| 1. |
- Gladh, Jörgen, et al.
(författare)
-
X-ray emission spectroscopy and density functional study of CO/Fe(100)
- 2012
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 136:3
-
Tidskriftsartikel (refereegranskat)abstract
- We report x-ray emission and absorption spectroscopy studies of the electronic structure of the pre-dissociative alpha(3) phase of CO bound at hollow sites of Fe(100) as well as of the on-top bound species in the high-coverage alpha(1) phase. The analysis is supported by density functional calculations of structures and spectra. The bonding of lying down CO in the hollow site is well described in terms of pi to pi* charge transfer made possible through bonding interaction also at the oxygen in the minority spin-channel. The on-top CO in the mixed, high-coverage alpha(1) phase is found to be tilted due to adsorbate-adsorbate interaction, but still with bonding mainly characteristic of vertical on-top adsorbed CO similar to other transition-metal surfaces.
|
|
| 2. |
- Bartosik, Jolanta, et al.
(författare)
-
Subendocardial versus transmural ischaemia in myocardial perfusion SPECT - a Monte Carlo study
- 2006
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 26:6, s. 343-350
-
Tidskriftsartikel (refereegranskat)abstract
- Myocardial perfusion imaging with single-photon emission computed tomography (SPECT) is useful for the evaluation of patients with known or suspected coronary artery disease. Parameters of interest are the reduction in the blood perfusion (severity) and the lesion volume (extent). The aim of this study was to evaluate these parameters, as calculated by automatic quantification software, for different cases of subendocardial and transmural myocardial lesions. Methods A computer phantom was used to simulate 32 male patients with different defect locations and activity uptakes, which were based on clinical patient studies. The Monte Carlo program SIMIND was used to simulate realistic SPECT projections which were reconstructed to give short-axis images, analysed by the AutoQUANT program using the same procedure as for a real patient. Results The results showed a disparity between the quantification of transmural and subendocardial lesions with the same lesion activity uptake reduction and this could be confirmed by visual interpretation. Neither the parameters given by the quantification program nor visual interpretation could distinguish between the transmural lesions and the subendocardial lesions with activity uptake reduction twice as high as in the corresponding transmural lesions. Conclusion Transmural lesions and the corresponding subendocardial lesions with the same activity uptake reduction could be separated by the quantification software for SPECT imaging and visual analysis. The subendocardial lesions with activity uptake reduction twice as high as in the corresponding transmural lesions could not be differentiated neither by the quantification software nor by visual interpretation. Thus these lesions will get the same scoring when analysed by the AutoQUANT program.
|
|
| 3. |
|
|
| 4. |
- Dalmo, Johanna, et al.
(författare)
-
Priming increases the anti-tumor effect and therapeutic window of 177Lu-octreotate in nude mice bearing human small intestine neuroendocrine tumor GOT1.
- 2017
-
Ingår i: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: 177Lu-[DOTA0, Tyr3]-octreotate (177Lu-octreotate) is used for treatment of patients with somatostatin receptor (SSTR) expressing neuroendocrine tumors. However, complete tumor remission is rarely seen, and optimization of treatment protocols is needed. In vitro studies have shown that irradiation can up-regulate the expression of SSTR1, 2 and 5, and increase 177Lu-octreotate uptake. The aim of the present study was to examine the anti-tumor effect of a 177Lu-octreotate priming dose followed 24 h later by a second injection of 177Lu-octreotate compared to a single administration of 177Lu-octreotate, performed on the human small intestine neuroendocrine tumor cell line, GOT1, transplanted to nude mice. RESULTS: Priming resulted in a 1.9 times higher mean absorbed dose to the tumor tissue per administered activity, together with a reduced mean absorbed dose for kidneys. Priming gave the best overall anti-tumor effects. Magnetic resonance imaging showed no statistically significant difference in tumor response between treatment with and without priming. Gene expression analysis demonstrated effects on cell cycle regulation. Biological processes associated with apoptotic cell death were highly affected in the biodistribution and dosimetry study, via differential regulation of, e.g., APOE, BAX, CDKN1A, and GADD45A. CONCLUSIONS: Priming had the best overall anti-tumor effects and also resulted in an increased therapeutic window. Results indicate that potential biomarkers for tumor regrowth may be found in the p53 or JNK signaling pathways. Priming administration is an interesting optimization strategy for 177Lu-octreotate therapy of neuroendocrine tumors, and further studies should be performed to determine the mechanisms responsible for the reported effects.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Fransson, Helen, et al.
(författare)
-
Validation of an automated method to quantify stress-induced ischemia and infarction in rest-stress myocardial perfusion SPECT.
- 2014
-
Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1532-6551 .- 1071-3581. ; 21:3, s. 503-518
-
Tidskriftsartikel (refereegranskat)abstract
- Myocardial perfusion SPECT (MPS) is one of the frequently used methods for quantification of perfusion defects in patients with known or suspected coronary artery disease. This article describes open access software for automated quantification in MPS of stress-induced ischemia and infarction and provides phantom and in vivo validation.
|
|
| 9. |
- Guðmundsson, Eirikur, et al.
