[en] In the thesis radiolabeled antibodies were tested for screening of cancer in patients without previous knowledge of tumour histopathology. They were tested as well targeting known cancer, sometimes in unknown clinical stage. Methods for detection enhancement utilizing double-tracer techniques and alternative routes of administration were also investigated. (385 refs., 11 tabs.)

[en] A review on the use of monoclonal antibodies labeled with positron emitting nuclides is presented. Potential radionuclides for labeling are e.g. ¹⁸F, ⁵⁵Co, ⁶⁴Cu, ⁶⁶Ga, ⁶⁸Ga, ⁷⁶Br, ⁸⁹Zr and ¹²⁴I. Radionuclides with short half-lives may be utilized especially by pretargeting approaches. Galliumisotopes have also been coupled to antibodies, using chelation methods. One promising nuclide for antibody labeling seems to be ¹²⁴I (t_1/2 = 4.2 d) as radioiodination of antibodies is a well-characterized procedure. Some of our own studies using ¹²⁴I labeled monoclonal antibodies in a nude mouse and rat human ovarian cancer xenograft are reported. (orig.)

[en] Bleomycin (BLM), a natural antibiotic toxic to dividing cells has been used for treatment of several forms of cancer. BLM has been labelled with various cations but most have turned out to be unstable in vivo. In-BLM has demonstrated high bone marrow uptake, but by using an In-111-bleomycin complex (BLMC) formed at low pH, the low in vivo stability and high bone marrow uptake can be avoided. Our premise is to combine radiotherapy and chemotherapy by using radionuclide-BLMC. In this study we used In-111-A_2a-c^'-BLMC in 28 head and neck cancer patients. Scintigraphic findings were compared to those of surgery, pre-operative radiology and proliferation markers. The injected patient activity was approximately 85 MBq, 100 MBq/mg. (Author)

[en] New radiopharmaceuticals have been introduced in nuclear medicine examinations, and on the other hand, the amount of many routine nuclear medicine procedures have been replaced with clinical methods utilising non-ionisating radiation (ultrasonography, MRI). To clarify the situation in Finland, a country wide survey on the use of radiopharmaceuticals in diagnostics and therapy was made in 1975, 1982, 1989, 1994, 1997 and will be made in 2000. A questionnaire was sent to all hospitals and institutes using unsealed sources in both diagnostic and therapeutic nuclear medicine procedures. For each procedure, the pharmaceutical used, the number of procedures and the typical administered activities were recorded. The collective effective doses from nuclear medicine examinations were calculated according to the ICRP formulae similarly for each survey. In Finland, in each of these years, more than 50,000 procedures in more than 30 different laboratories were performed. Significant changes in collective doses were observed: for example, the collective dose from I-131 was 350 manSv in 1975, and 20 manSv in 1997. In 1975, 68% (n=23967) of collective dose originated from I-131, whereas in 1997 the percentage of I-131 in collective dose was 10 % (n=1118). In 1994 and 1997, the use of the three radionuclides (Tc-99m, I-131 and Tl-201) accounted for 96% and 95% of the collective effective dose. Our results indicate that the collective effective dose from nuclear medicine examinations has decreased in last 25 years. National surveys form the basis when setting reference levels for typical nuclear medicine examinations. By introducing reference levels based on national practice it is possible to even decrease the collective effective dose. (author)

[en] New radiopharmaceuticals have been introduced in nuclear medicine examinations, and on the other hand, the amount of many routine nuclear medicine procedures have been replaced with clinical methods utilising non-ionisating radiation (ultrasonography, MRI). To clarify the situation in Finland, a country wide survey on the use of radiopharmaceuticals in diagnostics and therapy was made in 1975, 1982, 1989, 1994, 1997 and will be made in 2000. A questionnaire was sent to all hospitals and institutes using unsealed sources in both diagnostic and therapeutic nuclear medicine procedures. For each procedure, the pharmaceutical used, the number of procedures and the typical administered activities were recorded. The collective effective doses from nuclear medicine examinations were calculated according to the ICRP formulae similarly for each survey. In Finland, in each of these years, more than 50,000 procedures in more than 30 different laboratories were performed. Significant changes in collective doses were observed: for example, the collective dose from I-131 was 350 manSv in 1975, and 20 manSv in 1997. In 1975, 68% (n=23967) of collective dose originated from I-131, whereas in 1997 the percentage of I-131 in collective dose was 10 % (n=1118). In 1994 and 1997, the use of the three radionuclides (Tc-99m, I-131 and Tl-201) accounted for 96% and 95% of the collective effective dose. Our results indicate that the collective effective dose from nuclear medicine examinations has decreased in last 25 years. National surveys form the basis when setting reference levels for typical nuclear medicine examinations. By introducing reference levels based on national practice it is possible to even decrease the collective effective dose. (author)

[en] Depending on radionuclide characteristics, radioimmunotherapy (RIT) relies on radioactivity to destroy cells distant from immunotargeted cells. Therefore, even heterogeneous tumors (for antigen recognition) can be treated, because not all cells have to be targeted. Substantial complete response rates have been reported in patients with non-Hodgkin's lymphoma. Much more modest results have been reported for patients iwth bulky solid tumors, e.g. adenocarcinomas. The radiation doses delivered by targeting antibodies are generally too low to achieve major therapeutic responses. Dose escalation is limited by myelotoxicity, and higher doses need to be delivered to neoplasmas less radiosensitive than lymphomas. Various trials for both systematic and regional RIT have been reported on. Intraperitoneal adminostration has been applied for colorectal and ovarian carcinomas. Our own results indicate that, e.g., intraperitoneal pseudomyxoma can be treated with RIT. Myelotoxicity can be reduced by anti-antibody-enhancement, 2- and 3-step strategies, bispecific monoclonal antibodies (MABs), and extracorporeal immunoadsorption. The radionuclide has to be selected properly for each purpose; it can be a β-emitter, e.g. I-131, Y-90, Re-188, Re-186, Lu-177 or Sm-153, an α-emitter At-211 or Bi-212 or an Auger-emitter, e.g. I-125, I-123. One major problem with RIT, besides slow penetration rate into tumor tissue and low tumor-to-normal tissue ratio, is the HAMA response, which can be partly avoided by the use of humanized MAbs and immunosuppression. However, RIT will be, because of all the recent developments, an important form of cancer management. (orig.)

[en] Abstract only

[en] The aim of the study is to analyze two methods with no need for cell labelling and with a possibility to detect infections and to compare these to MDP-bone scintigraphy. (orig./MG)

[en] Abstract only

[en] Radiolabeled antibodies can add a dimension in the diagnostic imaging and staging of metastatic head and neck malignancies. In the oral cavity, oropharynx and larynx the vast majority of malignancies are squamous cell carcinomas. This common cellular origin makes it feasible to search these neoplasms for appropriate tumor-associated antigens which can be used for radioimmunoscintigraphy. The pretherapeutic staging of head and neck malignancies, including salivary gland tumors, is based on clinical findings and conventional radiology (computerized tomography, magnetic resonance imaging, ultrasonography). The routine use of monoclonal antibodies for imaging head and neck malignancies was made possible by the production of several monoclonal antibodies to tumor-associated membrane antigens. A review of the clinical trials reported in the literature, and our own results with ¹¹¹In-labeled anti-carcinoembryonic antigen (CEA) antibody in 42 patients are presented. (orig.)