131I Scan Research Articles

Captación de I-131 en un quiste renal: un resultado falso positivo

We present the case of a 60-year old male with a follicular pattern of multifocal invasive papillary thyroid carcinoma who had undergone total thyroidectomy. During post-surgical follow-up with I-131 scan, a I-131 deposit was observed in the upper left hemiabdomen. Due to suspicion that it could be a metastasis, an ultrasound and CT scan were performed, with the subsequent diagnosis of a left simple serous renal cyst. Once confirmed, drainage was performed under ultrasound control, obtaining I-131 in the analysis of its content.

I-131-uptake in renal cyst: a false positive result

We present the case of a 60-year old male with a follicular pattern of multifocal invasive papillary thyroid carcinoma who had undergone total thyroidectomy. During post-surgical follow-up with I-131 scan, a I-131 deposit was observed in the upper left hemiabdomen. Due to suspicion that it could be a metastasis, an ultrasound and CT scan were performed, with the subsequent diagnosis of a left simple serous renal cyst. Once confirmed, drainage was performed under ultrasound control, obtaining I-131 in the analysis of its content.

Usefulness of low iodine diet in managing patients with differentiated thyroid cancer - initial results

BackgroundLow iodine diet (LID) is recommended in patients with differentiated thyroid cancer before radioiodine administration. Patients with increased thyroglobulin (Tg) level, but negative 131I whole body scan present diagnostic and therapeutic dilemma. This study was designed to evaluate the benefit of a two-week LID in patients with elevated serum Tg levels and negative 131I whole body scans.Patients and methods.For the impact assessment of two-week LID on radioiodine tissue avidity, radioiodine scans before and after LID were compared. Sixteen patients with serum Tg > 2 μg/L, negative Tg-antibodies, and negative radioiodine scans underwent two-week LID before the 131I administration. Fourteen patients underwent diagnostic scanning and two patients received radioiodine therapy. Iodine concentration in the morning urine specimens were measured in each patient, a day before and 15th day after starting LID.ResultsFollowing self-managed LID, patients were able to significantly reduce their iodine body content by 50% (range 28–65%, p<0,001). 13 patients (82%) accomplished mild iodine deficiency (50-99 μg/L) and one patient (6%) achieved targeted moderate iodine deficient state (<50 μg/L). All diagnostic post-LID scans were negative. Both post-therapy 131I scans showed radioiodine accumulation outside of normal 131I distribution (neck region and diffuse hepatic uptake). This study demonstrated that two-week LID is effective way to decrease total body iodine content, although without a visible effect on post-LID diagnostic 131I scans.ConclusionsA more stringent dietary protocol and longer iodine restriction period are probably needed to achieve targeted moderate iodine deficiency in patients preparing for 131I administration. This might result in higher radioiodine avidity of thyroid remnant/metastases.

Use of 18FFDG-PET in patients with suspicion of recurrent differentiated thyroid cancer by elevated antithyroglobulin antibodies levels and negative 131I scan

Aim To evaluate the utility of 18FFDG-PET for patients diagnosed of differentiated thyroid carcinoma who present risk of disease and invaluable levels of thyroglobulin (Tg) by the presence of antibodies antithyroglobulin (AbTg). Material and methods Retrospective study of 7 women of 40 years old and histological diagnosis of differentiated thyroid cancer (7 papillary tumours) that were sent to our department for the accomplishment of 18FFDG-PET study because of suspicion of disease, due to 131I negative and high levels of AbTg, between the year 2002 and 2007. 11 PET scans were obtained after the intravenous injection of 370–434 MBq of 18FFDG in normoglycemia conditions and previous administration of muscle relaxant, hydration and diuretic. The results of 18FFDG-PET scans were confirmed by pathologic examination or clinical outcome and radiographic examination for more than 24 months. Results The prevalence of recurrence in our population was 57.14%. All patients presented levels of Tg lower than 3 ng/dl and AbTg superior to 200 UI/ml. Three patients had precedent thyroiditis. Out of 11 scans performed 3 of them were negative and 8 cases were found positive. It ruled out the existence of disease in three patients and localized the presence of recurrence in 4 patients. Conclusion 18F-FDG-PET is a useful diagnostic tool for the detection of recurrence as well as to rule out the existence of disease with a high accuracy, in patients with differentiated thyroid carcinoma with 131 I whole body scan negative but with pathological elevation of antithyroglobulin antibodies.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients affected by differentiated thyroid carcinoma, high thyroglobulin level, and negative 131I scan: review of the literature

