Radionuclide therapies have been applied in the diverse fields of medicine, and it has been demonstrated the usefulness of it, especially in the field of oncology. Accurate dosimetric assessment is imperative during radionuclide therapy, in order to optimize the treatment efficacy for target sites and to minimize the radiation exposure for normal organ. Recent advancement in imaging technology permits the precise determination of the absorbed dose non-invasively. This imaging based dosimetry can be routinely applicable to the bedside in the near future.
Treatment Outcome

PURPOSE: Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. Materials and METHODS: In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F=28:27) of low-likelihood for coronary artery disease were enrolled and (201)Tl rest / (99m)Tc-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. (201)Tl rest / (99m)Tc-MIBI stress / (201)Tl 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, Q(delay) (perfusion measurement), delta(delay) (Q(delay)-m) and Z(delay) ((Q(delay)-m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. RESULTS: Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was 51.8+/-6.5 and the highest segmental perfusion was 87.0+/-5.9, and they are 58.7+/-8.1 and 87.3+/-6.0, respectively in women. In the viability assessment, Q(delay) showed AUC of 0.633, while those for delta(delay) and Z(delay) were 0.735 and 0.716, respectively. The AUCs of delta(delay) and Z(delay) were significantly higher than that of Q(delay) (p=0.001 and 0.018, respectively). The diagnostic performance of delta(delay), which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. CONCLUSION: On automatic quantification of myocardial perfusion SPECT, the normal variation of perfusion measurements were considerable among segments. In the viability assessment, the parameters considering normal variation showed better diagnostic performance than the direct perfusion measurement. This study suggests that consideration of normal variation is important in the analysis of measurements on quantitative myocardial perfusion SPECT.
Area Under Curve ; Coronary Artery Bypass ; Coronary Artery Disease ; Female ; Humans ; Male ; Myocardium ; Perfusion ; ROC Curve ; Sensitivity and Specificity ; Tomography, Emission-Computed, Single-Photon ; Transplants

Background/Objectives: To analyze the clinical characteristics of differentiated thyroid cancer (DTC) in children and adolescents.Materials & Methods: Medical records of 31 DTC cases that were diagnosed and treated at Korea Cancer Center Hospital between 2002 and 2018 were retrospectively reviewed. Results: Most cases were papillary carcinoma (n=26), with female predominance (n=25). Median age was 16.4 years (range, 11.9-18.6 years). Extrathyroidal extension was present in 24 cases. Twenty cases had tumor involvement at cervical lymph nodes and three had lung metastasis. Twenty-two patients received radioactive iodide treatment with a median cumulative dose of 300 mCi (range, 100-920 mCi). During a median follow-up of 68.2 months (range, 2.3-191.4 months), serum thyroglobulin level was elevated in 15 patients. Among them, two cases had remnant thyroid tissue, 4 had recurrence at cervical lymph nodes, and the remaining 9 did not have any detectable lesion. All were alive, and 5-year event-free survival (EFS) was 45.2±10.1%. Age £15 years, tumor size, lymph node status (N1b), and distant metastasis had negative effects on EFS. On multivariate analysis, age and tumor size had prognostic significance. Conclusion For DTC of children and adolescents (£18 years old), age ≤15 years and tumor size were prognostic factor. Therefore, patients in this age group need meticulous follow-up. Further studies are necessary to answer the potential influence of age on the incidence and behavior of DTC.

Background/Objectives: To analyze the clinical characteristics of differentiated thyroid cancer (DTC) in children and adolescents.Materials & Methods: Medical records of 31 DTC cases that were diagnosed and treated at Korea Cancer Center Hospital between 2002 and 2018 were retrospectively reviewed. Results: Most cases were papillary carcinoma (n=26), with female predominance (n=25). Median age was 16.4 years (range, 11.9-18.6 years). Extrathyroidal extension was present in 24 cases. Twenty cases had tumor involvement at cervical lymph nodes and three had lung metastasis. Twenty-two patients received radioactive iodide treatment with a median cumulative dose of 300 mCi (range, 100-920 mCi). During a median follow-up of 68.2 months (range, 2.3-191.4 months), serum thyroglobulin level was elevated in 15 patients. Among them, two cases had remnant thyroid tissue, 4 had recurrence at cervical lymph nodes, and the remaining 9 did not have any detectable lesion. All were alive, and 5-year event-free survival (EFS) was 45.2±10.1%. Age £15 years, tumor size, lymph node status (N1b), and distant metastasis had negative effects on EFS. On multivariate analysis, age and tumor size had prognostic significance. Conclusion For DTC of children and adolescents (£18 years old), age ≤15 years and tumor size were prognostic factor. Therefore, patients in this age group need meticulous follow-up. Further studies are necessary to answer the potential influence of age on the incidence and behavior of DTC.

PURPOSE: Incidental parotid lesions on F-18 FDG-PET can mimic distant metastasis of underlying malignancy. The prevalence and the clinico-pathologic findings of PET positive parotid lesions have not been known. We investigated how often incidental parotid lesions are found on clinical FDG-PET studies and what the clinico-pathologic characteristics of those parotid lesions are in the present study. MATERIALS AND METHODS: We retrospectively reviewed 3,344 cases of FDG-PET which had been obtained in our hospital from May 2003 to Dec 2006. The indications of FDG-PET were: evaluation of known/suspected cancer (n=3,212) or screening of cancer in healthy subjects (n=132). Incidental parotid lesion on FDG-PET was defined as an un-expected FDG uptake in one of parotid glands which was not primary target lesion of current FDG-PET. FDG uptake was represented by maximum standardized uptake value (maxSUV). Final diagnosis was made by pathologic analysis or clinical follow-up assessment. RESULTS: Fifteen (0.45% = 15/3,344) incidental parotid lesions were found and they were all benign lesions. The maxSUV ranged from 1.7 to 8.6 (mean+/-s.d.=3.7+/-1.9). Final diagnoses of the incidental parotid lesions were; Warthin's tumor (n=2), pleomorphic adenoma (n=1), other un-specified benign lesion (n=1), and benign lesions under bases of imaging studies (n=3) and of clinical follow-up (n=8). CONCLUSION: All of incidentally found parotid lesions in clinical FDG-PET studies were confirmed as benign lesions with prevalence of 0.45%. Close follow up using PET or CT might be a reasonable approach for determining the nature of incidentally found parotid lesions.
Adenoma, Pleomorphic ; Diagnosis ; Follow-Up Studies ; Mass Screening ; Neoplasm Metastasis ; Parotid Gland ; Prevalence* ; Retrospective Studies

