• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.251-257
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• 2013

Spatial dose rates of high dose $^{131}I$ therapy patients were Measured Three dimensional (X, Y, Z) distributions. I have constructed geometrical an aluminum support structure for spatial dose meters placed in 5 different heights, 8 different azimuthal angles, 6 different time interval and distance 100 cm from High dose$^{131}I$ therapy patients. when the height of vertical plane Spatial dose distribution is 100 cm, the Spatial dose rates is max and the error range is low. the vertical plane Spatial dose rates was found to be 71.85 ${\mu}Sv/h$ on the average at a distance of 100 cm, height 100 cm, from the patients 24 hours after $^{131}I$ oral administration. I divided 12 patients into two groups. I have analysed group A (drinking 5 L water) and group B (drinking 3 L water) in order to measure decrease spatial dose rates. I have found the spatial distributions of patient dose rates is $44.9{\pm}7.2$ ${\mu}Sv/h$ in group A and $100.3{\pm}8.1$ ${\mu}Sv/h$ in group B by 24 after $^{131}I$ oral administration. the reduction factor was found to be approximately 54 % through drinking 5 L water during 24 hours.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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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.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1115-1118
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• 2016

Background: There is controversy about ablation efficacy of low or high doses of radioiodine-131 (RAI) in patients with differentiated thyroid cancers (DTC). The purpose of this prospective study was to determine efficacy of 30 mCi and 100 mCi of RAI to achieve successful ablation in patients with low to intermediate risk DTC. Materials and Methods: This prospective cross sectional study was conducted from April 2013 to November 2015. Inclusion criteria were patients of either gender, 18 years or older, having low to intermediate risk papillary and follicular thyroid cancers with T1-3, N0/N1/Nx but no evidence of distant metastasis. Thirty-nine patients were administered 30 mCi of RAI while 61 patients were given 100 mCi. Informed consent was acquired from all patients and counseling was done by nuclear physicians regarding benefits and possible side effects of RAI. After an average of 6 months (range 6-16 months; 2-3 weeks after thyroxin withdrawal), these patients were followed up for stimulated TSH, thyroglobulin (sTg) and thyroglobulin antibodies, ultrasound neck (U/S) and a diagnostic whole body iodine scan (WBIS) for ablation outcome. Successful ablation was concluded with stimulated Tg< 2ng/ml with negative antibodies, negative U/S and a negative diagnostic WBIS (triple negative criteria). ROC curve analysis was used to find diagnostic strength of baseline sTg to predict successful ablation. Results: Successful ablation based upon triple negative criteria was 56% in the low dose and 57% in the high dose group (non-significant difference). Based on a single criterion (follow-up sTg<2 ng/ml), values were 82% and 77% (again non-significant). The ROC curve revealed that a baseline sTg level ${\leq}7.4ng/ml$ had the highest diagnostic strength to predict successful ablation in all patients. Conclusions: We conclude that 30 mCi of RAI has similar ablation success to 100 mCi dose in patients with low to intermediate risk DTC. A baseline $sTg{\leq}7.4ng/ml$ is a strong predictor of successful ablation in all patients. Low dose RAI is safer, more cost effective and more convenient for patients and healthcare providers.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.6
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• pp.572-576
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• 2009

Purpose: Helicobacter (H) pylori infection has been considered the most important cause of gastritis, dyspepsia, and gastroduodenal ulcer. Radioiodine can be accumulated in the remaining thyroid tissue, salivary gland, and stomach. We investigated if the high radiation induced by radioiodine in the stomach after high dose radioiodine therapy (HD-RIT) is effective in the eradication of H. pylori infection. Materials and Methods: One hundred ninety nine patients (M:F=33:166, age $46.7{\pm}12.3$ years) who had HD-RIT (dose $159.1{\pm}25.9\;mCi$, range 120-250 mCi) after thyroidectomy due to well differentiated thyroid cancer were enrolled. To detect H. pylori infection, the urea breath tests (UBT) were performed at 1 hour before HD-RIT and at 4 weeks after HD-RIT. The results of UBT were classified as positive (${\geq}50\;dpm$) or negative (<50 dpm), and analyzed its values. Results: Of 199 patients, 103 (51.8%) patients had positive UBT before HD-RIT. Of these, 80 patients had follow-up UBT after HD-RIT. Among them, 76 (95.0%) patients had persistent positive UBT and only 4 (5.0%) patients were changed negative UBT. Among 76 patients with persistent positive UBT, 26 (34.2%) patients had increased the values of follow-up UBT, 49 (64.5%) had decreased them, and 1 (1.3%) had shown the same value. The different values of UBT between before and after HD-RIT were $62{\pm}66.1\;dpm$ in increased one of follow-up UBT, and $153.3{\pm}157.1\;dpm$ in decreased one of follow-up UBT. Conclusion: We conclude that the radiation induced by HD-RIT is ineffective in the eradication of H. pylori infection. However, it could be influential the degree or distribution of H. pylori infection.

• 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.