Differentiated thyroid carcinoma (DTC) is a slow-growing tumor that represents 1% of all malignant tumors and is the most frequent endocrine cancer. ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) imaging is an increasingly important imaging tool in oncology and is still under investigation in numerous studies looking into its efficacy and cost-effectiveness. Despite the fact that ¹⁸F-FDG-PET/CT has been shown to be a powerful and accurate diagnostic tool in patients affected by DTC with high serum thyroglobulin (Tg) levels and negative radioiodine (¹³¹I) total body scan, its definitive role is not completely clear, in particular regarding the role of thyroid stimulating hormone (TSH) and Tg value "cutoff" over which is better to perform the study. In this review, these issues are analyzed to clarify controversial aspects and identify established cornerstones. In particular, the literature analysis suggests that levothyroxine withdrawal is preferable in cases of relatively low Tg levels (<10 ng/ml) and good clinical compliance to hypothyroidism. Moreover, recombinant thyrotropin stimulating hormone (rTSH) could be a preferable alternative in patients clinically unable to tolerate therapy withdrawal. A Tg cutoff level over which to perform the study seems to be 10 ng/ml, a reasonable value maintaining high accuracy in terms of a good compromise between sensitivity and specificity.

Dietary Iodine Restriction in Preparation for Radioactive Iodine Treatment or Scanning in Well-Differentiated Thyroid Cancer: A Systematic Review

Dietary iodine is often restricted before radioactive iodine (RAI) scanning or treatment of well-differentiated thyroid cancer. Our objective was to examine the impact of a low-iodine diet (LID) before RAI treatment or scanning on the following outcomes: (i) the efficacy of thyroid remnant ablation (or residual disease elimination), (ii) urinary iodine measurements, (iii) RAI kinetics, and (iv) long-term thyroid cancer outcomes. We performed a systematic review of the English literature. We searched four electronic databases and conducted a hand search. Two reviewers independently screened citations and reviewed full-text articles and reached consensus on included articles. Two reviewers independently abstracted data. We reviewed 76 abstracts or citations and 26 full-text articles. Eight studies were included in the review. The most commonly studied diets allowed ≤ 50 µg/day of iodine for 1-2 weeks. In one study, 6-month successful remnant ablation rates were higher in patients following an LID than in controls. However, in another study, there was no significant benefit of an LID. LIDs reduce urinary iodine measurements and appear to increase I-131 uptake or lesional radiation compared to regular diets. No studies have examined long-term recurrence or mortality rates. Given that LIDs reduce urinary iodine measurements, increase I-131 uptake, and possibly improve efficacy of I-131 treatment, we currently favor the use of a 1-2-week LID before I-131 therapy or scanning. However, more research is needed to clarify the role of this dietary intervention.

Tumor thrombus in the great veins from papillary carcinoma of the thyroid:131I scan findings

甲状腺乳头状癌侵犯大静脉并形成瘤栓属罕见并发症。增强CT扫描、超声和正电子发射断层显像（PET）检查均能发现血栓，但无法判断血栓的性质。利用分化型甲状腺癌摄取碘的特性，^131Ⅰ扫描可以区分甲状腺癌造成的瘤栓与普通静脉血栓。

Prolonged Treatment With Antithyroid Drugs

Objective: To describe a case where continuous use of antithyroid medications was safely and effectively employed for the treatment of hyperthyroidism over a period of 14 years in a patient who refused radioactive ablative therapy and surgery. Case Report: The patient is a 71-year-old woman who presented with complaints of tachycardia and tremors along with a diffusely enlarged goiter without appreciable nodules. At the time of evaluation, she was clinically and biochemically hyperthyroid. An I123 thyroid uptake and scan revealed a toxic multinodular goiter. She was started on propylthiouracil therapy, which was discontinued due to generalized pruritus. After approximately 4 months of refusing alternative antithyroid therapy, she was started on methimazole. In the subsequent 14 years of management, she relapsed 3 times off antithyroid drugs. However, she never developed any major side effects with the maintenance of methimazole dose of 5 mg daily. Conclusions: The goal of treatment for hyperthyroidism is to render the patient euthyroid safely. However, when treated with radioactive ablative therapy or surgery, the patient is at high risk of being on lifelong thyroxine therapy. Therefore, it appears reasonable that well-informed patients who would prefer lifelong antithyroid therapy, as opposed to lifelong thyroxine therapy, should be given that option.

