Kost Susan D, Fraser Nicholas D, Carver Diana E, Pickens David R, Price Ronald R, Hernanz-Schulman Marta, Stabin Michael G
Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
Pediatr Radiol. 2015 Nov;45(12):1771-80. doi: 10.1007/s00247-015-3400-2. Epub 2015 Jul 4.
Organ dose is essential for accurate estimates of patient dose from CT.
To determine organ doses from a broad range of pediatric patients undergoing diagnostic chest-abdomen-pelvis CT and investigate how these relate to patient size.
We used a previously validated Monte Carlo simulation model of a Philips Brilliance 64 multi-detector CT scanner (Philips Healthcare, Best, The Netherlands) to calculate organ doses for 40 pediatric patients (M:F = 21:19; range 0.6-17 years). Organ volumes and positions were determined from the images using standard segmentation techniques. Non-linear regression was performed to determine the relationship between volume CT dose index (CTDIvol)-normalized organ doses and abdominopelvic diameter. We then compared results with values obtained from independent studies.
We found that CTDIvol-normalized organ dose correlated strongly with exponentially decreasing abdominopelvic diameter (R(2) > 0.8 for most organs). A similar relationship was determined for effective dose when normalized by dose-length product (R(2) = 0.95). Our results agreed with previous studies within 12% using similar scan parameters (e.g., bowtie filter size, beam collimation); however results varied up to 25% when compared to studies using different bowtie filters.
Our study determined that organ doses can be estimated from measurements of patient size, namely body diameter, and CTDIvol prior to CT examination. This information provides an improved method for patient dose estimation.
器官剂量对于准确估算CT检查时患者所接受的剂量至关重要。
确定接受胸部-腹部-盆腔诊断性CT检查的广泛范围儿科患者的器官剂量，并研究这些剂量与患者体型的关系。
我们使用先前验证过的飞利浦Brilliance 64排多层螺旋CT扫描仪（飞利浦医疗保健公司，荷兰贝斯特）的蒙特卡洛模拟模型，计算40例儿科患者（男:女 = 21:19；年龄范围0.6 - 17岁）的器官剂量。使用标准分割技术从图像中确定器官体积和位置。进行非线性回归以确定容积CT剂量指数（CTDIvol）标准化的器官剂量与腹盆腔直径之间的关系。然后我们将结果与独立研究获得的值进行比较。
我们发现CTDIvol标准化的器官剂量与呈指数下降的腹盆腔直径密切相关（大多数器官的R² > 0.8）。当通过剂量长度乘积进行标准化时，有效剂量也呈现类似关系（R² = 0.95）。我们的结果与使用类似扫描参数（例如，蝴蝶结滤过器尺寸、束准直）的先前研究结果在12%以内相符；然而，与使用不同蝴蝶结滤过器的研究相比，结果差异高达25%。
我们的研究确定，可以在CT检查前通过测量患者体型（即身体直径）和CTDIvol来估算器官剂量。该信息为患者剂量估算提供了一种改进方法。
