Abnormal finding was observed in the left femoral bone density image of a 55-year-old male patient who diagnosed a breast cancer. MRI results showed that it was a benign tumor similar to liposclerosing myxofibrous tumor(LSMT) sized about 2cm at left femoral neck. Bone mineral densitometry (BMD) determined numerically with T or Z-score is an prominent method for diagnosing osteoporosis and osteopenia. However, the image is not considered in the interpretation. The role of a radiologic technologist is important in BMD and it provides significant assistance in the treatment of patients

Purpose: When vitamin D3 is deficient in the body, it leads to osteoporosis, fractures at high risk. In addition, vitamin D3 deficiency is also associated with the pathogenesis of certain cancers and other diseases including multiple sclerosis, type 1 diabetes. In fact, the number of prescriptions for vitamin D3 requested to the Department of Nuclear Medicine at Asan Medical Center was increased. As such, the examination of vitamin D3 in the Department of Nuclear Medicine is a test that provides clinically meaningful indicators. However, due to the difficulty of stopping the production of the previously used vitamin D3 RIA reagent (DIA source ImmunoAsays^®, Belgium) to measure vitamin D3, a validity assessment experiment was conducted on vitamin D3 RIA reagent (Shinjin, Korea). Materials and Methods: For about two months from February 1 to March 31, 2023, the result values of the two reagents were analyzed for various concentrations of vitamin D3 samples (N=45) requested to the our clinic. The effectiveness of the alternative reagent was evaluated using the correlation coefficient between the existing and alternative reagents. We also measured the correlation coefficient between the 25-OH-vitamin D (Total) and the vitamin D3 reagents and the correlation with high performance liquid chromatography/mass spectrometry (HPLC) was analyzed. In addition, we caculated the difference(%) of the target value of the DEQAS(vitamin D External Quality Assessment Scheme, UK). The inter assay, intra assay, analytical sensitivity and recovery were evaluated for alternative reagents. Results: The correlation coefficient between the existing and alternative vitamin D3 kits was close to 1 with R²=0.7556(p<0.001) and there was good correlation between the 25-OH-vitamin D(Total) kit and alternative vitamin D3 kit with R²=0.9409(p<0.001). The correlation coefficient between the alternative vitamin D3 kit and HPLC measurement was close to 1 with R²=0.8384(p<0.001). In case of difference(%) assessment with DECAS reagents, the alternative vitamin D3 kits showed 7.17, 10.90, 15.10, 20.63, 20.52 in January 2022 and 1.02, -0.42, -0.04, -13.62, -12.50 in July2022 respectively. As a result of measuring the intra assay, the Coefficient of Variation (CV) value of the alternative vitamin D3 kit were 13.35, 7.73, 9.28 in low, medium, high concentration respectively. In case of the intra assay, CV value were 14.65, 6.10, 7.25 in low, medium, high concentration respectively. Except the CV value of low concentration, they were acceptable. The analytical senstivity was 0 ng/mL. But the recovery rate(%) performed not good enough at 30~162. Conclusion: Alternative reagents showed high correlation with existing reagents (p<0.001), 25-OH-vitamin D (Total), and high correlation with HPLC (p<0.001) and due to its high consistency with DEQAS materials, it is thought that reagents can be replaced and provide quantitatively reliable results. Considering that the normal level of the reference value of the alternative reagent is 30 to 150 ng/mL, it does not seem to be a major clinical problem, but further experiments need to be checked. Based on this, it is thought that even if the reagent of vitamin D3 is changed, accurate test data can be continuously provided.

