| 1. |
- Jakobson Mo, Susanna, et al.
(författare)
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Dopamine transporter imaging with [18F]FE-PE2I PET and [123I]FP-CIT SPECT – a clinical comparison
- 2018
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Ingår i: EJNMMI Research. - : Springer. - 2191-219X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dopamine transporter (DAT) imaging may be of diagnostic value in patients with clinically suspected parkinsonian disease. The purpose of this study was to compare the diagnostic performance of DAT imaging with positron emission computed tomography (PET), using the recently developed, highly DAT-selective radiopharmaceutical [18F]FE-PE2I (FE-PE2I), to the commercially available and frequently used method with [123I]FP-CIT (FP-CIT) single-photon emission computed tomography (SPECT) in early-stage idiopathic parkinsonian syndrome (PS).Methods: Twenty-two patients with a clinical de novo diagnosis of PS and 28 healthy controls (HC) participating in an on-going clinical trial of FE-PE2I were analyzed in this study. Within the trial protocol, participants are clinically reassessed 2 years after inclusion. A commercially available software was used for automatic calculation of FP-CIT-specific uptake ratio (SUR). MRI-based volumes of interest combined with threshold PET segmentation were used for FE-PE2I binding potential relative to non-displaceable binding (BPND) quantification and specific uptake value ratios (SUVR).Results: PET with FE-PE2I revealed significant differences between patients with a clinical de novo diagnosis of PS and healthy controls in striatal DAT availability (p < 0.001), with excellent accuracy of predicting dopaminergic deficit in early-stage PS. The effect sizes were calculated for FE-PE2I BPND (Glass’s Δ = 2.95), FE-PE2I SUVR (Glass’s Δ = 2.57), and FP-CIT SUR (Glass’s Δ = 2.29). The intraclass correlation (ICC) between FE-PE2I BPND FP-CIT SUR was high in the caudate (ICC = 0.923), putamen (ICC = 0.922), and striatum (ICC = 0.946), p < 0.001. Five of the 22 patients displayed preserved striatal DAT availability in the striatum with both methods. At follow-up, a non-PS clinical diagnosis was confirmed in three of these, while one was clinically diagnosed with corticobasal syndrome. In these patients, FE-PE2I binding was also normal in the substantia nigra (SN), while significantly reduced in the remaining patients. FE-PE2I measurement of the mean DAT availability in the putamen was strongly correlated with BPND in the SN (R = 0.816, p < 0.001). Olfaction and mean putamen DAT availability was correlated using both FE-PE2I BPND and FP-CIT SUR (R ≥ 0.616, p < 0.001).Conclusion: DAT imaging with FE-PE2I PET yields excellent basic diagnostic differentiation in early-stage PS, at least as good as FP-CIT SPECT.
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| 2. |
- Sandgren, Kristina, et al.
(författare)
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Histopathology-validated lesion detection rates of clinically significant prostate cancer with mpMRI, [68Ga]PSMA-11-PET and [11C]Acetate-PET
- 2023
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Ingår i: Nuclear medicine communications. - : Lippincott Williams & Wilkins. - 0143-3636 .- 1473-5628. ; 44:11, s. 997-1004
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Tidskriftsartikel (refereegranskat)abstract
- Objective: PET/CT and multiparametric MRI (mpMRI) are important diagnostic tools in clinically significant prostate cancer (csPC). The aim of this study was to compare csPC detection rates with [68Ga]PSMA-11-PET (PSMA)-PET, [11C] Acetate (ACE)-PET, and mpMRI with histopathology as reference, to identify the most suitable imaging modalities for subsequent hybrid imaging. An additional aim was to compare inter-reader variability to assess reproducibility.Methods: During 2016–2019, all study participants were examined with PSMA-PET/mpMRI and ACE-PET/CT prior to radical prostatectomy. PSMA-PET, ACE-PET and mpMRI were evaluated separately by two observers, and were compared with histopathology-defined csPC. Statistical analyses included two-sided McNemar test and index of specific agreement.Results: Fifty-five study participants were included, with 130 histopathological intraprostatic lesions >0.05 cc. Of these, 32% (42/130) were classified as csPC with ISUP grade ≥2 and volume >0.5 cc. PSMA-PET and mpMRI showed no difference in performance (P = 0.48), with mean csPC detection rate of 70% (29.5/42) and 74% (31/42), respectively, while with ACE-PET the mean csPC detection rate was 37% (15.5/42). Interobserver agreement was higher with PSMA-PET compared to mpMRI [79% (26/33) vs 67% (24/38)]. Including all detected lesions from each pair of observers, the detection rate increased to 90% (38/42) with mpMRI, and 79% (33/42) with PSMA-PET.Conclusion: PSMA-PET and mpMRI showed high csPC detection rates and superior performance compared to ACE-PET. The interobserver agreement indicates higher reproducibility with PSMA-PET. The combined result of all observers in both PSMA-PET and mpMRI showed the highest detection rate, suggesting an added value of a hybrid imaging approach.
