Immunszintigraphie mit 111ln-DTPA-markierten monoklonalen Antikörpern: Vergleich zwischen ECT und planarer Szintigraphie

Abstract

The present study was done in order to examine if the use of111ln-DTPA- labeled MAb fragments in place of 131l-labeled MAb fragments increases the sensitivity of tomographic immunoscintigraphy to reach the level of that of planar imaging techniques. In 11 patients with various primary tumors, local recurrences or metastases [colorectal carcinoma (n = 7), ovarian carcinoma (n = 2), papillary thyroid carcinoma (n = 1), undifferentiated carcinoma of the lung (n = 1)], immunoscintigraphy (IS) was carried out using 111ln-DTPA- labeled F(ab’)2 fragments of various MAbs (anti-CEA, OC 125, anti-hTG) and planar and tomographic imaging were compared intraindividually. By conventional diagnostic procedures, the presence of a tumor mass was confirmed (transmission computer tomography, ultrasound) or verified (131l whole-body scintigraphy, histology) in all cases. Immunoscintigraphy was positive in 9 out of 11 cases by ECT and in 10 out of 11 cases by planar imaging. When using 111 In-labeled MAb fragments, intraindividual comparison of ECT and planar imaging resulted in a similar sensitivity. The increased sensitivity of ECT using this tracer in contrast to 131l-labeled MAb fragments may be attributed to the fact that the physical properties of111 In are much more suitable for the gamma cameras most commonly used (single detector, 3/8” crystal); using 111 In-labeled MAb fragments, count rates sufficient for ECT can be obtained within a reasonable acquisition time. This allows to combine IS with the advantages of ECT regarding tumour localization and prevention of artefacts due to superposition of background.

Immunoscintigraphy in Laryngeal and Pharyngeal Carcinomas Using Indium-111 Labelled Monoclonal Antibody

“…The tumor size cannot be determined accurately from radionuclide images, but these images generally demonstrated the tumor site in good agreement with other radiological methods and surgery. The site resolution in radioimmunoscintigrams is, in our experience, 1-2 cm, but with single photon emission tomography (SPECT) the resolution is possibly better (25). The site resolution now achievable is not sufficient, because it does not enable one to distinguish between small transglottic, supraglottic and epiglottic tumor lesions.…”

Image Subtraction Analysis with Technetium-99M Labeled Monoclonal Antibody and Colloid for Evaluation of Liver Lesions: Phantom Measurements and Patient Studies

“…SPECT increases significantly the role of antibody imaging for detection of liver metastases (28,29), and should be used even routinely for liver studies. The findings should preferably be compared with the corresponding CT scans and, even better, may be obtained by fusion analysis of the CT and SPECT images (30).…”

Radioimmunoimaging of Non-Small Cell Lung Cancer with111In- and99MTc-Labeled Monoclonal Anti-Cea-Antibodies

“…There are now a few reports on imaging of lung cancer with polyclonal ( 1 1) and monoclonal anti-carcinoembryonic antigen (CEA)-antibodies ( 19,(22)(23)(24)(25)(26). Monoclonal antibodies against other pulmonary cancer cell antigens have been produced, and tested in xenograft studies (27)(28)(29).…”