Carroll F E, Waters J W, Andrews W W, Price R R, Pickens D R, Willcott R, Tompkins P, Roos C, Page D, Reed G
Department of Radiology, Vanderbilt University, Nashville, Tennessee.
Invest Radiol. 1994 Mar;29(3):266-72. doi: 10.1097/00004424-199403000-00003.
A prior study indicated that differences in the x-ray linear attenuation coefficients of cancerous and normal breast tissues tend to increase as the energy of the incident beam decreases. The authors investigated x-ray energies down to 20 keV. In the current study, the linear attenuation coefficients for normal and selected cancerous breast tissues within the energy range of 14 to 18 keV were determined.
Fifty breast biopsy specimens consisting of a mixture of breast malignancies, normal tissues, fat specimens, and tumors grown in rats were used. X-ray linear attenuation coefficients were measured for each sample within the energy range of 14.15 to 18 keV, using monoenergetic x-rays from beamline X-19A at the National Synchrotron Light Source at Brookhaven National Laboratory. Each sample was measured at 130 different energies starting at 14.15 keV with step sizes of 0.030 keV. Correlation of the measured attenuation coefficients for cellular makeup was performed.
The mean of linear attenuation coefficients for samples classified as "cancers" was 10.9% higher than the mean of samples classified as "normal" breast tissues and was 66.5% higher than the mean of samples classified as normal breast fat.
Differences in the linear attenuation coefficients of monochromatic x-rays between 14.15 and 18 keV do exist between normal and cancerous tissues, but there is some degree of overlap.
先前的一项研究表明，癌性和正常乳腺组织的X射线线性衰减系数差异往往会随着入射束能量的降低而增大。作者研究了低至20 keV的X射线能量。在本研究中，测定了14至18 keV能量范围内正常和选定癌性乳腺组织的线性衰减系数。
使用了50份乳腺活检标本，其中包括乳腺恶性肿瘤、正常组织、脂肪标本以及在大鼠体内生长的肿瘤的混合物。利用布鲁克海文国家实验室国家同步辐射光源X-19A光束线产生的单能X射线，在14.15至18 keV能量范围内测量每个样本的X射线线性衰减系数。每个样本从14.15 keV开始，以0.030 keV的步长在130个不同能量下进行测量。对测量的衰减系数与细胞组成进行了相关性分析。
分类为“癌症”的样本的线性衰减系数平均值比分类为“正常”乳腺组织的样本平均值高10.9%，比分类为正常乳腺脂肪的样本平均值高66.5%。
14.15至18 keV单色X射线的线性衰减系数在正常组织和癌性组织之间确实存在差异，但存在一定程度的重叠。
