• Nuclear Medicine and Molecular Imaging
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• 제43권4호
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• pp.259-279
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• 2009

Radioiodine ablation therapy has been considered to be a standard treatment for patient with differentiated thyroid cancer after total thyroidectomy. Patients may need to be hospitalized to reduce radiation exposure of other people and relatives from radioactive patients receiving radioiodine therapy. Medical staffs, nursing staffs and technologists sometimes hesitate to contact patients in radioiodine therapy ward. The purpose of this paper is to introduce radiation dosimetry, estimate radiation dose from patients and emphasize the safety of radiation exposure from patients treated with high dose radioiodine in therapy ward. The major component of radiation dose from patient is external exposure. However external radiation dose from these patients treated with typical therapeutic dose of 4 to 8 GBq have a very low risk of cancer induction compared with other various risks occurring in daily life. The typical annual radiation dose without shielding received by patient is estimated to be 5 to 10 mSv, which is comparable with 100 to 200 times effective dose received by chest PA examination. Therefore, when we should keep in mind the general principle of radiation protection, the risks of radiation exposure from patients are low and the medical personnel are considered to be safe from radiation exposure.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2523-2527
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• 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.

• Nuclear Medicine and Molecular Imaging
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• 제40권2호
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• pp.132-140
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• 2006

Well-differentiated thyroid cancer is the most common endocrine malignancy with an increasing incidence. Most patients with well-differentiated thyroid caner have a favorable prognosis with high survival rate. While surgery and radioiodine therapy is sufficient treatment for the majority of patients with differentiated thyroid cancer, a minority of these patients experiences progressive, life-threatening growth and metastatic spread of the disease. Because there is no prospective controlled study to evaluate the differences of management of thyroid cancer, it is hard to choose the best treatment option. And there are still lots of controversies about the management of this disease, such as surgical extent, proper use of radioiodine for remnant ablation and therapy, use of rhTSH instead of withdrawal of thyroid hormone, long-term follow-up strategy, thyroglobulin as a tumor marker, etc. In this review, recent data related to these conflicting issues and recent advances in diagnosis, radioiodine therapy and long-term monitoring of well-differentiated thyroid cancer are summarized.

• 대한핵의학회지
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• 제36권1호
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• pp.87-89
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• 2002

A 30 year-old female patient with papillary thyroid carcinoma received her fifth radioiodine ablation therapy after the subtotal thyroidectomy. The scan, which was peformed one week after the last therapy, revealed residual uptake in the thyroid bed and uptake in the anterior mediastinum suggesting metastasis. However, further evaluation of the thorax with chest CT and camera-based FDG PET confirmed normal thymus without metastatic focus. Occasionally thymus remains intact in adult and has avidity for I-131 and FDG. Therefore, normal thymus (instead of metastasis) should be considered in patients with well differentiated thyroid carcinoma and anterior mediastinal radioiodine uptake.

• 대한핵의학회지
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• 제34권1호
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• pp.22-29
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• 2000

목적: 방사성옥소 치료를 받은 갑상선암 환자의 수술 후 첫 진단 스캔과 치료 후 스캔을 비교하고 치료 후 스캔에서 더 많은 병소를 보이는 경우(불일치군)와 같은 경우(일치군) 사이에 임상경과에 차이가 있는 지를 알아보았다. 대상 및 방법: 방사성옥소 치료를 받은 분화된 갑상선암 환자 143명의 수술 후 첫 진단 스캔과 치료 후 스캔을 비교하였다. 진단 스캔은 방사성옥소 185 MBq를, 치료후 스캔은 $3.7{\sim}9.3$ GBq를 투여한 후 얻었다. 추적 진단 스캔에서 비정상 섭취가 없으며 혈청 갑상선글로불린치가 정상이면 잔여 갑상선조직이 제거된 것으로 판정하였다. 결과: 두 스캔사이에 차이를 보인 경우는 143명 중 25명(17.5%)으로, 진단 스캔보다 치료 후 스캔에서 더 많은 병소를 보인 경우가 22명(15.4%), 기절효과를 보인 경우가 3명(2.1%)이었다. 원격전이가 확인된 환자 14명 중 9명(64.3%)은 치료 후 스캔에서만 병소를 확인할 수 있었다. 기절 효과를 보인 3명 중 1명은 아치사손상에 의한 것으로 생각되나, 나머지 2명에서는 다음 진단 스캔에서도 보이지 않아 진단 스캔 용량에 의한 제거의 가능성을 보였다. 관해는 75명(58.1%)의 환자에서 이루어졌다. 잔여 갑상선의 제거율, 평균 방사성옥소 축적 용량은 불일치군과 일치군 사이에서 유의한 차이가 없었다. 결론: 185 MBq의 단일 용량의 방사성옥소를 이용하여 진단 스캔을 얻었을 때, 진단 스캔과 치료 후 스캔이 다른 경우는 17.5%에서 관찰되었으며, 특히 원격전이가 확인된 환자의 64.3%는 치료 후 스캔에서만 병소가 확인되었다. 진단 스캔과 치료 후 스캔 사이에 차이를 보인 환자군과 일치한 환자군에서 잔여 갑상선 제거율 및 방사성옥소 평균 축적용량은 유의한 차이가 없었다. 기절효과를 보인 병소는 추적검사에서 모두 제거되어 방사성옥소를 섭취할 능력의 일시적 장해뿐 아니라 진단용량에 의한 치료효과도 있었던 것으로 생각된다.

