Radionuclide therapy practice and facilities in Europe. EANM Radionuclide Therapy Committee.
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Publications and source records attributed to L Troncone.
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We report two cases of thyrotoxicosis resulting from hyperfunctioning lung metastases from differentiated thyroid cancer. In both patients, a simultaneous diagnosis of thyrotoxicosis and metastatic thyroid cancer was made, based on thyroid function tests as well as 131I whole-body scans showing low thyroid uptake of radioiodine and multiple foci of intense 131I uptake in the lungs. After total thyroidectomy (performed in Patient 2 only) and 131I therapy (cumulative dose of 12.3 GBq in Patient 1 and 9.6 GBq in Patient 2), there was a rapid clinical improvement with significant reduction of the pulmonary metastatic disease in both patients: Patient 1 became euthyroid, while Patient 2 became hypothyroid. Analysis of the 54 cases reported in the literature, including the 2 cases described here, shows this to be a very rare cause of thyrotoxicosis and one that can pose serious problems for both the diagnostic evaluation and choice of therapeutic strategy when compared with the much more common nonhyperfunctioning metastases from thyroid cancer. Lesser degrees of thyroid hormone secretion by differentiated thyroid cancer may be detected and exploited diagnostically by the chromatographic analysis of serum for endogenously labeled thyroid hormones after 131I administration.
BACKGROUND: Previous studies have suggested that an abnormal cardiac adrenergic tone may have a pathophysiological role in syndrome X (effort angina, positive exercise testing, angiographically normal coronary arteries). METHODS AND RESULTS: To evaluate cardiac adrenergic nerve function, we performed [123I]metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 12 patients with syndrome X and 10 control subjects. Cardiac MIBG uptake was assessed by the heart/mediastinum (H/M) ratio and by an MIBG uptake defect score (higher values=lower uptake). In syndrome X patients, we also correlated MIBG scintigraphic findings with stress myocardial perfusion as assessed by 201Tl scintigraphy. An inferior MIBG defect was observed in only 1 control subject, whereas 9 patients (P<.01) showed MIBG defects. The heart was totally or almost totally invisible on MIBG images in 5 patients, and predominantly regional defects were observed in 4. The H/M ratio was lower (1.70+/-0.6 versus 2.2+/-0.3, P=.03) and MIBG uptake defect score higher (35+/-31 versus 4+/-2, P=.003) in syndrome X patients. Reversible stress thallium perfusion defects were found in 62% of patients with MIBG defects but in no patient with normal MIBG uptake. MIBG defects persisted unchanged in 7 patients at a 5+/-3-month follow-up study. CONCLUSIONS: In this study, obvious defects in global and/or regional cardiac MIBG uptake, indicating an abnormal cardiac adrenergic nerve function, were detected in 75% of patients with syndrome X. These findings strongly support the cardiac origin of chest pain in syndrome X, although the mechanisms and the pathophysiological meaning of the abnormal cardiac MIBG uptake in these patients deserve further investigation.
Iodine-123 metaiodobenzylguanidine (123I-MIBG) radioaerosol is of potential use in the investigation of the neuroadrenergic function of the lungs; however, before the method can be successfully employed the following issues need to be clarified: (1) Does the nebulization affect the radiochemical purity of 123I-MIBG? (2) Is the pulmonary distribution of inhaled 123I-MIBG homogeneous in normal subjects? (3) Does the pulmonary clearance of inhaled 123I-MIBG reflect the functional status of the neuroadrenergic system of the lungs? In this study we performed: (1) a chromatographic study of nebulized 123I-MIBG; (2) a quantitative evaluation of the lung distribution of 123I-MIBG radioaerosol in normal subjects as compared with that of technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) and (3) an assessment of 123I-MIBG lung clearance both under control conditions and after pharmacologically induced beta-blockade, again compared with 99mTc-DTPA. For these purposes, eight normal subjects were divided randomly into an "MIBG group" and a "DTPA group" (four subjects each) and submitted to three scintigraphic studies each: a baseline study, and studies after the administration of a low (80 mg) and a high (160 mg) dose of propranolol. Radiochemical purity of nebulized 123I-MIBG ranged between 97.18% and 98.70%. The lung distribution of 123I-MIBG, as judged by the aerosol penetration index, was identical to that of 99mTc-DTPA under all study conditions. The 123I-MIBG clearance rate was slower than that of 99mTc-DTPA under baseline conditions (135+/-32 min vs 69+/-27 min, P<0.01) and increased significantly after propranolol administrations, while the 99mTc-DTPA clearance did not change. The following conclusions were drawn: (1) the nebulization does not affect the radiochemical purity of 123I-MIBG; (2) the lung distribution of 123I-MIBG is homogeneous in normal subjects; (3) the pulmonary clearance of 123I-MIBG reflects the functional status of the neuroadrenergic system of the lungs. Thus this scintigraphic method is suitable for research and perhaps for future clinical use.
