• The Korean Journal of Nuclear Medicine
• /
• v.37 no.6
• /
• pp.341-354
• /
• 2003

Radioactive iodine therapy using I-131 for hyperthyroidism has been used for more than 50 years, and generally considered safe and devoid of major side effects. Appropriate patient selection criteria and clinical judgement concerning patient preparation should be employed for its optimal use. It has not been possible to resolve the trade-off between efficient definite cure of hyperthyroidism and the high incidence of post-therapy hypothyroidism. The dose of the I-131 needed to maintain euthyroid state remains an area of uncertainity and debate. Early side effects are uncommon and readily managable. Other than the need for long-term monitoring and, in most cases, lifelong thyroid hormone treatment for late adverse consequences of this treatment remains only conjectural. We have reviewed general principles and recent advances in radioiodine treatment for Graves' hyperthyroidism, specially regarding to several controversies.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.1
• /
• pp.22-29
• /
• 2000

Purpose: We compared the first postoperative diagnostic and post-therapy scans of patients who received therapeutic doses of I-131, to investigate the difference in clinical outcomes between patients with concordant findings of diagnostic and post-therapy scans and patients with discrepant (more lesions in post-therapy scan) findings. Materials and Methods: The first postoperative diagnostic and post-therapy radioiodine scans of one hundred forty three patients with well differentiated thyroid carcinoma were reviewed. Diagnostic scans were obtained following ingestion of 185 MBq of I-131 and post-therapy scans were obtained after therapeutic dose of $3.7{\sim}9.3$ GBq of I-131. Successful ablation was defined as no radioiodine uptake on diagnostic radioiodine scan and normal range of serum thyroglobulin level (<10 ng/ml) during serum TSH elevation. Results: Discrepant scan findings were noted in 25 (17.5%) patients. Twenty-two patients (15.4%) showed more lesions in post-therapy scan and 3 patients (2.1%) showed stunning effect. Nine (64.3%) of 14 patients with distant metastasis revealed metastatic lesion(s) only on post-therapy scan. Stunning effect was considered as sublethal damage in 1 patient and treatment by a diagnostic dose in 2 patients. Ablation was achieved in 52.4% (75/143) of all patients. Ablation rate and mean cumulative radioiodine dose were not different statistically between concordant and discrepant groups. Conclusion: There were 17.5% difference between diagnostic and post-therapy scan findings when using 185 MBq of I-131 as a diagnostic dose. However, 64.3% of distant metastases were revealed only on post-therapy scan. Ablation rate and mean cumulative radioiodine dose were not different statistically between concordant and discrepant groups. The stunning effect was considered as not only sublethal damage but also treatment by a small diagnostic dose of radioiodine.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.1
• /
• pp.119-122
• /
• 2008

Radioiodine (I-131) Therapy has been known one of the methods treated with hyperthyroidism and thyroid tumor, using a separate ward. This technique has been already used for several decades, and its clinical efficacy proven. Today, Radioiodine takes a form of capsule through continuous development, so, 30 odd domestic hospitals run about 63 separate wards. And, its demands would increase continuously; because of tending upwards the patients had thyroid cancer. However, various kinds of wastes originate from a procedure of radioiodine therapy. Especially, when their radioactivity exceed permissible level (4 Bq/$cm^2$) set by Nuclear laws of the Republic of Korea, it regards as radioactive wastes, then, managed separately from origination to the last disposal.

• Nuclear Engineering and Technology
• /
• v.54 no.2
• /
• pp.689-700
• /
• 2022

In the present study, iodine-131 S values (r_T ← thyroid) were calculated for 30 target organs and tissues using the most recently developed Korean reference computational phantoms. The calculated S values were then compared with those of the International Commission on Radiological Protection (ICRP) reference computational phantoms to investigate the dosimetric impact of the Korean S values against those of the ICRP reference phantoms. The results showed significant differences in the S values due to the different anatomical/morphological characteristics between the Korean and ICRP reference phantoms. Most target organs/tissues showed that the S values of the Korean reference phantoms are lower than those of the ICRP reference phantoms, by up to about 4 times (male spleen and female thymus). Exceptionally, three target organs/tissues (gonads, thyroid, and extrathoracic region) showed that the S values of the Korean reference phantoms are greater, by 1.5-3.7 times. We expect that the S values calculated in the present study will be beneficially used to estimate organ/tissue doses of Korean patients under radioiodine therapy.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.6
• /
• pp.2523-2527
• /
• 2014

Background: Serum thyroglobulin detection plays an essential role during the follow-up of thyroid cancer patients treated with total/near total thyroidectomy and radioiodine ablation. The aim of this retrospective study was to evaluate the relationship between stimulated serum thyroglobulin (Tg) level at the time of high dose $^{131}I$ ablation and risk of recurrence, using a three-level classification in patients with differentiated thyroid cancer (DTC) according to the ATA guidelines. Also we investigated the relationship between postoperative stimulated Tg at the time of ablation and DxWBS results at 8-10 months thereafter. Materials and Methods: Patients with radioiodine accumulation were regarded as scan positive (scan+). If there was no relevant pathological radioiodine accumulation or minimal local accumulation in the thyroid bed region, this were regarded as scan negative (scan-) at the time of DxWBS. We classified patients in 3 groups as low, intermediate and high risk group for assessment of risk of recurrence according to the revised ATA guidelines. Also, we divided patients into 3 groups based on the stimulated serum Tg levels at the time of $^{131}I$ ablation therapy. Groups 1-3 consisted of patients who had Tg levels of ${\leq}2ng/ml$, 2-10 ng/ml, and ${\geq}10ng/ml$, respectively. Results: A total of 221 consecutive patients were included. In the high risk group according to the ATA guideline, while 45.5% of demonstrated Scan(+) Tg(+), 27.3% of patients demonstrated Scan(-) Tg(-); in the intermediate group, the figures were 2.3% and 90.0% while in the low risk group, they were 0.6% and 96.4%. In 9 of 11 patients with metastases (81.8%), stimulated serum Tg level at the time of radioiodine ablation therapy was over 10, however in 1 patient (9.1%) it was <2ng/mL and in one patient it was 2-10ng/mL (p=0.005). Aggressive subtypes of DTC were found in 8 of 221 patients and serum Tg levels were ${\leq}2ng/ml$ in 4 of these 8. Conclusions: We conclude that TSH-stimulated serum thyroglobulin level at the time of ablation may not determine risk of recurrence. Therefore, DxWBS should be performed at 8-12 months after ablation therapy.

