• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.40-46
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• 2009

Purpose: A whole body scan using a radioactive iodine (I-131) for the patients with differentiated thyroid cancer is generally an useful method to detect the remnant thyroid tissue, recurred lesion or metastasis lesion after a surgery. The high dose treatment using the radioactive iodine recently tends to increase, and a hospitalization wait for the treatment has been delayed for several months. In this hospital, the treatable patients per week were increased in number through expanding a water-purifier tank and the examination time also increased as the I-131 whole body scan patients increased. Improvement for this problem, this research reduce the existing examination time and classifying the lesion's exact position intended to by fabricating and utilizing the transmission scan tool and an excellent resolution for whole body imaging. Materials and Methods: After conducting the whole body scan for patients who visited the department from February to July 2008 and received the I-131 whole body scan using the ORBITER Gamma Camera. A rail was installed in the examination table for the transmission scan for show a contour of surface area and then the transmission image was obtained and fused to the whole body scan through fabricating the tool to put a flood phantom of diluted 2 mCi $^{99m}Tc$-pertechnetate. Results: Fused image of I-131 whole body scan and the transmission scan had the excellent resolution to discriminate an oral cavity or salivary gland region, neck region's lesion, and metastasis region's position through a simple marking, and could reduce the examination time of 8~28 minutes because without the additional local image. Conclusions: In I-131 whole body scan, the transmission scan can accurately show a contour of surface area through the attenuation of radioactivity, and is useful to indicate the remnant thyroid tissue or metastasis lesion's position by improving the resolution through the fusion image with alreadyexecuted I-131 whole body scan. Also, because the additional local image is not necessary, it can reduce the time required for the examination. It will extensively apply to other clinical examinations to be helpful for identifying an anatomical position because it shows the contour of surface area.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.98-103
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• 2014

Purpose: The effective half life of I-131 is useful to calculate radiation dose, period of hospitalization, and exposure dose of surrounding people from patient. However, it is difficult to measure. This study estimates the effective half life in whole body and thyroid in using of value of residual radioactivity obtained from the early and delay images of Dual time I-131 whole body scan. Also, the correlations between the effective half life and serum creatinine, GFR, and administration dose were investigated in this study. Materials and Methods: The targets were 50 patients administration high dose of I-131 from February to August in 2013, having normal range of serum creatinine and over $30{\mu}IU/mL$ of TSH levels. After administration radioactive I-131, the early scan in the 3rd day and the delay scan in the 5-6th days were performed. To measure the residual radioactivity in the whole body and thyroid, ROI was set and then background radioactivity was corrected to estimate. The effective half life was estimated by calculating the ratio of measured values between the early and delay images. To compare the effective half lives of the whole body and thyroid, it was analyzed by Independent t-test, and each correlation of the effective half life, GFR, serum creatinine, and the dose of administration were analyzed by calculating the pearson's correlation coefficient. All of the analysis were determined to be statistically significant when P<0.05. Results: The effective half life of the whole body was $17.06{\pm}5.50$ hours and of the thyroid was $17.22{\pm}5.41$ hours. The two effective half life did not show significant difference (P=0.887). As the value of GFR was increased, the effective half life of whole body (r=-0.407, P=0.003) and of thyroid (r=-0.473, P=0.001) were significantly decreased; as the value of serum creatinine was increased, the effective half life of whole body (r=0.309, P=0.029) and of thyroid (r=0.371, P=0.008) were significantly increased. In the administration dose, effective half life did not have correlations. Conclusion: The effective half life of I-131 of patients treated for their thyroids were estimated only by using the images of Dual time I-131 whole body scan. Also, the correlations with the effective life, GFR, and serum creatinine were examined. This study might be utilized for a study on optimization for the period of hospitalization of patients treated by high dose of I-131 and on evaluation for internal absorbed dose of MIRD schema in application of the effective half life.