Neuroblastoma (NB), a childhood radiosensitive tumor, is very aggressive and malignant, in its disseminated form, despite very intensive chemotherapy, prognosis continues to be dismal. Owing to its capacity to concentrate in NB lesions, large doses of 131-I-MIBG, have given very encouraging therapeutic results in patients resistant to conventional therapy as well as at diagnosis. We recently reported the first attempt in combination therapy (CO-TH) using 131-I-MIBG and cisplatin. This new form of CO-TH appears very effective in obtaining a rapid and excellent response in relapsed patients. In this report, we describe the results of further experience with CO-TH in disseminated NB. We have attempted to verify to what extent interaction between the effects of the two agents may produce therapeutic benefit, and we have sought the optimization of CO-TH use. Three stage IV NB patients were treated with CO-TH. The following treatment schedule, was planned: day 1, cisplatin 50 mg/m3 i.v. over 6 h; day 2, 131-I-MIBG 100-130 mCi at high specific activity (-1.1 Gbq/mg) i.v. over 6 h followed, a week later, by the same treatment combination. The therapeutic results were encouraging. However, hematological toxicity continued to represent a major limiting factor. In view of the overall effectiveness of CO-TH, at the price of lasting hematological toxicity, it may be indicated as a consolidation regimen some time before conditioning chemotherapy for autologous bone marrow transplantation.
Radioiodine whole-body imaging is the most accurate method in the diagnosis of metastases from differentiated thyroid cancer. However, false-positive images rarely occur. The authors report unusual cases of thymic hyperplasia and post-traumatic skull changes mimicking mediastinal, skull, or cerebral metastases. Nonthyroidal causes were diagnosed by other radionuclide studies (bone and brain scintigraphy) and CT scans. Follow-up and undetectable thyroglobulin levels helped confirm the benign cause.
UNLABELLED: The high sensitivity of metaiodobenzylguanidine (MIBG) scintigraphy for sympathomedullary tumors such as neuroblastoma and pheochromocytoma is well documented. The specificity of MIBG scintigraphy for these tumors is also high but has been incompletely characterized for other neural crest tumors and non-neural crest tumors of childhood. METHODS: The medical records and MIBG scans of all children who had undergone MIBG scintigraphy for known or suspected neuroblastoma or pheochromocytoma were retrospectively reviewed at five major referral centers. Those patients found to have pathologies other than neuroblastoma or pheochromocytoma form the basis of this study. RESULTS: One hundred children with a total of 110 lesions met the inclusion criteria. All had negative MIBG scans except 1 of 2 children with infantile myofibromatosis, 1 of 2 with neuroendocrine carcinomas, 1 of 2 with pancreaticoblastomas and 1 of 10 with primitive neuroectodermal tumors. CONCLUSION: MIBG scintigraphy is highly specific for neuroblastoma and pheochromocytoma. Only 4% (4/100) of nonsympathomedullary tumors (non-pheochromocytoma and non-neuroblastoma) in childhood showed MIBG uptake, of which only 2% (2/100) were of non-neural crest origin.
We present 131I scintigraphic findings in a patient with insular carcinoma of the thyroid showing diffuse abnormal uptake throughout the skeleton. The scintigraphy closely resembled the pattern of [131I]MIBG distribution in children with bone marrow metastases of neuroblastoma. The extent of involvement was underestimated by bone scintigraphy and radiography. Insular carcinoma of the thyroid in the bone marrow was subsequently demonstrated by biopsy. The patient was treated with 242 mCi 131I given in two courses, which led to severe myelosuppression and died as a result of progressive disease and severe pancytopenia 10 mo after initial therapy.
