TY - JOUR
T1 - Inhomogeneous deposition of radiopharmaceuticals at the cellular level
T2 - Experimental evidence and dosimetric implications
AU - Makrigiorgos, G. M.
AU - Ito, S.
AU - Baranowska-Kortylewicz, J.
AU - Vinter, D. W.
AU - Iqbal, A.
AU - Van Den Abbeele, A. D.
AU - Adelstein, S. J.
AU - Kassis, A. I.
PY - 1990
Y1 - 1990
N2 - We have undertaken an experimental examination of the conventional internal dosimetry assumptions of homogeneity of radionuclide deposition in tissues. The distribution of radiolabeled Microlite has been quantitated in mouse liver at the millimeter (multicellular) and the micrometer (cellular) levels. Measurements of radioactivity in 1-mm3 tissue samples indicate homogeneous radionuclide distribution; those derived from autoradiographs of 0.5-μm tissue sections show that, relative to other cells, the colloid was concentrated 200- to 1000-fold in liver macrophages. The dosimetric implications of such inhomogeneous radionuclide distribution in human liver, where similar radionuclide distribution is expected, are discussed on the basis of a recently developed model for calculating the dose at the cellular level, and the estimates are compared to conventional internal dosimetry predictions. It is demonstrated that during routine diagnostic examinations with 99mTc-Microlite, conventional dosimetry underestimates the dose to labeled human liver cells by factors of 8-30.
AB - We have undertaken an experimental examination of the conventional internal dosimetry assumptions of homogeneity of radionuclide deposition in tissues. The distribution of radiolabeled Microlite has been quantitated in mouse liver at the millimeter (multicellular) and the micrometer (cellular) levels. Measurements of radioactivity in 1-mm3 tissue samples indicate homogeneous radionuclide distribution; those derived from autoradiographs of 0.5-μm tissue sections show that, relative to other cells, the colloid was concentrated 200- to 1000-fold in liver macrophages. The dosimetric implications of such inhomogeneous radionuclide distribution in human liver, where similar radionuclide distribution is expected, are discussed on the basis of a recently developed model for calculating the dose at the cellular level, and the estimates are compared to conventional internal dosimetry predictions. It is demonstrated that during routine diagnostic examinations with 99mTc-Microlite, conventional dosimetry underestimates the dose to labeled human liver cells by factors of 8-30.
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M3 - Article
C2 - 2384804
AN - SCOPUS:0025148371
SN - 0161-5505
VL - 31
SP - 1358
EP - 1363
JO - Journal of Nuclear Medicine
JF - Journal of Nuclear Medicine
IS - 8
ER -