Radiochemical stability during infusion of 131I-labelled metaiodobenzylguanidine for therapeutic use

Altered Biodistribution of Radiopharmaceuticals: Role of Radiochemical/Pharmaceutical Purity, Physiological, and Pharmacologic Factors

“…In radiopharmaceutical formulations of 131 I-mIBG and 131 I-Bexxar®, radiolysis generates radiochemical impurities, such as free 131 I iodide. 42 In case of 131 I-Bexaar®, radiolysis may decrease the immunoreactivity of labeled monoclonal antibodies. To prevent the effects of radiolysis, 131 I-Bexxar® is supplied frozen and is safe for use when it is kept frozen (at Ϫ20°C) for several days.…”

“…131 I or 123 I labeled meta-iodobenzylguanidine (MIBG) is used specifically to depict and localize catecholamine-secreting tumors. 42 MIBG structurally resembles norepinephrine and, to some extent, shares its biological behavior in that it is taken up by an active, sodium-and energy-dependent amine uptake mechanism (uptake 1) in the cell membrane of sympathomedullary tissues and is stored into the intracellular catecholamine storing granules by another specific, active uptake mechanism. 69 The normal distribution usually shows uptake in the salivary glands, spleen, liver, and urinary bladder.…”

“…Thyroid and stomach uptake are primarily due to free radio iodide species due to in vivo dehalogenation. 42 Bilateral symmetric activity is sometimes evident in the neck and shoulders of children, and it seems to be related to uptake in brown adipose tissue. MIBG imaging is characterized by high specificity with very few (1%-5%) false-positive findings, ie, because of retention of radioactivity in the urinary tract, or the presence of adrenal hyperplasia following contralateral adrenalectomy or very rarely to non-NET or benign lesions.…”

Pitfalls and Limitations of SPECT, PET, and Therapeutic Radiopharmaceuticals

“…The present review does not seek to cover the same ground, as much of the material remains relevant and the main points are summarized in Table 1. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This review adopts a similar structure but focuses on radiopharmaceuticals introduced since 1996 and expands the scope to include newer PET and therapeutic radiopharmaceuticals.…”

Differentiated Thyroid Carcinoma After 131I-MIBG Treatment for Neuroblastoma During Childhood: Description of the First Two Cases

“…Due to its biochemical similarity to norepinephrine, MIBG is selectively concentrated by adrenergic tissue, including NBL (2). Due to the chemical instability of the drug and through degradation of MIBG by the liver, free 131 I is formed (3). Free 131 I will be taken up by the thyroid gland and may cause radiation damage, theoretically resulting in radiation thyroiditis, hypothyroidism, benign thyroid nodules, and, possibly, even differentiated thyroid carcinoma (DTC) (4,5).…”