Objective:To determine the peak skin dose (PSD) to patients from neuro-interventional procedures and evaluate the risk of the deterministic effect.Methods:Gafchromic XR RV3 films were used in a level A tertiary hospital in Beijing to measure the patients′ PSD from neuro-interventional procedures, mainly three common types of procedures, including vascular embolization, vascular angioplasty and vascular angiography. The films were scanned by Epson Expression 10000XL, read by ImageJ software, and analyzed by Film QA Pro?2014 software.Results:PSD was measured in 23 embolizations, 14 stentings and 12 arteriography. There were 20 patients whose PSD were equal or greater than 2 Gy, including 15 in vascular embolization and 5 in angioplasty. The PSDs to patients in cerebral arteriography were all below 2 Gy. The PSDs to some of the patients were higher than the threshold for deterministic effect recommended by ICRP Publication 118.Conclusions:There is a risk of deterministic effect in neurointerventional procedures. It is suggested that the patients be followed up to observe their radiation injury as well as to know in time the subsequent diagnosis and treatment.

肺部低剂量CT扫描在肺癌筛查、肺炎和肺血管等肺部疾病诊断中,主要通过降低管电压、管电流等方式,在能够获取足够诊断信息的基础上,大幅降低了受检者辐射剂量.目前研究主要采用对临床受检者和拟人肺部模体进行扫描的方式,以医师主观方法对低剂量CT的图像质量进行评价,多数研究报道在大幅降低管电流的条件下,结合IMR算法的低剂量CT可达到主观满意的图像质量.虽然目前还没有公认的低剂量CT扫描参数,但随着公众对辐射防护重视度的提高和研究的深入,低剂量CT扫描在临床肺部疾病筛查和诊断中将会得到普及.

Objective: To establish the relationship between the measured dose and the displayed dose in CT scans for children, and assess whether the displayed dose could be used as the basis to monitor the actual dose so as to provide data support for establishing a fast estimation method of actual dose in CT examination for children. Methods: The CT equipments with 16 slices detectors and 64 slices detectors of two manufacturers that often were used in clinical practice were selected in the research. CT dosage phantom that suited to children was used and pencil-ionization chamber was adopted to measure CT dose indexes of head scan and breast scan for children under various scan parameters. At the same time, displayed dose of the equipment was recorded and the ratio of measured dose and displayed dose was calculated . Results: The measured doses of the two manufacturers for head of children were 1.30-1.39 times and 1.17-1.26 times of displayed dose, respectively. And on thorax sequence, the measured doses were 1.95-2.27 times and 1.75-1.97 times of displayed dose, respectively. Based on above results, the measured dose of head was more close to the displayed dose than that of thorax sequence. Conclusion: In the CT examination of children, the ratio of measured dose to displayed dose shows good consistency under the different exposure conditions of same CT device model, and thus provides possibility to rapidly estimate the real dose on children according to the displayed dose in CT examinations.

在英国采用统一的哮喘管理指南显然更为有利.然而英国胸科学会(与苏格兰校际指南网络合作)和英国国家健康与临床优化研究所(NICE)具有两种相互独立且互不相同的理念,几乎不可能采用统一的指南1.

目的 研究不同水模体直径和重建层厚等因素对CT图像噪声的影响,探讨CT质量控制检测中水模体合理的直径范围,为完善我国CT质量控制检测规范提供数据支持.方法 采用GE公司的Revolution型CT机,在两档剂量水平,即CTDIw分别为30.20 mGy(120 kV、200 mAs)和49.82 mGy(120 kV、330 mAs)、图像重建层厚为5 mm和10 mm的条件下,分别对直径为16、18、20、22、24 cm的圆柱型均质水模体轴向扫描一圈,测量其CT值(水)和噪声等指标.比较不同水模体直径、不同层厚和不同剂量等条件下噪声测量值的差异.结果 噪声测量值随水模体直径增大而增大,随剂量增大而减小,在大小两档剂量水平下水模体直径分别为24、22 cm时的噪声值已超过现有检测标准;噪声随重建层厚的增大而减小.结论 噪声的测量结果与剂量、水模体直径、重建层厚等因素有关,在进行CT质量控制噪声项目的检测时,需规定所选择的剂量水平和层厚大小,并规定所选择水模体的直径大小.本研究结果提示CTDIw在接近50 mGy的条件下,18 ～ 22 cm可能是比较合理的水模体直径范围.

