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| 2. |
- Garkavij, Michael, et al.
(författare)
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Extracorporeal immunoadsorption from whole blood based on the avidin-biotin concept. Evaluation of a new method
- 1996
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 35:3, s. 309-312
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Tidskriftsartikel (refereegranskat)abstract
- This study of 36 rats with rat colon adenocarcinoma transplants was carried out to investigate the efficacy of a new method of whole blood immunoadsorption (WBIA) in removing biotinylated monoclonal antibodies (MAbs) directly from unseparated blood, in order to increase 'the tumor/normal-tissue uptake ratio', as compared with extracorporeal immunoadsorption (ECIA) of antibodies from plasma. Compared with the ECIA system, the overall volume of the WBIA system (comprising only a pump, an adsorption column, a drop-chamber and tubings) was less (3.6 vs. 6.2 ml), and procedure duration 2 h less. The 17 rats undergoing the WBIA procedure, started 12 h after i.v. injection of 4.0-4.5 MBq 125I-BR96-biotin, manifested neither hemolysis nor any other complication; no signs of organ edema were found at dissection; whole body and blood radioactivity values were reduced by 51% and 89.5%, respectively. The WBIA method was as effective as ECIA, but technically simpler, safer and more reliable.
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| 3. |
- Jonsson, Ann-Charlotte, et al.
(författare)
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Cell survival after Auger electron emission from stable intracellular indium exposed to monochromatic synchrotron radiation
- 1996
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 35:7, s. 947-952
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Tidskriftsartikel (refereegranskat)abstract
- The biological effect of Auger electrons emitted from indium in V79 cells was investigated. K-shell vacancies were induced by synchrotron x-rays. Two energies, 100 eV above and below the K-edge of indium, were used. The cell survival for controls was similar to that which has been reported by others, with D37 = 4.4 Gy. Indium-oxine-labelled cells exhibited a survival clearly below that of the controls, D37 = 3.2 Gy, but no significant difference in survival between irradiations above and below the K-edge could be observed. The explanation is, inter alia, that the number of photons interacting with indium atoms incorporated into the cell, is small compared with the number of photons interacting with other atoms in the cell. The toxicity of indium oxine made it impossible to incorporate a sufficient number of indium atoms into the cells to observe a difference in this study. However, monoenergetic irradiation above and below the K-edge, provides a technique for the investigation of basic biological effects of Auger processes.
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| 4. |
- Sjörgreen, Katarina, et al.
(författare)
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Parameters influencing volume and activity quantitation in SPECT
- 1996
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 35:3, s. 323-330
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Tidskriftsartikel (refereegranskat)abstract
- Several factors influence the accuracy to which information on the in vivo activity concentration can be obtained from SPECT images. The accuracy in image contrast and the quantitation of volume and activity has here been examined for a SPECT system aimed for absorbed dose determinations in systemic radiation therapy. The influence of source dimensions, object contrast, noise level, energy window width and the reconstruction filter was examined. All the investigated parameters affected the recoveries. Volumes of above 20 cm3 could be quantified to within +/- 20%, for object contrasts of above 96%, and within +/- 40% for object contrasts above 81%, providing limited levels of noise. Both the image contrast and the volume quantification is expected to be improved in situations with low object contrasts, if accurate correction for scattered photons can be developed. Obtained limitations in the quantitation of activity with the present method should be reduced by development of a more accurate background subtraction technique.
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| 5. |
- Tagesson, Magnus, et al.
(författare)
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A Monte-Carlo program converting activity distributions to absorbed dose distributions in a radionuclide treatment planning system
- 1996
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 35:3, s. 367-372
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Tidskriftsartikel (refereegranskat)abstract
- In systemic radiation therapy, the absorbed dose distribution must be calculated from the individual activity distribution. A computer code has been developed for the conversion of an arbitrary activity distribution to a 3-D absorbed dose distribution. The activity distribution can be described either analytically or as a voxel based distribution, which comes from a SPECT acquisition. Decay points are sampled according to the activity map, and particles (photons and electrons) from the decay are followed through the tissue until they either escape the patient or drop below a cut off energy. To verify the calculated results, the mathematically defined MIRD phantom and unity density spheres have been included in the code. Also other published dosimetry data were used for verification. Absorbed fractions and S-values were calculated. A comparison with simulated data from the code with MIRD data shows good agreement. The S values are within 10-20% of published MIRD S values for most organs. Absorbed fractions for photons and electrons in spheres (masses between 1 g and 200 kg) are within 10-15% of those published. Radial absorbed dose distributions in a necrotic tumor show good agreement with published data. The application of the code in a radionuclide therapy dose planning system, based on quantitative SPECT, is discussed.
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