[Values and limitations of radioimmunoscintigraphy with MoAb 225-28S in the diagnosis of posterior uveal melanoma]. / Valeurs et limites de la radio-immuno-scintigraphie avec MoAb 225-28S dans le diagnostic des mélanomes uvéaux postérieurs.

When evaluating a clinical situation in which a posterior uveal melanoma (PUM) is suspected, we have to use all available diagnostic procedures because it may be difficult to distinguish between amelanotic tumours and/or small melanomas. Early diagnosis of a small lesion is mandatory for successful conservative therapy. Radioimmunoscintigraphy (RIS) of malignant melanoma has become an encouraging tool in Nuclear Medicine. 99mTc labelled F (ab')2 fragments of MoAb 225-28S raised against cutaneous melanoma were used. Nine patients were examined: the clinical diagnosis was PUM in 7 cases and choroidal metastases in 2 cases. Due to the size and/or site of the tumor, six eyes were enucleated. In all of these cases histopathology revealed a malignant melanoma. One patient died with disseminated hepatic metastases, 2 months after observation. RIS was positive in 5 of 7 PUM (71.4%) and a false negative result was obtained in 2 patients. Two true negative scintigraphies were observed in the patients with breast carcinomas and choroidal metastases. On the basis of these results, RIS may be valuable to diagnose ocular malignant melanoma, but specificity of MoAb 225-28S needs to be assessed.

Possible relations between sensitivity to phenylthiocarbamide and goiter.

Taste sensitivity to phenylthiocarbamide (PTC) using the Harris-Kalmus method was studied in 193 patients with thyroid disease and in a control sample of 311 individuals living in the Emilia area of Italy. The patients were classified according to the morphology of struma (mononodular, polynodular, diffuse) and to the toxic and nontoxic forms of goiter. Eighteen percent were nontasters in the control sample; 37.2% were nontasters in patients with polynodular goiter (toxic and nontoxic forms). Highly significant differences between the two groups were observed. The results obtained on this Italian sample agree with the conclusions of other studies.

Multicenter study of immunoscintigraphy with radiolabeled monoclonal antibodies in patients with melanoma.

A multicenter study was performed to analyze the efficacy of 99mTc- and 111In-labeled F(ab')2 fragments of monoclonal antibody (MoAb) 225.28S (reactive with a high molecular weight melanoma associated antigen) to radioimage malignant lesions in patients with melanoma. A total of 254 melanoma patients, carrying 412 documented melanoma lesions, were studied in 10 nuclear medicine departments. A total of 377 lesions were visualized in 206 patients; in particular (a) 250 of 412 known lesions were visualized in 159 of 191 patients known to carry melanoma lesions; (b) 95 occult lesions were visualized in 61 patients of the same group; and (c) 32 lesions were visualized in 15 of 63 patients without diagnosed lesions. The melanomic nature of 101 of 127 radioimaged occult lesions was confirmed by clinical criteria and/or by additional laboratory investigations. These results indicate that immunoscintigraphy with radiolabeled F(ab')2 fragments of MoAb 225.28S can provide clinically useful information. Analysis of the variables influencing the outcome of immunoscintigraphy with 99mTc- and 111In-labeled F(ab')2 fragments of MoAb 225.28S confirmed the role of size, anatomic site, and level of high molecular weight melanoma associated antigen in melanoma lesions. Such analysis also showed, for the first time, the influence (a) of the isotope used to radiolabel the antibody fragments and (b) of the clinical stage of the patients. The present study has shown good agreement in the results obtained by the 10 nuclear medicine departments, suggesting that immunoscintigraphy with radiolabeled F(ab')2 fragments of MoAb 225.28S is a reliable procedure.

99mTc-HIDA dynamic scintigraphy for the diagnosis of gastroesophageal reflux of bile.

In 5 patients with partial gastric resection and esophagitis, in whom esophageal pH metry was unable to demonstrate significant gastroesophageal reflux (GER), we administered i.v. 5 mCi (185 MBq) of 99mTc-HIDA, the patient lying under a computer-assisted LFOV gamma camera. When gallbladder image was evident, caerulein was administered i.v. at a physiologic dose in order to induce gallbladder contraction, and in the subsequent 45 min the patient was asked to perform a standard series of manoeuvres that increase the intraabdominal pressure (Valsalva, etc.) and favour GER. Scintigraphic images and time/activity curves obtained from areas of interest corresponding to gastric remnant and distal esophagus showed that at least one of these manoeuvres in each case was followed by the appearance of the radiocompound in the distal esophagus, indicating a 99mTc-HIDA-tagged bile GER. Consequently, we believe that HIDA-GER dynamic scintigraphy may be more useful than esophageal pH metry in demonstrating the biliary origin of an esophagitis.

[Use of radioisotopes in the evaluation of coronary disease]. / Uso dei radioisotopi nella valutazione della cardiopatia coronarica.

A study on myocardial perfusion through scintigraphy with 201-Tl has been carried on in a group of 57 persons: among them 45 had myocardial infarction and 12 had myocardial ischemia in act. In consideration of this experience, the myocardial scintigraphy with 201-Tl seems to be a valid investigation method to support the electro-vectocardiography when evaluating, bloodlessly, ischemical cardiopathies. In general, the correlation between electro-vectorcardiographic and scintigraphic data has been satisfactory. Referring to stroken parts, we can say that also those cardiac sectors usually very difficult to be explored with other radio elements such as 131-CS and 42-K, have been adequately studied with 201-Tl. To sum up, we can say that scintigraphic investigation of myocardium with 201-Tl is certainly a valid blood-less method to diagnose ischemical cardiopathy with the advantage to be also a useful diagnostical element for the evaluation of the microcirculation.

133Xe regional lung perfusion and ventilation study with the computer-assisted gamma-camera.

A new method of studying regional lung functions using 133Xe and the computer-assisted scintillation camera is described. The method and the computer processing give details of the distribution of 133Xe during perfusion and ventilation and also measures of lung function. Some cases are described in detail, and the clinical significance of the method was confirmed in 45 cases.

Diagnostic value of computer-assisted quantitative radioisotope angiocardiography.

The cardiac cavities and large vessels were studied by radioisotope angiocardiography with 99mTc-labelled albumin, using a gamma-camera linked to Med-II, with subsequent digital scanning and analysis by coloured video unit (VDP2) of the areas of iso-activity. The results are illustrated of 8 cases selected from the aggregate case histories of 78 patients (1 normal, 4 congenital heart disease, 2 rheumatic, 1 cor pulmonale chronicum). The direct observation of the course of the bolus and the activity/time curves in areas of interest in the cardiac cavities and the lungs, together with the representation of the areas of iso-activity, were useful for diagnosis and physiopathological evaluation of the heart conditions in the patients.