The outlook for disseminated neuroblastoma (NB) continues to be dismal. NB is a radiosensitive tumour. Owing to its high concentration in NB lesions, [131I]meta-iodobenzylguanidine [131I]MIBG has the potential for specifically delivering very large radiation doses to the malignant cells. Encouraging results have been reported with [131I]MIBG used alone in patients resistant to conventional therapy and at diagnosis. We report the first attempt to explore the integration of this new treatment modality with chemotherapy. Among the drugs effective in NB, cisplatin was chosen because of its high degree of activity against NB, its mild haematological toxicity and the known synergism between cisplatin and radiation. 4 patients, 3 with relapsed, heavily pre-treated, progressive stage IV NB, and 1 with stage IV NB at diagnosis, all with a good [131I]MIBG uptake, were investigated with combined therapy (CO-TH). Two complete remissions and one partial remission were observed in these patients 4-6 weeks following only a single course of both cisplatin and [131I]MIBG at "standard" dosage. The only toxicity was haematological, which was significant and relatively long-lasting, but was not associated with any serious infections or bleeding tendency. The general condition of these patients during the entire study period was excellent. The fourth patient, investigated at diagnosis with a modified less intensive treatment, obtained a partial remission with mild haematological toxicity. During the subsequent courses of intensive multidrug chemotherapy, this patient showed haematological toxicity comparable with that experienced by patients treated with an identical drug combination, but without previous treatment with CO-TH. The provisional conclusion of this ongoing study is that this new form of CO-TH appears most effective in obtaining a rapid and excellent response in heavily pretreated relapsed patients with progressive disease, and should be further investigated in earlier stages of the disease.
The aim of the present study was to assess the utility of SPECT imaging with [123I]MIBG in patients with neuroblastoma (NB). Twenty-two children were studied (11 males and 11 females: age range: newborn to 11 years). A total of 39 studies were performed in different clinical phases. Both planar (at 24 and occasionally 48 hours) and SPECT (at 24 hours) imaging were performed in all cases. Planar studies gave a sensitivity of 87.5% (evidence of the disease in 21 of 24 studies performed in children with known NB lesions) and a specificity of 93.3% (true negative results in 14 of 15 studies performed in disease-free patients). In the same patients SPECT gave a sensitivity of 95.8% (23 of 24 positive studies and a specificity equal to that of planar scanning. In 5 of 21 studies positive at planar scanning SPECT showed 9 additional lesions. In conclusion, [123I]MIBG SPECT imaging compared to planar scanning can demonstrate a greater number of lesions. Its use seems to be indicated mainly in cases in which diagnostic assessment is difficult, such as small residual tumors or in the follow up of children no longer in therapy, in whom it can lead to an early diagnosis of relapse.
Norepinephrine (NE) is one of the many biologically active substances that are metabolized by the lung. The norepinephrine uptake in the lung has been widely investigated in animal studies in order to detect abnormalities of the endothelial cells. 131I- or 123I-labelled metaiodobenzylguanidine (MIBG) is a radioactive tracer that shares several metabolic pathways with NE; it has been used instead NE or both in animal and in human studies for the same purposes. It has been definitely demonstrated that MIBG lung uptake following intravenous administration is a reliable marker of minimal endothelial cell lesions and it allows one to investigate several conditions involving damage to the lung vasculature such as adult respiratory distress syndrome, post-actinic lung fibrosis or chemotherapic lung toxicity. MIBG could also potentially be used as a tracer of the neuroadrenergic system of the airways, once it has been deposited in the whole branches of the bronchial tree. With this in mind we evaluated the feasibility of the administration of MIBG in radioaerosol form. We first performed a chromatographic study on [123I]MIBG aliquots aerosolized for variable lengths of time (2-30 minutes). Radiochemical purity was always over 96%, thus demonstrating that aerosolization does not significantly modify the stability of the tracer. We then compared both the lung clearance curves and the scintigraphic images in two groups of normal subjects who respectively underwent [123I]MIBG and 99mTc-DTPA radioaerosol dynamic scintigraphy. We found that MIBG clearance to be significantly lower than that of DTPA (135 +/- 32 minutes versus 69 +/- 27 minutes, p < 0.01), probably due to its being trapped in the adrenergic nerve endings of the airways. The pulmonary distribution of both tracers was homogeneous, as demonstrated by the correspondence of the values for the aerosol penetration index in both groups of subjects. Such results warrant further research and pharmacologic tests.
The potential role [131I]MIBG therapy in untreated, inoperable cases of neuroblastoma (NB) in children was evaluated. Six children, aged 10 months-5 years, were treated at diagnosis. Five (4 stage III and 1 stage IV NB) underwent [131I]MIBG treatment alone (single doses ranging from 2.9 to 6.1 GBq of high specific activity [131I]MIBG. In one case (stage IV NB) [131I]MIBG was preceded by Cisplatin administration (20 mg/m2/day) given over a 5 day period. The results obtained in the first 5 cases were as follows: 1 complete response still lasting after 5 years; 1 partial and 1 minor response allowing further surgery and chemotherapy; 2 stabilization of the disease. The treatment was well tolerated with minimal toxicity. However, apart from the first case all these children relapsed and subsequently died. Therefore [131I]MIBG therapy (9.1 GBq given in 2 courses) combined with Cisplatin as a "radiosensitizer" was used in the sixth case, a patient with widespread bone metastases and massive bone marrow involvement. A very good partial response was obtained in this case. Further surgery (of the primary NB) and multidrug chemotherapy was then possible. In conclusion, [131I]MIBG therapy at diagnosis appears to be effective, low toxic treatment of NB; when integrated with Cisplatin its efficacy seems to improve even more.