Judicious use of recombinant TSH in the management of differentiated thyroid carcinoma

To evaluate the feasibility of using recombinant human TSH (rhTSH) in conjunction with ¹³¹I to treat patients with differentiated thyroid carcinoma. Between July 2003 and April 2009, 14 patients [mean age, 39.1 years (range 14-71 years)], of whom seven were treated for remnant ablation and seven for irresectable or metastatic disease, received rhTSH-aided ¹³¹I therapy. None had an adequate rise in TSH. The mean ¹³¹I dosage administered was 5206.3 MBq. Baseline thyroglobulin/anti-thyroglobulin (Tg/anti-Tg) and TSH levels were documented. rhTSH (0.9 mg) was given intramuscularly on days 1 and 2, and TSH levels were recorded. ¹³¹I was given when the TSH level rose to >30 μIU/ml. Tg/anti-Tg levels were measured at 3-month intervals. A ¹³¹I whole-body scan (¹³¹I scan) was performed 6 or 12 months after treatment. The baseline median valid Tg and TSH levels were 76.2 ng/ml (range 14.1 to >30000) and 3.63 μIU/ml (range 1.36-11.0), respectively. The rise in TSH level was 34.8-96.9 μIU/ml after the first rhTSH injection and 33.1 to >75 μIU/ml after the second injection. The post-therapy ¹³¹I scan showed uptake at disease sites in all patients, indicating the initial empirical adequacy of treatment. Follow-up ¹³¹I scan was positive for four patients, but negative for three of these patients after subsequent therapy. Complete resolution of disease was seen in eight patients and partial resolution in four after 3 months of therapy; one had stable disease; and in one patient with progressive disease, complete resolution was achieved after repeated ¹³¹I doses with thyroxine withdrawal. After a median follow-up of 39.2 months, all patients were alive and no disease recurrence was observed. The overall response rate at 3 months was 86% and had improved to 93% at the time of this review. The final ablation rate in seven patients was 100%. Apart from notable neck swelling in four patients, which was responsive to medication, and headache in two patients, no significant short-term side-effects of therapy were seen. In our setting, the use of rhTSH-aided ¹³¹I ablation and treatment was safe and effective.

Tumor Thrombus in the Great Veins from Papillary Carcinoma of the Thyroid: 131I Scan Findings

Tumor invasion of great veins and forming thrombus is a rare complication in papillary carcinoma of thyroid. Contrast computed tomography, ultrasound, and positron emission tomography scan can demonstrate the thrombus but will not help to diagnose the nature of the thrombus. Demonstration of the cause of the thrombus by (131)I scan is possible because tumor tissue in the vein will be iodine avid, but simple thrombus will not.

Radioiodine Accumulation in a Large Adnexal Cystadenofibroma

Posttherapy or diagnostic whole-body radioiodine (131I) scans are conducted to observe metastases of differentiated thyroid carcinomas. Sometimes, false-positive scans occur due a variety of lesions. Here we report a patient with marked radioiodine accumulation in a large adnexal cystadenofibroma, a benign ovarian tumor. A 51-year-old woman underwent subtotal thyroidectomy due to an enlarged-multinodular goiter that caused mild compression to trachea. In her preoperative neck ultrasonography, there were mixed cystic-solid nodules without suspicious ultrasound features that were smaller than 1 cm. Pathologic examination revealed multifocal papillary thyroid carcinoma. The residual thyroid tissue was ablated with 3.7 GBq radioiodine (131I) when the serum thyroglobulin concentration was 28.7 ng/mL and the serum thyroid-stimulating hormone level was 50 microIU/mL. A posttherapy whole-body scan on the 10th day after ablation revealed well-demarcated, circumscribed radioiodine uptake in the right pelvic region. Pelvic ultrasonography revealed a solid-cystic lesion with a diameter of 9 cm in the right pelvic region. Six months later, the lesion accumulated marked radioiodine in the whole-body scan (with 185 MBq 131I). The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Pathologic examination revealed a benign cystadenofibroma without any coexisting thyroid tissue. As far as we can ascertain, this is the first report of a radioiodine-accumulating cystadenofibroma. The mechanism for radioiodine accumulation in this patient's tumor is unclear.