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| 3. |
- Sandgren, Kristina, et al.
(författare)
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Radiation dosimetry of [Ga-68]PSMA-11 in low-risk prostate cancer patients
- 2019
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Ingår i: EJNMMI Physics. - : Springer. - 2197-7364. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Background: 68Ga-labeled Glu-NH-CO-NH-Lys(Ahx)-HBED-CC ([68Ga]PSMA-11) has been increasingly used to image prostate cancer using positron emission tomography (PET)/computed tomography (CT) both during diagnosis and treatment planning. It has been shown to be of clinical value for patients both in the primary and secondary stages of prostate cancer. The aim of this study was to determine the effective dose and organ doses from injection of [68Ga]PSMA-11 in a cohort of low-risk prostate cancer patients.Methods: Six low-risk prostate cancer patients were injected with 133–178 MBq [68Ga]PSMA-11 and examined with four PET/CT acquisitions from injection to 255 min post-injection. Urine was collected up to 4 h post-injection, and venous blood samples were drawn at 45 min, 85 min, 175 min, and 245 min post-injection. Kidneys, liver, lungs, spleen, salivary and lacrimal glands, and total body where delineated, and cumulated activities and absorbed organ doses calculated. The software IDAC-Dose 2.1 was used to calculate absorbed organ doses according to the International Commission on Radiological Protection (ICRP) publication 107 using specific absorbed fractions published in ICRP 133 and effective dose according to ICRP Publication 103. We also estimated the absorbed dose to the eye lenses using Monte Carlo methods.Results: [68Ga]PSMA-11 was rapidly cleared from the blood and accumulated preferentially in the kidneys and the liver. The substance has a biological half-life in blood of 6.5 min (91%) and 4.4 h (9%). The effective dose was calculated to 0.022 mSv/MBq. The kidneys received approximately 40 mGy after an injection with 160 MBq [68Ga]PSMA-11 while the lacrimal glands obtained an absorbed dose of 0.12 mGy per administered MBq. Regarding the eye lenses, the absorbed dose was low (0.0051 mGy/MBq).Conclusion: The effective dose for [68Ga]PSMA-11 is 0.022 mSv/MBq, where the kidneys and lacrimal glands receiving the highest organ dose.
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| 4. |
- Sandgren, Kristina, et al.
(författare)
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Registration of histopathology to magnetic resonance imaging of prostate cancer
- 2021
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Ingår i: Physics and Imaging in Radiation Oncology. - : Elsevier. - 2405-6316. ; 18, s. 19-25
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: The diagnostic accuracy of new imaging techniques requires validation, preferably by histopathological verification. The aim of this study was to develop and present a registration procedure between histopathology and in-vivo magnetic resonance imaging (MRI) of the prostate, to estimate its uncertainty and to evaluate the benefit of adding a contour-correcting registration.Materials and methods: For twenty-five prostate cancer patients, planned for radical prostatectomy, a 3D-printed prostate mold based on in-vivo MRI was created and an ex-vivo MRI of the specimen, placed inside the mold, was performed. Each histopathology slice was registered to its corresponding ex-vivo MRI slice using a 2D-affine registration. The ex-vivo MRI was rigidly registered to the in-vivo MRI and the resulting transform was applied to the histopathology stack. A 2D deformable registration was used to correct for specimen distortion concerning the specimen's fit inside the mold. We estimated the spatial uncertainty by comparing positions of landmarks in the in-vivo MRI and the corresponding registered histopathology stack.Results: Eighty-four landmarks were identified, located in the urethra (62%), prostatic cysts (33%), and the ejaculatory ducts (5%). The median number of landmarks was 3 per patient. We showed a median in-plane error of 1.8 mm before and 1.7 mm after the contour-correcting deformable registration. In patients with extraprostatic margins, the median in-plane error improved from 2.1 mm to 1.8 mm after the contour-correcting deformable registration.Conclusions: Our registration procedure accurately registers histopathology to in-vivo MRI, with low uncertainty. The contour-correcting registration was beneficial in patients with extraprostatic surgical margins.
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| 5. |
- Strandberg, Sara, et al.
