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- Jönsson, L., et al.
(författare)
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Quantitative analysis of phantom studies of 111In and 68Ga imaging of neuroendocrine tumours
- 2018
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Ingår i: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Nuclear medicine imaging of neuroendocrine tumours is performed either by SPECT/CT imaging, using 111In-octreotide or by PET/CT imaging using 68Ga-radiolabelled somatostatin analogs. These imaging techniques will give different image quality and different detection thresholds for tumours, depending on size and activity uptake. The aim was to evaluate the image quality for 111In-SPECT and 68Ga-PET imaging, i.e. the smallest volume possible to visualize for different source-to-background activity ratios. The accuracy of quantification of lesion volume and activity was also investigated to develop an objective evaluation for radionuclide therapy eligibility. The phantom study was performed using the NEMA IEC Body Phantom with six hot spheres having inner diameters of 10, 13, 17, 22, 28, and 37 mm, filled with either 68Ga or 111In with sphere-to-background ratios (SBRs) of no background activity, 5:1, 2.5:1, and 1.25:1. Activity ratios of 1.25:1 and 2.5:1 are clinically found for lesions close to the liver and spleen. Clinical acquisition and reconstruction protocols were applied. Line profiles were drawn to evaluate the smallest detectable volume within a given SBR. Recovery curves based on threshold-based VOIs, threshold-based VOIs adapted to the background and CT-based ROIs were obtained for all SBRs and sphere diameters, allowing for quantification. Results: The 10-mm sphere was not possible to detect in SPECT images. It was detectable in PET images for SBRs of 2.5:1 and higher. In a background corresponding to the activity uptake in the liver, spheres larger than 22–37 mm were detectable in the 111In-SPECT images and spheres larger than 13–22 mm were detectable in the 68Ga-PET images. The maximum activity concentration was accurately quantified for spheres larger than 22 mm in the PET images; however, the quantification was impaired by sphere size and background activity. Conclusions: It was not possible to detect the 10-mm sphere in any of the SPECT images. In a background corresponding to the activity uptake in the liver, spheres larger than approximately 30 mm were visible in the 111In-SPECT images and spheres larger than approximately 17 mm were visible in the 68Ga-PET images. Sphere diameter and background activity strongly affect the possibility of a correct quantification.
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- Arthur, Rohan, et al.
(författare)
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Optimising the production cost of urea from black liquor
- 2014
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Ingår i: Pulp & paper, bioenergy, bioproducts. - Bundoora : Appita Inc. - 9780987168443 ; , s. 91-95
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Konferensbidrag (refereegranskat)abstract
- A conceptual design of an integrated facility for the co-production of ammonia and electricity from black liquor gasification has been studied. The integrated process exchanges black and green liquor, steam, electricity and sulfur with the adjacent Kraft pulp mill. A triple bottom line analysis has indicated that a competitive ammonia price (A$516/t) can be realized for a relatively small scale production 20ktpa of NH3 with an internal rate of return of 13.7%. This is achieved through a novel process design which also produces electricity and steam for the pulp mill. The plant has a carbon footprint at 50% of the average and 33% below world best practice for NH3. Social benefits are also predicted for the regional community.
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- Olofsson, Birgitta, et al.
(författare)
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Development of dementia in patients with femoral neck fracture who experience postoperative delirium : A three-year follow-up study
- 2018
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Ingår i: International Journal of Geriatric Psychiatry. - : John Wiley & Sons. - 0885-6230 .- 1099-1166. ; 33:4, s. 623-632
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Tidskriftsartikel (refereegranskat)abstract
- Objectives It remains unclear to what extent postoperative delirium (POD) affects the incidence of dementia in hip fracture patients, and the methods used to detect delirium and dementia require validation. The aim of this study was to investigate the development of dementia within 3 years of femoral neck fracture repair surgery, with a focus on POD as a potential predictive factor.Methods Patients were assessed for cognition, delirium, depression, psychological well-being, and nutritional status during their hospitalization as well as 4, 12, and 36 months after the operation. Logistic regression models were used to analyse factors associated with POD and factors associated with the development of dementia.Results The study sample consisted of 135 patients without a history of dementia, of whom 20 (14.8%) were delirious preoperatively and 75 (55.5%) postoperatively. Three years after their operations, 43/135 patients (31.8%) were diagnosed with dementia. A greater portion of patients diagnosed with dementia (39/43, 90.6%) than patients with no dementia (36/92, 39.1%) were included among the 75 patients who had experienced POD (P<0.001). In a logistic regression model, after adjustment for covariates (age, sex, diabetes, delirium pre- and postoperatively, hyperactive delirium, days with delirium, urinary tract infection, and Mini Nutritional Assessment score), POD emerged an independent predictor for the development of new dementia (odds ratio, 15.6; 95% confidence interval, 2.6-91.6) within 3 years after the operation.Conclusion Geriatric hip fracture patients who exhibit POD should be monitored closely for the development of dementia.
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