| 1. |
- Palmér, Emilia, et al.
(author)
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Cone beam CT for QA of synthetic CT in MRI only for prostate patients
- 2018
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In: Journal of Applied Clinical Medical Physics. - : Wiley. - 1526-9914. ; 19:6, s. 44-52
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Journal article (peer-reviewed)abstract
- Purpose: Magnetic resonance imaging (MRI)-only radiotherapy is performed without computed tomography (CT). A synthetic CT (sCT) is used for treatment planning. The aim of this study was to develop a clinically feasible quality assurance (QA) procedure for sCT using the kV-cone beam CT (CBCT), in an MRI-only workflow for prostate cancer patients. Material and method: Three criteria were addressed; stability in Hounsfield Units (HUs), deviations in HUs between the CT and CBCT, and validation of the QA procedure. For the two first criteria, weekly phantom measurements were performed. For the third criteria, sCT, CT, and CBCT for ten patients were used. Treatment plans were created based on the sCT (MriPlannerTM). CT and CBCT images were registered to the sCT. The treatment plan was copied to the CT and CBCT and recalculated. Dose–volume histogram (DVH) metrics were used to evaluate dosimetric differences between the sCT plan and the recalculated CT and CBCT plans. HU distributions in sCT, CT, and CBCT were compared. Well-defined errors were introduced in the sCT for one patient to evaluate efficacy of the QA procedure. Results: The kV-CBCT system was stable in HU over time (standard deviation <40 HU). Variation in HUs between CT and CBCT was <60 HU. The differences between sCT–CT and sCT–CBCT dose distributions were below or equal to 1.0%. The highest mean dose difference for the CT and CBCT dose distribution was 0.6%. No statistically significant difference was found between total mean dose deviations from recalculated CT and CBCT plans, except for femoral head. Comparing HU distributions, the CBCT appeared to be similar to the CT. All introduced errors were identified by the proposed QA procedure, except all tissue compartments assigned as water. Conclusion: The results in this study shows that CBCT can be used as a clinically feasible QA procedure for MRI-only radiotherapy of prostate cancer patients.
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| 2. |
- Alfonzo, Emilia, et al.
(author)
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No survival difference between robotic and open radical hysterectomy for women with early-stage cervical cancer: results from a nationwide population-based cohort study
- 2019
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In: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 116, s. 169-177
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Journal article (peer-reviewed)abstract
- Purpose: The aim of the study was to compare overall survival (OS) and disease-free survival (DFS) after open and robotic radical hysterectomy for early-stage cervical cancer. Patients and methods: This was a nationwide population-based cohort study on all women with cervical cancer stage IA1-IB of squamous, adenocarcinoma or adenosquamous histological subtypes, from January 2011 to December 2017, for whom radical hysterectomy was performed. The Swedish Quality Register of Gynaecologic Cancer was used for identification. To ensure quality and conformity of data and to disclose patients not yet registered, hospital registries were reviewed and validated. Cox and propensity score regression analysis and univariable and multivariable regression analysis were performed in regard to OS and DFS. Results: There were 864 women (236 open and 628 robotic) included in the study. The 5-year OS was 92% and 94% and DFS was 84% and 88% for the open and robotic cohorts, respectively. The recurrence pattern was similar in both groups. Using propensity score analysis and matched cohorts of 232 women in each surgical group, no significant differences were seen in survival: 5-year OS of 92% in both groups (hazard ratio [HR], 1.00; 95% confidence interval [CI], 0.50–2.01) and DFS of 85% vs 84% in the open and robotic cohort, respectively (HR, 1.08; 95% CI, 0.66–1.78). In univariable and multivariable analysis with OS as the end-point, no significant factors were found, and in regard to DFS, tumour size (p < 0.001) and grade 3 (p = 0.02) were found as independent significant risk factors. Conclusion: In a complete nationwide population-based cohort, where radical hysterectomy for early-stage cervical cancer is highly centralised, neither long-term survival nor pattern of recurrence differed significantly between open and robotic surgery. © 2019 The Authors
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| 3. |
- Arshamian, Artin, et al.
