In-house preparation of iodine -131 metaiodo benzyl guanidine for scintigraphy of neuroendocrine tumors. Fourteen years experience in South India

Iodine-131 metaiodobenzyl guanidine ((131)I-MIBG) is routinely used for imaging and treatment of neuroendocrine tumors (NET). As the commercially available radiopharmaceutical was very expensive, we developed an in-house method of labeling MIBG with (131)I in 1993. A total of 247 batches of (131)I-MIBG were prepared and used in our hospital between April 1993 and September 2006. We report our experience over these 14 years of preparation of this tracer in our hospital radiopharmacy, for the scintigraphy of NET. The technique of preparation is simple and the labeled product was found to be of acceptable quality. With the routine availability and cost effectiveness, the utilization of this radiopharmaceutical for scintigraphy increased remarkably in our institution.     

PET imaging of CCND1 mRNA in human MCF7 estrogen receptor positive breast cancer xenografts with oncogene-specific [64Cu]chelator-peptide nucleic acid-IGF1 analog radiohybridization probes.

Treatment of breast cancer is hampered by a large unmet need for rapid, sensitive, specific staging and stratification of palpable and nonpalpable abnormalities. Mammography and physical examination miss many early breast cancers, yet detect many benign lesions. Cyclin D1, encoded by CCND1 messenger RNA (mRNA), and insulin-like growth factor 1 receptor (IGF1R) are key regulators of cell proliferation that are overexpressed in most breast cancers. Therefore, we hypothesized that malignant breast masses could be imaged and quantitated externally by PET with a dual-specificity probe that targets both CCND1 mRNA and IGF1R. METHODS: We designed a CCND1-specific peptide nucleic acid (PNA) hybridization sequence (CTGGTGTTCCAT), separated by a C-terminal spacer to a cyclized IGF1 peptide analog (d-Cys-Ser-Lys-Cys), for IGF1R-mediated endocytosis. On the N-terminus we attached a chelator (1,4,7-tris(carboxymethylaza)cyclododecane-10-azaacetyl [DO3A]) for the positron-emitting nuclide (64)Cu. We administered the [(64)Cu]CCND1-IGF1 analog radiohybridization probes, as well as sequence controls, by tail vein to immunocompromised female NCr mice bearing human MCF7 estrogen-dependent, receptor-positive xenografts. We imaged the mice by PET and CT 4 and 24 h later, and measured tissue distribution of the radiohybridization probes. RESULTS: We observed 8 +/- 2-fold higher PET intensity in the center of the breast cancer xenografts than in the contralateral tissues at 24 h after injection of the [(64)Cu]CCND1-IGF1 analog radiohybridization probe. IGF1 blocking yielded significantly weaker images (P < 0.05) relative to the tumor-free side at 24 h after injection, as did a PNA mismatch probe, a peptide mismatch probe, and free (64)CuCl(2). CONCLUSION: These results are consistent with our hypothesis for radiohybridization PET of overexpressed CCND1 mRNA, dependent on IGF1R-mediated endocytosis, in suspect masses. Early noninvasive detection of initial cancerous transformation, as well as invasive or recurrent breast cancer, with dual-specificity radiohybridization probes, might enable molecularly targeted staging, stratification, and choice of therapy.     

Primary lymph node gastrinoma in jejunal mesentery.

Primary gastrinomas have been reported in lymph nodes within the gastrinoma triangle. We report a 56-year-old woman with possible primary lymph node gastrinoma in the jejunal mesentery. Six months after excision of the tumor, she is asymptomatic and serum gastrin level is normal.     

PET imaging of VPAC1 expression in experimental and spontaneous prostate cancer.

