| 1. |
- Sundin, Maria, 1965, et al.
(författare)
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Mars - a target for teachers and science students
- 2020
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Ingår i: Contribution to IAU 367S, Education and Heritage in the Era of Big Data in Astronomy, 8-12 December 2020..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A case study is here presented of an interdisciplinary course about Mars for teachers and science students. We aim to share the experience of creating an interdisciplinary approach with lecturers spanning physics, geology, radiation physics and philosophy. Issues in ethics, morality, rights and obligations, conflict management and human psychology as well as rocket orbits, fuel economy, radiation hazards and knowledge of the solar system have proven to be a valued and successful initiative for the further training of teachers and science students. The focus of the course is on planning for a journey with humans to the planet Mars. This provides a great opportunity to package complex societal problems in a physics context. The course is offered with a special sustainability content mark. Mankind has always had a strong and dependent relationship with the physical landscape. The land has given us food and shelter but also imposed challenges and disasters. Understanding the physical environment has been crucial for our survival and development. The same will be equally, or more important for Mars where life conditions are much more extreme. We highlight similarities and differences in the geologic processes that have shaped Earth and Mars. What conditions do the future explorers on Mars have to manage? We then enter the modern era and explore the dynamic Martian landscape of today. Also, by learning to read the landscape we may find locations of shelter such as vast systems of lava tubes, or locations of essential resources such as preserved glacial ice etc. A journey to Mars will cause substantially higher personal irradiation than obtained on Earth. The radiation part of the course lectures starts with defining the different radiation types and the biological effects these different types of radiation will cause. Then, the difference between the irradiation on Earth to the elevated irradiation in space and on Mars is described. Thereafter, it is discussed if this elevated radiation burden can cause acute biological effects, e.g. fatigue, vomiting and death, and late biological effects as cancer induction. Last, possible radiation protection strategies are described and discussed. The philosophy of space exploration consists of philosophical approaches to ethics, presently applied to the topic of Mars exploration and colonization, with environmental ethics (anthropocentric vs ecocentric) and value theory at its core. Four main uses of philosophy are distinguished: ethics, aesthetics, cognition and existentialism. Research has shown that visual representation is an important part for students to be able to create a deeper understanding of concepts as well as context about the material that is taught. Interdisciplinary and complex societal problems have also been shown to be important in science teaching. One way for the teacher to develop his/her teaching is to take further education courses in universities whose focus is to seek and discuss the complex societal problems as well as its solutions from a physics and teacher perspective. Future research could be done on the impact of this course on the education in different levels.
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| 2. |
- Sundin, Maria, 1965, et al.
(författare)
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Mars – a target for teachers and science students
- 2021
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Ingår i: Proceedings of the International Astronomical Union, Vol 15, Symposium 367S. - 1743-9213 .- 1743-9221.
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Konferensbidrag (refereegranskat)abstract
- An interdisciplinary course about Mars for teachers and science students is presented. The focus of the course is on planning for a journey with humans to the planet Mars. Issues in ethics, morality, rights and obligations, conflict management and human psychology as well as rocket orbits, fuel economy, radiation hazards and knowledge of the solar system are included. Examination of the teacher students include interpretation of the course material for future pedagogical usage.
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| 3. |
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| 4. |
- Arvidsson, Jonathan, et al.
(författare)
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Image Fusion of Reconstructed Digital Tomosynthesis Volumes From a Frontal and a Lateral Acquisition
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 410-415
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Tidskriftsartikel (refereegranskat)abstract
- Digital tomosynthesis (DTS) has been used in chest imaging as a low radiation dose alternative to computed tomography (CT). Traditional DTS shows limitations in the spatial resolution in the out-of-plane dimension. As a first indication of whether a dual-plane dual-view (DPDV) DTS data acquisition can yield a fair resolution in all three spatial dimensions, a manual registration between a frontal and a lateral image volume was performed. An anthropomorphic chest phantom was scanned frontally and laterally using a linear DTS acquisition, at 120 kVp. The reconstructed image volumes were resampled and manually co-registered. Expert radiologist delineations of the mediastinal soft tissues enabled calculation of similarity metrics in regard to delineations in a reference CT volume. The fused volume produced the highest total overlap, implying that the fused volume was a more isotropic 3D representation of the examined object than the traditional chest DTS volumes.
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| 5. |
- Bernhardt, Peter, 1966, et al.
(författare)
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A novel quantitative image-based method for evaluating cranial symmetry and its usefulness in patients undergoing surgery for unicoronal synostosis.
