[Order of management for nuclear medicine for sentinel lymph node (SLN) diagnosis].
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Biomedical subjects
Publications and source records attributed to G Lottes.
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AIM: In an earlier study (study I) we had calculated the costs for FDG-PET investigations with our satellite concept (19). 433 patients were included in the study. Compared to the general indications for PET examinations the proportions of investigations were somewhat untypical: Both parameters have changed actually. Therefore we carried out a renewed data analysis (study II). METHODS: All economic parameters were kept, in order to ensure the comparability of both studies. Only an adjustment of the costs to actual conditions was performed. RESULTS: Proportions of investigations: Oncology 63%, Neurology 28%, Cardiology 9%; 3.5 investigations per working day. According to the increased number of investigations the structure of the total costs (DM 1601831) shows a small rise of the percentage costs for the FDG (41% to 42%) and a percentage decrease of the fixed overheads (48% to 43%). The percentage of personnel costs has increased (11% to 15%), the average cost per investigation has diminished: They amounted to DM 2783 in the earlier study (ranging from DM 2458 to 3463). The new data analysis results in the average cost of DM 2366 (-15%) per investigation (ranging from DM 2114 to 2840). Exemplary calculations show that a minimum of the costs will be achieved, if four investigations per day are performed. Retaining all parameters, which do not refer to the costs of the FDG, the average amount for one investigation would vary from DM 2000 (no delivery time) to DM 3300 (4 hours of delivery time). CONCLUSIONS: The results are in good agreement to the general laws of economic science, according to which an increase of the "number of units" with the same fixed overheads will result in a relative reduction of the costs of the "products". A further increase in the frequency of investigations will lead to a rise of the average costs per investigation, because of the physical decay of the FDG delivered once a day.
AIM: One of the main arguments against the acceptance and introduction of FDG PET as a regular benefit in the statutory Medical Insurance system in Germany are its (alleged) high costs. The aim of the present study has been to determine empirically over a period of twelve months the costs of FDG PET, making use of a satellite concept. METHODS: Documentation on performance and consumption data has been assembled for purposes of cost analysis. After analysis these data provided the basis for an assessment of the costs. In view of the high proportion of fixed overheads and strong fluctuations in consumption values, it was not possible to allocate reliably in an individual FDG PET investigation the various types of costs to individual causes. A monthly cost assessment procedure was therefore adopted. For this purpose data were recorded in the department for Nuclear Medicine, while the statistical assessment of the consumption data and analysis of the costs were undertaken in the Institute of Industrial and Hospital Management. RESULTS: Over the twelve month observation period (November 1995 to October 1996, 177 working days) 433 patients were included in the study: 244 with brain diseases 37 cardiac patients, 130 whole body studies and 22 combined studies (brain and whole body scans). The non volume based costs, maintenance charges and depreciation accounted for the highest proportion of the total costs (48%). The FDG-related costs accounted for 41% of the total costs, while the personnel costs amounted to 11% and the film costs to only 0.45%. The total costs incurred amounted to DM 1,205,050. CONCLUSION: These data represent a first empirical cost analysis for FDG PET based on a satellite concept and form a starting point for a cost/benefit analysis of this procedure.
To date, positron emission tomography (PET) is the most powerful tool for the non-invasive study of biochemical processes. Besides its usefulness for basic research PET has been proven to be superior to conventional diagnostic methods in several clinical indications. However, the introduction of PET into clinical practice has been hindered considerably by its costs. Several American studies lend support to the hypothesis that PET may be more cost-effective than the conventional diagnostic work-up-at least for some of its clinical indications. In Germany, however, this hypothesis has still not been verified.
With the ever increasing number of PET-systems in operation the associated problems of radiation protection gain increasing significance. Compared to "conventional" nuclear medicine there is a need for better shielding since the production of positron emitters also yields neutrons and secondary gamma radiation. Due to the short half-lives involved the radiochemistry has to handle high initial activities. Moreover the 511 keV energy of the positron-emitters results in the vicinity of the patient in a higher exposure rate than other nuclear medicine isotopes. For these reasons the typical effective dose to cyclotron personnel is about 2 mSv per year. The whole-body dose to the radiochemists is reported to be 0-20 microSv per charge, and to the medical personnel 10-50 microSv per application. The radiation exposures of the patients are comparable to those common in "conventional" nuclear medicine.
The only curative approach for osteoid osteoma is operative removal of the nidus, but intraoperative detection of the nidus is difficult even when an X-ray amplifier is used. A simple probe-guided operative procedure using technetium-99m methylene diphosphonate is described, and the results and follow-up in 12 patients are reported. In addition physical properties of the probe have been evaluated by phantom measurements.
In this article guidelines for single-photon emission computerized tomography (SPECT) of the brain are presented by the Task Group "Neurology" of the European Association of Nuclear Medicine (EANM). Under separate headings are discussed: the pathophysiologic principles of various brain diseases, pharmacokinetics and pharmacodynamics of various radiopharmaceuticals, physical principles of SPECT imaging, computerized data processing, clinical protocols and the evaluation of SPECT results.
It was the aim of this study to compare benzodiazepine (Bz) receptor binding and cerebral perfusion in patients with partial epilepsy. Single photon emission tomography (SPET) studies with the flow-marker technetium 99m hexamethylpropylene amine oxine (99mTc-HMPAO) and with the 123I-labelled Bz-receptor ligand Ro 16-0154 (123I-Iomazenil) were performed in 12 patients with partial epilepsy, all with normal magnetic resonance imaging (MRI) and computed tomography (CT) scans. The SPET studies with 123I-Iomazenil were carried out 5 min and 2 h after injection. At 2 h the distribution of activity was very similar to the expected distribution of Bz-receptors in the human brain, known from positron emission tomography (PET) work and post-mortem studies. Early images showed a significantly higher tracer accumulation in the area of the basal ganglia, cerebellum, and naso-pharyngeal space. This finding is caused by non-specific binding and the contribution of the tracer in the blood pool in this phase. Also after 2 h p.i. of 123I-Iomazenil, 9 of the 12 patients showed a focal decrease of of Bz-receptor binding. Ten patients had focal flow abnormalities with 99mTc-HMPAO SPET. In 8 subjects impairment of flow was seen in sites of reduced 123I-Iomazenil uptake. 123I-Iomazenil is suitable for Bz-receptor mapping. In this series of patients, Bz-receptor mapping with SPET seems to offer no advantage over 99mTc-HMPAO in the detection of epileptic foci.
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N-Isopropyl-p-123I-amphetamine (123I-IMP) single photon emission computer tomography studies were performed on 17 patients suffering from amyotrophic lateral sclerosis (ALS). All patients displayed varying degrees of impaired fixation of 123I-IMP in the whole brain. These findings were not related to the clinical variants of ALS and the age of the patients. A correlation between the severity of the disease and the degree of impaired fixation could be observed. In addition, patients suffering from ALS for longer periods showed more pronounced impairment of 123I-IMP fixation.
99mTc-HMPAO-SPECT and SPECT with the 123I-labelled benzodiazepine (Bz) receptor ligand Ro 16-0154 were performed in 10 patients suffering from partial epilepsy, without cerebral lesion in MRT or CT.2 h p.i. of Ro 16-0154 the distribution of activity correlated with the known distribution of Bz-receptors in the human brain. Perfusion and receptor-binding were found decreased in 7 patients of each study in the suspicious brain-area. 123I-labelled Ro 16-0154 is suitable for Bz-receptor mapping by SPECT. The decrease of Bz-receptor binding in epileptic foci, as described in PET-studies, was also detected by SPECT in 7 of 10 patients.