Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37232-2675, USA.
J Nucl Med. 2010 Jun;51(6):929-32. doi: 10.2967/jnumed.109.073015. Epub 2010 May 19.
The phantoms used in standardized dose assessment are based on a median (i.e., 50th percentile) individual of a large population, for example, adult males or females or children of a particular age. Here we describe phantoms that model instead the influence of obesity on specific absorbed fractions (SAFs) and dose factors in adults.
The literature was reviewed to evaluate how individual organ sizes change with variations in body weight in mildly and severely obese adult men and women. On the basis of the literature evaluation, changes were made to our deformable reference adult male and female total-body models. Monte Carlo simulations of radiation transport were performed. SAFs for photons were generated for mildly and severely obese adults, and comparisons were made to the reference (50th) percentile SAF values.
SAFs studied between the obese phantoms and the 50th percentile reference phantoms were not significantly different from the reference 50th percentile individual, with the exception of intestines irradiating some abdominal organs, because of an increase in separation between folds caused by an increase in mesenteric adipose deposits. Some low-energy values for certain organ pairs were different, possibly due only to the statistical variability of the data at these low energies.
The effect of obesity on dose calculations for internal emitters is minor and may be neglected in the routine use of standardized dose estimates.
标准化剂量评估中使用的体模基于大量人群的中位数（即第 50 百分位数）个体，例如成年男性或女性，或特定年龄的儿童。在这里，我们描述了模拟肥胖对成人特定吸收分数（SAF）和剂量因子影响的体模。
回顾文献，评估在轻度和重度肥胖的成年男性和女性中，个体器官大小随体重变化的情况。根据文献评估，对我们的可变形参考成人男性和女性全身模型进行了修改。进行了辐射传输的蒙特卡罗模拟。为轻度和重度肥胖成人生成了光子的 SAF，并与参考（第 50 百分位数）SAF 值进行了比较。
与肥胖体模和第 50 百分位参考体模相比，SAF 研究值与参考第 50 百分位个体没有显著差异，除了肠道照射某些腹部器官的情况，因为肠系膜脂肪沉积增加导致褶皱之间的分离增加。某些器官对的某些低能量值有所不同，可能仅由于这些低能量数据的统计可变性。
肥胖对内部发射体剂量计算的影响很小，在标准化剂量估计的常规使用中可以忽略不计。
