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- Thorngren-Jerneck, Kristina, et al.
(författare)
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Cerebral glucose metabolism measured by positron emission tomography in term newborn infants with hypoxic ischemic encephalopathy
- 2001
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Ingår i: Pediatric Research. - 1530-0447. ; 49:4, s. 495-501
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Tidskriftsartikel (refereegranskat)abstract
- Total and regional cerebral glucose metabolism (CMRgl) was measured by positron emission tomography with 2-(F-18) fluoro-2-deoxy-D-glucose ((18)FDG) in 20 term infants with hypoxic ischemic encephalopathy (HIE) after perinatal asphyxia. All infants had signs of perinatal distress, and 15 were severely acidotic at birth. Six infants developed mild HIE, twelve moderate HIE, and two severe HIE during their first days of life. The positron emission tomographic scans were performed at 4-24 d of age (median, 11 d). One hour before scanning, 2-3.7 MBq/kg (54-100 µCi/kg) (18)FDG was injected i.v. No sedation was used. Quantification of CMRgl was based on a new method employing the glucose metabolism of the erythrocytes, requiring only one blood sample. In all infants, the most metabolically active brain areas were the deep subcortical parts, thalamus, basal ganglia, and sensorimotor cortex. Frontal, temporal, and parietal cortex were less metabolically active in all infants. Total CMRgl was inversely correlated with the severity of HIE (p < 0.01). Six infants with mild HIE had a mean (range) CMRgL of 55.5 (37.7-100.8) mol.min(-1).100 g(-1), 11 with moderate HIE had 26.6 (13.0-65.1) µmol.min(-1).100 g(-1), and two with severe HIE had 10.4 and 15.0 µmol.min(-1).100 g(-1), respectively. Five of six infants who developed cerebral palsy had a mean (range) CMRgl of 18.1 (10.2-31.4) µmol.min(-1).100 g(-1) compared with 41.5 (13.0-100.8) µmol.min(-1).100 g(-1) in the infants with no neurologic sequela at 2 y. We conclude that CMRgl measured during the subacute period after perinatal asphyxia in term infants is highly correlated with the severity of HIE and short-term outcome.
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| 2. |
- Brun, Eva, et al.
(författare)
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FDG PET studies during treatment: Prediction of therapy outcome in head and neck squamous cell carcinoma.
- 2002
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Ingår i: Head and Neck. - : Wiley. - 1043-3074. ; 24:2, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Positron emission tomography (PET) provides metabolic information of tissues in vivo. The purpose of this study was to assess the value of PET with 2-[(18) F] fluoro-2-deoxy-D-glucose (FDG) in prediction of therapy outcome (tumor response, survival, and locoregional control) in locally advanced HNSCC. METHODS: Between 1993 and 1999 47 patients underwent PET before (PET(1)) and after (PET(2)) 1 to 3 weeks of radical treatment with evaluation of metabolic rate (MR) and standardized uptake value (SUV) of FDG. All patients received radiotherapy, and 10 also received neoadjuvant chemotherapy. Median follow-up time was 3.3 years. RESULTS: Low and high MR FDG at PET(2), with median value as cutoff, was associated with complete remission in 96% and 62% (p =.007), with 5-year overall survival in 72% and 35% (p =.0042) and with local control in 96% and 55% (p =.002), respectively. CONCLUSIONS: FDG PET in the early phase of treatment of HNSCC is associated with tumor response, survival, and local control. Copyright 2002 John Wiley & Sons, Inc.
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| 7. |
- Hindorf, Cecilia, et al.
(författare)
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Time dependence of the activity concentration ratio of red marrow to blood and implications for red marrow dosimetry.
- 2002
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Ingår i: Cancer. - : Wiley. - 1097-0142 .- 0008-543X. ; 94:4 Suppl, s. 1235-1239
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The method for red marrow dosimetry in radioimmunotherapy, in the absence of specific activity uptake in red marrow, is based on the activity measured in the blood or plasma. The activity concentration ratio of red marrow to blood is then assumed to be constant. The aim of the current study was to determine whether this ratio varies with time after injection. METHODS: Measurements were carried out with both animals and patients.Tumor-bearing rats were intravenously injected with iodine-131-, iodine-125-, indium-111-, or rhenium-188-labeled BR96, a chimeric immunoglobulin G1 monoclonal antibody. (All were chelate-labeled, except for iodine-131, which was iodogen-labeled.) Measurements were made of the activity concentration in blood and bone marrow at different points in time after injection, and the ratio of activity concentration in red marrow and blood as a function of time postinjection (RMBLR[t)]) was calculated. For patients treated with iodine-131-labeled monoclonal antibody (LL2, Immunomedics Inc., Morris Plains, NJ; anti-CD22; immunoglobulin G2 isotype of mouse origin), blood samples were drawn and scintillation camera images taken at different times after injection. The red marrow activity concentration in the sacrum was determined by activity quantification from regions of interest. The activity concentration in blood was also measured. The RMBLR(t) was calculated based on these data. RESULTS: For both patients and rats, the RMBLR(t) was increased 72 hours after injection. Furthermore, it was found that the use of a constant RMBLR can lead to an over- or underestimation of the absorbed dose in bone marrow. CONCLUSIONS: These data demonstrate the difficulty in using fixed values of the activity concentration ratio of red marrow to blood for dosimetry.