- 2013
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Ingår i: The Journal of craniofacial surgery. - 1536-3732. ; 24:1, s. 166-9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Unicoronal synostosis presents with cranial asymmetry. Fixed points are difficult to identify; surgical results are therefore difficult to evaluate. The aim of this study was to develop a computer-based method for evaluation of forehead symmetry to enable evaluation of surgical results in unicoronal synostosis. Methods: The MATLAB tool was programmed to segment computed tomographic images, leaving the outermost contour. Cephalometric images were segmented manually due to lower contrast. A center-point (O) and an end-point were manually defined in the midline of the forehead and at the nonfused coronal suture, respectively. The program then found a point (p) on the fused side, at the same distance from the O as the end-point. The contours of the left and right side of the forehead were thereafter superimposed, and the position of minimal area mismatch of the sides was identified. To correct for growth between preoperative images and follow-up, the number of mismatching pixels was related to the area outlined by the contour of the forehead, the end-point and p. Two quantities, the relative symmetry change and the absolute symmetry change, were defined and evaluated by repeated measurements on spherical and elliptical phantoms and 15 patients. Results: Measurements with the MATLAB program were reliable with an SD of 0.26% to 5.39% for the expected range of differences. The SD was lower for measurements on computed tomographic images than for measurements on cephalometric images. The SD was also lower in patients with large surgical improvement than in patients with little improvement. The results support the use of relative symmetry change to evaluate surgical results. Conclusions: Our new computer-based method is capable of measuring forehead symmetry with good precision. This method can be used for systematic evaluation of surgical outcome for unicoronal synostosis and other asymmetric skull deformities.
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| 6. |
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| 7. |
- Fischer, Sara, et al.
(författare)
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Intracranial volume is normal in infants with sagittal synostosis.
- 2015
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Ingår i: Journal of plastic surgery and hand surgery. - 2000-6764. ; 49:1, s. 62-64
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Premature sagittal synostosis results in an elongated, narrow skull shape, scaphocephaly. It has been unclear whether the intracranial volume (ICV) of these children is different from that of normal children. The aim of the present study was to precisely determine the ICV in a large cohort of children with premature sagittal synostosis and to compare it to the ICV of a sex- and age-matched control group. All patients (n = 143) with isolated sagittal synostosis registered in the Göteborg Craniofacial Registry until the end of 2012 with a preoperative CT examination were identified. For each case, a sex- and age- (±30 days) matched control was identified from children who had undergone CT for post-traumatic or neurological reasons. The ICV was measured in a semi-automatic MATLAB program with functions such as region growing, watershed, and thresholding in axial CT slices. The ICV was calculated using the Cavalieri principle. The mean (± SEM) values of ICV for children with sagittal synostosis and for corresponding controls were 866 ± 13 ml and 870 ± 15 ml, respectively. The mean ages of these groups were 173 ± 8 days and 172 ± 8 days, respectively. Subgroup analysis of sex and age at CT (≤180 days and >180 days) did not reveal any differences in ICV between cases and controls. Precise determination of ICV in addition to the use of adequate controls has made it possible to conclude that children with premature isolated sagittal synostosis have a normal ICV.
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| 8. |
- Hagmarker, Linn, et al.
(författare)
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A new quantitative image-based method for evaluation of bony temporal hollowing in metopic synostosis
- 2016
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Ingår i: Journal of Plastic Surgery and Hand Surgery. - : Medical Journals Sweden AB. - 2000-656X .- 2000-6764. ; 50:6, s. 343-348
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Premature craniosynostosis is a congenital disorder causing a skull deformity. For both functional and cosmetic reasons, the deformity is surgically treated with a cranioplasty before the age of 1 year. Temporal hollowing is a common and undesirable remaining deformity after cranioplasty for metopic synostosis. The most common method to determine the degree of temporal hollowing is subjective judgement of the temporal region. The aim of the present project was to develop a quantitative semi-automatic computer tool for objective measurement of bony temporal hollowing. Methods: Using MATLAB, a tool was developed to segment computed tomography images, defining the outermost contour. The images were dorsally limited to the widest point of the head. In each case, a sex-and age-matched control was identified and the contours compared. The bony temporal hollowing of the cases was calculated. Results: The intra-user coefficient of variation (CV) was 5.0% (95% CI = 4.2%-6.2%) and the inter-user CV was 3.0% (95% CI = 2.1%-8.6%). For clinical testing purposes, the tool was used in 14 patients, seven of whom had been operated on with a spring-assisted cranioplasty and seven with a cranioplasty using a bone graft. Conclusions: In summary, this study presents a new tool for objective measurement of the surgical result after cranioplasty for metopic synostosis.
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| 9. |
- Hagmarker, Linn, et al.
