[Radiation exposure of staff during endovascular brachytherapy with Re-188 after PTA in the peripheral blood stream]. / Strahlenexposition des Personals bei der endovaskulären Brachytherapie (EVBT) mit Re-188 nach PTA im peripheren Stromgebiet.

Endovascular brachytherapy using a balloon catheter filled with Re-188 solution is a promising method for the prophylaxis of restenosis in peripheral blood circulation after percutaneous transluminal angioplasty (PTA) treatments. Thereby about 20 GBq Re-188 with a specific activity of about 5 GBq/ml are used. The high ionisation density of the beta radiation with high energy leads to selective irradiation of the blood vessel wall near the catheter, whereas the surrounding tissue remains almost unaffected. However the hospital staff has to carry out some work steps within close range to the high activity during preparation and therapy, causing a high risk of skin exposure, in particular at the hands. Estimations and measurements of the maximal local skin dose were made with thin-layered thermoluminescence dosimeters. It was assessed that the annual dose limit for skin of 500 mSv may be exceeded considerably when using conventional procedures and considering the expected number of 75 treatments per annum. By using the newly developed rhenium-188 application device "FlowMedical Application System" the exposure risk for the staff could be reduced drastically. The maximum skin dose of 76 mSv for the radiologist and of 50 mSv for the physicist was decreased to 2 mSv per treatment for both of them. Consequently, from the radiation protection point of view, the itm Rhenium-PTA is a safe method. Any exceeding of the dose limit can be prevented.

Scintigraphic techniques for the diagnosis of infectious disease of the musculoskeletal system.

In imaging infectious diseases of the musculoskeletal system, the metabolic information provided by nuclear medicine studies complements the structural information of radiologic modalities. Often the diagnosis can be confirmed by combining the methods in a diagnostic algorithm. The decision about whether a single study is best depends on the clinical setting and the questions that require an answer. Whereas radiography, magnetic resonance imaging (MRI), and computed tomography (CT) usually focus on a single area, nuclear medicine imaging offers the advantage of whole body imaging. However, despite significant improvements it cannot approach the detailed anatomical visualization provided by MRI or CT. In most cases scintigraphy is a very sensitive (e.g., bone scan, positron emission tomography) and often quite specific tool (e.g., white blood cell scintigraphy). The metabolic information of the single scintigraphic procedure depends on the accumulation mechanism. For the work-up of infectious disorders different radiopharmaceuticals can be used, and the decision for the best modality should be tailored to the clinical question and the special pathophysiologic condition of the infection. This article describes the most common nuclear medicine studies and their clinical relevance in some infectious diseases.

Prognostic significance of (18)F-FDG and (99m)Tc-methylene diphosphonate uptake in primary osteosarcoma.

UNLABELLED: The purpose of this retrospective analysis was to evaluate the prognostic significance of both initial glucose metabolism as measured by (18)F-FDG PET and osteoblastic activity as measured by (99m)Tc-methylene diphosphonate (MDP) bone scintigraphy in osteosarcoma. METHODS: In 29 patients (18 male, 11 female; age range, 5-41 y) with primary osteosarcoma, (18)F-FDG uptake and (99m)Tc-MDP uptake were measured semiquantitatively (average and maximum tumor-to-nontumor ratios [T/NT(av) and T/NT(max), respectively]) using PET and bone scintigraphy at the time of diagnosis. After chemotherapy, the patients underwent surgery for their primary tumor, and the response was determined histologically. Cumulative overall survival and event-free survival were determined by clinical and imaging follow-up of 7-72 mo (median, 28 mo). RESULTS: Clinical and imaging follow-up revealed that the disease relapsed or failed to achieve complete remission in 9 patients and that 6 patients died of the disease. Both overall and event-free survival were significantly better in patients with a low (18)F-FDG T/NT(max) (less than the median) than in patients with a high (18)F-FDG T/NT(max) (at least the median). The negative relationship of (18)F-FDG T/NT(av), (99m)Tc-MDP T/NT(max), and (99m)Tc-MDP T/NT(av) with overall and event-free survival did not reach a level of significance. (18)F-FDG uptake values correlated moderately and positively with (99m)Tc-MDP uptake values, but a level of significance was reached only between (18)F-FDG T/NT(max) and (99m)Tc-MDP T/NT(av). CONCLUSION: The initial glucose metabolism of primary osteosarcoma as measured by (18)F-FDG PET using T/NT(max) provides prognostic information. High (18)F-FDG uptake correlates with poor outcome. Thus, (18)F-FDG uptake may be complementary to other well-known factors in judging the prognosis in osteosarcoma.

3-[123I]Iodo-L-alpha-methyl tyrosine transport into human fibroblasts and comparison with Ewing's sarcoma cells.

The cellular transport systems and the transport kinetics of [123I]IMT uptake into non-malignant extracranial cells were characterized for the first time. Human fibroblasts were chosen as non-malignant extracranial cells as they are found ubiquitous in the body. [123I]IMT is exclusively transported into fibroblasts via the sodium independent system L. An apparent Michaelis constant K(m) = 116.2 +/- 18.9 microM and a maximum transport velocity V(max) = 191.6 +/- 13.9 pmol x (10(6) cells)(-1) x min(-1) were calculated for the sodium-independent transport. These results were compared with those determined in two malignantly transformed extracranial cell lines, the human Ewing's sarcoma cell lines VH-64 and CADO-ES-1.