(författare)
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11C-acetate PET/CT in pre-therapeutic lymph node staging in high-risk prostate cancer patients and its influence on disease management : a retrospective study
- 2014
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Ingår i: EJNMMI Research. - : Springer. - 2191-219X. ; 4:55, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Radiation treatment with simultaneous integrated boost against suspected lymph node metastases may be a curative therapeutic option in patients with high-risk prostate cancer (>15% estimated risk of pelvic lymph node metastases according to the Cagiannos nomogram). 11C-acetate positron emission tomography/computed tomography (PET/CT) can be used for primary staging as well as for detection of suspected relapse of prostate cancer. The aims of this study were to evaluate the association between positive 11C-acetate PET/CT findings and the estimated risk of pelvic lymph node metastases and to assess the impact of 11C-acetate PET/CT on patient management in high-risk prostate cancer patients.Methods: Fifty consecutive prostate cancer patients referred for primary staging with 11C-acetate PET/CT prior to radiotherapy with curative intention were enrolled in this retrospective study.Results: All patients showed increased 11C-acetate uptake in the prostate. Pelvic lymph node uptake was seen in 42% (21/50) of the patients, with positive external iliac lymph nodes in 71% (15/21) of these. The overall observed proportion of PET/CT-positive pelvic lymph nodes at patient level was higher than the average estimated risk, especially in low-risk groups (<15%). There was a significant association between observed proportion and estimated risk of pelvic lymph node metastases in groups with ≤45 and >45% estimated risk. Treatment strategy was altered due to 11C-acetate PET/CT findings in 43% (20/47) of the patients.Conclusions: The observed proportion of 11C-acetate PET/CT findings suggestive of locoregional metastases was higher than the estimated risk, suggesting that the Cagiannos nomogram underestimates the risk for metastases. The imaging results with 11C-acetate PET/CT have a considerable impact on patient management.
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| 6. |
- Unéus, Erica Irene, et al.
(författare)
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Cerebellar and Cerebral Amyloid Visualized by [18F]flutemetamol PET in Long-Term Hereditary V30M (p.V50M) Transthyretin Amyloidosis Survivors
- 2022
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Ingår i: Frontiers in Neurology. - : Frontiers Media S.A.. - 1664-2295. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Hereditary transthyretin (ATTRv) amyloidosis caused by the V30M (p. V50M) mutation is a fatal, neuropathic systemic amyloidosis. Liver transplantation has prolonged the survival of patients and central nervous system (CNS) complications, attributed to amyloid angiopathy caused by CNS synthesis of variant transthyretin, have emerged. The study aimed to ascertain amyloid deposition within the brain in long-term ATTRv amyloidosis survivors with neurological symptoms from the CNS.Methods: A total of 20 patients with ATTR V30M having symptoms from the CNS and a median disease duration of 16 years (8–25 years) were included in this study. The cognitive and peripheral nervous functions were determined for 18 patients cross-sectionally at the time of the investigation. Amyloid brain deposits were examined by [18F]flutemetamol PET/CT. Five patients with Alzheimer's disease (AD) served as positive controls.Result: 60% of the patients with ATTRv had a pathological Z-score in the cerebellum, compared to only 20% in the patients with AD. 75% of the patients with transient focal neurological episodes (TFNEs) displayed a pathological uptake only in the cerebellum. Increased cerebellar uptake was related to an early age of onset of the ATTRv disease. 55% of the patients with ATTRv had a pathological Z-score in the global cerebral region compared to 100% of the patients with AD.Conclusion: Amyloid deposition within the brain after long-standing ATTRv amyloidosis is common, especially in the cerebellum. A cerebellar amyloid uptake profile seems to be related to TFNE symptoms.
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| 7. |
- Andersson, Olov, 1979-
(författare)
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Methods for Scalable and Safe Robot Learning
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Robots are increasingly expected to go beyond controlled environments in laboratories and factories, to enter real-world public spaces and homes. However, robot behavior is still usually engineered for narrowly defined scenarios. To manually encode robot behavior that works within complex real world environments, such as busy work places or cluttered homes, can be a daunting task. In addition, such robots may require a high degree of autonomy to be practical, which imposes stringent requirements on safety and robustness. \setlength{\parindent}{2em}\setlength{\parskip}{0em}The aim of this thesis is to examine methods for automatically learning safe robot behavior, lowering the costs of synthesizing behavior for complex real-world situations. To avoid task-specific assumptions, we approach this from a data-driven machine learning perspective. The strength of machine learning is its generality, given sufficient data it can learn to approximate any task. However, being embodied agents in the real-world, robots pose a number of difficulties for machine learning. These include real-time requirements with limited computational resources, the cost and effort of operating and collecting data with real robots, as well as safety issues for both the robot and human bystanders.While machine learning is general by nature, overcoming the difficulties with real-world robots outlined above remains a challenge. In this thesis we look for a middle ground on robot learning, leveraging the strengths of both data-driven machine learning, as well as engineering techniques from robotics and control. This includes combing data-driven world models with fast techniques for planning motions under safety constraints, using machine learning to generalize such techniques to problems with high uncertainty, as well as using machine learning to find computationally efficient approximations for use on small embedded systems.We demonstrate such behavior synthesis techniques with real robots, solving a class of difficult dynamic collision avoidance problems under uncertainty, such as induced by the presence of humans without prior coordination. Initially using online planning offloaded to a desktop CPU, and ultimately as a deep neural network policy embedded on board a 7 quadcopter.
