Rivard M J, Wierzbicki J G, Van den Heuvel F, Martin R C, McMahon R R
Department of Radiation Oncology, Harper Hospital Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, USA.
Med Phys. 1999 Jan;26(1):87-96. doi: 10.1118/1.598472.
Using Monte Carlo methods, neutron dosimetry for 252Cf Applicator Tube (AT) type medical sources available from Oak Ridge National Laboratory (ORNL) has for the first time been determined in terms of TG-43 formalism. This approach, as compared to previous "along-away" formalisms, demonstrates the relative angular independence of dose rate data, when the geometry factor has been removed. As the ORNL-made 252Cf AT type sources are considerably physically larger than most clinical sources used today, the radial dose function increases for radii less than 3.0 mm due to breakdown of the line source model. A comparison of the 252Cf neutron radial dose function with those for other medical sources revealed similarities with that from 137Cs. Differences with respect to previous 252Cf AT source neutron dosimetry data generally increased at increasing distances. This was attributed to differences in the various 252Cf AT source models and phantom compositions. The current status of 252Cf medical source fabrication and calibration procedures at ORNL is presented.
利用蒙特卡罗方法，首次根据TG - 43形式体系确定了橡树岭国家实验室（ORNL）提供的252Cf施源器管（AT）型医用源的中子剂量学。与先前的“沿-远”形式体系相比，当去除几何因子时，该方法展示了剂量率数据相对角度的独立性。由于ORNL制造的252Cf AT型源在物理尺寸上比当今使用的大多数临床源大得多，由于线源模型的失效，对于半径小于3.0 mm的情况，径向剂量函数会增加。将252Cf中子径向剂量函数与其他医用源的进行比较，发现与137Cs的相似。与先前252Cf AT源中子剂量学数据的差异通常在距离增加时增大。这归因于各种252Cf AT源模型和模体成分的差异。介绍了ORNL的252Cf医用源制造和校准程序的现状。