OBJECTIVE: Considering the increased use of [18F]FDG PET or PET/CT, the clinical significance of thyroid incidentalomas is the subject of controversy. The aim of this study was to determine the incidence of malignancies associated with thyroid incidentalomas detected by pre-treatment PET or PET/CT in patients with cervical cancer. METHODS: We retrospectively reviewed the medical records of patients with cervical cancer who had thyroid incidentalomas detected by pre-treatment PET or PET/CT and were treated at our institute between January 2001 and December 2009. RESULTS: Of 327 patients who underwent pre-treatment PET or PET/CT, 33 patients had thyroid incidentalomas (10.1%) and 4 patients were diagnosed with thyroid malignancies by percutaneous needle aspiration (PCNA) or surgery. To put it concretely, of 33 patients with thyroid incidentaloma, 16 patients had a diffuse uptake and 17 patients had a focal uptake. Four of 17 patients with focal uptake were diagnosed with thyroid malignancies (23.5%). One patient with a focal uptake had an atypical cell based on PCNA, but did not undergo additional studies. The mean SUVmax of thyroid malignancies did not differ from that of benign thyroid diseases. CONCLUSION: Thyroid incidentalomas are frequently detected by pre-treatment PET or PET/CT in patients with cervical cancer. Focal uptake on PET or PET/CT has a high risk of thyroid cancer.
Fluorodeoxyglucose F18 ; Humans ; Incidence ; Medical Records ; Needles ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography ; Proliferating Cell Nuclear Antigen ; Retrospective Studies ; Thyroid Gland ; Thyroid Neoplasms ; Uterine Cervical Neoplasms

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate surgical completeness in endoscopic total thyroidectomy with central neck dissection via unilateral axillo-breast approach (UABA) compared with bilateral axillo-breast (BABA) and open approach (OA) by means of the radioactive iodine uptake (RAIU) ratio and thyroglobulin (Tg) of remnant thyroid. SUBJECTS AND METHOD: From July 2010 to March 2013, 82 patients who had underwent total thyroidectomy with central neck dissection and postoperative radioactive iodine (RAI) ablation for papillary thyroid carcinoma were enrolled. Of these patients, 27 patients underwent UABA, 24 patients BABA, and 31 patients OA. Clinicopathologic data, surgical outcome, stimulated Tg and RAIU ratio on the first postoperative RAI ablation scan were compared among 3 groups. RESULTS: Patients in the endoscopic surgery groups (UABA, BABA) were younger than those in the OA groups. Invasiveness such as operation time, postoperative pain, and drain amount in UABA was less than that in BABA and severer than that in OA. Other variables regarding clinicopathologic and surgical data were not significantly different. Stimulated Tg and RAIU ratio did not show significant differences among 3 groups (p=0.659 and p=0.664). CONCLUSION: The completeness of UABA was comparable with that of BABA and OA. The UABA may be a safe option for patients who need endoscopic thyroidectomy for papillary thyroid carcinoma.
Endoscopy ; Humans ; Iodine ; Methods ; Neck Dissection* ; Neck* ; Pain, Postoperative ; Thyroglobulin ; Thyroid Gland ; Thyroid Neoplasms ; Thyroidectomy*

BACKGROUND AND OBJECTIVES: Surgical options for low-risk papillary thyroid carcinoma (PTC) have been in debate. The purpose of this study was to analyze the treatment results of lobectomy and prophylactic ipsilateral central lymph node dissection (cND) for low-risk PTC. SUBJECTS AND METHOD: We retrospectively analyzed 906 patients who were diagnosed as PTC pre- or post-operatively and underwent lobectomy and/or prophylactic ipsilateral cND from 2001 to 2010. Studied variables were clinicopathologic data, complications, sites of recurrence, overall survival, and recurrence free survival rates. RESULTS: Fifty two (5.7%) patients showed recurrence during follow-up. Of the 52 recurrent cases, 32 (61.5%) cases recurred in a remnant thyroid only, 11 (21.2%) cases in a lymph node (LN) only, and 9 (17.3%) cases in a remnant thyroid and the LN. One (0.1%) patient showed permanent vocal cord palsy. Overall survival rate at 10 years was 99.6%. Overall recurrence free survival rates at 5 and 10 years were 97.1% and 81.0%, respectively. Risk factors for recurrences were old age (>45), contralateral nodule(s) at initial surgery, large tumor, no prophylactic cND, and pathological LN metastasis. CONCLUSION: Lobectomy with prophylactic ipsilateral cND may be a good option for low risk PTC patients due to excellent overall survival rates, recurrence rates, and minimal complication rates.
Follow-Up Studies ; Humans ; Lymph Node Excision* ; Lymph Nodes* ; Neck* ; Neoplasm Metastasis ; Recurrence ; Retrospective Studies ; Risk Factors ; Survival Rate ; Thyroid Gland* ; Thyroid Neoplasms* ; Thyroidectomy ; Vocal Cord Paralysis

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.