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| 8. |
- Bolling, Anne, et al.
(författare)
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SHAKE - an approach for realistic simulation of rough roads in a moving base driving simulator
- 2010
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Ingår i: Trends in driving simulation design and experiments. - Arcueil : Institut national de recherche sur les transports et leur securite, INRETS. - 9782857826859 ; , s. 135-143
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Konferensbidrag (refereegranskat)abstract
- With today’s advanced measurement equipment for measuring roads, it is possible to measure road geometry at high precision within a large span of wavelengths. Detailed information about the roads longitudinal and lateral profile, including macro texture, would in theory be sufficient for a realistic reproduction of road induced vibration and noise in a driving simulator. Especially, it would be possible to create a direct connection between the visual information of the road condition and the ride experience, which would increase the level of realism in the simulation. VTI has during three years performed an internal project called SHAKE with the aim to develop and implement models in VTI driving simulator III that use measured road data for generating realistic vibrations and audible road noise connected to the visual impression presented on the projection screen. This has indeed resulted in an more realistic driving experience, and a validation study with test persons driving both in the simulator and in the field has been undertaken. The OpenDRIVE standard is used as a framework for describing the road properties (e.g. visual, vibrations and noise). For this purpose some augumentations to the OpenDRIVE standard had to be made. This paper describes the technical implementations in the driving simulator, along with results from test drives on the implemented road sections
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| 9. |
- Haraldsson, Mattias, et al.
(författare)
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Marginalkostnadsskattningar för buss och lätt lastbil : buller, trafiksäkerhet och vägslitage
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna rapport är att beräkna marginalkostnader för buller, trafiksäkerhet och vägslitage för bussar och lätta lastbilar. Bullerkostnaderna beräknas med modellen Nord 2000 tillsammans med kalkylvärden från ASEK 5. Marginalkostnaden för trafiksäkerhet beräknas utifrån olycksstatistik i STRADA, en fördelning av trafikarbete mellan landsbygd och tätort samt kalkylvärden från ASEK 5. Marginalkostnaden för vägslitage beräknas genom att justera de värden för genomsnittliga tunga fordon som finns i ASEK 5. Justeringen görs utifrån antalet standardaxlar. För bussar beräknas antalet standardaxlar med hjälp av statistik från fordonsregistret, medan antalet standardaxlar hos lätta lastbilar beräknas utifrån fordonstypens maximala totalvikt. Marginalkostnaden för buller har differentierats på vägar med olika ÅDT och omgivning med olika tät befolkning.
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| 10. |
- Haraldsson, Mattias, et al.
(författare)
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Samhällsekonomisk analys av rundvirkestransporter med 90-tonslastbilar : delprojekt inom Sammodalitetsprojektet
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna rapport är att göra en samhällsekonomisk analys som visar hur de kostnader som rundvirkestransporter med lastbil ger upphov till, skulle påverkas om fordonens totalvikt tilläts öka från 60 till 90 ton och samtidigt få en tillåten maxlängd på 30 meter. Analysen görs på två sätt. Först redovisas genomsnittliga kostnader per fordonskilometer för olika fordonsstorlekar. Dessutom görs en kalkyl, som utgår från scenarier om hur mycket trafikarbetet skulle påverkas om större fordon tilläts. För att analysera hur transporterna av rundvirke genomförs i olika scenarier används den svenska godstransportmodellen Samgods. Flödesberäkningar från denna används därefter tillsammans med uppgifter från Nationella vägdatabasen (NVDB) för att beräkna samhällsekonomiska kostnader. Dessa beräkningar tar hänsyn till vägtyp och andra lokala förutsättningar och fångar därmed upp den variation i samhällsekonomiska kostnader som finns. Beräkningarna sammanfattas med den totala kostnaden för att transportera rundvirke med lastbil i Sverige under ett år. Enligt simuleringarna minskar trafikarbetet med 21 procent om 60-tonsfordon ersätts med 90-tonsfordon, om man inte tar hänsyn till brorestriktionerna. Detta ger en total samhällsekonomisk kostnadssänkning med 4 procent eller 163 miljoner kronor årligen. Då ska man dock komma ihåg att kostnaden för bärighetsåtgärder på broar, vilket är en förutsättning för att scenariot ska kunna realiseras, inte är inkluderade i analysen. Om vissa broar är spärrade för trafik med 90-tonsfordon är det inte generellt lönsamt att ersätta 60-tonsfordon, eftersom den samhällsekonomiska kostnaden då ökar med 15 procent. Redan idag är det dock möjligt att använda 90-tonsfordon på ett antal stråk som är viktiga för rundvirkestransporter.
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