Metastatic neuroblastoma (NB) continues to have a dismal prognosis. NB is a radiosensitive tumor. Owing to its high concentration in the NB lesions, Metaiodobenzylguanidine (MIBG) has the potential for specifically delivering very large radiation doses to the malignant cells. Encouraging results have been reported with [131I]MIBG used alone in patients resistant to conventional therapy and at diagnosis. We report the first attempts to explore the integration of this new treatment modality with chemotherapy. Among the drugs effective in NB, cisplatin was chosen because of its high degree of activity against NB, its mild hematologic toxicity and the known synergism between cisplatin and radiation. Four patients, 3 with relapsed, heavily pre-treated, progressive stage IV NB, and 1 with stage IV NB at diagnosis, all with a good [131I]MIBG uptake, were investigated with the combined therapy. Two complete remissions and one partial remission were observed in the relapsed patients 4-6 weeks following only one single course of both cisplatin and [131I]MIBG at the "standard" dosage. The only toxicity was hematologic, which was significant and relatively long-lasting, but was not associated with any serious infections or bleeding tendency. The general condition of these patients during the entire study period was excellent. The 4th patient, investigated at diagnosis with a modified less intensive treatment, obtained a partial remission with a mild hematologic toxicity. The provisional conclusion of this preliminary study is that this new form of combined therapy appears very effective in heavily pretreated relapsed patients with progressive disease, and could also be investigated in refractory patients and in patients at diagnosis.
An important drawback of radioiodinated MIBG prepared by isotopic exchange (maximum specific activity: 100 Ci/mmol) is that a considerable amount of carrier is present in the "ready to use" radiopharmaceutical, thus affecting MIBG uptake in the target cells. To improve the therapeutic utility of MIBG an interesting method was developed for the no-carrier-added (n.c.a.) radioiodination of MIBG via a halodesilylation reaction using 3-trimethylsilybenzylguanidine (TMSBG) as precursor. In order to investigate its possible clinical usefulness, n.c.a. [125I]- and [131I]MIBG was prepared according this procedure. HPLC analysis of the labeling mixture showed that the labeling yield reached values greater than 98% within 20 minutes at 70 degrees C. HPLC fraction containing [131I]MIBG was then recovered and tetrahydrofurane was removed under nitrogen stream. Biodistribution studies were performed in BALB/c normal mice and compared with those obtained using [131I]MIBG prepared by isotopic exchange. Preliminary results showed that at 4 hours myocardial uptake was significantly higher than that of c.a. MIBG (20.3 +/- 0.4 %ID/g). Adrenal uptake gradually increased over time; at 24 hours adrenal uptake was almost twofold that a 1 hour. MIBG uptake was also studied in the human neuroblastoma cell line SH-SY5Y which has a specific uptake system for MIBG. The kinetic parameters for MIBG in this line are: km = 0.27 +/- 0.03 microM, Vmax = 39.5 + 1.8 pmol/10(6) cell/10 min. Preliminary data from in vitro binding studies showed that significantly higher levels of specifically incorporated radioactivity can be achieved using n.c.a. [125I]MIBG instead of c.a. [125I]MIBG.
The aim of this study was to evaluate the effectiveness of a recently developed radiolabelled somatostatin analog (111In-pentetreotide) for the detection and localization of both medullary thyroid carcinoma (MTC) and carcinoid tumors, and to compare the results obtained with the results of 99mTc(V)-DMSA, and radioiodinated MIBG imaging. 111In-pentetreotide scintigraphy was performed in 9 patients with MTC and in 9 patients with carcinoid tumor. Whole body and SPECT studies were performed at 4 and 24 hours post-injection. SMS scintigraphy gave a positive result in 5 out of 7 patients with proven MTC lesions, and in 7 out of 9 patients with known lesions of carcinoid tumor. It gave a negative result in 2 MTC patients with high levels of calcitonin but with no evidence of disease at conventional diagnostic modalities. The scintigraphic results were comparable with those obtained with 99mTc(V)-DMSA in MTC and were superior to those of radioiodinated MIBG in both MTC and carcinoid tumors. When compared with the modifications of calcitonin levels brought about by the acute administration of octreotide ("Octeotride test"), these correlated well in 8 out of 9 patients studied.
