| THE I131 UPTAKE STUDY IN KOREAN CHILDREN |
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Chong Moo Park1, Chang Hwa Ann1, Chui Sung Suh2, Jin Moo Kang3 |
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| 韓國兒童甲狀腺의 放射性同位元素 I 131 이攝取에 關한 硏究 |
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朴鍾皮1, 宋昌華1, 徐 哲星2, 姜 眞無3 |
1大邱東山基督病院 小兒 科
2大邱東山基督病院 放射 線 科
3大邱東山基督病院 同 位元素室 |
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| Abstract |
Few reports are available on the uptake of radioactive iodine as a test of thyroid function in children. Probably this would be the first report of a radioactive iodine uptake study in Korea, for children as well as adults.
The uptake of radioactive iodine within a 24-hour period as measured by many authors was in the range of 10 to 50 per cent. Most authors did not find marked differences between children and adults or between children of different ages. A difference in the 24-hour thyroid accumulation of iodine was also reported in different localities; thus the observed uptake from persons on the east and west coasts of the United States was lower than that from the central United States. It was suggested that these differences are due to different contents of iodine in the diet. The aim of this study was to determine the normal uptake of R. A. I. by the thyroid uptake
in normal Korean children including children of different ages and sex, during a 6-hour and 24-hour period. Another purpose of this report is to present the difference in iodine uptake between normal and abnormal children, including cases of malnutrition, simple goiter, cretinism, mongolism, and cerebral palsy which are closely related to the growth and development of the children. Material and Technique: A total of 492 korean children, with an age range of 4 months to 15 years, were studied. For the benefit of comparative study the subjects were divided into three major groups: the first group consisted of 254 normal children; the second group comprised 80 patients with malnutrition (age range 7 month to 10 years); the third group included 158 patients with various diseases, including cretinism, simple goiter, myxedema, mongolism, and cerebral palsy.
The tracer doses used were 25 gc for each child. A scintillation counter was used for counting at both 6 hours and 24 hours after adminstration of the tracer dose for each group. The count was obtained at a distance of 30 cm. from the thyroid and the mean count of three different readings was taken and corrected for the background irradiation. The percentage of thyroid I131 uptake was calculated from the formula.
Results
The results were classified into three groups. Group I: This group included 254 normal children with normal growth and development as shown by measurements and bone age. a) The 6 hour I131 thyroid uptake by these chidren was in the range of 15. 3% to 29.5% (Average 22.4%). b) The 24 hour I131 thyroid uptake by the same group was in the range of 28.1% to 40.4% (Average 34. 6 % ). In general the higher uptake was observed in orphans whose growth and development were within normal limits as compared with normal non-orphan children attending the Child Health Conference. The ratio was 36.6% :45. 8% for 24 hours. The 6 hour I131 uptake for normal orphan children was in the range of an averge of 36.6% and that of non-orphan children was 34.6%. The high I131 uptake vras presumably correlated with low iodine intake of children in Taegu
area and especially, inadequate intake of iodine in orphan children. Group II: This group consisted of 80 malnurished children who were mostly orphan children. The 6 hour iodine uptake by this group ranged from 25. 5% to 71. 2% (average 42.9%). The range of I131 uptake for 24 hours was from 11. 2% to 87% (average 45. 8%).
The result of this study revealed that malnurished children have a higher uptake of I131 as compared with normal children. Such a high uptake would, in all probability, be due to depletion of body stores of iodine secondary to iodine deficiency in the diet. A relatively higher uptake of I131 for 6 hours and 24 hours were observed in the femcle group than in the male group. There were also age differences in uptake of I131 and proportionally the highest uptake was found in the group of 6 to 8 years of age. However, most previous authors
had reported that no age or sex difference in uptake. Group III: This group comprised 158 abnormal children, including simple goiter, cretinism myxedema, mongolism and cerebral palsy. The range of I131 uptake by each group is as follows: 1.The patients with simple goiter have an average I131 uptake of 45. 3% for 6 hours and*
56.2% (14. 5%〜82%) for 24 hours, which was a relatively high uptake as compared with normal Korean children.
2.The average I131 uptake by patients with cretinism was 34.5% (ranging from 8. 0. % to 90 %), which was somewhat lower than normal Korean children. 3.Patients with myxedema take up from 6.7% to 13. 5% (average 10. 8%) for 6 hours and 5. 8% to 13. 5 % (average 11. 6%) for 24 hours, which were the lowest values in our series. 4.Patients with mongolism and cerebral palsy had an average I131 uptake of 36% (ranging: from 15% to 65%). During this study we found very rare and interesting cases of four patients with congenital femilial goiterous cretinism. These were four siblings from the same parents who had no hypothyroidism. The six and 24 hour uptakes by these siblings were abnormally high, ranging: from 60% to 89%. The serum cholesterol levels of these four patients ranged from 200 to 350 mg, %. Their growth and development, including body easurements and bone age, showed marked retardation. Pathological examination of their thyroid biopsy revealed hyperplastic change with immature development. Summary and Conclusions: 1. I131 uptake was measured at periods of 6 and 24 hours in 252 normal and 240 abnormal children in Korea. 2. In general the I131 uptake by normal Korean chidren was somewhat higher than that of foreign children. 3.I131 uptake by malnurished children was somewhat higher than that of normal children. The findings suggest that a state of iodine deficiency is prevalent in Korean euthyroid children. 4.we observed some difference in I131 uptake by different age and sex groups, although most authors reported no significant difference in sex or age. A higher uptake by the 6 to 8 year age group and by the female group was observed. 5.We found four siblings who had congenital familial goiterous cretinism with marked retardation in growth and development as well as high uptake of I131, which resulted frorw failure in hormonal synthesis in the thyroid gland. Therefore, a high uptake of I131 by
some cases of cretinism must be interpreted with caution and an iodide repletion test must be done before a definite conclusion is reached. |
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