In this paper, the medium correction factor for lung, muscle, blood and bone was calculated using analytical method and MCNP simulation for different beam qualities. To validate the calculation method, the medium correction factor of the PTW-30013 ionization chamber for air was specified by measuring the air kerma and the absorbed dose to water calibration coefficients in the standard radiation field of 60Co in Secondary Standards Dosimetry Laboratory (SSDL) of Iran. The value of the medium correction factor for muscle and blood was gotten close to one because of their close density and atomic composition to water. For lung, the medium correction factor was calculated more over 1.08 for different beam qualities. Also, this factor for the bone was determined less than 0.98. The results of this study revealed that for accurate measurement of absorbed dose in low (e.g., lung) or high (e.g., bone) density materials, by ionization chambers calibrated in term of absorbed dose to water, the medium correction factor has to be considered.

在本文中，使用分析方法和MCNP模拟针对不同光束质量计算了肺，肌肉，血液和骨骼的介质校正因子。为了验证该计算方法，在美国第二标准剂量测定实验室（SSDL）中通过测量空气比释动能和60Co标准辐射场中水的吸收剂量到水的校准系数，来指定PTW-30013空气电离室的介质校正因子。伊朗。肌肉和血液的中等校正因子的值接近于1，因为它们的密度和与水的原子组成接近。对于肺部，对于不同的光束质量，计算得出的介质校正因子大于1.08。而且，确定该骨骼的因子小于0.98。