• 대한핵의학회지
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• 제34권4호
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• pp.265-275
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• 2000

The thyroid gland is an interesting endocrine organ where a spectrum of tumors with different behavior arise. At one end of spectrum there is differentiated thyroid carcinoma (DTC) with excellent prognosis, whereas at the other end of the spectrum is anaplastic thyroid cancer which has universally poor outcome. Radioiodine (I-131) therapy has been in use for the treatment of thyroid diseases since 1946. It was introduced by Seidlin et al. 1) Although the use of I-131 has been vouge for a long time, its use in therapy for well differentiated thyroid cancer is still controversial 2). This is because, thyroid cancers (TC) are generally slow growing tumors, with low mortality and normal spans of survival. To record recurrence and mortality, long term follow up studies over a period of two to three decades are needed to establish definite conclusions on the acceptable mode of treatment The incidence of the disease being very low a large number of cases needed to establish a meaningful statistical data is lacking as most published reports feat with small series. Here again in the problem encountered are the differing protocols for treatment with I-131, the indications for treatment which may include or exclude ablation of residual thyroid tissue, cervical nodal and distal metastases. The dosage of I-131 used for ablation of residual thyroid tissue and metastatic disease also vary. The most reliable conclusion regarding I-131 treatment are obtained from studies reported on a large series of patients followed over a period of 2 decades or more from a single institute with a more or less unchanged protocol of management.

• Journal of Medicine and Life Science
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• 제19권3호
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• pp.95-102
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• 2022

This retrospective study aimed to investigate whether there was a difference in the success rate of removal of residual thyroid tissue in patients with the same cutoff serum thyroglobulin (Tg) value-measured 2 weeks after thyroid hormone withdrawal (THW)-for different radioactive iodine (RAI) activities. We identified 132 patients with papillary thyroid cancer who were treated with total thyroidectomy and RAI therapy to evaluate the efficacy of three radioactivities of I-131: 1,110, 3,700, and 5,550 MBq. Serum Tg testing was performed 1 week before RAI treatment and 2 weeks after THW (pre-Tg); the cutoff pre-Tg level was below 10 ng/mL. Stimulated Tg levels were measured on the day of I-131 administration (off-Tg). After 6 months of treatment, we compared the groups for complete ablation, defined as no uptake on a diagnostic I-131 scan, stimulated Tg level of <1.0 ng/mL, and Tg antibody level of <100 ng/mL. Ninety-five patients (72.0%) achieved complete ablation, with 57.1% (8/14), 78.2% (68/87), and 61.3% (19/31) in the 1,110 MBq, 3,700 MBq, and 5,550 MBq groups, respectively. There was no significant difference in the complete ablation rates between the three groups. In the multivariate analysis, the off-Tg level was a significant predictor of complete ablation. RAI therapy with low radioactivity (1,110 MBq) seemed sufficient for ablation in patients with papillary thyroid cancer with a pre-Tg level below 10 ng/mL. The off-Tg level is a promising and useful predictor of complete ablation after initial RAI therapy.

• Nuclear Medicine and Molecular Imaging
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• 제40권6호
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• pp.322-326
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• 2006

목적: 갑상선암 방사성요오드 치료를 위한 전처치로 1주${\sim}$2주간 저요오드식이를 시행하는 것이 국제 권고안에서 권고되고 있으나 각 병원마다 저요오드식이를 자체적인 교육방법에 따라 시행하고 있으며 저요오드식이를 통해 체내 요오드량을 효과적으로 낮추었는지에 대한 측정도 대부분의 병원에서 시행되지 않고 있어, 연구자들의 병원에 의뢰된 환자들의 소변 내 I/Cr비를 측정하여 고전적인 엄격한 저요오드식 이를 1주일간 시 행하는 방법과 덜 엄격한 저요오드식이를 2주일간 시행하는 방법을 비교하여 그 적절성을 평가하고자 하였다. 대상 및 방법: 2006년 4월 10일부터 6월 19일까지 본원에 의뢰된 27명의 환자를 대상으로 제한 및 허용식품 목록, 영양사 교육 유무, 예시 식단 유무, 저요오드식이 기간을 비교하여 가장 빈도가 높은 2가지 방법, 즉 관용적인 기준을 채택하는 군과 엄격한 제한식품을 설명한 군으로 나누어 두 군의 아침 소변을 채집, iodide selective electrode method를 사용하여 소변 내 요오드량을 측정하고 이를 소변 내 크레아티닌으로 나누어 I/Cr비를 구하였다. 두 군의 결과는 t-test를 이용하여 검정하였다. 결과: 두 군간의 특성에는 유의한 차이가 없었으며 각 군에서의 소변 내 I/Cr 비는 2주간 덜 엄격한 저요오드식이 군에서 $289.75{\pm}188.24{\mu}g/g$, 1주간 엄격한 저요오드식이를 시행한 군에서는 $127.87{\pm}78.52{\mu}g/g$으로 측정되었으며 1주간 엄격하게 시행한 군에서 유의하게 낮았다 (p=0.008). 2주간 덜 엄격한 저요오드식이를 시행한 군에서는 14명중 3명(21.42%), 1주간 엄격한 저요오드식이를 시행한 군에서는 13명중 6명(46.15%)이 방사성요오드치료를 위한 적정한 수준으로 제시된 소변 내 요오드배설량 $100{\mu}g/g$이하를 만족했다. 결론: 2주간 덜 엄격한 저요오드식이를 시행한 군에서 1주간 엄격한 교육을 시행한 군보다 높은 소변 내 I/Cr비가 나온 것을 볼 때 교육 방법을 엄격하게 시행하지 않고 간단하게 변형된 방법을 사용할 경우 기간을 길게 하더라도 치료에 필요한 적정 수준의 체내 요오드량 감소를 달성하기 어려울 것으로 판단된다. 그러나 1주간 엄격한 저요오드식이를 시행한 군에서도 체내 요오드량의 감소가 충분히 감소하는 비율이 여전히 낮기 때문에 엄격한 저요오드식이 방법을 2주간 시행하는 것이 더바람직하리라 기대된다.

