Fearnow E C, Jaszczak R J, Harris C C, Stanfield J A, Coleman R E
Radiology. 1985 Nov;157(2):517-20. doi: 10.1148/radiology.157.2.2996052.
A linear attenuation coefficient for water (mu = .15 cm-1) at 140 keV has been used in the determination of left ventricular volumes (LVV) by attenuation-corrected equilibrium methods. This theoretical value ignores the effect of Compton scatter and thus may be too high for human LVV determinations. The effective attenuation coefficient, mu', of the human chest was determined in ten normal volunteers using a Tc-99m esophageal source imaged with a gamma camera. Values for mu' at 30 degrees LAO in end-expiration, quiet breathing, and end-inspiration were .125 +/- .006 cm-1, .125 +/- .005 cm-1, and .113 +/- .007 cm-1, respectively (95% confidence interval). Values of mu' at 45 degrees LAO were .122 +/- .006 cm-1, .119 +/- .007 cm-1, and .099 +/- .009 cm-1, respectively, for the same conditions. The measured value of mu' for the source in a water phantom was .127 +/- .001 cm-1. This suggests that a value of mu' of .125 cm-1 may be appropriate for use in determining LVV in patients.
在通过衰减校正平衡法测定左心室容积（LVV）时，使用了水在140 keV下的线性衰减系数（μ = 0.15 cm⁻¹）。该理论值忽略了康普顿散射的影响，因此对于人体LVV测定可能过高。使用γ相机对10名正常志愿者进行Tc - 99m食管源成像，测定了人体胸部的有效衰减系数μ'。在左前斜30度、呼气末、平静呼吸和吸气末时，μ'的值分别为0.125±0.006 cm⁻¹、0.125±0.005 cm⁻¹和0.113±0.007 cm⁻¹（95%置信区间）。在相同条件下，左前斜45度时μ'的值分别为0.122±0.006 cm⁻¹、0.119±0.007 cm⁻¹和0.099±0.009 cm⁻¹。水模体中源的μ'测量值为0.127±0.001 cm⁻¹。这表明μ'值为0.125 cm⁻¹可能适用于测定患者的LVV。
