Vanderbilt University, Nashville, TN, USA.
J Nucl Med. 2012 Nov;53(11):1807-13. doi: 10.2967/jnumed.112.106138. Epub 2012 Sep 11.
A new generation of reference computational phantoms, based on image-based models tied to the reference masses defined by the International Commission on Radiological Protection (ICRP) for dose calculations, is presented.
Anatomic models based on nonuniform rational b-spline modeling techniques were used to define reference male and female adults, 15-y-olds, 10-y-olds, 5-y-olds, 1-y-olds, newborns, and pregnant women at 3 stages of gestation, using the defined reference organ masses in ICRP publication 89. Absorbed fractions and specific absorbed fractions for internal emitters were derived using standard Monte Carlo radiation transport simulation codes.
Differences were notable between many pairs of organs in specific absorbed fractions because of the improved realism of the models, with adjacent organs usually closer and sometimes touching. Final estimates of absorbed dose for radiopharmaceuticals, for example, were only slightly different overall, as many of the differences were small and most pronounced at low radiation energies. Some new important organs were defined (salivary glands, prostate, eyes, and esophagus), and the identity of a few gastrointestinal tract organs changed.
A new generation of reference models for standardized internal and external dose calculations has been defined. The models will be implemented in standardized software for internal dose calculations and be used to produce new standardized dose estimates for radiopharmaceuticals and other applications.
介绍了新一代基于与国际辐射防护委员会 (ICRP) 定义的用于剂量计算的参考质量相关联的基于图像的模型的参考计算体模。
使用非均匀有理 B 样条建模技术的解剖模型用于定义参考男性和女性成年人、15 岁、10 岁、5 岁、1 岁、新生儿和处于妊娠 3 个阶段的孕妇,使用 ICRP 出版物 89 中定义的参考器官质量。使用标准蒙特卡罗辐射传输模拟代码得出了内部发射体的吸收分数和特定吸收分数。
由于模型的逼真度提高,许多对器官的特定吸收分数差异明显,通常相邻器官更接近,有时甚至接触。例如,放射性药物的吸收剂量的最终估计值总体上只有略有不同,因为许多差异较小,在低辐射能量下最为明显。定义了一些新的重要器官(唾液腺、前列腺、眼睛和食管),并且一些胃肠道器官的身份发生了变化。
已经定义了新一代用于标准化内部和外部剂量计算的参考模型。这些模型将在内部剂量计算的标准化软件中实现,并用于为放射性药物和其他应用产生新的标准化剂量估计值。