• The Korean Journal of Nuclear Medicine
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• v.24 no.1
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• pp.80-86
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• 1990

Fifty seven patients with differentiated thyroid carcinoma were performed radioactive iodine-131 whole body scans after administration of diagnostic dose $(2\sim10\;mCi)$ and therapeutic dose $(30\sim150\;mCi)$ within three months. We evaluated the state of radioactive iodine-131 uptakes in whole body scan to detect correct metastasis of thyroid carcinoma. The results are as follows: 1) In 20 of the 57 patients (35%), the therapeutic scan showed the additional uptakes that were not seen in the diagnostic scan. 2) In 9 (64.2%) of the 14 patients who had been received the thyroid ablation theraphy with I-131 previously, new additional lesions were found in the therapeutic scan but only 11 (25%) of the 32 patients who had not been received the thyroid ablation theraphy disclosed new uptake lesions (p < 0.01). 3) The additional uptake lesions of therapeutic scan were significantly more common in the bony metastatic foci (55.7%) than other areas (p < 0.01). In 11 (55%) of 20 patients, additional uptake regions were anterior neck areas (thyroid bed or regional lymph node). We conclude that diagnostic scan with $2\sim5$ mCi I-131 is inadequate in evaluating residual iodine avid tissues of patients with thyroid carcinoma. Also post-theraphy I-131 whole body scan would be important to evaluate the correct staging and prognosis of thyroid carcinoma, and to follow-up patients.

• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.117-124
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• 2001

Serum thyroglobulin measurement and I-131 whole-body scintigraphy (WBS) are well-established methods for the detection of recurrence in the follow-up of patients with thyroid carcinoma. However, inconsistent results are observed frequently, and these two methods are not always able to detect recurrence. In some patients, serum thyroglobulin level is elevated but the WBS is negative, because the recurrent tumor is too small and below the sensitivity of the diagnostic scan, or there is a dissociation between thyroglobulin synthesis and the iodine frapping mechanism. In such cases, various nuclear imaging methods including Tl-201 Tc-99m-sestamibi, and F-18-FDG PET can be used besides anatomical imaging methods. Among them, FDG PET localizes recurrent lesions in WBS-negative thyroid carcinoma with high accuracy. Several studies have suggested that empirical high-dose I-131 therapy resulted in a high rate of visualization in post-therapy scans with evidence of subsequent improvement. An important question is when to operate on patients with recurrent tumor. We believe that surgical removal is the best means of treatment for patients with localized persistent tumor, despite the high-dose I-131 therapy. with tumor in thyroid remnant, and with isolated recurrence in the lymph node, lung or bone. In addition, we recommend palliative resection of locally unresectable mass with subsequent treatment with high-dose I-131 therapy. Before I-131 therapy, the evaluation of sodium-iodide symporter expression in thyroid carcinoma can predict iodine uptake. Retinoic acid is known to induce redifferentiation, and to enhance I-131 uptake in thyroid carcinoma. Retinoic acid therapy may represent an alternative approach before high-dose I-131 therapy.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.206-211
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• 2000

Objectives: Any uptake of I-131 after total thyroidectomy means the remant thyroid tissue or distant metastasis of the thyroid cancer. However diffuse hepatic uptake of I-131 without abnormal uptake was showen in many cases on I-131 whole body scan. The aim of this study was to classify the liver uptake after I-131 scan and to evaluate the analysis of this finding. Materials and Methods: Between 1982 and 1998, 104 patients(l4 males, 90 females) with normal liver function underwent I-131 scan after total thyroidectomy. Prospectively we reviewed the films of the whole body scan and analysed the correlations between results of radioiodine uptake, pathologic diagnosis, prognostic factors, lymphatic metastasis, and thyroid function test. Result: Diffuse hepatic uptake was found in 44 of 104(42%) patients. 10 of 39(26%) patients on I-131 100mCi, and 34 of 63(54%) on I-131 150mCi showed hepatic uptake. 52 of 104(50%) patients was locally invasive thyroid cancer. The rate of the hepatic uptake was no significant differences with the thyroid hormone levels(T3, Free T4) and thyroglobulin between uptake group and non-uptake group. Conclusion: The rate of I-131 uptake was high in high-dose radioiodine treatment group. However, we can not find any correlation among the thyroid functions, the extent of metastasis or the extent of local invasion. We need further study to find out the causes of the hepatic uptake of I-131 after total thyroidectomy, besides liver metabolism of I-131 attached thyroid hormones.

• The Korean Journal of Nuclear Medicine
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• v.29 no.4
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• pp.451-459
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• 1995

Thirty-eight patients with metastatic well-differentiated thyroid carcinoma treated with 200mCi $^{131}I$ were studied. There were false negative serum thyroglobulin values during TSH suppression or at anti-thyroglobulin antibody(+) and discrepancies between findings of whole body scan and serum thyroglobulin level. After one to five cycles of 200mCi $^{131}I$ therapy, complete remission and partial remission were achieved at 5.3% and 57.9%, respectively. We concluded that all of serum thyroglobulin, TSH, anti-thyroglobulin antibody, $^{131}I$ or $^{123}I$ whole body scan were necessary in follow up of metastatic well-differentiated thyroid carcinoma. Also, if there was no response after repetitive 200mCi $^{131}I$ therapy, higher doses of $^{131}I$ therapy should be considered.