Among U.S. men, prostate cancer (PC) accounts for 29% of all newly diagnosed cancers. A reliable scintigraphic agent to image PC and its metastatic or recurrent lesions and to determine the effectiveness of its treatment will contribute to the management of this disease. All PC overexpresses VPAC1 receptors. This investigation evaluated a probe specific for a (64)Cu-labeled receptor for PET imaging of experimental human PC in athymic nude mice and spontaneously grown PC in transgenic mice. METHODS: The probe, TP3939, was synthesized, purified, and labeled with (64)Cu and (99m)Tc. Using a muscle relaxivity assay, biologic activity was assessed and inhibitory concentrations of 50% calculated. Receptor affinity (Kd) for human PC3 cells was determined using (99m)Tc-TP3939 and (64)CuCl(2.) Blood clearance and in vivo stability were studied. After intravenous administration of either (64)Cu-TP3939 or (64)CuCl(2) in PC3 xenografts and in transgenic mice, PET/CT images were acquired. Prostate histology served as the gold standard. Organ distribution studies (percentage injected dose per gram [%ID/g]) in normal prostate were performed. The ratios of tumor to muscle, tumor to blood, normal prostate to muscle, and tumor to normal prostate were determined. RESULTS: Chemical and radiochemical purities of TP3939 were 96.8% and 98% +/- 2%, respectively. Inhibitory concentrations of 50% and affinity constants were 4.4 x 10(-8) M and 0.77 x 10(-9) M, respectively, for TP3939 and 9.1 x 10(-8) M and 15 x 10(-9) M, respectively, for vasoactive intestinal peptide 28. Binding of (64)CuCl(2) to PC3 was nonspecific. Blood clearance was rapid. In vivo transchelation of (64)Cu-TP3939 to plasma proteins was less than 15%. (64)Cu-TP3939 uptake in PC was 7.48 +/- 3.63 %ID/g at 4 h and 5.78 +/- 0.66 %ID/g at 24 h after injection and was significantly (P < 0.05) greater than with (64)CuCl(2) (4.79 +/- 0.34 %ID/g and 4.03 +/- 0.83 %ID/g at 4 and 24 h, respectively). The ratios of PC to normal prostate at 4 and 24 h were 4 and 2.7, respectively. (64)Cu-TP3939 distinctly imaged histologic grade IV prostate intraepithelial neoplasia in transgenic mice, but (18)F-FDG and CT did not. CONCLUSION: Data indicate that TP3939, with its uncompromised biologic activity, delineated xenografts and cases of occult PC that were not detectable with (18)F-FDG. (64)Cu-TP3939 is a promising probe for PET imaging of PC. It may also be useful for localizing recurrent lesions and for determining the effectiveness of its treatment.     

Afferent loop syndrome: the role of Tc-99m mebrofenin hepatobiliary scintigraphy

Afferent loop syndrome is caused by intermittent mechanical obstruction of the afferent loop of a gastrojejunostomy and may present early as an acute type or late as a chronic type. The authors describe two patients who were examined for a history of bilious vomiting after gastrojejunostomy, and who were thought to have afferent loop syndrome (chronic type) based on clinical findings. Results of routine investigations, such as upper gastrointestinal endoscopy, and ultrasonography were inconclusive. Findings from the barium meal follow-through studies were normal in the first patient and revealed a dilated duodenum in the second patient. Tc-99m bromotriethyl-iminodiacetic acid has been used to identify afferent loop obstruction as represented in these studies.     

Unusual cause for miliary lung mottling in a child

A 12-year-old boy presented to us with a diagnosis of disseminated tuberculosis which was made based on a history of prolonged fever, multiple neck swellings and radiological findings of bilateral multiple micronodular opacities. Examination showed a diffuse thyroid gland swelling. He was diagnosed to have papillary thyroid carcinoma with distant metastases to cervical lymphnode on histopathology and to lungs.     

A case of Turner syndrome with hyperparathyroidism in an adult

Turner syndrome is a hereditary chromosomal anomaly that affects girls and women. A result of gonadal dysgenesis, its primary characteristics are short stature, osteoporosis, neck webbing, and cardiac defects. Turner syndrome may also involve the auditory system and kidneys. We report the case of a woman with Turner syndrome who presented late in adulthood with severe osteoporosis and hypercalcemia. She was subsequently diagnosed with primary hyperparathyroidism secondary to a parathyroid adenoma. After excision of the adenoma, the woman's serum calcium level normalized. To the best of our knowledge, only 4 other cases of Turner syndrome with hyperparathyroidism have been reported in the literature.