Fluoroscopy X-Ray Organ-Specific Dosimetry System (FLUXOR) for Estimation of Organ Doses and Their Uncertainties in the Canadian Fluoroscopy Cohort Study.
Fluoroscopy X-Ray Organ-Specific Dosimetry System (FLUXOR) for Estimation of Organ Doses and Their Uncertainties in the Canadian Fluoroscopy Cohort Study.
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DOI：
10.1667/rade-20-00212.1
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发表时间：
2021-04-01
影响因子：
3.4
通讯作者：
Zablotska LB
中科院分区：
文献类型：
--
作者：
Apostoaei AI;Thomas BA;Hoffman FO;Kocher DC;Thiessen KM;Borrego D;Lee C;Simon SL;Zablotska LB
作为评估加拿大荧光透视队列研究（CFCS）中1930年至1969年期间接受结核病治疗的63，715例患者的寿命疾病死亡率和发病率的持续努力的一部分，我们开发了一种新的荧光透视X射线器官特异性剂量测定系统（FLUXOR）来估计各种器官和组织的辐射剂量。大约45%的患者接受了伴随X线透视的医疗程序，包括人工气胸（胸膜腔中的空气导致肺萎陷）、气腹（腹膜腔中的空气）、胸膜腔液体抽吸和胃肠造影。此外，患者还接受了胸部X光片，以诊断和监测疾病状态。FLUXOR利用年龄、性别和体型相关的剂量系数进行荧光透视和X线摄影检查，使用最新计算混合拟人幻影中的辐射传输模拟进行估计。该模型包括更新的心脏模型，并进行了调整，以匹配相关时间段内加拿大结核病患者的估计平均身高和体重。未记录在个体荧光透视或X线摄影检查期间使用的患者特定数据（机器设置、暴露持续时间、患者方向）。患者的剂量是基于对当时91名执业医生的访谈、历史文献和患者记录中的估计手术次数推断出的参数值。FLUXOR使用概率分布来表示每个剂量测定参数的未知真实平均值的不确定性。队列特定亚组中的所有患者都存在不确定性，该亚组由治疗时的年龄、性别、手术类型、检查时间段和地区（新斯科舍省或其他省份）定义。蒙特卡洛技术被用来传播不确定性，通过采样每个参数的替代平均值。估计每个亚组患者每次检查的替代平均剂量，根据接受的检查次数确定每个个体的总平均剂量。重复该过程以产生每个患者的平均器官剂量的替代队列向量。本文介绍了肺、女性乳房、活跃骨髓和心壁的剂量估计。所有63，715例患者的平均器官剂量的均值和95%置信区间（CI）为肺320（160，560）mGy，女性乳腺250（120，450）mGy，心壁190（100，340）mGy，活性骨髓92（47，160）mGy。大约60%的患者的四个研究器官的平均剂量低于10 mGy，10%的患者接受10至100 mGy，25%的患者接受100至1，000 mGy，5%的患者接受1，000 mGy以上。气胸是对队列平均剂量贡献最大的医疗程序。四个感兴趣器官每次手术估计剂量不确定性的主要贡献者是暴露持续时间、管电压、管输出和患者相对于X射线管的方向的不确定性，其中暴露持续时间的不确定性通常是主要来源。患者方向的不确定性对于女性乳房的剂量很重要，而对于心脏壁的剂量，不确定性程度较低。检查次数的不确定性是约30%患者不确定性的重要因素。估计的器官剂量及其不确定性将用于分析癌症和非癌症疾病的发病率和死亡率。CFCS队列是对现有放射流行病学队列的重要补充，考虑到几年来接受的中高剂量，辐射类型（仅外部辐射），辐射类型（仅X射线），性别平衡组合以及包括所有年龄段的人。
As part of ongoing efforts to assess lifespan disease mortality and incidence in 63,715 patients from the Canadian Fluoroscopy Cohort Study (CFCS) who were treated for tuberculosis between 1930 and 1969, we developed a new FLUoroscopy X-ray ORgan-specific dosimetry system (FLUXOR) to estimate radiation doses to various organs and tissues. Approximately 45% of patients received medical procedures accompanied by fluoroscopy, including artificial pneumothorax (air in pleural cavity to collapse of lungs), pneumoperitoneum (air in peritoneal cavity), aspiration of fluid from pleural cavity and gastrointestinal series. In addition, patients received chest radiographs for purposes of diagnosis and monitoring of disease status. FLUXOR utilizes age-, sex- and body size-dependent dose coefficients for fluoroscopy and radiography exams, estimated using radiation transport simulations in up-to-date computational hybrid anthropomorphic phantoms. The phantoms include an updated heart model, and were adjusted to match the estimated mean height and body mass of tuberculosis patients in Canada during the relevant time period. Patient-specific data (machine settings, exposure duration, patient orientation) used during individual fluoroscopy or radiography exams were not recorded. Doses to patients were based on parameter values inferred from interviews with 91 physicians practicing at the time, historical literature, and estimated number of procedures from patient records. FLUXOR uses probability distributions to represent the uncertainty in the unknown true, average value of each dosimetry parameter. Uncertainties were shared across all patients within specific subgroups of the cohort, defined by age at treatment, sex, type of procedure, time period of exams and region (Nova Scotia or other provinces). Monte Carlo techniques were used to propagate uncertainties, by sampling alternative average values for each parameter. Alternative average doses per exam were estimated for patients in each subgroup, with the total average dose per individual determined by the number of exams received. This process was repeated to produce alternative cohort vectors of average organ doses per patient. This article presents estimates of doses to lungs, female breast, active bone marrow and heart wall. Means and 95% confidence intervals (CI) of average organ doses across all 63,715 patients were 320 (160, 560) mGy to lungs, 250 (120, 450) mGy to female breast, 190 (100, 340) mGy to heart wall and 92 (47, 160) mGy to active bone marrow. Approximately 60% of all patients had average doses to the four studied organs of less than 10 mGy, 10% received between 10 and 100 mGy, 25% between 100 and 1,000 mGy, and 5% above 1,000 mGy. Pneumothorax was the medical procedure that accounted for the largest contribution to cohort average doses. The major contributors to uncertainty in estimated doses per procedure for the four organs of interest are the uncertainties in exposure duration, tube voltage, tube output, and patient orientation relative to the X-ray tube, with the uncertainty in exposure duration being most often the dominant source. Uncertainty in patient orientation was important for doses to female breast, and, to a lesser degree, for doses to heart wall. The uncertainty in number of exams was an important contributor to uncertainty for ~30% of patients. The estimated organ doses and their uncertainties will be used for analyses of incidence and mortality of cancer and non-cancer diseases. The CFCS cohort is an important addition to existing radio-epidemiological cohorts, given the moderate-to-high doses received fractionated over several years, the type of irradiation (external irradiation only), radiation type (X rays only), a balanced combination of both genders and inclusion of people of all ages.