(författare)
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Characterisation of a planar dosimetry method estimating the absorbed dose to the bone marrow during 177Lu-DOTATATE treatment
- 2016
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer. - 1619-7070 .- 1619-7089.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aim: An image based method for bone marrow dosimetry, earlier presented by our research group, has shown a significant correlation between the absorbed dose to the bone marrow and haematological toxicity in 177Lu-DOTATATE treatment. The aim of this study was to further evaluate and optimise the method. Materials and Methods: 46 patients with advanced neuroendocrine tumours were treated with 177Lu -DOTATATE on 2-6 occasions. The patients were evaluated using the 4 planar gamma camera images collected at 2, 24, 48 and 168 hours after injection. The whole body was divided into a high- and a low uptake compartment, using a threshold based segmentation tool in the image platform PhONSAi, developed in-house. The segmentation tool starts by including the highest uptake focus and then gradually includes foci with lower and lower uptakes until a threshold is reached where the number of foci escalates. The threshold determines the proportion of the foci that is included in the two compartments. Visual inspection was used to determine the threshold valuewhere all high uptake tissues (i.e. kidney, spleen, liver and tumours) were included in the high uptake compartment. For thresholds around this value the activity in the two compartments was determined by the conjugate view method and the bonemarrow dose was calculated as a sum of the self and cross dose in the low uptake compartment and the cross dose from the high uptake compartment. Results: The visual analysis implies a threshold value of 10%of the maximum number of foci. A correlation was found between the absorbed bone marrow dose and haematological toxicity with p-values ranging from 0.001 to 0.02 for thresholds between 2 % and 25 %, the strongest correlation was found at 15 %. The mean absorbed bone marrow dose were 0.20-0.22 Gy per 7.4 GBq for threshold values between 10-25 %, and increased to 0.28 Gy for the lower values. No significant difference was observed in coefficient of variation (8.2-8.7 %) for the individual mean absorbed doses when varying the threshold value. Conclusion: The individual variation in absorbed dose is maintained at a low level when varying the threshold value for the determination of the compartment sizes. This implies that the method is stable for estimation of bone marrow doses and its correlation to haematological toxicity.
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| 10. |
- Hagmarker, Linn, et al.
(författare)
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Evaluation of planar versus hybrid SPECT image methodology for bone marrow dosimetry during 177Lu-DOTATATE treatments reveals the obstacles with bone marrow metastases and cross-irradiation for the SPECT activity concentration quantification
- 2018
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Ingår i: 31st Annual Congress of the European Association of Nuclear Medicine (EANM’18). 13-17 October, Dusseldorf, Germany.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction. The aim of this study is to compare the recently developed planar image-based method for bone marrow dosimetry with a hybrid method using SPECT/CT imaging at 24 h.p.i. of 177Lu-DOTATATE. Predictive ability of the methods is compared by investigating correlations of determined absorbed bone marrow dose, with haematological toxicity during the course of four treatment cycles. The aim is also to investigate the activity distribution in the vertebral column, and how the hybrid methodology can be optimized. Methods and Materials. 45 patients with advanced neuroendocrine tumours treated with 177Lu-DOTATATE at Sahlgrenska University Hospital in 2011-2016 (ILUMINET-study, EUDRACT nr 2011-etc) were included in this study. Absorbed bone marrow doses were calculated as the sum of the cross-doses from high-uptake organs and the remainder of the body, and the self-dose. Cross-doses were determined by time-activity curves created using planar images and a two-compartment method in the image platform PhONSAi. The self-dose was calculated using the time-activity concentration curve for the remainder of the body adjusted with the activity concentration determined in spheres placed in the vertebral bodies in SPECT-images. To improve recovery and reduce cross-irradiation of false counts in the SPECT-image, we utilized the Monte Carlo based reconstruction code SARec. Three activity concentrations were calculated to represent the activity concentration in the bone marrow; one mean (mean SPECT) and one median (median SPECT) activity concentration based on all visible vertebras and one where vertebras enclosing metastases were manually excluded (w/o Mets SPECT). Results. The planar method, the hybrid methods mean SPECT, median SPECT, and w/o Mets SPECT, yielded absorbed bone marrow doses after treatment cycle one at 0.19 (0.12-0.32), 0.35 (0.12-1.25), 0.29 (0.11-0.92) and 0.29 (0.15-0.81) Gy/7.4 GBq, respectively. A significant dose-response relationship was established after treatment cycle one between decreased platelet counts and absorbed bone marrow dose using the planar method (p=0.025, r=-0.16). With hybrid methods, a significant correlation was firstly found after treatment cycle two between absorbed dose and decreased platelet counts using median SPECT (p=0.018, r=-0.35). Conclusion. Early significant dose-response relationships were established. Despite using SARec-reconstructed SPECT-imaging for specific measurement of activity concentration in bone marrow cavities, the hybrid methods were not able to perform better than the planar method. The hybrid methods yielded higher absorbed bone marrow doses compared to the planar method as both bone metastases and cross-irradiation will influence the activity quantification. Further studies on minimizing influence of bone metastases and cross-irradiation are on-going.
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