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| 8. |
- Jönsson, Lena M, et al.
(författare)
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A dosimetry model for the small intestine incorporating intestinal wall activity and cross-doses.
- 2002
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Ingår i: Journal of Nuclear Medicine. - 0161-5505. ; 43:12, s. 1657-1664
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Tidskriftsartikel (refereegranskat)abstract
- Current internal radiation dosimetry models for the small intestine, and for most walled organs, lack the ability to account for the activity uptake in the intestinal wall. In existing models the cross-dose from nearby loops of the small intestine is not taken into consideration. The aim of this investigation was to develop a general model for calculating the absorbed dose to the radiation-sensitive cells in the small intestinal mucosa from radionuclides located in the small intestinal wall or contents. Methods: A model was developed for calculation of the self-dose and cross-dose from activity in the intestinal wall or contents. The small intestine was modeled as a cylinder with 2 different wall thicknesses and with an infinite length. Calculations were performed for various mucus thicknesses. S values were calculated using the EGS4 Monte Carlo simulation package with the PRESTA algorithm and the simulation results were integrated over the depth of the radiosensitive cells. The cross-organ dose was calculated by summing the dose contributions from other intestinal segments. Calculations of S values for self-dose and cross-dose were made for monoenergetic electrons, 0.050–10 MeV, and for the radionuclides 99mTc, 111In, 131I, 67Ga, 90Y, and 211At. Results: The self-dose S value from activity located in the small intestinal wall is considerably greater than the S values for self-dose from the contents and the cross-dose from wall and contents except for high electron energies. For all radionuclides investigated and for electrons 0.10–0.20 MeV and 8–10 MeV in energy, the cross-dose from activity in the contents is higher than the self-dose from the contents. The mucus thickness affects the S value when the activity is located in the contents. Conclusion: A dosimetric model for the small intestine was developed that takes into consideration the localization of the radiopharmaceutical in the intestinal wall or in the contents. It also calculates the contribution from self-dose and cross-dose. With this model, more accurate calculations of absorbed dose to radiation-sensitive cells in the intestine are possible.
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| 10. |
- Larsson, Jörgen, et al.
(författare)
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Distribution of iodine 125-labeled alpha1-microglobulin in rats after intravenous injection
- 2001
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Ingår i: Journal of Laboratory and Clinical Medicine. - : Elsevier BV. - 0022-2143 .- 1532-6543. ; 137:3, s. 165-175
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Tidskriftsartikel (refereegranskat)abstract
- The 28-kd plasma protein alpha(1)-microglobulin is found in the blood of mammals and fish in a free, monomeric form and as high-molecular-weight complexes with molecular masses above 200 kd. In this study, iodine 125-labeled free and high-molecular weight rat alpha(1)-microglobulin (a mixture of alpha(1)-microglobulin/alpha(1)-inhibitor-3 and alpha(1)-microglobulin/fibronectin complexes) were injected intravenously into rats. The distribution of the proteins was measured by using scintillation camera imaging. Both forms of (125)I-labeled alpha(1)-microglobulin were rapidly cleared from the blood, with a half-life of 2 and 16 minutes for the initial and late phase, respectively, for free alpha(1)-microglobulin; and a half-life of 3 and 130 minutes for the initial and late phase, respectively, for the complexes. After 45 minutes, 6%, 16%, 27%, 13%, and 34% of the free (125)I-labeled alpha(1)-microglobulin and 18%, 21%, 6%, 10%, and 42% of the (125)I-labeled alpha(1)-microglobulin complexes were found in the blood, gastrointestinal tract, kidneys, liver, and the remainder of the body, respectively. The local distribution of injected (125)I-labeled alpha(1)-microglobulin in intestines and kidneys was investigated by microscopy and autoradiography. In the intestine, both forms were distributed in the basal layers, villi, and luminal contents. The results also suggested intracellular labeling of epithelial cells. Well-defined local regions containing higher concentrations of injected protein could be seen in the intestine. In the kidneys, both forms were found mostly in the cortex. Free (125)I-labeled alpha(1)-microglobulin was found predominantly in epithelial cells of a subset of the tubules, whereas the (125)I-labeled complexes were more evenly distributed. Intracellular labeling was indicated for both alpha(1)-microglobulin forms. The results thus indicate a rapid transport of (125)I-labeled alpha(1)-microglobulin from the blood to most tissues.
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