67.74%、98.63%、99.52%、89.28%、96.10%,床旁固定铅裙对第1操作者屏蔽率分别为10.39%、4.53%、57.67%、0.68%、4.66%、54.38%、9.68%。 结论?冠状动脉介入诊疗过程中操作者所受辐射剂量主要来源于导管床上方散射辐射,以左足位、左前斜位、足位、右足位、右前斜位最显著;左头位、头位时操作者所受辐射剂量除了来源于导管床上方散射辐射,也有部分来源于导管床下方散射辐射。充分了解各体位时所受辐射剂量构成特征,有助于日常辐射防护有的放矢。     

低能X射线术中放射治疗的辐射屏蔽

目的 依据国内外标准和指南评估低能X射线术中放射治疗室的屏蔽需求,测量屏蔽材料的透射系数、关注位置的周围剂量当量率水平以及防护装置的应用效果,为此类设备屏蔽方案的设计和防护装置的应用提供参考。方法 分别依据我国GBZ 121标准、英国医学物理与工程研究所（IPEM）75号报告和美国国家辐射防护与测量委员会（NCRP）151号报告计算INTRABEAM术中放射治疗室所需的屏蔽厚度。实际测量固体水板、屏蔽贴片和防辐射围裙对于此设备产生低能X射线的透射系数,对模拟治疗条件下关注位置处的周围剂量当量率进行测量并评估辐射防护屏的应用效果。结果 依据不同标准和指南计算得到治疗室全部关注点处所需铅屏蔽厚度均<0.6 mm,差异为亚毫米水平。此设备产生的低能X射线在屏蔽物质中衰减明显,0.05 mm铅当量屏蔽贴片和0.25 mm铅当量防辐射围裙的透射系数为0.068和0.0038。使用球形施用器在空气中进行照射时,距离射线源1和2 m处测得的周围剂量当量率为10.7和2.6 mSv/h。将施用器置于小水箱中后,相应的周围剂量当量率降为3.8和0.9 μSv/h,防护屏的使用可以使2 m处的周围剂量当量率降为本底水平。结论 低能X射线术中放射治疗设施的屏蔽需求较低,设备产生的射线有效能量低,但在邻近未屏蔽辐射源位置的剂量率较高,应优化设计治疗室屏蔽方案并合理使用防护装置。     

婴儿头颅CT中铋屏蔽对辐射剂量和影像质量的影响

目的 研究婴儿头颅CT检查中使用铋屏蔽材料降低眼晶状体受照剂量的效果及对图像质量的影响。方法 使用适合患儿使用的自制铋屏蔽防护眼罩、婴儿体模,采用热释光探测器测量受照剂量。CT扫描条件选择120 kV、130 mA轴位扫描,分别进行铋屏蔽和无屏蔽两组模体测试,比较模体内相当于晶状体位置的受照剂量;应用同样CT扫描参数,对临床疑为颅内出血的99例患儿佩戴铋屏蔽眼罩后进行头部扫描,由2名高年资医生分别进行图像质量评估,并比较评分的一致性。结果 体模实验显示,无屏蔽时眼罩后方区域吸收剂量为25 mGy,经铋防护眼罩屏蔽后眼罩后方的吸收剂量为17 mGy,降低辐射剂量32%。佩戴铋屏蔽眼罩对患儿头部CT图像质量无明显影响。结论 在婴儿头颅CT扫描中使用铋屏蔽防护眼罩,可明显降低眼晶状体放射吸收剂量,同时对CT图像质量的影响是可接受的。     

数字摄影受检者辐射剂量调查

目的 了解数字摄影（DR）检查中受检者的辐射剂量水平,为数字放射摄影受检者指导水平的制定提供基础数据。方法 使用热释光剂量计TLD测量受检者不同部位、不同投照方向的入射体表剂量（ESD）;使用剂量面积乘积仪测量受检者不同部位、不同投照方向的剂量面积乘积（DAP）,并利用测量的DAP值,估算出有效剂量（E）。结果 同类检查中,kV和mAs的变化范围较大,不同部位DR检查中ESD、DAP和E的差别均具有统计学意义（F=33.47、24.68、43.19,P<0.05）。其中,ESD和DAP均以腰椎（LAT）最高,均数为4.62mGy/次和2.26Gy·cm²/次;E以腹部（AP）最高,均数为0.59mSv,高于腰椎（LAT）的0.31mSv。结论 DR在加强受检者放射防护最优化方面很有潜力,应尽快建立适合我国国民体质特征的数字放射摄影受检者辐射剂量的指导水平。     