Nuclear medicine imaging techniques, whether applied in the initial diagnosis or in assessing the response to therapy, are indispensable in the evaluation of malignant diseases that afflict infants and children. The major role of these techniques (bone, 67Ga and 201Tl scintigraphy, imaging with labeled leucocytes, immunoscintigraphy) is that of complementing, in an essential manner, other first choice diagnostic investigations (radiological, bioptic, etc.) such as in evaluating malignant skeletal tumors, soft tissue sarcomas, lymphomas, leukemia and histiocytosis X. Nevertheless, due to their high tissue specificity and/or diagnostic reliability, 99mTc-MDP (or analogues) imaging in the screening of bone metastases, 123/131I-MIBG scintigraphy in the diagnosis and management of neuroblastoma and 131I whole body scan in staging postoperatively differentiated thyroid cancers are proposed as first choice modalities. Well established (131I therapy) or recently developed (131I-MIBG therapy and radioimmunotherapy) therapeutic modalities are available today to be either integrated with or to substitute the conventional treatment of differentiated thyroid carcinoma and neuroblastoma.
The role of adrenal scintigraphy in the noninvasive characterization of silent adrenal masses was investigated in 40 patients. The mass had been detected by US or CT performed in the evaluation of non-malignant extra-adrenal diseases (25 cases) or during staging or follow-up of a malignant extra-adrenal neoplasm (15 cases). In all cases radio-cholesterol scintigraphy (74 MBq i.v. of 131I-6 beta-iodomethylnorcholesterol in 19 cases; 11 MBq i.v. of 75Se-6 beta-selenomethylnorcholesterol in 21 cases) was performed; in 7 cases also 131I-MIBG scan (18.5-37 MBq i.v.) was carried out. When compared with CT data, radiocholesterol scintigraphy (standard or after suppression with dexamethasone) showed: concordant uptake (increased uptake of radiocholesterol on the side of the adrenal mass) in 24/26 patients with adrenal cortical adenoma; discordant uptake (absent or decreased uptake on the side of the adrenal mass) in 12 patients: 5 with adrenal metastases and 7 with non-adenomatous benign space-occupying lesions (2 ganglioneuromas, 1 post-traumatic hemorrhagic lesion, 3 adrenal cysts, 1 myelolipoma); indeterminate uptake (symmetric bilateral uptake) in 4 patients: 2 with a small adenoma, 1 with adrenal metastasis and 1 with a "false incidentaloma" (hepatic regenerative nodule). The results confirm the utility of radiocholesterol scintigraphy in demonstrating the benignity of adrenal lesions (particularly in identifying adrenocortical adenomas) and assess its place among the procedures used to characterize silent adrenal masses. The possible use of MIBG scintigraphy is also discussed.
Results of treatment with 131-I-Metaiodobenzylguanidine (131-I-MIBG) in patients with resistant neuroblastoma appear encouraging if one considers that most of the patients had far advanced, intensively pre-treated disease. To further explore the potential role of this new drug in untreated patients, we treated 3 children with stage III neuroblastoma. All three of our cases received 131-I-MIBG at relatively low dose with the complete disappearance of the tumor mass in case 1, whereas in cases 2 and 3 CT scan showed a significant reduction of the tumor mass and, interestingly enough, no evidence of 131-I-MIBG uptake of a tracer dose in the remaining tumor. Particularly, in case 2, the persistence and subsequent progression of part of the tumor mass without 131-I-MIBG uptake after a therapeutic dose of 131-I-MIBG, which apparently destroyed the 131-I-MIBG-positive cell population, clearly suggest heterogeneity at diagnosis, with a dual neuroblastoma cell population, one with 131-I-MIBG uptake and the other without. Besides the biological implications of the 131-I-MIBG uptake heterogeneity in neuroblastoma at diagnosis, our findings suggest that in stage III neuroblastoma patients even a relatively small dose of 131-I-MIBG administered at diagnosis is sufficient to destroy either the primary tumor completely (case 1) or the part of the tumor (case 2 and 3) which shows 131-I-MIBG uptake, without any significant hematologic toxicity. Furthermore, a single course of 131-I-MIBG at the dosage employed does not appear to jeopardize the subsequent use of chemotherapy. In conclusion, if our data are confirmed by further investigation, 131-I-MIBG may be included as a front line drug shortly followed by chemotherapy in future treatment strategies of advanced neuroblastoma without or with minimal bone marrow infiltration.