[Process-directed leadership structure and organization: collective responsibility improves the standards].
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Decision Making, Organizational↗
Biomedical subjects
B Högström
Publications and source records attributed to B Högström.
The conceptual design of a radiation oncology planning system.
The conceptual design of a three-dimensional, radiation oncology planning system is described. To assure that clinical needs were met, the working routines in two major Swedish radiation oncology departments were analysed in detail. Generic work flow was identified and mapped and compared to those in other institutions. The flow was partitioned into a number of nodes that together formed a basis for the design of the system handling logistics. The design criteria of this system emphasised accommodation of current clinical practice and traditional treatment modalities, and facilitated means to validate the computational techniques. The system should also allow for new procedures and was based on the analysis of current practice and a synthetic idea of how 3D treatment planning should be done. The final product supports the treatment planning work in its entirety. It is believed that the techniques followed are of interest to those engaged in computer systems of similar purposes and complexities.
Computer Systems↗
Efficacy assessment of imaging technologies and contrast media.
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Contrast Media↗
The economic impact of diagnostic imaging: relevance of efficacy and outcome measures.
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Cost Control↗
Effects of isosmolar contrast media on the renal cortical blood flow in mice.
PURPOSE: In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of i.v. infusion of a nonionic monomeric contrast medium (iohexol), a nonionic dimeric contrast medium (iodixanol), and mannitol of corresponding osmolalities were studied. RESULTS: All infusions produced marked effects on the distribution and velocity of renal cortical blood flow. Renal cortical blood flow was inhomogeneous as regards the different capillaries. There was an initial rapid rise in the blood flow in some capillaries after all infusions, while decreased flow was seen in other capillaries. The initial increase in renal cortical blood flow (RCBF) was significantly (p < 0.05) more pronounced after infusion of iohexol than after infusion of mannitol 0.69 mol/l. In all other respects, the effects of contrast media on RCBF were the same as the effects of mannitol solutions with a corresponding osmolality. The effects of each contrast medium were the same as those of mannitol of corresponding osmolality. In the capillaries showing increased blood flow, the peak value was encountered slightly later after the infusion of iodixanol than after the infusion of iohexol. This was considered to be related to differences in viscosity rather than osmolality. CONCLUSION: The difference in osmolality between iodixanol and iohexol is of no significance with regard to their effects on RCBF.
Animals↗
Effects of mannitol and iohexol infusions on the renal cortical blood flow in dehydrated mice.
In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of intravenous infusions of equimolar concentrations of mannitol and iohexol were studied in normal lean mice and obese/hyperglycemic mice after dehydration overnight. All infusions produced marked effects in distribution and velocity of renal cortical blood flow. Initially increased blood flow was seen in a number of capillaries after infusion of both mannitol and iohexol, and renal cortical blood flow was inhomogeneous for different capillaries. A significantly (p < 0.05) larger number of capillaries with decreased blood flow, within the first minutes after start of infusion, was observed after infusion of iohexol to normal mice when the animals had been dehydrated overnight. Our results indicate that the minor adverse effects on renal cortical blood flow caused by the infusion of contrast medium are potentiated by dehydration.
Animals↗
In vivo fluorescence microscopy of microcirculation in the renal cortex of mice. Part V. Effects of mannitol and iohexol infusions in normal, obese/hyperglycemic and diabetic mice.
In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of i.v. infusions of mannitol and iohexol were studied in normal and obese/hyperglycemic mice and in mice with streptozotocin-induced diabetes mellitus. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. The infusions of contrast medium were initially followed by a significantly larger number of capillaries with decreased blood flow in the obese/hyperglycemic mice (p < 0.05) than in the diabetic and nondiabetic mice. The variations in obese/hyperglycemic groups were, however, large. The effects were the same in normal and diabetic animals.
Animals↗
In vivo fluorescence microscopy of microcirculation in the renal cortex of mice. Part III. Effects of mannitol and iohexol infusions after pretreatment with cyclosporin A.
In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in normal mice and in mice pretreated with the nephrotoxic drug cyclosporin A. The cortical circulation was studied after i.v. infusions of a nonionic low osmolar contrast medium (iohexol) and after infusions of mannitol. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was simultaneously an increased number of capillaries with decreased blood flow following all infusions. The decreased blood flow after infusion of iohexol was more pronounced when the animals had been pretreated with cyclosporin A. The difference was only significant (p < 0.05) during a short part of the observation period of 30 min, but it may indicate that kidneys previously exposed to cyclosporin A are more susceptible to infusions of iohexol.
Animals↗
In vivo fluorescence microscopy of microcirculation in the renal cortex of mice. Part IV. Effects of mannitol and iohexol infusions after temporary renal ischemia.