• Korean Journal of Psychosomatic Medicine
• /
• v.21 no.2
• /
• pp.132-139
• /
• 2013

Objectives: The aims of this study were to know the prevalence of cognitive disorders in patients with thyroid cancer, and identify related variables to them. Methods: Subjects were consisted of fourty-two patients with thyroid cancer, who were admitted for radioiodine ablative therapy at 6-12 months after total thyroidectomy. The data were obtained from interviews about history and assessments of depression and cognitive function(Korean Version of the Montreal Cognitive Assessment, MoCA-K). Results: 1) Among subjects, those with below 22 of total score of the MoCA-K were twenty-one(50.0%). 2) Upon age, education, Pre-radioiodine therapy thyroid stimulating hormone(TSH), there were statistically significant difference between subgroup with above 23 of the total MoCA-K score and those below 22. 3) The total scores of the MoCA-K in subjects had significant correlation with age, education, comorbidity, Pre-radioiodine therapy TSH, total score of the HDRS-17. Conclusions: Cognitive disorders were more prevalent among patients with thyroid cancer before radioiodine therapy. Therefore, further study should be needed to clarify the mechanism for the cognitive disorders in thyroid cancer. Furthermore, physicians should pay attention to the cognitive function and prepare preventative measures for cognitive disorder during management of thyroid cancer.

• Korean Journal of Veterinary Research
• /
• v.64 no.2
• /
• pp.10.1-10.9
• /
• 2024

Hyperthyroidism, characterized by elevated thyroid hormone levels and thyroid gland hyperplasia or adenoma, is a prevalent endocrinopathy in older cats. Treatment options include antithyroid drugs, surgical thyroidectomy, and radioiodine therapy (RAIT), which is non-invasive treatment option that can achieve complete remission. However, efficacy and safety of RAIT in hyperthyroid cats have not been investigated in South Korea. This study includes 10 hyperthyroid cats with RAIT. Initial assessments comprised history, physical examination, blood analysis, and serum total T4 (tT4) concentration. Thyroid scintigraphy revealed hyperactivity and enlargement of thyroid gland at 24 hours before the RAIT. Radioiodine (RAI) was injected subcutaneously with 2 to 6 mCi, determined by the fixed dose or the scoring system based on severity of clinical signs, tT4 concentration, and thyroid size individually. After RAIT, the concentration of serum tT4 and liver enzymes were significantly decreased at discharge. However, no significant differences were noted in blood urea nitrogen, creatinine, symmetric dimethylarginine, hematocrits, and white blood cell counts pre- and post-treatment. Although 4 cats received RAI twice, clinical signs disappeared and tT4 levels decreased following the RAIT. All 10 cats achieved complete remission after 6 months without critical adverse effect. The safety and the effectiveness of RAIT was confirmed based on protocols reported other countries. Therefore, RAIT could be considered the treatment option and prevent adverse effects from medication or surgery. This preliminary study presents the first evaluation of RAIT for hyperthyroid cats using locally produced RAI in South Korea and provide valuable insight for clinicians and further studies.

• The Korean Journal of Nuclear Medicine
• /
• v.19 no.1
• /
• pp.29-36
• /
• 1985

The results of radioiodine treatment of 88 patients are reported. As in the case presented above, careful follow-up with continuous administration of adequate amount of thyroid hormone is very important. To check whether recurrent lesions have appeared or not, scintigrams with test dose of $I^{131}$, usually 1 to 10 mCi, are taken in general. However, it is important that there is a fact that administration of much larger dose (30 to 100 mCi) of $I^{131}$ may result in presenting additional lesions on the scintigrams. Recently, clinical usefulness of serum thyroglobulin determination has been mentioned in literatures from the standpoint of follow-up study of patients after radioiodine treatment. Although this technique seems to be valuable, we have to be aware of the possibility of fluctuation of data which may occur in connection with administration of thyroid hormone. Finally, I would like to say that radioiodine treatment is an effective method for thyroid cancer if patients are adequately selected. However, radioiodine treatment itself is sometimes not enough from the standpoint of radiation dose to the lesions. In such cases, we should not hesitate to consider combination therapy with other modalities. Therefore, in order to overcome this undesirable disease, cooperation between nuclear medicine specialists and other oncologists, such as radiotherapists, is necessary.

• 대한핵의학회:학술대회논문집
• /
• 2001.05a
• /
• pp.11-18
• /
• 2001

• The Korean Journal of Nuclear Medicine
• /
• v.9 no.1
• /
• pp.15-19
• /
• 1975