[Simple kinetic analysis of 99mTc-GSA by direct integral linear least square regression method: calculation of hepatic blood flow and receptor index based on three-compartment model]
Katada R. Shuke N. Saitoh Y. Yamamoto W. Aburano T. Sato J. Ishikawa Y.
Department of Radiology, Asahikawa Medical College.
To obtain both hepatic blood flow and an index of asialoglycoprotein receptor amount by simple calculation in the asialoglycoprotein receptor imaging with 99mTc-DTPA-Galactosyl Human Serum Albumin (99mTc-GSA), we have tested the applicability of the direct integral linear least square regression (DILS) method based on a linear 3-compartment model (Bronqvist, 1984) to the kinetic analysis of 99mTc-GSA scintigraphy. DILS method can provide hepatic blood flow (k1) and the product of receptor amount and forward binding rate constant (k1k3/k2) as a receptor index, without requiring iterative calculation and initial estimates of the parameters. To compare DILS method with nonlinear least square regression (NLS) method as a standard, data from 35 patients with liver dysfunction were analyzed by both methods. The effect of the data noise to parameter estimate were simulated, and both DILS and NLS method could provide reliable parameter estimate which is relatively insensitive to the data noise. In estimated model parameters, both hepatic blood flow (k1) and the receptor index (k1k3/k2) showed significant correlation between 2 methods (r2 = 0.96, p < 0.0001; r2 = 0.99, p < 0.0001, respectively). We concluded that DILS method was comparable to NLS method in determination of the model parameters and could be useful in the asialoglycoprotein receptor imaging.
[Nuclear medicine applications in HIV/AIDS]
Department of Radiology, National Defense Medical College.
Acquired immunodeficiency syndrome (AIDS) is now believed to be an uncurable disease despite significant advances in the area of antiretroviral therapy for patients with HIV infection. In Japan, it is essential to realize AIDS-defining diseases, particularly because it is not until HIV-infected patients are found that AIDS manifestations develop. Some of the opportunistic infections and AIDS-related tumors are curable by earlier diagnosis and treatment, so that nuclear medicine plays the major role in diagnosing and monitoring AIDS-defining diseases. AIDS complications were correlated with CD4+ lymphocyte counts and utility of nuclear medicine in HIV/AIDS was stressed.