A body-size-dependent series of Chinese adult standing phantoms for radiation dosimetry


 Phantoms of diﬀerent sizes, which have been indicated by several studies, have a signiﬁcant impact on the accuracy of dose calculations. Therefore, it is necessary to establish a body-size-dependent series of Chinese standing adult phantoms to improve the accuracy of radiation dosimetry. In this study, the Chinese reference polygon-mesh phantom CRAM S/CRAF S have been reﬁned ﬁrst. And a method for automatically constructing lymph nodes in a mesh phantom has been proposed. Then based on the reﬁned phantoms, this study has developed 42 anthropometric standing adult computational phantoms, 21 models for each gender, with a height range of 145-185 cm, and weight as a function of BMI corresponding to healthy, overweight, and obese. The parameters were extracted from the National Occupational Health Standards (GBZ) document of the People’s Republic of China, which covers more than 90% of the Chinese population. For a given body height and mass, scale in proportion to a factor to reﬂect the change of adipose tissue and the internal organs. The rest part is adjusted manually to match the target parameters. In addition, the constructed body-size-speciﬁc phantoms have been implemented into the in-house THUDose Monte Carlo code to calculate the dose coeﬃcients for photon external exposures, which in the antero-posterior, postero-anterior, right lateral geometries. The results showed that organ dose coeﬃcients varied signiﬁcantly with body size at low energies (< 2 MeV) and high energies (> 8 MeV), due to the diﬀerences in anatomy. Organ dose coeﬃcient diﬀerences between a phantom of a given size and a reference phantom vary by up to 40% at the same height and up to 400% at diﬀerent heights. The inﬂuence of body size diﬀerences on the dose coeﬃcients demonstrates that the body-size-dependent Chinese adult phantoms have great promise for a wide range of applications in radiation dosimetry.