Detection of Metastases to Internal Jugular Vein and Superior Vena Cava on 131-I Scan

Abstract: We report a rare case of a tumor thrombus in the right internal jugular vein (IJV), superior vena cava (SVC), and right subclavian vein due to metastatic thyroid carcinoma, which was detected on an 131-Iodine whole-body scan. A 48-year-old man with a case of follicular variant of papillary carcinoma thyroid was treated twice with high doses of I-131, 188, and 185 mCi (6956 and 6845 MBq respectively), post total thyroidectomy. His post-therapy scan showed an elongated area of I-131 concentration in the right lower neck, which extended to the upper mediastinum Serum thyroglobulin levels were elevated on both occasions to more than 800 ng/mL. As this appeared resistant to radioactive iodine, the patient was referred for surgical management. CT scan was done, which showed a heterogeneously enhancing thrombus in the right IJV, extending to the confluence of the brachiocephalic veins and into the superior vena cava (SVC). A nonenhancing thrombus was also seen in the right subclavian vein. Per-operatively, it was found that the patient had a thrombus in the right IJV, SVC, and right subclavian vein. The patient underwent right IJV thrombectomy with partial resection of the right subclavian vein and repair of the SVC. The histopathology was follicular thyroid carcinoma forming a tumor thrombus in the IJV, SVC, and right subclavian vein. A large dose I-131 scan done 6 weeks postsurgery revealed no abnormal concentration in the whole-body scan. Though the Tg levels were still elevated, it had now decreased to 121 ng/mL.

A Comparison Between Diagnostic I-123 and Posttherapy I-131 Scans in the Detection of Remnant and Locoregional Thyroid Disease

The aim of this study was to compare pretherapy diagnostic I-123 scans with 7-day posttherapy I-131 scans days in detecting remnant thyroid disease as well as locoregional metastases in patients who had undergone thyroidectomy for differentiated thyroid cancer. The I-123 and I-131 scans from 53 patients were reviewed. The number of lesions identified on each scan was compared as well as the relative intensity of each lesion on the I-123 and I-131 scans using region-of-interest-derived lesion to background ratios. For the I-123 diagnostic scans, 1.0 to 1.6 mCi of activity was administered orally 24 hours before scan acquisition. Patients received therapeutic doses of I-131 ranging from 30.7 to 362.2 mCi orally, on the same day but after acquisition of the I-123 scan. All posttherapy I-131 scans were performed 7 days after radioablative therapy with I-131. Of the 53 patients, 14 had concordant scans, with an equal number of lesions detected by both scans. Thirty-nine I-123/I-131 scan pairs showed discordance, with 27 patients demonstrating more lesions on the I-123 scans. Of the 142 total lesions, 35% were detected only by I-123 pretherapy images compared with 15% detected only on posttherapy images. In a subgroup of 42 patients I-123 scans showed 56 lesions (out of a total of 116) that demonstrated either a better lesion to background ratio than I-131 or were seen exclusively by I-123. The use of diagnostic I-123 pretherapy scintigraphy seems to be superior in many patients to posttherapy I-131 imaging obtained at 7 days in detecting locoregional metastases or remnant in postsurgical patients. This is likely due to the fact that 1 week is too long to wait to perform posttherapy imaging.

Comparisons of I-123 diagnostic and I-131 post-treatment scans for detecting residual thyroid tissue and metastases of differentiated thyroid cancer

