Morita S, Umezaki N, Ishibashi M, Kawamura S, Inada C, Hayabuchi N
Department of Radiology, Kurume University Hospital, Japan.
Ann Nucl Med. 1998 Oct;12(5):303-6. doi: 10.1007/BF03164918.
Radioactivity after administration of 123I-sodium iodide was measured in breast milk samples obtained from a patient with postpartum thyroiditis. The breast milk was collected over 93 h during the infant's regular feeding times. The radioactivity in the breast milk was calculated with a 123I capsule of the same lot number as the standard source. 123I was excreted exponentially with an effective half-life of 5.5 h; 2.5% of the total radioactivity administered was excreted in the breast milk over the 93 h, 95% of which was excreted within the first 24 h, and 98.2% within 36 h. The first milk sample collected at 7 h after administration of the radiopharmaceutical contained 48.5% of the total radioactivity excreted. We estimated the potential absorption of radioactivity to an infant's thyroid in uninterrupted breast-feeding to be 30.3 mGy. With a 24-hour interruption, the absorbed radioactivity would be 1.25 mGy; with a 36-hour interruption, it would be 0.24 mGy. According to our calculations, breast feeding should be curtailed for 36 h to reduce the infant's exposure to 123I radioactivity. By using a correction factor based on maximum radioactivity from another 123I capsule of the same lot, we were able to ascertain the appropriate protocol for our patient and establish a measurement method that can be applied in similar clinical situations.
对一名产后甲状腺炎患者采集的母乳样本进行了123I-碘化钠给药后的放射性测量。在婴儿正常喂食期间，共收集了93小时的母乳。母乳中的放射性用与标准源批号相同的123I胶囊进行计算。123I呈指数排泄，有效半衰期为5.5小时；给药的总放射性中有2.5%在93小时内排泄到母乳中，其中95%在最初24小时内排泄，98.2%在36小时内排泄。给药后7小时采集的第一份母乳样本含有排泄的总放射性的48.5%。我们估计，在不间断母乳喂养的情况下，婴儿甲状腺对放射性的潜在吸收量为30.3毫戈瑞。如果中断24小时，吸收的放射性将为1.25毫戈瑞；如果中断36小时，将为0.24毫戈瑞。根据我们的计算，母乳喂养应中断36小时，以减少婴儿对123I放射性的暴露。通过使用基于同一批次另一个123I胶囊最大放射性的校正因子，我们能够确定适合我们患者的方案，并建立一种可应用于类似临床情况的测量方法。