• Journal of radiological science and technology
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• v.4 no.1
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• pp.55-62
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• 1981

This study was conducted, during the period of 20-30th, July in 1981, to survey measurement methods in thyroid uptake rate test in Seoul city. The results were summarized as follows: 1. For the great part of nuclear medcine department, a mount of radioiodine($^{131}I$) administrated to the patients was $50-100{\mu}Ci$ in thyroid uptake rate test. 2. Distribution of scintillation, counter with crystal size of $1\frac{1}{2}inch$ was 43%, 3inch(22%), 2.5inch(14%) and $2\frac{1}{2}inch$ was 7% in RAI uptake rate test. 3. When RAI uptake rate test was performed, distribution of collimator in use was flat field type collimator(78%) in general and cylindrical type collimator was 22%. 4. High voltage applied to the P-M tube was $900{\sim}1000V$(50%) and most units provided $3{\sim}15%$ of the window range for the $^{131}I$ peak $\gamma-ray$ energy. 5. Distribution on the use of neck phantom for measurements standard solution was 57% and distribution of b filter in use for room background counts and extrathyroidal tissue was 43% and 50%. 6. The distance between the counter and the source was 25cm(58%) in measuring radioactivity of standard solution, thyroid tissue and background radioactivity count. 7. The early uptake measurements(2, 4, 6 hours) are done after administration of the radioiodine dose and also 24-hour and 48-hour uptake measurements are done in routine test.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.3-9
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• 2014

Purpose: Our goals were to evaluate the effect of high dose radioiodine treatment for thyroid cancer by taking in laxatives. Materials and Methods: Twenty patients(M:F=13:7, age $46.3{\pm}8.1\;yrs$) who underwent high dose radioiodine treatment were seperated into Group 1 taking $^{131}I$ 5,500 MBq and Group 2 with the use of laxatives after taking $^{131}I$ 5,500 MBq. The whole body was scanned 16 hours and 40 hours after taking radioactive iodines by using gamma camera, the ROIs were drawn on the gastro-intestinal tract and thigh for calculation of reduction ratio. At particular time during hospitalization, the radioactivity remaining in the body was measured in 1 meter from patient by using survey meter (RadEye-G10, Thermo Fisher Scientific, USA). Schematic presentation of an Origin 8.5.1 software was used for spatial dose rate. Statistical comparison between groups were done using independent samples t-test. P value less than 0.05 was regarded as statistically significant. Results: The reduction ratio in gastro-intestinal 16 hours and 40 hours after taking laxatives is $42.1{\pm}6.3%$ in Group 1 and $72.1{\pm}6.4%$ in Group 2. The spatial dose rate measured when discharging from hospital was $23.8{\pm}6.7{\mu}Sv/h$ in Group 1 and $8.2{\pm}2.4{\mu}Sv/h$ in Group 2. The radioactivity remaining in the body is much decreased at the patient with laxatives(P<0.05). Conclusion: The use in combination with laxatives is helpful for decreasing radioactivity remaining in the body. The radioactive contamination could be decreased at marginal individuals from patients.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.653-659
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• 2019

The purpose of this study is to measure the (air dose rate of radiation dose) the discharged patient who was administrated high dose $^{131}I$ treatment, and to predict exposure radiation dose in public person. The dosimetric evaluation was performed according to the distance and angle using three copper rings in 30 patients who were treated with over 200mCi high dose Iodine therapy. The two observer were measured using a GM surverymeter with 8 point azimuth angle and three difference distance 50, 100, 150cm for precise radion dose measurement. We set up three predictive simulations to calculate the exposure dose based on this data. The most highest radiation dose rate was showed measuring angle $0^{\circ}$ at the height of 1m. The each distance average dose rate was used the azimuth angle average value of radiation dose rate. The maximum values of the external radiation dose rate depending on the distance were $214{\pm}16.5$, $59{\pm}9.1$ and $38{\pm}5.8{\mu}Sv/h$ at 50, 100, 150cm, respectively. If high dose Iodine treatment patient moves 5 hours using public transportation, an unspecified person in a side seat at 50cm is exposed 1.14 mSv radiation dose. A person who cares for 4days at a distance of 1 meter from a patient wearing a urine bag receives a maximum radiation dose of 6.5mSv. The maximum dose of radiation that a guardian can receive is 1.08mSv at a distance of 1.5m for 7days. The annual radiation dose limit is exceeded in a short time when applied the our developed radiation dose predictive modeling on the general public person who was around the patients with Iodine therapy. This study can be helpful in suggesting a reasonable guideline of the general public person protection system after discharge of high dose Iodine administered patients.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.110-119
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• 2003

Purpose: Radioiodine (I-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. Materials and Methods: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age $50{\pm}11$ years) of papillary thyroid cancer. Among them 43 patients were treated with ${\Leq}7.4GBq$, while 15 patients with ${\geq}9.25GBq$. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up I-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. Results: MPD measured by CF method using tracer and therapeutic doses were $13.3{\pm}1.9\;and\;13.8{\pm}2.1GBq$, respectively (p=0.20). They showed a significant correlation (r=0.8, p<0.0001). Exposed doses to blood measured by CF and biological methods were $1.54{\pm}0.03\;and\;1.78{\pm}0.03Gy$ (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-dose group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). Conclusion: Measurement of MPD using CF method is reliable, and the high-dose I-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.