Detection of Occult Thymoma Using Tc-99m tetrofosmin Scintigraphy / 핵의학분자영상

Tetrofosmin is a ligand that forms a lipophilic, cationic complex with Tc-99m.1) Tc-99m tetrofosmin was developed as a myocardial perfusion imaging agent and also used to depict tumors.1-3) Mediastinal tumors is also detected by Tc-99m tetrofosmin.2-5) We report a case of extracardiac mediastinal activity detected by Tc-99m tetrofosmin scintigraphy, which revealed thymoma.

Dual Lingual Thyroid Mimicking Mono-ectopic Thyroid in the Anterior View of Tc-99m Sodium Pertechnetate Thyroid Scan / 핵의학분자영상

Ectopic thyroid is not common disease and double ectopic thyroid is rare. Until January of 2008, dual ectopic thyroid has been reported only 23 cases in international literatures. Tc-99m sodium pertechnetate scan is playing an important role in the diagnosis of ectopic thyroid. In most of the cases, dual lingual thyroid tissues could be detected as two radiotracer uptake foci. We report a case of dual lingual thyroid mimicking mono-lingual thyroid in the anterior view of thyroid scan. Lateral view helped in this case to detect the dual lingual thyroid. With lateral view, the anatomical position and relationship could be examined in more detail.

Significant Mismatch between FDG Uptake and Size after Chemotherapy in a Patient with Non-small Cell Lung Cancer / 핵의학분자영상

A 75-year-old man with non-small cell lung cancer (NSCLC) underwent F-18 fluorodeoxyglucose (FDG) PET/CT for staging. PET/CT showed distant metastases to intra-abdominal lymph nodes (LNs) as well as bilateral mediastinal LNs (stage IV). He underwent PET/CT (restaging PET/CT) 1 week after the completion of first-line chemotherapy (docetaxel + carboplatin). It showed markedly increased FDG uptake in primary tumor, whereas tumor size decreased significantly, compared to prior PET/CT. This lesion was aggravated on follow-up CT 3 months after the completion of chemotherapy. Although there are several reports that FDG PET has potential to evaluate early response to chemotherapy and prognosis, there are a few cases to show mismatch between FDG uptake and size on PET/CT. Thus we report a case of NSCLC showed increased FDG uptake of primary tumor while decreased tumor size on restaging PET/CT.

Effectiveness of 99mTc-tetrofosmin for assessment of heart functions in micropigs

This study examined the suitability of a nuclear imagingtechnique using 99mTc-tetrofosmin as an agent to assess theheart functions of healthy micropigs. The mean age of thepigs was 360 days (male), and the mean body weight was35.3kg ranging from 34.5-36kg. There were no significantperfusion defects in any of the reconstructed images.Gated single-photon emission computed tomographyimaging can be used to calculate the ventricular volumeand ejection fraction (EF). In this case, an EF of 79% wascalculated from the ventricular volume of the end-systolicimage (10 ml) subtracted from that of the end-diastolicvolume (49 ml). A perfusion defect (particularly the apex,lateral wall) is unlikely because of the presence of apreserved wall motion in a segment with a defect. It isconcluded that quantitative cardiac scintigraphy, using99mTc-tetrofosmin is an adequate technique for estimatingthe heart functions of healthy micropigs.

Improved Specificity of 18F-FDG PET/CT for Lymph Node Staging of Non-Small Cell Lung Cancer Considering Calcified Lymph Node as Benign / 핵의학분자영상

PURPOSE: We evaluated the diagnostic value of 18F-FDG PET/CT (PET/CT) in lymph node staging of non-small cell lung cancer (NSCLC) considering calcification and histologic types as well as FDG uptake. MATERIALS AND METHODS: Fifty-three patients (38 men, 15 women; mean age, 62 years) with NSCLC underwent surgical resection (tumor resection and lymph node dissection) after PET/CT. After surgery, we compared PET/CT results with the biopsy results, and analyzed lymph node metastases, based on histologic types. PET diagnosis of lymph node metastasis was determined by maximum SUV (maxSUV) > 3.0, and PET/CT diagnosis was determined by maxSUV > 3.0 without lymph node calcification. RESULTS: By PET diagnosis, the sensitivity, specificity, and accuracy of overall lymph node staging were 45% (13 of 29), 91% (228 of 252), and 86% (241 of 281). Specificity was 91% in both squamous cell carcinoma and adenocarcinoma, while sensitivity was 71% in squamous cell carcinoma and 36% in adenocarcinoma. When we excluded calcified lymph node with maxSUV > 3.0 from metastasis by PET/CT diagnosis, specificity improved to 98% in squamous cell carcinoma and 97% in adenocarcinoma. The degree of improvement was not dependent on histologic types. CONCLUSION: PET/CT improved specificity of lymph node staging by reducing false positive lymph node regardless of histologic types of NSCLC.

Correlation of Pre-treatment FDG Uptake to Therapeutic Response and Relapse in Patients with Small Cell Lung Cancer / 핵의학분자영상

PURPOSE: We evaluated correlation of 18F-FDG uptakes, therapeutic response and relapse in pre-treatment 18F-FDG PET/CT in patients with SCLC. MATERIALS AND METHODS: We included 26 patients with pathologically proven small cell lung cancer. Total 102 lesions (26 lungs, 69 lymph nodes and 8 metastatic lesions) were evaluated. All patients underwent 18F-FDG PET/CT for staging. The maxSUV was used as a parameter of 18F-FDG uptake. The patients were divided into responders and non-responders according to response criteria on chest CT scan after 3 cycles of chemotherapy. We compared maxSUV between two groups by using independent t-test. To access correlation with 18F-FDG uptake and relapse, maxSUV and interval time to relapse was analyzed by correlation analysis. The cutoff value of maxSUV was evaluated by ROC curve. RESULTS: Twelve-one patients (81%) were responders and five patients were non-responders on follow-up chest CT scan. The mean maxSUV of main lung lesions in responders and non-responders were 14.15+/-3.72 and 9.17+/-2.15, respectively. The maxSUV in the responders was significantly lower than that in non-responders (p<0.05). According to ROC curve, point of cut that predicts therapeutic response was 8.98 with 100% sensitivity and 57% specificity. The correlation analysis between 18F-FDG uptakes and interval time to relapse showed a significant negative correlation (p<0.05, r=-0.757). CONCLUSION: The pre-treatment 18F-FDG uptake of responders was significantly lower than that of non-responders. Patients with high 18F-FDG uptake in pre-treatment 18F-FDG PET/CT relapse earlier.

Development and Evaluation of Classification Codes and Retrieval Program of the Interpretation of Nuclear Medicine Imaging Studies / 대한의료정보학회지

OBJECTIVE: To evaluate usefulness of the classification codes and retrieval program of the interpretation of nuclear medicine imaging studies. METHODS: We retrieved specific results of the interpretation of 3,613 nuclear medicine imaging studies from database server of the Chonnam National University Hwasun Hospital using classification code retrieval program or by searching narrative phrases using structured query language(SQL). Accuracy of the retrieved results as well as retrieval time in each group were compared. RESULTS: Retrieved results using SQL showed lower accuracy than those using classification codes. There was no delay of response or overload of network traffic whether we used either retrieval program or SQL. CONCLUSION: Retrieval of specific results from database of the interpretation of nuclear medicine imaging studies using classification codes with retrieval program was more accurate and convenient than searching narrative phrases using SQL.