目的 探讨国内医用X射线诊断工作场所放射防护检测中存在的问题,试验比较国产和进口两款X-γ剂量率仪响应时间性能,评估其在医用X射线诊断工作场所放射防护检测中的适用性.方法 在一台医用X射线摄影机上,使用固定的管电压(70 kV),分别设定不同的管电流获取高中低三档剂量,曝光时间从10 ms递增至1000 ms,记录不同曝光时间下两种X-γ剂量率仪的周围剂量当量率读数.结果 国产RJ32-2106P型X-γ剂量率仪在3档剂量水平的X射线中,低剂量档时间响应为160 ms,中、高剂量档对应的响应时间为50 ～64ms;AT1123的响应时间在3个剂量档均稳定在80～ 100 ms左右.结论 在医用X射线诊断机房防护检测时,应根据X射线辐射场,选择能够测量短时间出束和脉冲辐射场的设备进行测量.RJ32-2106P和AT1123X-γ剂量率仪在不同剂量水平下时间响应在200 ms以内,适用于医用X射线诊断机房的放射防护检测.

Objective To provides reasonable and feasible suggestions for radiological protection to interventional staff by measuring the dose level in different auxiliary protective facilities at the standing position of interventional staff.Methods According to the characteristics of DSA equipment,451P ionization chamber tourimeter was used to measure the ambient Dose Equivalent rate at different heights of interventional staff with using different auxiliary protective equipment.The effect of radiological protection was compared between different auxiliary protective facilities.Results The dose level of double-tube exposure is much bigger than that of the single-tube exposure.The shielding effect of using a lead semen for the first surgeon is better than the second surgeon.The using of a lead screen in double-tube exposure can reduce the dose of 31％ ～ 99％ for the first surgeon and reduce the dose of 12％ ～90％ for the second surgeon.The using of a lead screen in single-tube exposure can reduce the dose of the first surgeon 4％ ～ 65％ of the dose,and reduce the 2％ ～ 30％ of the dose for the second surgeon.The dose of head,chest and abdomen of interventional staff can be significantly reduced through improving the existing auxiliary protective facilities,but the protective effect to the foot is not obvious.Conclusion The using of lead screens and improving the auxiliary protective equipment can shield the X-rays of interventional staff in varying degrees,it can protect interventional staff and reduce the radiation dose level.

Objective To establish a method for reducing the dose to the eye lens of interventional staff,and provide the data basis for improving radiological protection measures.Methods One piece of interventional equipment coupled with conventional auxiliary protective devices and two types of common neural interventional procedures were selected to monitor 46 and 35 procedures before and after the device modification.The doses to the eye lens of staff were measured with direct-reading dosimeters for analysis of dose trends.Results After modification of the devices,the average dose to the left eye lens decreased from (9.71 ±10.86) to (3.23 ±5.59) μSv for the first operator,from (9.51 ± 12.34) to (0.68 ± 0.78) μSv for the second in cerebral angiography;whereas the dose decreased from (14.83 ± 19.13) to (4.17±4.59) for the first operator and from (14.12±21.76) to (1.23 ±1.57)μSv for the second in embolization procedure,respectively.The left eye lens doses measured before and after the modification showed significant difference (U =-2.760,-2.467,-1.967,-2.655,P ＜0.05).Conclusions The modification of the auxiliary radiological protective devices may effectively reduce the dose to the eye lens dose.This method was shown to be feasible for the improvement of radiological protection of interventional staff.

Objective To study the relationship between the nominal beam width and CTDI measurement efficiency of wide beam multi-slice spiral CT to provide data support for improving the specification for quality control testing of CT in China.Methods Dose measurements were performed on a 128 detector row CT scanner.The effect of beam widths on CTDI100 and CTDI300 was assessed for acquisitions from 5 mm to 80 mm.The CTDI100 is based on application of the readily available 150 mm long CT dose body phantoms and the 100 mm pencil ionization chamber.CTDI300 is supported by measurements with ex-tended 450 mm CT dose body phantom and a 300 mm long pencil CT ionization chamber.CTDI300 was used instead of CTDI∞ to calculate the CTDI measurement efficiency.An amended CTDI100.NT according to IEC and IAEA publications was calculated and compared with CTDI300.Results The CTDI100 measurement efficiency decreased with the increase of beam widths.The ratio of CTDI100 to CTDI300 was 0.62 from 5 am,at a beam width of 80 am,the measurement efficiency dropped to 0.56.Through the IEC and IAEA correction formula,the ratio of amended CTDI100,NT to CTDI∞ can be maintained at a relatively constant level.Conclusion The widely used CT dose index CTDI100 is lack of accuracy in evaluating the CT dose of widebeam multi-slice spiral CT.The correction formula can characterize the dose level of wide beam multi-slice spiral CT to a constant ratio.On how to accurately express and measure the dose of wide beam CT by a simple way,the international community is still on the road.

