介入诊疗区域内辐射场的测定与评价

目的测量和评价介入诊疗区域内常规穿刺平面辐射剂量的分布特点，绘制相应的等剂量曲线示意图。方法在介入诊疗区域内常规穿刺平面建立测量平台，以X射线发生中心为测量中心，选取常规正位和常规侧位两个基本体位，在八个方向上每0．10m选择一个测量点，每个测量点测量3次，取算术平均值，校正并折算为mGy／h。结果成功测量相关数据并绘制介入诊疗区域内常规穿刺平面正、侧位辐射剂量分布示意图。结论患者右侧是高辐射场区域，一般为手术人员站立处，辐射强度较高，必须加以防护。患者左上辐射场的强度相对较高，往往安装心脏起搏器时医师容易站在此处，应加以提示。实习医师和进修医师也常在此处观摩手术，应尽量避免。患者左下常为护师给患者输液、加药处，应予以注意。足侧偏左常为电生理技师操作仪器处，虽然辐射强度不大，但也应注意。     

优化CT辐射剂量技术在心脏扫描中的研究

CT冠状动脉成像技术已经成为临床评价冠状动脉的无创性的重要检查手段,然而随着采集层厚变薄、扫描范围增大及采集效率的改变,其辐射剂量较对其他部位检查的明显要高.如何在保证图像质量的前提下,有效降低辐射剂量已愈加引起研究人员的关注.现就其最新的研究进展予以综述.     

High filtration in interventional practices reduces patient radiation doses but not always scatter radiation doses

Objectives:In fluoroscopy-guided interventional practices, new dose reduction systems have proved to be efficient in the reduction of patient doses. However, it is not clear whether this reduction in patient dose is proportionally transferred to operators’ doses. This work investigates the secondary radiation fields produced by two kinds of interventional cardiology units from the same manufacturer with and without dose reduction systems.Methods:Data collected from a large sample of clinical procedures over a 2-year period (more than 5000 procedures and 340,000 radiation events) and the DICOM radiation dose structured reports were analysed.Results:The average cumulative H_p(10) per procedure measured at the C-arm was similar for the standard and the dose reduction systems (452 vs 476 μSv respectively). The events analysis showed that the ratio H_p(10)/KAP at the C-arm was (mean ± SD) 5 ± 2, 10 ± 4, 14 ± 4 and 14 ± 6 μSv·Gy⁻¹·cm⁻² for the beams with no added filtration, 0.1, 0.4 and 0.9 mm Cu respectively and suggested that the main cause for the increment of the ratio H_p(10)/KAP vs the “standard system” is the use of higher beam filtration in the “dose reduction” system.Conclusion:Dose reduction systems are beneficial to reduce KAP in patients and their use should be encouraged, but they may not be equally effective to reduce occupational doses. Interventionalists should not overlook their own personal protection when using new technologies with dose reduction systems.Advances in knowledge:Dose reduction technology in interventional systems may increase scatter dose for operators. Personal protection should not be overlooked with dose reduction systems.     

优化CT辐射剂量技术在心脏扫描中的研究

CT冠状动脉成像技术已经成为临床评价冠状动脉的无创性的重要检查手段,然而随着采集层厚变薄、扫描范围增大及采集效率的改变,其辐射剂量较对其他部位检查的明显要高.如何在保证图像质量的前提下,有效降低辐射剂量已愈加引起研究人员的关注.现就其最新的研究进展予以综述.     

Measurement of radiation doses in the most frequent simple examinations in paediatric radiology and its dependence on patient age

Radiation doses to patients were measured in four X-ray rooms specifically devoted to paediatric radiology, from two hospitals. The study was performed for the most frequent simple examinations, namely abdomen, hip and pelvis, skull, spine and chest. Patients were classed into four different age groups: 0.1-1 year, greater than 1-5 years, greater than 5-10 years and greater than 10-14 years. Operating X-ray generator parameters and entrance surface doses were recorded for all groups. Representative values were obtained for standard working conditions prior to any correcting action being taken. Dose values are reported, and some of the differences between the results found in the rooms for each examination are discussed. Without attempting to relate adult and paediatric radiology, the entrance surface doses measured and the provisionally recommended CEC values for similar examinations in adult patients are compared.     

