Agricultural, Medical and Industrial School, P.O. Box 31485-498, Karaj, Iran.
Med Phys. 2010 Oct;37(10):5370-5. doi: 10.1118/1.3488971.
The formalism recommended by Task Group 60 (TG-60) of the American Association of Physicists in Medicine (AAPM) is applicable for beta sources. Radioactive biocompatible and biodegradable 153Sm glass seed without encapsulation is a beta- emitter radionuclide with a short half-life and delivers a high dose rate to the tumor in the millimeter range. This study presents the results of Monte Carlo calculations of the dosimetric parameters for the 153Sm brachytherapy source.
Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate two-dimensional dose distributions around the source. The dosimetric parameters of AAPM TG-60 recommendations including the reference dose rate, the radial dose function, the anisotropy function, and the one-dimensional anisotropy function were obtained.
The dose rate value at the reference point was estimated to be 9.21 +/- 0.6 cGy h(-1) microCi(-1). Due to the low energy beta emitted from 153Sm sources, the dose fall-off profile is sharper than the other beta emitter sources. The calculated dosimetric parameters in this study are compared to several beta and photon emitting seeds.
The results show the advantage of the 153Sm source in comparison with the other sources because of the rapid dose fall-off of beta ray and high dose rate at the short distances of the seed. The results would be helpful in the development of the radioactive implants using 153Sm seeds for the brachytherapy treatment.
美国医学物理学家协会（AAPM）第 60 工作组（TG-60）推荐的形式适用于β源。放射性生物相容和可生物降解的 153Sm 玻璃种子无需封装，是一种β发射放射性核素，半衰期短，在毫米范围内对肿瘤提供高剂量率。本研究介绍了 153Sm 近距离治疗源剂量学参数的蒙特卡罗计算结果。
使用（MCNP）蒙特卡罗辐射输运代码的版本 5 来计算源周围的二维剂量分布。获得了 AAPM TG-60 建议的剂量学参数，包括参考剂量率、径向剂量函数、各向异性函数和一维各向异性函数。
参考点处的剂量率值估计为 9.21 +/- 0.6 cGy h(-1) microCi(-1)。由于 153Sm 源发射的低能β射线，剂量衰减曲线比其他β发射源更陡峭。本研究中计算的剂量学参数与几种β和光子发射种子进行了比较。
结果表明，153Sm 源与其他源相比具有优势，因为β射线的快速剂量衰减和种子短距离处的高剂量率。这些结果有助于使用 153Sm 种子进行近距离治疗的放射性植入物的开发。