(author)
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The functional neuroanatomy of odor evoked autobiographical memories cued by odors and words
- 2013
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 51:1, s. 123-131
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Journal article (peer-reviewed)abstract
- Behavioral evidence indicates that odor evoked autobiographical memories (OEAMs) are older, more emotional, less thought of and induce stronger time traveling characteristics than autobiographical memories (AMs) evoked by other modalities. The main aim of this study was to explore the neural correlates of AMs evoked by odors as a function of retrieval cue. Participants were screened for specific OEAMs and later presented with the odor cue and its verbal referent in an fMRI paradigm. Because the same OEAM was retrieved across both cue formats (odor and word), potential cue dependent brain activations were investigated. The overall results showed that odor and word cued OEAMs activated regions typically associated with recollection of autobiographical information. Although no odors were presented, a verbal cuing of the OEAMs activated areas associated with olfactory perception (e.g., piriform cortex). However, relative to word cuing, an odor cuing of OEAMs resulted in more activity in MTL regions such as the parahippocampus, and areas involved in visual vividness (e.g., occipital gyrus and precuneus). Furthermore, odor cues activated areas related to emotional processing, such as limbic and tempopolar regions significantly more. In contrast, word cues relative to odor cues recruited a more widespread and bilateral prefrontal activity. Hippocampus activity did not vary as function of the remoteness of the memory, but recollection of OEAMs from the 1st vs the 2nd decade of life showed specific activation in the right OFC, whereas the 2nd reflected a higher activation in the left inferior frontal gyrus.
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| 4. |
- Blennow, Kristina, et al.
(author)
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The role of beliefs, expectations and values in decision-making favoring climate change adaptation : implications for communications with European forest professionals
- 2020
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In: Environmental Research Letters. - : IOP Publishing. - 1748-9326.
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Journal article (peer-reviewed)abstract
- Beliefs, expectations and values are often assumed to drive decisions about climate change adaptation. We tested hypotheses based on this assumption using survey responses from 508 European forest professionals in 10 countries. We used the survey results to identify communication needs and the decision strategies at play, and to develop guidelines on adequate communications about climate change adaptation. We observed polarization in the positive and negative values associated with climate change impacts accepted by survey respondents. We identified a mechanism creating the polarization that we call the 'blocked belief' effect. We found that polarized values did not correlate with decisions about climate change adaptation. Strong belief in the local impacts of climate change on the forest was, however, a prerequisite of decision-making favoring adaptation. Decision-making in favor of adaptation to climate change also correlated with net values of expected specific impacts on the forest and generally increased with the absolute value of these in the absence of "tipping point" behavior. Tipping point behavior occurs when adaptation is not pursued in spite of the strongly negative or positive net value of expected climate change impacts. We observed negative and positive tipping point behavior, mainly in SW Europe and N-NE Europe, respectively. In addition we found that advice on effective adaptation may inhibit adaptation when the receiver is aware of effective adaptation measures unless it is balanced with information explaining how climate change leads to negative impacts. Forest professionals with weak expectations of impacts require communications on climate change and its impacts on forests before any advice on adaptation measures can be effective. We develop evidence-based guidelines on communications using a new methodology which includes Bayesian machine learning modeling of the equivalent of an expected utility function for the adaptation decision problem.
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| 5. |
- Broekman, Maarten J. E., et al.
(author)
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Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data
- 2022
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:8, s. 1526-1541
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Journal article (peer-reviewed)abstract
- Aim: Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species.Location: Worldwide.Time period: 1998-2021.Major taxa studied: Forty-nine terrestrial mammal species.Methods: Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types.Results: IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively.Main conclusions: We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data.
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| 6. |
- Ekdahl, Linnea, et al.
