ABSTRACT
PURPOSE: The aim of this study was to determine the influence of H2RAs to the 24-h I-131 uptake in the thyroid gland. MATERIAL AND METHODS: A prospective study with quasi-experimental pre- and post-study design was done. Subjects with normal fT4 level who fulfilled the inclusion criteria were selected. All subjects received 0.2 mCi of I-131 orally, and the thyroid uptake calculations were performed at 24 h later. The same procedure was performed 4 weeks later. All of the subjects were asked to consume H2RAs 1 h before the administration of I-131 of the second procedure. Both 24-h thyroid uptakes were statistically analysed. RESULTS: A total of 14 subjects were enrolled in this study. Most of them were women (78%) with an average age of 37.6 years old (range: 20-55). This study showed a median of 24-h thyroid uptake of I-131 before and after H2-receptor antagonist of 20.6% (range: 11.1-57.8%) and 16.7% (range: 8.1-39.4%) respectively. CONCLUSION: H2-receptor antagonist caused a significance reduction of 24-h I-131 uptake value in the thyroid gland.
ABSTRACT
One of the treatment options for benign thyroid nodules is radioactive iodine (RAI). However, this treatment is more effective for hot/warm solid thyroid nodules. Cold thyroid solid nodules are characterized by the lack of iodine uptake compared to normal thyroid tissue. Oral retinoic acid (RA) is a synthetic derivative of Vitamin A. The effect of RA on the uptake of RAI is still controversial. The aim of this study was to evaluate the effect of RA in the ability of a cold solid thyroid nodule to take up RAI. Individuals with a cold solid thyroid nodule based on ultrasonography and thyroid scintigraphy were included. Participants with liver dysfunction, smokers, and pregnant patients were excluded from the study. Each participant underwent thyroid uptake scintigraphy twice (pre- and post-RA consumption) using 35-37 MBq NaI-131. Participants consumed RA at a dose of 1 mg/kg body weight (BW) followed with 1.5 mg/kg BW. This study was approved by Dr. Hasan Sadikin General Hospital Ethic Committee. A total of 12 cold thyroid solid nodules were evaluated. The mean percentage of the nodule uptake value pre- and post-intervention was 1.11% and 0.62%, respectively (P = 0.004), while normal thyroid tissue uptake values pre- and post-intervention were 27.57% and 13.40%, respectively (P = 0.002). The percentage alteration of nodules and normal thyroid tissue uptake value were 42.4% and 51.5% lower, respectively (P = 0.354). This study showed that RA reduces the ability of cold solid thyroid nodule, as well as normal thyroid tissue, to take up RAI.
