• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.93-98
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• 2021

meta-iodobenzylguanidine is one of the norepinephrine analogs and reuptakes together with norepinephrine with norepinephrine transporter. The radioiodinated ligand, ¹²³I-meta-iodobenzylguanidine, is the most widely used for single photon emission computed tomography imaging to diagnose functional abnormalities and tumors of the sympathetic nervous system. In this study, we performed cellular uptake studies of ¹²³I-meta-iodobenzylguanidine in positive- and negative-norepinephrine transporter cells in vitro to verify the uptake activity for norepinephrine transporter. After ¹²³I-meta-iodobenzylguanidine was injected via a tail vein into normal mice, Single photon emission computed tomography/computed tomography images were acquired at 1 h, 4 h, and 24 h post-injection, and quantified the distribution in each organ including the adrenal medulla as a norepinephrine transporter expressing organ. In vitro cell study showed that ¹²³I-meta-iodobenzylguanidine specifically uptaked via norepinephrine transporter, and significant uptake of ¹²³I-meta-iodobenzylguanidine in the adrenal medulla in vivo single photon emission computed tomography images. These results demonstrated that single photon emission computed tomography imaging with ¹²³I-meta-iodobenzylguanidine were able to quantify the biodistribution in vivo in the adrenal medulla in normal mice.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.2
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• pp.71-76
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• 2022

Indigenous diagnostic dose of ¹³¹I-labeled meta-iodobenzylguanidine ([¹³¹I]mIBG) was prepared via Cu⁺ catalyzed isotope exchange reaction generated in situ by sodium metabisulfite for imaging of neuroblastoma tumor. [¹³¹I]mIBG was produced in overall 85-90% radiochemical yield. The average amount of radioactivity of [¹³¹I]mIBG was 2164 MBq (1998-2331MBq) with an average specific activity > 1000 MBq/mg at the end of synthesis. The radiochemical purity was ≥ 99.9% after purification through Dowex-1 × 8 ion exchange resin (100-150 mesh) at the date of preparation. The stability of [¹³¹I]mIBG at concentration 480-555 MBq/mL was > 97% at 4 ℃ after 4 days. The room temperature (25 ℃) stability of [¹³¹I]mIBG was > 98% after 24 h. Biodistribution of [¹³¹I]mIBG in patient showed uptake in salivary glands, liver, spleen and excreted though urinary bladder. Neuroendocrine medicated uptake into tumor lesion and metastatic sites were noted which strongly correlate with the morphological abnormalities of patient.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.247-253
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• 2017

Approximately 10-15% of pheochromocytomas are malignant. There are insufficient histologic criteria for the diagnosis of malignant pheochromocytoma. Thus, the term malignant pheochromocytoma is restricted to tumors with local invasion or distant metastases. We experienced a case of malignant pheochromocytoma recurred with spinal metastasis 4 years after the surgery for huge benign pheochromocytoma. A 68-year-old female was admitted for trunk and back pain. The patient had a history of surgery 4 years ago for a $10.0{\times}9.5{\times}7.5cm$ sized benign pheochromocytoma at the left adrenal gland. A thoracolumbar magnetic resonance imaging showed a tumor in the 7th thoracic vertebral body and a 24-hour urinary norepinephrine increased, suggesting metastatic recurrence of malignant pheochromocytoma. After metastasectomy in the 7th thoracic vertebral body, urine catecholamine was normalized and pain also disappeared. However, a metastatic lesion was found in the paraaortic area on a follow-up abdominal computed tomography scan and an additional metastasectomy was performed. The pathology confirmed the diagnosis of metastatic pheochromocytoma in the paraaortic lymph nodes. She is supposed to be treated with adjuvant iodine 131-meta-iodobenzylguanidine therapy. In our experience, a close follow-up should be considered in patients who had a huge benign pheochromocytoma due to the possibility of malignant metastases.