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- Fröling, Morgan, 1966-, et al.
(författare)
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Bio-CCS - a model based case study from the mid Sweden region
- 2015
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Ingår i: Proceedings of Global Cleaner Production and Sustainable Consumption, Sitges Barcelona, November 1-4, 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In its 2014 report, IPCC recommend Carbon Capture and Storage not only for fossil power plants but also for bioenergy to beable to meet the 2 degree target. In a case study, models for CCS applied to a combined heat and power (CHP) plant inÖstersund, Sweden, using wood chips as main fuel was assessed. The goal was to gain knowledge to be prepared to takemore rapid action if policy instruments are implemented in future. More "traditional" technology with absorption inmonoethanolamine (MEA) and subsequent underground storage uses a significant part of produced electricity, and in anenergy system perspective it is not necessarily the most efficient use of a limited wood resource. For processes withcomparatively low net climate impact, like bio-CHP, alternatives significantly more energy efficient per unit of capturedcarbon dioxide but only able to capture part of the total emitted carbon can be considered. One such alternative is to capturecarbon dioxide using microalgae. Key issues for assessment of processes in this case are how to store the carbon captured inthe algae biomass (e.g. in products) and for how long the carbon will be withdrawn from atmosphere with such storage.
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| 2. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust maximization of tumor control probability for radicality constrained dose painting by numbers of head and neck cancer
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential and robustness to increase the tumor control probability (TCP) for robustly optimized dose painting plans compared to conventional homogeneous dose plans for head and neck cancers.Material and Methods We optimized a set of dose painting plans with a robust TCP maximizing objective under different mean dose constraints for the primary clinical target volume (CTVT). These plans were optimized with the robust mini-max algorithm together with dose-responses driven by standardized uptake values (SUV) from 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with iso-center displacements. We also analyzed the impact on TCP predictions by considering dose-response uncertainties.Results The average increase in TCP with dose painting ranged between 3 to 20 percentage points (p.p.) which depended on the allowed integral CTVT dose. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. Patients with large tumors and large spread of SUV gained the greatest TCP increases. By considering dose-response uncertainties, a decrease of the TCP for a homogeneous dose yielded an increasing dose painting potential.Conclusions We have found that it is feasible to optimize FDG-PET driven dose painting plans that robustly increase the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest potential TCP increases were found for patients with larger and more SUV heterogeneous tumors, which may give guidance for patient selection to further test the presented dose painting formalism.
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| 3. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust maximization of tumor control probability for radicality constrained dose painting by numbers of head and neck cancer
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential and robustness to increase the tumor control probability (TCP) for robustly optimized dose painting plans compared to conventional homogeneous dose plans for head and neck cancers.Material and Methods We optimized a set of dose painting plans with a robust TCP maximizing objective under different mean dose constraints for the primary clinical target volume (CTVT). These plans were optimized with the robust mini-max algorithm together with dose-responses driven by standardized uptake values (SUV) from 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with iso-center displacements. We also analyzed the impact on TCP predictions by considering dose-response uncertainties.Results The average increase in TCP with dose painting ranged between 3 to 20 percentage points (p.p.) which depended on the allowed integral CTVT dose. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. Patients with large tumors and large spread of SUV gained the greatest TCP increases. By considering dose-response uncertainties, a decrease of the TCP for a homogeneous dose yielded an increasing dose painting potential.Conclusions We have found that it is feasible to optimize FDG-PET driven dose painting plans that robustly increase the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest potential TCP increases were found for patients with larger and more SUV heterogeneous tumors, which may give guidance for patient selection to further test the presented dose painting formalism.
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| 4. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust maximization of tumor control probability for radicality constrained radiotherapy dose painting by numbers of head and neck cancer
- 2019
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Ingår i: Physics and Imaging in Radiation Oncology. - : ELSEVIER. - 2405-6316. ; 12, s. 56-62
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Radiotherapy with dose painting by numbers (DPBN) needs another approach than conventional margins to ensure a geometrically robust dose coverage for the tumor. This study presents a method to optimize DPBN plans that as opposed to achieve a robust dose distribution instead robustly maximize the tumor control probability (TCP) for patients diagnosed with head and neck cancer. Material and methods: Volumetric-modulated arc therapy (VMAT) plans were optimized with a robust TCP maximizing objective for different dose constraints to the primary clinical target volume (CTVT) for a set of 20 patients. These plans were optimized with minimax optimization together with dose-responses driven by standardized uptake values (SUV) from F-18-fluorodeoxyglucose positron emission tomography ((18)FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with isocenter displacements. Results: The average increase in TCP with DPBN compared to a homogeneous dose treatment ranged between 3 and 20 percentage points (p.p.) which depended on the different dose constraints for the CTVT. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. The standard deviation of SUV multiplied by the CTVT volume were found to correlate with the TCP gain with R-2 >= 0.9. Conclusions: Minimax optimization of DPBN plans yield, based on the presented TCP modelling, a robust increase of the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest TCP gains were found for patients with large and SUV heterogeneous tumors, which may give guidance for patient selection in prospective trials.