We assessed the performance of 37 MBq I-123 as a diagnostic imaging agent in patients with differentiated thyroid cancer using comparisons with their corresponding high-dose post-treatment I-131 scans. We reviewed diagnostic I-123 whole-body scans and post-treatment I-131 scans of 69 patients who underwent I-131 therapy for differentiated thyroid carcinoma (47 papillary and 22 follicular). Diagnostic scans were performed 24 h following the oral administration of 37 MBq of I-123. I-131 doses were administered 3 days after the I-123 diagnostic scans using 2.22-7.4 GBq (median = 5.55 GBq). All images for diagnostic I-123 scans and the corresponding post-treatment I-131 scans were interpreted by consensus of at least 2 experienced radiologists. They evaluated the accumulations of radioiodine in the following 5 sites: thyroid bed, cervical and mediastinal lymph nodes, lung, bone and others. The concordance rates between I-123 scans and I-131 scans were calculated. A total of 108 sites were identified on the post-treatment I-131 scans. Seventy-seven sites (71%) were also identified on the I-123 diagnostic scans. The concordance rates between I-123 diagnostic scans and I-131 post-treatment scans were high for thyroid bed and bone metastases (89 and 86%, respectively), while they were low for lymph node and lung metastases on post-treatment scans (61 and 39%, respectively). Diagnostic scanning with relatively low dose I-123 is not always predictive of subsequent therapeutic I-131 uptake, especially for lymph node and lung metastases of differentiated thyroid cancer.

Value of 18F-FDG-PET/PET-CT in differentiated thyroid carcinoma with radioiodine-negative whole-body scan: a meta-analysis

The aim of this study was to evaluate the diagnostic accuracy of 18F-fluorodeoxyglucose-PET (FDG-PET) and FDG-PET/computed tomography (CT) in the detection of recurrent or metastatic differentiated thyroid carcinoma (DTC) that was not identified by radioiodine whole-body scintigraphy (WBS). A total of 25 studies (comprising 789 patients) that were published from January 1990 to September 2008 were reviewed. These studies evaluated the role of FDG-PET and FDG-PET/CT in the detection of recurrent or metastatic DTC that radioiodine WBS failed to detect. Systematic methods were used to identify, select, and evaluate the methodological quality of the studies and to summarize the overall findings of sensitivity and specificity. In total, 17 studies with 571 patients who had recurrent or metastatic DTC and a radioiodine-negative whole-body scan were collected, and the overall patient-based sensitivity and specificity of FDG-PET were 0.835 [95% confidence interval (CI): 0.791-0.873] and 0.843 (95% CI: 0.791-0.886), respectively. Of these studies, six included lesion-based data, totaling 237 lesions, and the pooled lesion-based sensitivity and specificity were 0.916 (95% CI: 0.863-0.953) and 0.775 (95% CI: 0.660-0.865), respectively. The pooled sensitivity and specificity in the DTC patients who presented with elevated serum thyroglobulin and negative 131I scan were 0.885 (95% CI: 0.828-0.929) and 0.847 (95% CI: 0.715-0.934), respectively. In the six studies where the 165 patients were diagnosed by using FDG-PET/CT, pooled sensitivity and specificity were 0.935 (95% CI: 0.870-0.973) and 0.839 (95% CI: 0.723-0.920), respectively. FDG-PET is especially effective in detecting patients with elevated thyroglobulin levels and normal radioiodine WBS; FDG-PET/CT is a more sensitive method in the follow-up of thyroid cancer recurrence or metastases, particularly in those with negative WBS.

Radioiodine Therapy for Thyroid Cancer Depicted Uterine Leiomyoma

A 55-year-old woman underwent radioiodine therapy for papillary carcinoma of the thyroid. Post-therapeutic I-131 scan revealed radioiodine uptake in the pelvic region and in the thyroid bed. CT revealed a huge mass connected to the uterus. The tumor was operated on and histologically proven to be a leiomyoma of the uterus. Some physiological conditions or nonthyroidal diseases can cause false positives in patients with postoperative thyroid cancer. We suggest that uterine leiomyoma might be added to the pitfall list, although the mechanism of I-131 uptake remains unclear.

Effectiveness of retinoic acid treatment for redifferentiation of thyroid cancer in relation to recovery of radioiodine uptake

