Chu Philip W, Stewart Carly, Kofler Cameron, Mahendra Malini, Wang Yifei, Chu Cameron A, Lee Choonsik, Bolch Wesley E, Smith-Bindman Rebecca
Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California.
Department of Radiology, The University of Chicago, Chicago, Illinois.
Radiat Res. 2025 Jan 1;203(1):1-9. doi: 10.1667/RADE-24-00178.1.
Estimation of absorbed organ doses used in computed tomography (CT) using time-intensive Monte Carlo simulations with virtual patient anatomic models is not widely reported in the literature. Using the library of computational phantoms developed by the University of Florida and the National Cancer Institute, we performed Monte Carlo simulations to calculate organ dose values for 9 CT categories representing the most common body regions and indications for imaging (reflecting low, routine, and high radiation dose examinations), stratified by patient age (in children) and effective diameter (in adults, using "diameter" as a measure of patient size). Our sample of 559,202 adult and 103,423 pediatric CT examinations was prospectively assembled between 2015-2020 from 156 imaging facilities from 27 healthcare organizations in 20 U.S. states and 7 countries in the University of California San Francisco International CT Dose Registry. Organ doses varied by body region and exam type. For example, the mean brain dose associated with head CT was 20 mGy [standard deviation (SD) 14] for head low dose, 46 mGy (SD 21) for head routine dose, and 64 mGy (SD 31) for head high dose scan protocols. The mean colon doses associated with abdomen and pelvis CT were 19 mGy (SD 12), 32 mGy (SD 28), and 69 mGy (SD 42) for low, routine, and high dose examinations, respectively. Organ doses in general varied modestly by patient diameter, and for many categories the organ doses among the largest quartile of patients were no more than 10% higher than doses in the smallest quartile. For example, for abdomen and pelvis high dose, the colon dose increased from 67 to 74 mGy from the smallest to the largest patients (10% increase). With few exceptions, pediatric organ doses also varied relatively little by patient age, except for the youngest children who, on average, had higher organ doses. Thyroid dose, however, tended to increase with age in neck or cervical spine and chest CT. Overall, the highest organ doses were to the skin, thyroid, brain, and eye lens. Mean organ doses differ substantially by site. The organ dose values included in this report are derived from empirical clinical exams and offer useful, representative values. Large inter-site variations demonstrate areas for radiation dose reduction.
使用带有虚拟患者解剖模型的耗时蒙特卡罗模拟来估算计算机断层扫描（CT）中使用的器官吸收剂量，在文献中并未广泛报道。利用佛罗里达大学和美国国家癌症研究所开发的计算体模库，我们进行了蒙特卡罗模拟，以计算代表最常见身体部位和成像指征（反映低、常规和高辐射剂量检查）的9种CT类别的器官剂量值，并按患者年龄（儿童）和有效直径（成人，使用“直径”作为患者体型的度量）进行分层。我们对559,202例成人和103,423例儿科CT检查的样本，于2015年至2020年间前瞻性地从美国20个州和7个国家的27个医疗保健组织的156个成像设施中收集，纳入加利福尼亚大学旧金山分校国际CT剂量登记处。器官剂量因身体部位和检查类型而异。例如，与头部CT相关的平均脑剂量，头部低剂量扫描为20 mGy[标准差（SD）14]，头部常规剂量为46 mGy（SD 21），头部高剂量扫描方案为64 mGy（SD 31）。与腹部和盆腔CT相关的平均结肠剂量，低剂量检查为19 mGy（SD 12），常规剂量为32 mGy（SD 28），高剂量检查为69 mGy（SD 42）。一般来说，器官剂量随患者直径的变化不大，对于许多类别，最大四分位数患者的器官剂量比最小四分位数患者的剂量高不超过10%。例如，对于腹部和盆腔高剂量检查，结肠剂量从最小患者的67 mGy增加到最大患者的74 mGy（增加10%）。除少数例外情况外，儿科器官剂量也随患者年龄变化相对较小，除了最年幼的儿童平均器官剂量较高。然而，在颈部或颈椎以及胸部CT中，甲状腺剂量往往随年龄增加。总体而言，最高的器官剂量出现在皮肤、甲状腺、脑和晶状体。平均器官剂量因部位而异。本报告中包含的器官剂量值来自经验性临床检查，提供了有用的代表性值。较大的部位间差异表明了辐射剂量降低的领域。
