Methimazole discontinuation before radioiodine therapy in patients with Graves' disease.

INTRODUCTION: Although radioiodine therapy (RIT) has been used for the treatment of hyperthyroidism for many decades, there is no consensus on the optimal time of methimazole (MMI) discontinuation before RIT. The aim of this clinical trial is to study the effect of three different time points of MMI discontinuation on response to RIT. METHOD AND PATIENTS: Overall, 151 patients (18-65 years old), with Graves' disease who were taking MMI and referred to I-131 therapy, were consecutively assigned to one of three groups, and MMI was discontinued for 24-48, 48.1-72, and 72.1-168 h in group, 1, 2, and 3, respectively. Radioiodine uptake was measured in all patients and the radioiodine dose was calculated according to the Quimby formula to deliver 7.4 MBq of I-131 per gram of thyroid weight. Response to RIT was assessed at 1, 3, 6, and 12 months after RIT. RESULTS: A total of 102 women and 49 men were included in the study. The mean administered dose of I-131 was 362.9±188.7 MBq (9.8±5.1 mCi) and the mean time to response for radioiodine was 4.1±3.6 months. There was no significant difference between the three groups in age, thyroid weight, anti-TPO level, radioactive iodine uptake level, and radioiodine dose (P>0.1). Response to RIT at 1, 3, 6, and 12 months after administration was also not different between the three groups (P>0.57). CONCLUSION: No difference was found in the response to treatment between patients with MMI discontinuation for 24-48, 48.1-72, and 72.1-96 h before RIT. Shorter discontinuation of MMI before RIT may be preferable in most patients. Video Abstract: http://links.lww.com/NMC/A39.

Diagnostic utility of 99mTc-EDDA-tricine-HYNIC-Tyr3-octreotate SPECT for differentiation of active from inactive pulmonary tuberculosis.

OBJECTIVE: The current study was performed to evaluate the impact of Tc-EDDA-tricine-HYNIC-Tyr-octreotate in the differentiation of active from inactive pulmonary tuberculosis lesions. PATIENTS AND METHODS: Ten consecutive patients (six male and four female, age range 24-83 years) with proven pulmonary tuberculosis (with a positive smear or culture) were enrolled in the study. At 120 min after injection of 740 MBq of Tc-EDDA-tricine-HYNIC-Tyr-octreotate, planar and single-photon emission computed tomography (SPECT) images of the thorax were taken. A semiquantitative evaluation of lesion and nonlesion areas was performed. The scan was repeated following the same protocol after standard treatment for tuberculosis after a negative sputum culture. RESULTS: Semiquantitative evaluation of the lesions showed a statistically significant higher uptake before treatment in both planar and SPECT images (P=0.005 and 0.007, respectively). Lesion-to-nonlesion ratios were also higher in the pretreatment sets on both planar and SPECT images (1.4±0.2 vs. 1.19±0.15, P=0.001, for planar images and 2.32±0.55 vs. 1.32±0.32, P=0.0001, for SPECT images). CONCLUSION: Tc-EDDA-tricine-HYNIC-Tyr-octreotate scintigraphy may help to differentiate between active and inactive pulmonary tuberculosis. SPECT imaging and semiquantitative evaluation are indispensable for increasing the diagnostic yield of this method. Larger studies are needed to corroborate our results.

Diagnostic value of 99mTc-bombesin scintigraphy for differentiation of malignant from benign breast lesions.

OBJECTIVE: In this study, we evaluated the diagnostic accuracy of (99m)Tc-bombesin scintigraphy for differentiation of benign from malignant palpable breast lesions. (99m)Tc-Bombesin is a tracer with high affinity for gastrin-releasing peptide receptor, which is overexpressed on a variety of human tumors including breast carcinoma. MATERIALS AND METHODS: We examined 33 consecutive women who were referred to our center with suspicious palpable breast lesions but had no definitive diagnosis in other imaging procedures. A volume of 370-444 MBq of (99m)Tc-bombesin was injected and dynamic 1-min images were taken for 20 min immediately after injection in anterior view. Thereafter, two static images in anterior and prone-lateral views were taken for 5 min. Finally, single-photon emission computed tomography images were taken for each patient. Definitive diagnosis was based on biopsy and histopathological evaluation. RESULTS: The scan findings were positive in 19 patients and negative in 11 on visual assessment of the planar and single-photon emission computed tomography images. Pathologic examination confirmed breast carcinoma in 12 patients with positive scans and benign pathology for 18 patients. The overall sensitivity, specificity, negative and positive predictive values, and accuracy of this radiotracer for diagnosis of breast cancer were 100, 66.1, 100, 63, and 76%, respectively. Semiquantitative analysis improved the specificity of the visual assessment from 66 to 84%. CONCLUSION: Our study showed that (99m)Tc-bombesin scintigraphy has a high sensitivity and negative predictive value for detecting malignant breast lesions, but the specificity and positive predictive value of this radiotracer for differentiation of malignant breast abnormalities from benign ones are relatively low.