Comparison of the radiation doses in lumbar CT and myelography

The radiation doses of the vertebral bodies and ovaries in lumbar CT and myelography were compared using a phantom. The CT examinations were performed with two different scanners using four different programs. At CT the radiation maximum doses of the vertebral bodies were higher than at myelography but the ovarian doses were lower. The radiation exposure does not prevent the use of CT instead of myelography, but the area of examination and the number of pictures should be limited to the minimum based on the clinical enquiry.     

Analysis of radiation doses in the percutaneous treatment of varicocele in adolescents

PURPOSE: Varicocele is a common clinical condition that affects 15% of the male population and is an important cause of male infertility. Fluoroscopy-guided percutaneous treatment with retrograde sclerosis is a good alternative to surgery. We report our experience in calculating the total radiation dose to patient and the associated risk. MATERIALS AND METHODS: Our study was performed on 67 patients undergoing percutaneous treatment of varicocele with transbrachial approach and retrograde sclerosis. Thirteen dosimeters with two TLD detectors were positioned on the patients' skin. Calculation of the Entrance Surface Dose and application of appropriate transmission coefficients of the depth-dose allowed us to determine the Equivalent Doses for the single organs. Similar studies were conducted during plain abdominal x-ray and urography for comparative purposes. RESULTS: The mean effective dose during percutaneous treatment of varicocele was 18 mSv, whereas the dose for abdominal x-ray was 1.31 mSv and that for urography was 4.6 mSv. DISCUSSION AND CONCLUSIONS: Examinations involving the use of x-rays have been estimated to contribute to half of all the radiation absorbed by the population, and the number of both diagnostic examinations and interventional procedures is steadily rising. Radiation exposure, especially in children, requires special consideration. Percutaneous treatment of varicocele is a valuable alternative to surgery, not least because of reduced exposure. The use of specially-built lead coats and the creation of regional referral centres employing specialised staff are two possible measures that could further reduce radiation doses and dispel concerns about this procedure.     

Evaluation of radiation doses during radiological tests

The purpose of this document is to provide radiologists with a simple, but realistic means of determining the individual dose delivered to a patient during a radiological examination both in the region under investigation and at any other particularly sensitive organs. Fourteen types of examinations were considered corresponding to those most frequently carried out in France. The choice of examinations and methods of taking the films approaches as closely as possible, the average situations, and the frequency of different techniques is influenced by the results of a national study of radiodiagnostic examinations carried out in France in 1982. In the first section, the influence on the radiation dose of varying different physical parameters and techniques is analysed, with an aim of defining the limits of validity of the presented dosimetric values and the possible adaptation of these values to any individual situation, which is slightly different from these considered in this study. The second section describes the model used for determining the absorbed dose presented in the tables, concerning each type of examination, as well as bibliographic references referring to methods and results of determining the dose. The suggested calculation model may be used as a base for dose estimation for other types of examination.     

Uncertainties in doses and risks from internal radiation

Many uncertainties exist in current estimates of radiation doses and risks: larger uncertainties exist with internal radiation. These arise mainly from the many steps used to derive doses, and partly from lack of statistical precision in deriving risks from epidemiology studies. The size of these uncertainties has been estimated by a number of expert dosimetrists: for some nuclides these are very large. The recent report by the CERRIE committee recommended that uncertainties should be acknowledged and dealt with by the government. Its parent committee, COMARE, backed these findings. A number of practical recommendations are suggested for government action in the light of the CERRIE report.     

曲面体层摄影受检者的X线辐射剂量研究

目的：测量颌骨牙列曲面体层摄影人体不同组织器官的X线吸收剂量,并计算当量剂量、有效剂量以及涎腺有效剂量。方法：使用仿真成年人体模测量颌骨牙列曲面体层摄影时腮腺、颌下腺、舌下腺、下颌骨表面、眼晶体、垂体、受照区皮肤、颈椎红骨髓、甲状腺、乳腺、卵巢以及睾丸等器官组织的X线吸收剂量,计算各器官组织的X线当量剂量、有效剂量以及涎腺有效剂量。结果：X线吸收剂量0μGy~730.50μGy,当量剂量0μSv~730.50μSv,有效剂量36.28μSv,涎腺有效剂量47.78μSv。结论：颌骨牙列曲面体层摄影受检者X线吸收剂量、当量剂量、有效剂量均较小,对眼晶体、甲状腺、性腺等敏感器官组织有较高安全性,从放射防护角度,使用曲面体层摄影观察上下颌牙列、牙槽骨的形态是合理的。