Determination of optimal fluoroscopic angulations for aorto-coronary ostial interventions from coronary computed tomography angiography

BackgroundAn optimal aorto-coronary angiographic projection, characterized by an orthogonal visualization of the proximal coronary artery, is crucial for interventional success. We determined the distribution of optimal C-arm positions and assessed their feasibility by invasive coronary angiography.MethodsOrthogonal aorto-coronary ostial angulations were determined in 310 CT data sets. In 100 patients undergoing subsequent invasive angiography, we assessed if the CT-predicted angulations were achievable by the C-arm system. If the predicted projection was not achievable due to mechanical constraints of the C-arm system, the most close, achievable angulation was determined. Patient characteristics were analyzed regarding the distribution of optimal angulations and its feasibility by the C-arm system.ResultsFor the left ostium, CT revealed a mean angulation of LAO 23 ?± ?21°/cranial 25 ?± ?23° (90% of patients with a LAO/cranial angulation, 3% LAO/caudal, 4% RAO/cranial, 3% RAO/caudal) and were achievable by the C-arm system in 87% of patients. For the right ostium, the mean CT-predicted orthogonal angulation was LAO 36 ?± ?37°/cranial 36 ?± ?51° (84% LAO/cranial, 2% LAO/caudal, 14% RAO/caudal) and achievable by the C-arm system in 45% of patients. For the left ostium, a higher body weight was associated with a steeper LAO/cranial angulation being less feasible by the C-arm system due to mechanical constraints.ConclusionsOrthogonal aorto-left coronary angulations show a relative narrow distribution predominately in LAO/cranial position whereas a wider range of angulations was found for the right coronary ostium. The feasibility of CT-predicted angulations by the C-arm system is more restricted for the right than the left coronary ostium.     

Lead-rubber shielding effect on radiation dose to the gonads from a bilateral hand X-ray examination

IntroductionRecent guidance from the British Institute of Radiology (BIR) and the American Association of Physicists in Medicine (AAPM) focuses on cessation of patient Lead-rubber (Pb) shielding placed within the Field of View (FOV) that may influence image exposure or quality. Furthermore, the BIR assert shielding organs greater than 5 cm from the primary X-ray beam will have a negligible effect to the received radiation dose. Bilateral hand X-rays are frequently and repeatedly requested for the diagnosis and ongoing management of arthritic conditions. There is a lack of literature regarding the effect of Pb shielding during bilateral hand X-ray examinations. This research aimed to investigate the scattered secondary radiation dose to the gonads during a bilateral hand X-ray, with and without the use of Pb shielding outside the FOV at a greater distance than 5 cm from the primary beam.MethodsUsing an anthropomorphic phantom and constructed upper limbs, radiation was recorded to the male and female gonads. Thermoluminescent dosimeters (TLD's) (?" x ?" x 0.15″ TLD-100H) were placed in groups of three upon the testes and within the left and right ovary to record the ionising radiation dose. Three collimated exposures were completed using a standard clinical practice hand X-ray protocol of 60 kVp and 2.5 mAs with a source to image distance (SID) of 100 cm. The mean and standard deviation of the radiation dose was calculated for both with and without Pb shielding. A paired two-sample t-test was conducted to determine statistical significance (p ≤ 0.05).ResultsData analysis demonstrated dose measured to the testes of 5.3 μGy (SD 0.8) without Pb shielding and 2.3 μGy (SD 0.2) with Pb (reduction of 3 μGy; 56.6%). Left ovary doses measured 40.6 μGy (SD 1.2) without Pb shielding and 28.8 μGy (SD 1.7) with Pb (reduction of 11.9 μGy; 29.2%) and right ovary doses measured 39.5 μGy (SD 1.9) without Pb shielding and 26.6 μGy (SD 1.0) with Pb (reduction of 12.8 μGy; 32.4%). The paired two-sample t-test presented a statistically significant dose reduction (p = 0.0039).ConclusionThe study demonstrated dose limitation from scattered secondary radiation to the gonads when Pb shielding was used during a bilateral hand X-ray at distances greater than 5 cm from the primary X-ray beam on anatomy outside the FOV.Implications for practiceThe use of Pb shielding over the gonad area during a bilateral hand X-ray examination aligns to ALARP best practice and provides prospects for patient (male and female) dose reduction.     