Objective:To investigate and analyze the status of quality control of medical X-ray diagnostic equipment in Shigatse, and propose recommendations for quality improvement. Methods: Applying quality control tests to all the medical X-ray diagnostic equipment in the sampled hospitals and analyzing the results by statistic method.Results: The qualification rates of equipment for fluoroscopy, radiography and computed tomography are 80%, 40% and 50%, respectively. The qualification rates is 57.1% in all of different levels of the hospitals. Conclusion: The status of quality control of medical X-ray diagnostic equipment in Shigatse is grasped. Both of the testing of quality control and the training of the technician should be strengthened in the future, all over Tibet Autonomous Region.

Objective To establish the method for extremity dose measuring for interventional staff,and compare the extremity dose to interventional staff on traditional interventional devices with single X-ray tube to that on the new devices with double tubes,and thus support the monitoring of the doses and the improvement of the radiological protection.Methods Thethermoluminescence dosimeters (TLD) were calibrated with personal dose equivalent Hp (0.07).The extremity doses of 231 person-time from 4 kinds of interventional procedures were measured on 2 interventional devices with single X-ray tube and 3 devices with double X-ray tubes.The doses obtained on different kinds of interventional devices were analyzed.Results The TLD shows good linear fitting with Hp (0.07) calibration.The extremity doses,which in the therapeutic procedures were higher than those in the graphic ones,perform positively relevance to the exposure time.Comparing the same kind of interventional procedures on devices with double and single X-ray tubes,the former shows shorter exposure time with higher extremity dose to interventional staff than the latter.Conclusion The interventional devices with double X-ray tubes significantly improve the efficiency of the interventional procedures while increase the dose to interventional staff.The radiological protection should be strengthened to protect the health of the interventional staff.

Objective To establish the methods for measuring the dose to occupational staff's eye lens in interventional procedures with direct-reading dosimeters,and to realize the real-time monitoring of eye lens dose and warning for high dose rate,thus providing the scientific basis of the staff radiological protection in interventional procedures.Methods Direct-reading dosimeters were calibrated with personal dose equivalent HP (3).The eye lens doses for occupational staff in different kinds of interventional procedures were measured by the devices with both single-and double X-ray tubes.The data obtained fromthe direct-reading dosimeters was compared to those obtained from TLDs.Results Direct-reading dosimeters showed good linear fitting with the calibration of HP (3),and the coefficients of variation were lower than 5％.The average eye lens HP (3) for the main operator in coronary arteriography and stent implantation in brain obtained by direct-reading dosimeters were 12.0 and 24.5 μSv,respectively,whereas those obtained by TLDs were 11.9 and 22.7 μSv,respectively.The direct-reading dosimeters gave similar t~nds as TLDs do so.The direct-reading dosimeters were able to provide eye lens HP (3) in each individual interventional procedure,and to monitor the real-time dose rate as well.Conclusions The calibration of HP (3) and the data gained by direct-reading dosimeters are reliable.Therefore,the methods for real-time measurement of eye lens dose for occupational staff in interventional procedures are successfully established.

Objective To establish methods of measuring the eye lens dose to interventional staff,to obtain relevant dose data and to provide a scientific basis for reducing eye lens dose.Methods Two kinds of dosimeters,thermoluminescent dosimeter (TLD) and optically stimulated luminescence dosimeter (OSLD),were selected to measure the personal dose equivalent HP (3) to eye lens of occupational staff in several kinds of interventional procedures,including cardiovascular interventional procedures,cerebrovascular interventional procedures etc.Five types of Digital Subtraction Angiography (DSA) equipment were chosen in the study,including single tube equipment and double tube equipment.Results The eye lens dose HP (3) to interventional staff varied significantly with different interventional procedures.The lowest dose is shown in the coronary angiography procedure,while the highest dose shown in the cerebral stenting procedure.For the same type of interventional procedure,the eye lens dose to the primary interventionist was the highest.For same interventionist,the dose to the left eye was obviously higher than that to the right eye.In addition,the measured results of OSLD were apparently higher than that of TLD.Conclusions Both TLD and OSLD could be used to measure eye lens dose,and the ways of calibrating TLD to evaluate personal dose equivalent HP (3) were feasible.The reason of significant difference between the measured results of TLD and OSLD needs further research.