el-Khatib E E, Podgorsak E B, Pla C
Med Phys. 1986 Nov-Dec;13(6):928-35. doi: 10.1118/1.595821.
In radiotherapy, the radiation beam is sometimes shaped so as to deliver different doses to different organs or give a homogeneous dose to structures of different densities. This objective is achieved by the use of attenuating materials introduced into the beam. These attenuators alter the primary as well as the scattered radiation components of the beam. There is at present no accurate method of dose calculation for these situations. Most calculations are performed considering only the effect of the attenuators on the primary radiation beam and can produce large errors in dosimetry. In the present study, the broad beam attenuation is investigated in homogeneous phantoms for various radiation field sizes, photon beam energies, and depths in phantom. A calculational method taking account of primary as well as first scatter radiation is developed. This method predicts reasonably well the transmission through lead attenuators for the various experimental conditions investigated.
在放射治疗中，有时会对辐射束进行塑形，以便向不同器官输送不同剂量的辐射，或者对不同密度的结构给予均匀剂量的辐射。这一目标是通过在辐射束中引入衰减材料来实现的。这些衰减器会改变辐射束的原发射线以及散射辐射成分。目前，对于这些情况尚无精确的剂量计算方法。大多数计算仅考虑衰减器对原发射线束的影响，可能会在剂量测定中产生较大误差。在本研究中，针对均匀模体中不同的辐射野尺寸、光子束能量以及模体中的深度，对宽束衰减进行了研究。开发了一种同时考虑原发射线和一次散射辐射的计算方法。该方法对于所研究的各种实验条件下通过铅衰减器的透射情况预测得相当准确。
