| 1. |
- Blad, B., et al.
(författare)
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A current injecting device for electrical impedance tomography
- 1994
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Ingår i: Physiological Measurement. - 0967-3334. ; 15:2A
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Tidskriftsartikel (refereegranskat)abstract
- Electrical impedance tomography (EIT) has to be improved in order to become an accepted diagnostic technique in clinical use. The aim of this study is to improve the hardware of this technique and preferably upgrade the current injecting device. Instead of using a constant current generator the idea is to implement a voltage source and measure current accurately, in order to improve the resolution in the image. The performance of such a device is analysed, particularly concerning theoretical and practical limitations. The amplitude and phase accuracy, noise and settling time are measured and presented in diagrams. The results show that improvements are possible to achieve and that such a device will improve the stability of an EIT system and the image quality.
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| 3. |
- Persson, Bertil R.R., et al.
(författare)
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Effects of microwaves from GSM mobile phones on the blood-brain barrier and neurons in rat brain
- 2005
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Ingår i: PIERS 2005 - Progress in Electromagnetics Research Symposium, Proceedings. - 1933077077 - 9781933077079 ; , s. 638-641
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Konferensbidrag (refereegranskat)abstract
- Our group has since 1988 studied the effects of different intensities and modulations of 915MHz RF in a rat model where the exposure takes place in a TEM-cell during various time periods and post exposure recovery times. The power fed into TEM-cells was 0.125, 1.25, 12.5 or 125mW corresponding to whole body SAR (determined experimentally): 0.2, 2, 20 or 200mW/kg. The rats were awake and not restrained during exposure and after the recovery period the animals were anaesthetized and sacrificed by perfusion-fixation with 4% formaldehyde. Paraffin embedded 5 μm. thick brain slices were stained for albumin by applying albumin antibodies (Dakopatts), by which albumin is revealed as brownish discolorations. Dark neurons were revealed by staining for RNA/DNA with cresyl violet. In series of more than 1800 Fisher rats, we have proven that sub thermal power levels from both pulse-modulated and continuous RF fields - including those from real GSM mobile phones - have the potency to significantly open the BBB for the animals' own albumin (but not fibrinogen) to pass out into the brain and to accumulate in the neurons and glial cells surrounding the capillaries. Albumin extravasations are most prominent at the lower SAR values. This dose-response behaviour suggests some kind of energy or electromagnetic field strength windowing effect. A linear dose-response relationship for dark neurons was found at 50 days after exposure, with most prominent occurrence at SAR 200mW/kg.
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| 5. |
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| 7. |
- Bolmsjo, M. S., et al.
(författare)
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A new instrument for survey monitoring of airborne xenon-133
- 1982
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 27:6, s. 861-866
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Tidskriftsartikel (refereegranskat)abstract
- Methods are reviewed for measuring xenon-133 contamination of the air in medical clinics. The principles of a new, simple, and low cost monitor are outlined. Results from experimental tests in laboratories and medical clinics were encouraging, indicating that the monitor is a valuable tool for survey measurements of 133Xe contamination in nuclear medicine departments.
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| 8. |
- Bolmsjo, M. S., et al.
(författare)
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Trapping and re-use system for radioactive xenon in nuclear medicine
- 1978
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155. ; 23:1, s. 77-89
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Tidskriftsartikel (refereegranskat)abstract
- Different methods of trapping radioactive xenon are reviewed. Trapping by adsorption on activated charcoal has the advantage of being simple and cheap and also makes it possible to recycle the xenon. An activated charcoal trapping system is described which can extract 133Xe from 100l of expired air in 10 min from patients undergoing diagnostic pulmonary or circulation studies. Details of the construction are discussed. The trapped gas can be rapidly released and returned to the spirometer. Substantial reduction of costs can be achieved with 133Xe; this becomes even more important as accelerator-produced 127Xe comes into more general use.
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| 9. |
- Bolmsjö, M. S., et al.
(författare)
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Factors affecting the trapping performance of xenon holdup-filters in nuclear medicine applications
- 1982
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Ingår i: Medical Physics. - : Wiley. - 0094-2405. ; 9:1, s. 96-105
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Tidskriftsartikel (refereegranskat)abstract
- Activated charcoal traps are used in nuclear medicine departments to capture exhaled radioactive xenon gas. In the present study, the trapping performance of charcoal was investigated for different physical qualities in experimental and clinical situations. Various factors affecting the trapping capacity are identified, such as the charcoal mass, moisture and carbon�dioxide concentrations in the sweep gas, gas�flow rate through the trap, and temperature. Improper drying of the exhaled air prior to passage through the charcoal bed appears to be a critical factor, leading to a much earlier breakthrough of xenon. Commercial xenon traps intended for ambient temperature operation were found to be useful only for a limited number of patients due to an early breakthrough point. By refrigerating the trap, however, a much larger capacity was achieved. If correctly managed, xenon traps constitute a useful alternative for isolating radioactive xenon wastes in clinical and experimental applications.
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