• 대한핵의학회:학술대회논문집
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• 1996.05a
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• pp.185-185
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• 1996

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.51-52
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• 2006

A 39-year-old female patient who had undergone a total thyroidectomy for a papillary thyroid carcinoma underwent a whole body scan with I-131. The I-131 scan was performed 72 hours after administering 185 MBq (5 mCi) of an I-131 solution. The anterior image of the head, neck, and upper chest showed multiple areas of increased uptake in the mediastinal area considering of functional metastasis. However, radioactivity was not evident in the image taken after removing her clothes and muffler. The image obtained after placing the muffler on the pallet showed that the radioactivity was still present. It is well known that artifacts on an I-131 scan can be produced by styling hair sputum, drooling during sleep, chewing gum, and paper or a cloth handkerchief that is contaminated with the radioactive iodine from either perspiration or saliva. This activity might be mistaken for a functional metastasis. Therefore, it is essential that an image be obtained after removing the patient's clothes. In this study, artifacts due to a contaminated muffler on the I-131 scan were found. These mimicked a functional metastasis of the mediastinal area in a patient with a papillary thyroid carcinoma.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.272-273
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• 2004

We experienced a case with meningioma showing false positive I-131 uptake. A 55-years old female patient underwent high dose (150 mCi) radioactive iodine therapy to ablate remnant tissue after total thyroidectomy for papillary thyroid cancer. in addition to intense tracer uptake in thyroid bed, there was mild but focal abnormal uptake in left frontal lobe of the brain on post-therapy I-131 whole body scan. Subsequent brain MR imaging showed single mass lesion in left frontal lobe and the mass was resected under the impression of brain metastasis of thyroid carcinoma. Pathologic report confirmed meningioma from the surgical specimen.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.49-56
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• 2008

Purpose: Whole body imaging with radioiodine can detect functioning metastases. Non-physiologic I-131 uptake detected on images usually is interpreted as suggesting functioning thyroid metastases. However, extra-thyroidal I-131 accumulation does not always imply thyroid cancer metastases and has been reported in many circumstances. In order to avoid unnecessary therapeutic interventions it is important to distinguish false-positive sites of I-131 localization. We study here to remove false-positive sites around esophagus region on I-131 whole body imaging in patients who were administrated thyroidectomy. Materials and Methods: From April to August in 2007, we had the patients who had visited our department after they received thyroidectomy due to thyroid cancer. They were given I-131, and performed radioiodine body scan after 41 to 50 hours. Patients were whole-body-scanned for the speed of 8 cm per minute. After that, we took anterior and posterior static images around the patients' neck measured by 300 thousand counts per image. We selected 44 patients who had hot spots around neck region, we divided the patients into two groups. One group was given 0.5 L of water and the other group was given 0.5 L of water with 1 g of Vitamin C dissolved. The patients were asked to drink the fluid for one minute in sitting position and after that, we measured 300 kilo counts per image again. We compared prior anterior, posterior static images with anterior, posterior images after the patients had water or water that Vitamin C resolved. Results: In using water, both observer 1 and 2 interpreted 6 patients were washed out. In the water with Vitamin C resolved, observer 1 and 2 interpreted 9 and 8 patients were washed out. Observer 1 and 2 interpreted 6 and 5 patients had 'indeterminate' when they used water. Both observer 1 and 2 interpreted 6 patients had 'indeterminate' when they used water with Vitamin C resolved. When they used water, observer 1 interpreted 10 patients had 'unchanged' and observer 2 interpreted 11 patients had 'unchanged'. Differently, when they used water with vitamin C resolved, observer1 had 8 patients having 'unchanged'and observer 2 had 9. Conclusion: As a result, by making patients drink 0.5 liter of water which has vitamin C resolved helped getting rid of false-positive sites in esophagus. Therefore, based on this study, we believe that drinking water with vitamin C dissolved is very in terms of reducing false-positive hot spot around the esophagus for the iodine-131 whole body scan.