Indium-111-labeled white blood cells: dosimetry in children

The distribution of [111In]oxine-labeled leukocytes was studied by whole-body gamma camera imaging in nine pediatric patients. Images were obtained at approximately 24 hr after administration of the material. Organ distribution was estimated from stored data by manual region of interest assignment. Dosimetry estimates based on geometric mean and conjugate view absolute activity calculations showed close agreement in these patients. Leukocytes were distributed in liver, spleen and marrow. The mean percent uptakes +/- s.d. were: spleen, 31.2 +/- 18.3%; liver, 26.3 +/- 10.8%; and marrow, 14.2 +/- 5.7%. A significant portion (28.3 +/- 9.9%) of administered white cell activity was found outside these organs in the remainder of the body. Mean organ absorbed doses (rad/mCi) were: spleen, 115.0 +/- 84.8; liver, 13.9 +/- 7.8; marrow, 7.6 +/- 3.8; and total body 2.5 +/- 1.0. The mean organ absorbed doses (rad/dose administered) were: spleen, 13.7 +/- 10.6; liver, 1.48 +/- 0.62; marrow, 0.79 +/- 0.26; and total body, 0.28 +/- 0.09.