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| 5. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust treatment planning of dose painting for prostate cancer based on ADC-to-Gleason score mappings : what is the potential to increase the tumor control probability?
- 2021
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Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 60:2, s. 199-206
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential to increase the tumor control probability (TCP) with ‘dose painting by numbers’ (DPBN) plans optimized in a treatment planning system (TPS) compared to uniform dose plans. The DPBN optimization was based on our earlier published formalism for prostate cancer that is driven by dose-responses of Gleason scores mapped from apparent diffusion coefficients (ADC).Material and MethodsFor 17 included patients, a set of DPBN plans were optimized in a TPS by maximizing the TCP for an equal average dose to the prostate volume (CTVT) as for a conventional uniform dose treatment. For the plan optimizations we applied different photon energies, different precisions for the ADC-to-Gleason mappings, and different CTVT positioning uncertainties. The TCP increasing potential was evaluated by the DPBN efficiency, defined as the ratio of TCP increases for DPBN plans by TCP increases for ideal DPBN prescriptions (optimized without considering radiation transport phenomena, uncertainties of the CTVT positioning, and uncertainties of the ADC-to-Gleason mapping).ResultsThe median DPBN efficiency for the most conservative planning scenario optimized with a low precision ADC-to-Gleason mapping, and a positioning uncertainty of 0.6 cm was 10%, meaning that more than half of the patients had a TCP gain of at least 10% of the TCP for an ideal DPBN prescription. By increasing the precision of the ADC-to-Gleason mapping, and decreasing the positioning uncertainty the median DPBN efficiency increased by up to 40%.ConclusionsTCP increases with DPBN plans optimized in a TPS were found more likely with a high precision mapping of image data into dose-responses and a high certainty of the tumor positioning. These findings motivate further development to ensure precise mappings of image data into dose-responses and to ensure a high spatial certainty of the tumor positioning when implementing DPBN clinically.
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| 9. |
- Carlman, Inga, et al.
(författare)
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Models and methods as support for sustainable decision-making
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Since the 1960s the urgency to steer mankind towards a more sound environment has grown. Currently humanity is in a transition period between today’s old paradigm - business as usual - and the new one, aiming at operationalize sustainable development goals. There is a growing understanding, that to move towards sustainable development ecological sustainability is necessary but not sufficient. Steering society in this direction necessitates making decisions that at least do not counteract sustainability.Such decisions have to rest firmly on a natural scientific basis. Natural laws, such as thermodynamics and conditions set by ecosystems, can therefore not been ignored, when a) searching for technical solutions to environmental problems and fully understand the consequences of such solution and b) improving steering instruments to guide human actions.During the years a number of models/methods/systems have been developed to underpin sustainable decision-making. Related to ecosystems we have e.g. the carrying capacity and resilience models, to resource use there are Life Cycle Assessment (LCA) and Ecological Footprints, to economy there are eco-economy and green economy, to law there are Environmental Law Methodology (ELM) and Sustainable law. Emergy synthesis, an environmental accounting and assessment method takes a wider grip embracing everything from thermodynamics to economy.There still is no “standard method” for this kind of decisions, which makes it important to contrast different methods. Some methods might enforce each other, whereas others might drive in different directions. It is therefore important to understand the methods in relation to each other.
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| 10. |
- Carlman, Inga, et al.
(författare)
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Models and methods as support for sustainable decision-making with focus on legal operationalisation
- 2015
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Ingår i: Ecological Modelling. - : Elsevier BV. - 0304-3800 .- 1872-7026. ; 306, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- Since the 1960s the urgency to steer mankind towards a more sound environment has grown. Currently humanity is in a transition period between today’s old paradigm – business as usual – and the new one, aiming at operationalise sustainable development goals. There is a growing understanding, that to move towards sustainable development, ecological sustainability is necessary but not sufficient. Steering society in this direction necessitates making decisions that at least do not counteract sustainability.Such decisions have to rest firmly on a natural scientific basis. Natural laws, such as thermodynamics, and conditions set by ecosystems can therefore not been ignored, when (a) searching for technical solutions to environmental problems and to fully understand the consequences of such solutions, and (b) improving steering instruments to guide human actions.Over the years a number of models/methods/systems have been developed to underpin sustainable decision-making, such as Environmental Impact Assessment (EIA), Life Cycle Assessment (LCA), Ecological Footprints, and Cost Benefit Analysis (CBA). Ecological modelling contributes or complements such methods. Emergy analysis, an environmental accounting and assessment method takes a wider grip embracing both ecology and economy. Less known is environmental legal modelling.This paper puts ecological models in the context of societal steering systems for sustainable development, and focuses on a legal model for implementing environmental policy goals.
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