In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in mice. The effects of i.v. infusions of mannitol and iohexol were studied in untreated mice as well as in mice after temporary renal ischemia. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous with respect to different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was an initial increase in the number of capillaries with a decreased blood flow following 30 min of ischemia. This increase was reduced by both types of infusions, suggesting a beneficial effect on renal cortical blood flow. Neither mannitol nor contrast medium exhibited any adverse effects in ischemic kidneys that would be likely to affect renal function. However, 5 min after the infusions there was an increasing number of capillaries with decreased blood flow in all groups.
Animals↗
In vivo fluorescence microscopy of microcirculation in the renal cortex of mice. Part I. An experimental model for contrast media studies.
An experimental model using in vivo fluorescence microscopy for studies of renal cortical blood flow was tested in 40 mice. The model was suitable for testing a wide variety of hypotheses concerning alterations in renal cortical blood flow, including the possibility of inhomogeneous capillary blood flow distribution in response to i.v. infusions. The experimental model was tested for the effects of i.v. infusion of mannitol (0.3 mol/l). Effects of anesthesia and mechanical kidney fixation on renal cortical blood flow were studied. Neuroleptic analgesia was less hazardous to the animals than pentobarbital. Due to artifacts from respiratory and peristaltic motion, it was not possible to use neuroleptic analgesia without mechanical kidney fixation. A rating scale was designed for evaluating the capillary blood flow. The correlation between repeated ratings by the same observer was 0.806 and between 2 different observers 0.59.
Anesthesia↗
In vivo fluorescence microscopy of microcirculation in the renal cortex of mice. Part II. Effects of mannitol and contrast media infusions.
In vivo fluorescence microscopy was used for experimental studies of renal cortical microcirculation in 46 mice. The cortical circulation was studied after i.v. infusions of mannitol of various osmolalities as well as nonionic low osmolar (iohexol) and ionic high osmolar (metrizoate) contrast media. All infusions produced an increase in the number of capillaries with increased blood flow, significantly more pronounced after the infusion of iohexol, metrizoate and mannitol 1.46 mol/l than after the infusion of mannitol 0.3 mol/l. However, the renal cortical blood flow was inhomogeneous with respect to different capillaries. While the blood flow was increased in some capillaries it was to some extent simultaneously decreased in others, significantly more after infusion of metrizoate than after infusion of mannitol 0.3 mol/l.
Animals↗
The Alvik glenoplasty for the unstable shoulder. Modification of the Eden-Hybbinette operation in 66 cases.
66 shoulders treated with the Alvik modification of the Eden-Hybbinette operation for recurrent anterior dislocation or subluxation were examined with an average follow-up of 6 years. Two shoulders had redislocated and one had subluxations. Forty-five of the 57 cases radiographically examined showed bony healing of the transplant; nonunion of the transplant occurred in 6 cases and resorption in another 6. The objective results were excellent in 35 cases, good in 18, fair in 3, and poor in 3 cases. The patients' subjective rating was excellent or good in 61 of the 66 cases. The Alvik operation can be recommended.
Adult↗
Variance measurements with two semiconductor dose detectors.
Variance measurements were performed with pairs of semiconductor detectors of different ionization volumes in continuous and pulsed radiation fields. By a statistical analysis the relative variance of the detector was separated from that of the accelerator. The relative variance of the detector signal was shown to be correlated to the detector volume and to the dose per pulse. From the measurements the number of events per pulse within the detector volume was estimated and the number of pulses needed to have a reading with a given precision was estimated.
Cobalt Radioisotopes↗
Health economics in diagnostic imaging.
New technologies, such as magnetic resonance imaging, are frequently cited as major contributors to the growth of national health care expenditure. The cost-effectiveness of this modality is commonly challenged, and the lack of health economic documentation increases the level of criticism. Some common methods for evaluating imaging methods with regard to efficacy, cost, and benefits are, therefore, reviewed. Limitations in the assessment of diagnostic imaging are discussed, together with some suggestions as to which methodological approaches may be useful in this field of research.
Costs and Cost Analysis↗
Safety of gadodiamide injection in two different age groups.
A meta-analyses was performed to evaluate the safety of gadodiamide injection (OM-NISCAN) for magnetic resonance imaging in two different age groups (< 65 years; > or = 65 years). Data on vital signs, clinical laboratory parameters, and subjectively experienced adverse events were reviewed for 734 patients included in 19 European Phase II and III trials with gadodiamide injection (0.1 mmol/kg body weight or 0.3 mmol/kg body weight) used in magnetic resonance imaging. One hundred sixty-four patients were 65 years of age or older. No statistically significant differences were shown between this population and the population younger than 65 years of age with respect to vital signs or clinical laboratory parameters. A total of 48 adverse events, discomfort excluded, were reported, with no significant difference in frequency between the two age groups. Injection-associated discomfort was significantly (P = .0025) more frequent in the younger (9.2%) than in the older group (2.5%). Gadodiamide injection is in conclusion a safe contrast medium in older as well as in younger patients.
Adult↗