Purpose: Critical value report (CVR) are intended to prevent delays in diagnosis and treatment, as results outside the reference range can cause serious harm to patients. After conducting a survey on the status of warning value reporting in each institution's laboratory that performs nuclear medicine specimen testing, the level of preparedness for patient safety was identified, and the category, guidelines, and reporting system for warning value reporting tests were checked and applied effectively and objectively. The purpose of this study was to share these methods and suggest policies and plans for improvement plans. Materials and Methods: A questionnaire related to warning value reporting was prepared with 20 questions using Excel and sent by e-mail to 46 medical institutions and trusted institutions undergoing domestic nuclear medicine specimen test certification review from 2024.03.18 to 2024.4.09. Based on the contents of the questionnaire, the setting of warning value reporting items for each institution and the overall trend of work were analyzed using distribution maps, etc. Results: Of the 46 medical institutions, 32 responded via e-mail, showing a response rate of 69.5% of the 22 items. The most common warning value reporting setting item was FreeT4 (N=8), followed by HAVIgM (N=7), neonatal TSH, HBcIgM (N=6), Cyclosporine (N=4), TSH, PTH, PSA, and neonatal FT4 (N =3), Thyroglobulin (N=2), and other HCVAb, T3, AFP, ACTH, CA125, CA19-9, CA15-3, Cortisol, Aldosterone, HBsAg, AB(++), Prolactin (N= 1). It seven organizations (24.1%) set warning value reporting items due to the request from the prescription department and 19 organizations (65.5%) set their own items in preparation for each certification audit. Conclusion: The reason why each institution that conducts nuclear medicine specimen testing tends to have a high tendency to set its own warning value reporting items is not because of the demands of the prescribing department or clinician, but because it is included as an important factor in each certification review item, so the items are required by necessity. It was found that among the total responses, 6 organizations (18.7%) do not report warning values, which appears to be determined by each organization's situation. If each institution recognizes the importance of warning value reporting and sets the items and scope, it is recommended to have a warning value reporting monitoring system. Taking into account the possibility of changes in the patient population, etc., it is recommended that the prescribing department, clinicians, and quality control managers within the department establish standards. We suggest that arrangements be reviewed regularly. It is believed that if warning value reporting items and standard values are set considering the importance of patient safety, etc. , it can contribute to promoting the importance of nuclear medicine specimen testing and increasing reliability.

Purpose: Insulin assays are highly sensitive to pre-analytical handling issues. While numerous studies have reported that the stability of insulin in non-hemolyzed samples is affected by time and temperature, there is limited information regarding the impact of delayed sample separation. Although research on this topic using the electrochemiluminescence immunoassay (ECLIA) method is actively conducted both domestically and internationally, studies utilizing the immunoradiometric assay (IRMA) are primarily performed abroad. Therefore, this study aimed to evaluate the stability of insulin in response to delayed separation of primary samples and storage conditions of secondary samples using the IRMA method. Subjects and Methods: The study included a total of 21 participants. Blood samples were processed and stored under different conditions to create serum and plasma samples divided into three groups. Group A: Secondary samples were stored at room temperature for 5 hours and at 2-8 ℃ for 48 hours. Group B: Secondary samples were stored at 2-8 ℃ for 5 hours and at -24 ℃ for 48 hours. Group C: Primary samples were stored at room temperature for 5 hours and at 2-8 ℃ for 48 hours before separation. Insulin concentrations in each group were measured using the IRMA method. The measured values were compared to insulin concentrations from secondary samples separated immediately after blood collection. The stability of insulin concentrations in each group was evaluated using regression analysis and the Wilcoxon signed-rank test for non-parametric paired sample comparisons. Statistical analysis was performed with MedCalc software (ver. 22.063), and a p-value of <0.05 was considered statistically significant. Results: The serum samples separated after storing the primary samples at 2-8 ℃ for 48 hours showed a positive correlation coefficient of 0.9974. However, the percentage deviation was -19.35%, and the p-value was <0.05, indicating a statistically significant difference. Similarly, for plasma samples stored as secondary samples at 2-8 ℃ for 5 hours and 48 hours, the correlation coefficients were 0.9803 and 0.9944, respectively, showing positive correlations. However, the percentage deviations were -7.45% and -6.32%, with p-values of <0.05 for both, demonstrating statistical significance. Conclusion: This study evaluated the stability of insulin assays under various conditions of delayed sample separation and storage methods. It is recommended that insulin assays be performed immediately after blood collection by promptly centrifuging and separating the samples. When storage is necessary, it is crucial to store samples in a separated state. Serum samples were stable when stored at room temperature or at 2-8 ℃ for 5 hours, and stability was maintained even after 48 hours of storage at 2-8 ℃ or -24 ℃. However, delayed sample separation may result in significant differences in test values, emphasizing the need for careful handling and storage of samples.