• Journal of Yeungnam Medical Science
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• 제32권2호
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• pp.138-142
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• 2015

L-thyroxine (LT4) withdrawal prior to radioactive iodine (RAI) ablation therapy is a commonly used method for successful treatment of patients with papillary thyroid cancer (PTC). However, a prolonged period of hypothyroidism induced by LT4 withdrawal is sometimes associated with impaired quality of life and cardiopulmonary dysfunction in PTC patients. Furthermore, LT4 withdrawal may have a trophic effect on residual cancer by means of increased thyrotropin. We report on 2 cases of metastatic PTC patients with malignant pleural effusion (MPE) whose disease showed rapid worsening after LT4 withdrawal and RAI therapy. The first case is a 65-year-old woman who had PTC with multiple distant metastases and MPE. During LT4 withdrawal for RAI therapy, MPE showed rapid worsening, and the patient required repetitive therapeutic thoracentesis. The second case is a 49-year-old woman with PTC who underwent 3 additional operations for cancer recurrence in the neck lymph nodes and 6 times of RAI treatments. While preparing for the $7^{th}$ RAI treatment by withdrawing LT4, she developed MPE which became progressively aggravated after RAI therapy. Both patients experienced increased pleural effusion during the LT4 withdrawal period and a rise in the thyroglobulin level was observed after RAI therapy. MPE was not controlled with therapeutic thoracentesis and pleurodesis. Eventually, both patients died of rapid disease progression after RAI therapy. In summary, LT4 withdrawal may have an adverse effect on metastatic PTC patients, particularly those with MPE.

• 대한두경부종양학회지
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• 제15권1호
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• pp.46-51
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• 1999

Background: Total thyroidectomy and postoperative radiodiodine ablation therapy in differentiated thyroid carcinomas enhance the reliability of serum thyroglobulin(Tg) levels and radioiodine scan in detecting recurrence or distant metastasis. There have been, however, some limitations in using these methods under certain conditions. Recently, several reports have indicated that thyroid peroxidase(TPO) could be used as an alternative tumor marker. We aimed to estimate the significance of serum TPO levels in differentiated thyroid carcinoma. Materials and Methods: Forty-eight patients who had undergone total thyroidectomy due to papillary thyroid carcinomas and who had been followed-up for at least 3 years were classified into two groups: 27 patients without any evidence of recurrence in group 1; and 20 patients with recurrence or distant metastasis in group 2. All patients were examined by radioiodine scans. Serum Tg, TSH, antithyroglobulin antibody, and TPO were measured and the relationships were statistically analyzed. The sensitivity and specificity of $^{131}I$ scan, serum Tg, and serum TPO were evaluated. Results: Serum Tg levels were $3.81{\pm}5.16ng/mL$ in group 1 and $147.02{\pm}193.75ng/mL$ in group 2. Only 2 patients in group 1 showed Tg levels exceeding 10ng/mL. In contrast, 4 patients in group 2 were under 10ng/mL. Serum antithyroglobulin antibody and TSH levels showed no statistical difference between the two groups. In group 1, 16 patients showed negative serum TPO results, and 4 patients in group 2 showed negative results. There was no correlation among serum Tg levels, antithyroglobulin antibody titers, and serum TPO levels in each group. In group 2, 4 patients with negative serum Tg levels showed positive TPO results and positive whole body scans. Two cases with false negative $^{131}I$ scans showed positive serum TPO and Tg results. In 4 cases showing false negative serum TPO levels, serum Tg levels and $^{131}I$ scans were positive. Conclusion: Serum Tg levels, radioiodine scans, and serum TPO levels can be clinically used as complementary methods in the diagnosis of recurrent or metastatic thyroid carcinomas. Serum TPO levels may be helpful when other methods fail to detect recurrences or distant metastasis in highly suspected patients.