(författare)
-
Metastatic potential in renal cell carcinomas <= 7 cm : swedish kidney cancer quality register data
- 2011
-
Ingår i: European Urology. - Basel : Karger. - 0302-2838 .- 1873-7560. ; 60:5, s. 975-982
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Renal cell carcinoma(RCC) represents 2-3% of all malignancies and accounts for approximately 90% of all kidney malignancies. An increasing proportion of RCCs are discovered incidentally, and the average tumor diameter at diagnosis has decreased over the last few decades. Small RCCs have often been regarded by many as relatively harmless. Objective: The objective was to evaluate the incidence of local T-category distribution and lymph node and distant metastases in relation to tumor size in RCCs <= 7 cm in a nationally based patient population. Design, setting, and participants: Data were extracted from the National Swedish Kidney Cancer Register containing 3489 RCCs diagnosed between 2005 and 2008. This is a population-based registry including 99% of all RCCs diagnosed nationwide. The study included 2033 patients having a tumor <= 7 cm in diameter. Measurements: The size of the tumors was compared with sex, age, cause of diagnosis, Fuhrman grade, RCC type, and TNM category. Results and limitations: Most RCCs were discovered incidentally and incidence correlated inversely to tumor size. There were 887 (43%) patients with category T1a tumors, 836 (40%) with category T1b, 174 (8%) with T3a, 131 (6%) with T3b/c, and 12 (1%) patients had invasion of adjacent organs (T4). A total of 309 (15%) patients had lymph node and/or distant metastases. Of the 177 1- to 2-cm RCCs, category T3 tumors were identified in three patients and lymph node and/or distant metastases were identified in 8 (5%). Only for tumors <= 1 cm was there neither advanced stage nor metastasis. The occurrence of locally advanced growth, lymph node and distant metastases, and high tumor grade correlated to tumor size. Patients with Fuhrman grade III or IV had a fourfold greater risk of metastases than grades I or II. Conclusions: Lymph node and distant metastases occur even in small RCCs. Risk of metastases increases with tumor size. The data clearly show that small RCCs also have a malignant potential and should be properly evaluated and adequately treated. (C) 2011 European Association of Urology. Published by Elsevier B. V. All rights reserved.
|
|
| 10. |
- Lilja, Ylva, et al.
(författare)
-
Visual pathway impairment by pituitary adenomas: quantitative diagnostics by diffusion tensor imaging.
- 2017
-
Ingår i: Journal of neurosurgery. - 1933-0693. ; 127:3, s. 569-579
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE Despite ample experience in surgical treatment of pituitary adenomas, little is known about objective indices that may reveal risk of visual impairment caused by tumor growth that leads to compression of the anterior visual pathways. This study aimed to explore diffusion tensor imaging (DTI) as a means for objective assessment of injury to the anterior visual pathways caused by pituitary adenomas. METHODS Twenty-three patients with pituitary adenomas, scheduled for transsphenoidal tumor resection, and 20 healthy control subjects were included in the study. A minimum suprasellar tumor extension of Grade 2-4, according to the SIPAP (suprasellar, infrasellar, parasellar, anterior, and posterior) scale, was required for inclusion. Neuroophthalmological examinations, conventional MRI, and DTI were completed in all subjects and were repeated 6 months after surgery. Quantitative assessment of chiasmal lift, visual field defect (VFD), and DTI parameters from the optic tracts was performed. Linear correlations, group comparisons, and prediction models were done in controls and patients. RESULTS Both the degree of VFD and chiasmal lift were significantly correlated with the radial diffusivity (r = 0.55, p < 0.05 and r = 0.48, p < 0.05, respectively) and the fractional anisotropy (r = -0.58, p < 0.05 and r = -0.47, p < 0.05, respectively) but not with the axial diffusivity. The axial diffusivity differed significantly between controls and patients with VFD, both before and after surgery (p < 0.05); however, no difference was found between patients with and without VFD. Based on the axial diffusivity and fractional anisotropy, a prediction model classified all patients with VFD correctly (sensitivity 1.0), 9 of 12 patients without VFD correctly (sensitivity 0.75), and 17 of 20 controls as controls (specificity 0.85). CONCLUSIONS DTI could detect pathology and degree of injury in the anterior visual pathways that were compressed by pituitary adenomas. The correlation between radial diffusivity and visual impairment may reflect a gradual demyelination in the visual pathways caused by an increased tumor effect. The low level of axial diffusivity found in the patient group may represent early atrophy in the visual pathways, detectable on DTI but not by conventional methods. DTI may provide objective data, detect early signs of injury, and be an additional diagnostic tool for determining indication for surgery in cases of pituitary adenomas.
|
|