Purpose: Lu-177 Dotatate SPECT/CT imaging is important for diagnosing and monitoring neuroendocrine tumors. While reconstruction protocols are well-established for scans like Tc-99m and I-131 SPECT/CT, standardized reconstruction conditions for Lu-177 Dotatate remain limited. This study aimed to determine optimal reconstruction tendencies by analyzing phantom and clinical data using different combinations of Iteration (I), Subset (S), and Gaussian Filter (GF). Image quality was assessed using standardized uptake value (SUV), contrast, and qualitative visual evaluation. Materials and Methods: Phantom and clinical images were acquired using a Symbia Intevo 16 system with MELP collimator. ACR PET phantom was prepared at a 200 mCi Dose A level. Clinical data were collected from 10 patients who underwent Lu-177 Dotatate therapy under identical acquisition conditions. SUV and contrast were measured using VOIs; phantom analysis used a 25 mm cylinder, and clinical analysis used identifiable tumors. Twenty-seven reconstruction settings were evaluated (3 I × 3 S × 3 GF combinations), and images were ranked based on SUVmax and contrast. Pearson correlation and Friedman tests with post hoc analysis were used to analyze data. Results: Increasing GF while keeping I and S constant led to decreased SUVmax. Increasing S with fixed I and GF resulted in higher SUV_max, although this effect diminished at GF=16. Similarly, increasing I with constant S and GF led to higher SUVmax, but gains were minimal at higher GF. The results for contrast indicated a decreasing trend as a higher GF was applied. Rankings of phantom and patient images based on SUVmax and contrast showed consistent top-performing conditions across both datasets. The rankings of the phantom data images and the clinical patient data based on SUVmax and contrast conditions showed that the top 40% of ranked conditions were consistent between the two datasets. Pearson correlation revealed a strong correlation in SUVmax (r=0.937) and a strong correlation in contrast (r=0.692) between phantom and patient data. Friedman analysis showed that two conditions (I16/S1/GF16 and I16/S2/GF16) had significantly lower SUVmax values compared to others (p<0.05), while the remaining 25 conditions did not differ significantly (p>0.05). Conclusion: In this study, quantitative and qualitative evaluations of Lu-177 Dotatate SPECT/CT images were performed using various reconstruction conditions based on both phantom and clinical patient data. The analysis of SUV_max and contrast revealed numerical trends depending on the variation of Iteration, Subset, and Gaussian Filter, and a strong correlation was observed between the phantom and clinical data. Statistically significant differences were confirmed for certain conditions based on SUV_max, and appropriate reconstruction settings were selected through qualitative assessment by nuclear medicine physicians. Currently, our institution has adopted two reconstruction conditions, I16/S4/GF0 and I24/S2/GF8, based on the results of this study for clinical image provision, and these settings have demonstrated stable performance in terms of image quality and interpretability.

Purpose This study evaluates the effect of uptake times (2.5 hours vs. 3.5 hours post-injection) on the diagnostic quality of whole-body bone scans using ^99mTc -DPD, focusing on contrast between bone and soft tissue. The aim is to determine whether shorter uptake times can ensure sufficient diagnostic quality while enhancing patient convenience and clinical workflow efficiency, particularly during periods of radiopharmaceutical shortages. Materials and Methods A total of 60 patients, divided into a normal group (n=30) and a lesion group (n=30), were included in this study. All scans were performed using Siemens gamma cameras equipped with LEHR collimators. Scans were conducted at 2.5- and 3.5-hours post-injection. Regions of interest (ROIs) were defined for femoral bone and adjacent soft tissue to calculate uptake ratios. Statistical analysis was performed using paired t-test to compare uptake ratios. Imaging conditions and radiopharmaceutical doses were carefully standardized across all patients to minimize variability. Results In the normal group, the mean uptake ratio increased from 70.1% ± 4.7% at 2.5 hours to 72.6% ± 4.3% at 3.5 hours, showing a statistically significant difference (p < 0.05). Similarly, in the lesion group, uptake ratios improved from 90.7% ± 4.3% to 92.7% ± 3.9%, also demonstrating statistical significance (p < 0.05). While the 3.5-hour uptake time produced slightly better lesion contrast and improved diagnostic utility, the 2.5-hour scans provided comparable results in visual quality and diagnostic accuracy, making them a viable option in resource-constrained environments. Conclusion The findings suggest that while a 3.5-hour uptake time yields optimal diagnostic quality and superior lesion contrast, the 2.5-hour time point remains a practical alternative, especially in high-demand clinical settings or during radiopharmaceutical supply constraints. This study supports the development of flexible, optimized bone scan protocols that maintain high diagnostic standards without compromising operational efficiency.

