The Energy Dependence of the Photoelectric Attenuation Coefficient of Substances

Shiraz University of Medical Sciences

A. Vyas¹  S. Chatterjee¹  R. Ravanfar Haghighi²  P. Kumar² 

[1] Indian Institute of Astrophysics, Bangalore 560034, India;MedicalPhysics Unit, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 India

关键词: X-ray;    Photoelectric effect;    Attenuation coefficient;    Photon energy;   

DOI  :  

学科分类：生物科学（综合）

来源: Shiraz University of Medical Sciences

【 摘 要 】

Introduction:The photoelectric attenuation coefficient of substances is known to depend upon the energy E of the photon and the effective atomic number of substances (Zeff) as (Zeff x /E y ).  No definitive values about these indices x, y are given in the literature. The index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0.Methodology:We followed a methodology to find both the exponent y explicitly, from a formula which does not contain x. Through this way, the risk of one parameter leading to an estimation error for the other is automatically eliminated. With the value of y being unmistakably established, we determined the exponent x for different elements.Results:It was found from the NIST data that ‘y’ = 3.0669 for most substances with low atomic number but no single value can be assigned for the exponent ‘x’. Conclusions:These results help us to perform model calculations for the attenuation coefficients of different substances. They can also provide important inputs for the diagnostic purposes in the DECT method.

【 授权许可】

CC BY