Retinoic acid (RA) treatment has been used for redifferentiation of metastatic thyroid neoplasia that have lost radioiodine (131I) uptake with heterogeneous results. Retrospective analysis of the recovery rate of 131I uptake after RA treatment in patients from 11 Spanish hospitals. Twenty-seven patients (14 men, 13 women) with papillary [21], follicular [4], and oncocytic [2] thyroid cancer initially treated with total thyroidectomy plus 131I, and with 131I negative metastatic disease, were given 13-cis RA (0.66-1.5 mg/kg for 5-12 weeks) followed by a therapeutic 131I dose (3700-7400 MBq); 3 months later thyroglobulin levels and computed tomography imaging were performed. In 9 out 27 cases (33%) (8 papillary, 1 follicular) optimal positive 131I scan was observed after RA treatment; in the remaining 18, 10 had a suboptimal uptake (7 papillary, 2 follicular, 1 oncocytic) and in the rest there was no 131I uptake recovery (6 papillary, 1 follicular, 1 oncocytic). In 17 positive responses to RA (either optimal or suboptimal) in which image follow-up was available, decrease or stabilization of metastatic growth was observed in 7, while tumor mass increased at short term in the remaining 10. No major side effects were detected. Quite a high rate of 131I uptake recovery after RA treatment may be obtained in advanced differentiated thyroid cancer, but the potential modification of the natural course of the disease is uncertain. A better biological characterization of these tumors allowing the identification of potential responders to RA may improve the outcome of RA coadjuvant therapy.

Clinical Implications of Diffuse Hepatic Uptake Observed in Postablative and Post-Therapeutic I-131 Scans

Diffuse hepatic uptake of I-131 either on diagnostic or post-therapeutic scans is a usual finding in patients with differentiated thyroid carcinoma. The aim of this study was to evaluate the frequency and clinical significance of diffuse hepatic uptake of radioiodine on post-therapeutic (PT) and postablative (PA) whole-body scans.A total of 720 PA and 172 PT I-131 scans in a total of 732 patients with differentiated thyroid carcinoma were retrospectively reviewed. Residual thyroid tissue and diffuse liver uptake of I-131 were classified from 0 to 4. The correlation between the liver and thyroid remnant uptake score, dose of radioiodine, serum thyroglobuline (Tg), liver function test levels (ALT, AST), liver ultrasonography, presence of metastatic foci, and recurrent disease were examined.Diffuse hepatic uptake was observed in 701 of 722 (94.2%) PA and 162 of 172 (97%) PT whole body I-131 scans. Hepatic radioiodine uptake was positively correlated with the dose of administered I-131 and increased levels of serum AST and ALT. Liver uptake scores of patients with hepatosteatosis were significantly higher than all study groups. However, no evidence of a relationship between diffuse visualization of liver and serum thyroglobulin levels, uptake score of thyroid remnants, presence of local or distant metastatic foci on I-131 scan, and recurrence rate could be demonstrated.The lack of correlation between hepatic radioactive iodine (RAI) uptake and Tg levels, functioning metastatic tissue or thyroid remnants suggests that this finding may be related to factors other than thyroid tissue. The positive correlation between administered RAI dose, hepatic enzymes and hepatosteatosis support the conclusion that diffuse hepatic RAI uptake may be related to different mechanisms as well.

False-Positive Whole-Body I-131 Scan In Thyroid Carcinoma Caused By Gastrooesophageal Reflux Disease

Many false-positive findings on I-131 scans have been reported. Recognition of them may avoid unnecessary repeated therapeutic doses of radioactive iodine. The authors describe a false positive cervical and mediastinal radioiodine uptake due to gastro oesophageal reflux disease in a 63 yr-old man with papillary thyroid cancer. Trough this case report, causes of such scintigraphic features are reviewed.

The Role of Radioactive Iodine Therapy in Young Patients With Papillary Thyroid Cancer

The aim of this study was to investigate the outcome of postoperative radioactive iodine (I-131) therapy in young patients with papillary thyroid carcinoma (PTC). This retrospective study reviewed the medical records of primary PTC patients, 18 years old or younger, who were treated at Chang Gung Medical Center in Taiwan from January 1977 to December 2006. Forty-eight patients who had undergone postoperative I-131 therapy with a minimum dose of 1.1 GBq (30 mCi) were enrolled in this retrospective study. At the end of follow-up, patients were classified as "local disease" or "distant metastases" according to I-131 scan results. The I-131 whole-body scan results revealed "local disease" in 34 patients, and "distant metastases" in 14 patients. Patients with distant metastases received significantly larger doses of I-131 than those with local disease (P = 0.0086). One-month postoperative serum thyroglobulin differed markedly between patients with local disease and those with distant metastases (P = 0.001). After a mean follow-up period of 11.2 +/- 5.7 years, overall survival in the 48 patients was 97.9%. I-131 therapy is effective for young PTC patients, and should be given to all young PTC patients postoperatively in addition to thyroid hormone administration, particularly those with distant metastases.