Purpose: This study aims to compare the ejection fraction (EF%) values derived from static and dynamic salivary gland scintigraphy and assess whether there are statistically significant differences between the two imaging techniques. Materials and Methods: Thirty patients (10 males, 20 females; mean age: 65.9 years) complaining of xerostomia underwent dynamic salivary scintigraphy with 185 MBq (5 mCi) of 99mTc-pertechnetate. Imaging was performed using a Discovery NM630 gamma camera (GE Healthcare, USA). Vitamin C powder (2 g) was administered as a stimulant at 40 minutes after radiotracer injection. Dynamic images were acquired at 60-second intervals for 50 minutes. Static images were reconstructed by summing specific frame sets pre- and post-stimulation. Ejection fraction was calculated using the Xeleris Functional Imaging Workstation (GE Healthcare, USA), with regions of interest applied to the right parotid and submandibular glands. Statistical analysis was conducted using paired t-tests and correlation coefficients. Results: The ejection fraction average was 81.94±7.94% when calculated using a dynamic method and 80.94±7.95% when calculated using a static method, which was larger when calculated using a dynamic method by a difference of 0.99±3.21% and the correlation was 0.918, and there was no statistically significant difference(P > 0.05). Conclusion: The scan time and equipment operation time are different according to the dynamic and static methods, and each method has advantages and disadvantages. As designating the stimulation time or image composition time, there was a limitation in deriving results according to retrospective analysis, but in this study, since there is no significant difference in the ejection fraction according to method, it is considered that the scan will proceed more efficiently if a more efficient method is selected and used for each laboratory according to the situation among the two methods.

Purpose: Breast cancer is the most common among women worldwide, with one in eight women receiving this diagnosis in their lifetime. The National Comprehensive Cancer Network (NCNN) recommends receptor type testing for all breast cancer patients, which helps predict outcomes and guide treatment decisions. Breast cancer has three subtypes: hormone receptor-positive, HER2- positive, and triple-negative breast cancer, depending on the expression of hormone receptor and HER2. The purpose of this study is to introduce a general understanding and usefulness of ¹⁸F-fluoroestradiol(FES) PET/CT imaging, and to investigate the SUVmax value of ¹⁸F-FES and ¹⁸F-FDG PET/CT Images. Materials and Methods: Summarizing of approval process by Korea Food and Drug Administration(KFDA) and national insurance benefits status of ¹⁸F-fluoroestradiol(FES) in Korea. To confirm the usefulness of ¹⁸F-FES PET/CT Scan, We analyzed the latest meta-analysis papers, and a paired-sample t-test(wilcoxon signed -rank test) was performed on SUVmax value measurements for 41 patients who underwent both ¹⁸F-FES PET/CT and ¹⁸F-FDG PET/CT within a month interval from Jan. 2022 to Dec. 2023. Results: ¹⁸F-fluoroestradiol(FES) was approved by KFDA in November 2019, and national insurance benefits were garneted by government in December 2020. Our study reveal that irrespective of the lesion's anatomical site, the ¹⁸F-FES SUVmax exhibited an average of 7.8±5.9, while the ¹⁸F-FDG SUVmax demonstrated an average of 6.3±3.3. Considering the location of the lesions within the breast only, the ¹⁸F-FES SUVmax average at 7.1±5.4, with the ¹⁸F-FDG SUVmax average at 6.2±3.5. Conversely, lesions were located outside the breast an average ¹⁸F-FES SUVmax of 8.9±6.6 and an average ¹⁸F-FDG SUVmax of 6.4±3.2. Conclusions: We can find that, there was no significant difference on SUVmax value between ¹⁸F- FES and ¹⁸F-FDG PET/CT images. However, approximately 70% of breast cancer patients are diagnosed with estrogen receptor-positive breast cancer in Korea, therefore considering the importance of hormone therapy in recurred or metastatic breast cancer treatment. ¹⁸F-FES PET/CT scan is very useful clinical implementation, when evaluating breast cancer hormone receptors through the imaging, Especially, the patients who tumor biopsy is difficult or impossible conditions.