(author)
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Increased Institutional Surgical Experience in Robot-Assisted Radical Hysterectomy for Early Stage Cervical Cancer Reduces Recurrence Rate: Results from a Nationwide Study
- 2020
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In: JOURNAL OF CLINICAL MEDICINE. - : MDPI AG. - 2077-0383. ; 9:11
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the impact of institutional surgical experience on recurrence following robotic radical hysterectomy (RRH) for early stage cervical cancer. All women in Sweden who underwent an RRH for stage IA2-IB1 cervical cancer at tertiary referral centers from its implementation in December 2005 until June 2017 were identified using a Swedish nationwide register and local hospital registers. Registry data were controlled by a chart review of all women. Recurrence rates and patterns of recurrence were compared between early and late (<= 50 vs. >50 procedures) institutional series. Six hundred and thirty-five women were included. Regression analysis identified a lower risk of recurrence with increased experience but without a clear cut off level. Among the 489 women who did not receive adjuvant radio chemotherapy (RC-T), the rate of recurrence was 3.6% in the experienced cohort (>50 procedures) compared to 9.3% in the introductory cohort (p < 0.05). This was also seen in tumors < 2 cm regardless of RC-T (p < 0.05), whereas no difference in recurrence was seen when analyzing all women receiving RC-T. In conclusion, the rate of recurrence following RRH for early stage cervical cancer decreased with increased institutional surgical experience, in tumors < 2 cm and in women who did not receive adjuvant RC-T.
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| 7. |
- Frölich, Emilia, 1982-
(author)
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Från Kingston till Göinge : autencitet, identitet och representationer av det förflutna i svensk reggaekultur
- 2022
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Doctoral thesis (other academic/artistic)abstract
- This thesis explores the role of history in popular culture with a particular focus on the Swedish reggae scene. It examines how cultural meaning applied to music bears strong connections to historical representations, and how individuals understand, communicate, and reproduce selective notions of the past in relationship to popular music. History is viewed as an essential cultural component in this thesis, a component equipped with the ability to articulate political resistance, and express a sense of identity and belonging. The overall purpose is to examine how history is constructed, represented and used in the Swedish reggae scene, and how notions of origin and authenticity are expressed. The empirical chapters examine how different representations of the past in Swedish reggae relates to notions of origin, place and authenticity. These representations are constructed through social interactions, but also through interaction with texts, objects, and cultural practices.As the thesis shows, different representations of pasts and notions of origins exists in Swedish reggae, connecting to various geographical, cultural, and historical contexts. The hybridization of reggae becomes an important factor that contributes to making Swedish reggae something special and unique. In the Swedish reggae scene, which is predominatly white, the hybridization can be understood as an attempt to free oneself from aspects of reggae associated with Black experiences of white oppression. The use of local, regional, and national cultural expressions and representations of the past creates a distance to the Jamaican reggae traditions, and the historical narratives of slavery, colonialism and racial discrimination that reinforces the Black identification in Jamaican reggae. Instead, by relating to Swedish historical milieus, traditions and events, a closer and more relatable understanding of reggae is created. However, the thesis also shows that not all actors who consume and produce reggae in Sweden identify with the Swedish hybrid version. In such cases, its typical Swedishness is seen as an undesirable departure from the history and traditions of Jamaican reggae. Jamaican reggae is then perceived as a cultural heritage that should be preserved and respected in its original form - not in a copied or remodelled version.
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| 8. |
- Gunnlaugsson, Adalsteinn, et al.
(author)
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Target definition in radiotherapy of prostate cancer using magnetic resonance imaging only workflow
- 2019
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In: Physics and imaging in radiation oncology. - : Elsevier BV. - 2405-6316. ; 9, s. 89-91
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Journal article (peer-reviewed)abstract
- In magnetic resonance (MR) only radiotherapy, the target delineation needs to be performed without computed tomography (CT). We investigated in thirteenpatients with prostate cancer, how the clinical target volume (CTV) was affected, when the target delineation procedure was changed from using both CT and MRimages to using MR images only. The mean volume of the CTVCT/MR was 61.0 cm3 as compared to 49.9 cm3 from MR-only based target delineation, corresponding toan average decrease of 18%. Our results show that CTVMR-only was consistently smaller than CTVCT/MR, which has to be taken into consideration before clinicalcommissioning of MR-only radiotherapy.
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| 9. |
- Gustafsson, Christian, et al.