Assessing protection against radiation exposure after prostate 125I brachytherapy

PurposeTo expand the radiation dose rate measurement data set by measuring radiation under various prostate ¹²⁵I brachytherapy situations.Methods and MaterialsMeasurements were obtained from 63 consecutive unselected patients at Tokyo Medical Center, Japan. Differences in factors during measurements, such as body postures, distances from the skin surface, and measurement directions were considered. Furthermore, shielding effects of lead-lined underwear, consisting mainly of 0.1-mm thickness of lead, were also assessed.ResultsRadiation exposure varies according to the patient's body posture, with results differing as much as approximately 40.0% in measured radiation dose rates at 30 cm from the anterior skin surface. Weight, body mass index, and tissue thickness showed good correlations with measured radiation dose rates. The magnitude of radiation exposure attenuation by shielding was approximately 95.8%, similar to the attenuation ratio based on tissue measurements made in the lateral direction. The respective mean times required to reach 1 mSv were 1.2, 7.6, and 65.4 days in the standing position and 0.6, 4.6, and 40.4 days in the supine position at the site of contact, and at 30 and 100 cm from the anterior skin surface.ConclusionsThis study obtained supplemental information pertaining to radiological protection and confirmed that shielding can be an effective tool for reducing exposures.     

辐射巡测仪探头的射线屏蔽装置的设计与应用

目的 为精确测量日本福岛县内本地辐射水平,准确评价去污治理效果,开发一套用于辐射巡测仪探头的射线屏蔽装置。方法 选用铅合金作为屏蔽装置的主要制作材料。分别在放射监管实验室内和福岛县某受污染地区进行各项实验,测量不同铅板和铅筒对射线的衰减效果。根据测量结果,综合考虑遮蔽效果、制造成本及实用性等因素,设计整套屏蔽装置。结果 整套屏蔽装置由一个主遮蔽体、一个探头遮蔽体和一个带盖子的托架组成。主遮蔽体为高10 cm、厚3 cm的铅筒,探头遮蔽体为高8 cm、厚2 cm的铅筒,托架盖子为厚1 cm的圆形铅板。结论 使用该装置能够有效屏蔽来自被测地周边环境的辐射干扰,准确地测量本地辐射水平,更好地评估放射性污染治理的效果,对福岛受污染地区灾后重建工作有一定利用价值。     

Evaluation of coronary angiographic projections to balancethe clinical yield with the radiation risk

Objective Radiation safety principles dictate that imaging procedures should minimise the radiation risks involved, without compromising diagnostic performance. This study aims to define a core set of views that maximises clinical information yield for minimum radiation risk. Angiographers would supplement these views as clinically indicated. Methods An algorithm was developed to combine published data detailing the quality of information derived for the major coronary artery segments through the use of a common set of views in angiography with data relating to the dose-area product and scatter radiation associated with these views. Results The optimum view set for the left coronary system comprised four views: left anterior oblique (LAO) with cranial (Cr) tilt, shallow right anterior oblique (AP-RAO) with caudal (Ca) tilt, RAO with Ca tilt and AP-RAO with Cr tilt. For the right coronary system three views were identified: LAO with Cr tilt, RAO and AP-RAO with Cr tilt. An alternative left coronary view set including a left lateral achieved minimally superior efficiency (<5%), but with an ～8% higher radiation dose to the patient and 40% higher cardiologist dose. Conclusion This algorithm identifies a core set of angiographic views that optimises the information yield and minimises radiation risk. This basic data set would be supplemented by additional clinically determined views selected by the angiographer for each case. The decision to use additional views for diagnostic angiography and interventions would be assisted by referencing a table of relative radiation doses for the views being considered.     

介入诊疗中重要站立区域辐射剂量的测定与评价

目的 给出介入诊疗中重要站立区域的概念，测量这一区域辐射剂量的分布并分析其特点，为介入工作人员特别是第一术者的放射防护提出建议和理论依据。方法 在重要站立区域内，从距地面10cm处向上至180cm处，每10cm选取一个测量点，选用介入诊疗中比较常用的冠脉造影程序，分3种状态：①不使用床上、下防护屏。②使用床上、下防护屏。③使用床上、下防护屏和铅衣防护进行辐射剂量的测定。每实验点重复测量3次，取算术平均值，经刻度校正并折算为mGy／h。结果 成功测量3种状态下的相关数据并绘制介入诊疗中重要的站立区域剂量分布示意图。结论 对第一术者重要站立区域内的辐射防护在整个介入放射防护体系的建立中具有重要的地位，应足够重视这一区域的放射防护。要注意尽可能的联合选用多种防护手段，特别不要忽视上、下防护屏和铅衣的选用。建议在第一术者足踝前部放置一活动铅挡板，或把下防护帘延长至地面以保护下肢足踝部。     

脑血管造影术中X射线机房内辐射剂量分布研究

目的 研究脑血管造影术中不同照射方向下X射线机房内辐射剂量场的分布情况.方法 选用脑血管造影术程序,选取后前位、前后位、右前斜30°、左前斜30°、右侧位和左侧位6种照射方式,使用451B型空气电离室巡测仪对以散射模体为中心、半径为3 m范围内的辐射场的剂量率分布进行测量.结果 后前位及右侧位照射时主要操作人员所受到的辐射剂量最低,均为0.4 mGy/h;左侧位照射时主要操作人员受到的辐射剂量最高,为1.54 mGy/h;机架侧区域的辐射剂量水平最低,均小于10 μGy/h.结论 在脑血管造影术中,医护操作人员应尽可能选择剂量较低的后前位及右侧位照射方式投照,并合理选择工作位置,可明显降低受照剂量.

Abstract：

Objective To determine the distribution of irradiation dose in X-ray room with different radiation directions in cerebral angiography operations.Methods The Model 451B air ionization chamber survey meter was used to measure the irradiation dose distribution in the X-ray room when cerebral angiographies were performed at high kV and high dose.The doses were measured within 3 m when the phantom was irradiated in posterior-anterior (PA) position, anterior-posterior(AP) position, right anterior oblique (RAO) 30°, left anterior oblique (LAO) 30°, right-lateral (RL) position, and left-lateral(LL) position, respectively.Results Both the relative data and the distribution curves of the six radiation directions were obtained by using the same interventional operation model.The irradiation dose to the primary operator was minimal in P-A and RL positions,at 0.4 mGy/h, and was maximal in LL position, at up to 1.54 mGy/h.Furthermore, the lowest irradiation dose level was found to be lower than 10 μ Gy/h at the side of the framework field.Conclusions Low-irradiation position and rational work place were proposed to reduce the operators' absorption dose during interventional radiology procedures.     

高能医用电子直线加速器的机房屏蔽设计方案国内外比较

目的 分别根据中、外放射治疗机房辐射屏蔽标准,对低能医用电子直线加速器机房设计方案进行对比,为修订和完善现行国家标准提供参考。方法 按照美国国家辐射防护与测量委员会（NCRP）151号报告、英国电离辐射法规（IRR）17号和国家标准GBZ/T 201,对于一个每日平均治疗125例患者（90%为调强放疗技术）的6 MV X射线医用电子直线加速器机房,分别设计机房屏蔽方案,对比关注点（主束次屏蔽区A、B点、主束主屏蔽区C、D点、侧墙次屏蔽点E、室顶主屏蔽点F和室顶次屏蔽点G）所需的混凝土屏蔽厚度、治疗室内使用面积、室内层高和室顶承重。结果 按照NCRP 151号报告和IRR 17号法规,计算得到的A、B、C、D、E、F和G点所需的混凝土屏蔽厚度分别为79、105、136、166、104、137、76 cm和94、126、183、189、119、175、92 cm。而按照我国标准GBZ/T 201计算得到的相应关注点所需的混凝土屏蔽厚度是最厚的,特别是主束主屏蔽厚度的增加明显,分别为117、133、207、227、121、175、94 cm。与此同时,与NCRP 151号报告计算得到的屏蔽方案相比,治疗室内使用面积、室内层高显著降低,分别减小11.24%和7.13%,室顶承重增加更为明显（25.20%）。结论 与NCRP 151号报告和IRR 17号法规相比,按照我国现行屏蔽标准所推荐的计算方法和评价指标计算得到的屏蔽厚度是最大的,特别是现行国家标准中要求的瞬时剂量当量率评价指标会显著增加主屏蔽区所需的屏蔽厚度。     

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

The aim of this study was to assess the effect of eye and testicle shielding on radiation dose to the lens and the testes of patients undergoing CT examinations. Fifty-one male patients underwent CT twice with identical protocols initially without, the second time with protective garments. Doses to the testes and the lenses were recorded with beryllium oxide-based dosimeters. The dose to the testes and lenses from CT exposure was reduced by 96.2% ± 1.7% and 28.2% ± 18.5%, when testicle and eye shielding was used, respectively. The effect of the eye shielding on the eye lens dose was found to depend on the x-ray tube position when the eye is primarily exposed during the scan. The maximum eye lens dose reduction achieved was found to be 43.2% ± 6.5% corresponding to the anterior position of the tube. A significant correlation between the patient’s body mass index and dose exposure could not be found. Eye and testicle shields, apart from being inexpensive and easy to use, were proven to be effective in reducing eye lens and testicle radiation dose burden from CT exposures.