(author)
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Registration free automatic identification of gold fiducial markers in MRI target delineation images for prostate radiotherapy
- 2017
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In: Medical physics (Lancaster). - : Wiley. - 0094-2405. ; 44:11, s. 5563-5574
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Journal article (peer-reviewed)abstract
- Purpose: The superior soft tissue contrast of magnetic resonance imaging (MRI) compared to computed tomography (CT) has urged the integration of MRI and elimination of CT in radiotherapy treatment (RT) for prostate. An intraprostatic gold fiducial marker (GFM) appears hyperintense on CT. On T2-weighted (T2w) MRI target delineation images, the GFM appear as a small signal void similar to calcifications and post biopsy fibrosis. It can therefore be difficult to identify the markers without CT. Detectability of GFMs can be improved using additional MR images, which are manually registered to target delineation images. This task requires manual labor, and is associated with interoperator differences and image registration errors. The aim of this work was to develop and evaluate an automatic method for identification of GFMs directly in the target delineation images without the need for image registration.Methods: T2w images, intended for target delineation, and multiecho gradient echo (MEGRE) images intended for GFM identification, were acquired for prostate cancer patients. Signal voids in the target delineation images were identified as GFM candidates. The GFM appeared as round, symmetric, signal void with increasing area for increasing echo time in the MEGRE images. These image features were exploited for automatic identification of GFMs in a MATLAB model using a patient training dataset (n = 20). The model was validated on an independent patient dataset (n = 40). The distances between the identified GFM in the target delineation images and the GFM in CT images were measured. A human observatory study was conducted to validate the use of MEGRE images.Results: The sensitivity, specificity, and accuracy of the automatic method and the observatory study was 84%, 74%, 81% and 98%, 94%, 97%, respectively. The mean absolute difference in the GFM distances for the automatic method and observatory study was 1.28 1.25 mm and 1.14 +/- 1.06 mm, respectively.Conclusions: Multiecho gradient echo images were shown to be a feasible and reliable way to perform GFM identification. For clinical practice, visual inspection of the results from the automatic method is needed at the current stage.
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| 10. |
- Gustafsson, Christian, et al.
(author)
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Using C-Arm X-ray images from marker insertion to confirm the gold fiducial marker identification in an MRI-only prostate radiotherapy workflow
- 2018
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In: Journal of Applied Clinical Medical Physics. - : Wiley. - 1526-9914. ; 19:6, s. 185-192
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Journal article (peer-reviewed)abstract
- Prostate cancer radiotherapy workflows, solely based on magnetic resonance imaging (MRI), are now in clinical use. In these workflows, intraprostatic gold fiducial markers (GFM) show similar signal behavior as calcifications and bleeding in T2-weighted MRI-images. Accurate GFM identification in MRI-only radiotherapy workflows is therefore a major challenge. C-arm X-ray images (CkV-images), acquired at GFM implantation, could provide GFM position information and be used to confirm correct identification in T2-weighted MRI-images. This would require negligible GFM migration between implantation and MRI-imaging. Marker migration was therefore investigated. The aim of this study was to show the feasibility of using CkV-images to confirm GFM identification in an MRI-only prostate radiotherapy workflow. An anterior-posterior digitally reconstructed radiograph (DRR)-image and a mirrored posterior-anterior CkV-image were acquired two weeks apart for 16 patients in an MRI-only radiotherapy workflow. The DRR-image originated from synthetic CT-images (created from MRI-images). A common image geometry was defined between the DRR- and CkV-image for each patient. A rigid registration between the GFM center of mass (CoM) coordinates was performed and the distance between each of the GFM in the DRR- and registered CkV-image was calculated. The same methodology was used to assess GFM migration for 31 patients in a CT-based radiotherapy workflow. The distance calculated was considered a measure of GFM migration. A statistical test was performed to assess any difference between the cohorts. The mean absolute distance difference for the GFM CoM between the DRR- and CkV-image in the MRI-only cohort was 1.7 ± 1.4 mm. The mean GFM migration was 1.2 ± 0.7 mm. No significant difference between the measured total distances of the two cohorts could be detected (P = 0.37). This demonstrated that, a C-Arm X-ray image acquired from the GFM implantation procedure could be used to confirm GFM identification from MRI-images. GFM migration was present but did not constitute a problem.
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