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Anttila M, Koivisto J, Luoma ML, Anttila H. How to adopt technologies in home care: a mixed methods study on user experiences and change of home care in Finland. BMC Health Serv Res 2023; 23:1342. [PMID: 38042800 PMCID: PMC10693073 DOI: 10.1186/s12913-023-10368-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
BACKGROUND There is a need for better adoption of technology to meet the needs of home care professionals, older people, and informal caregivers. METHODS Mixed methods were used to describe and analyse quantitative and qualitative data in a Finnish governmental programme called KATI. The study was three-fold: it 1) listed what kinds of technologies were piloted and deployed in a national study, 2) provided information from the perspectives of home care professionals about requirements to use technology by using focus-group interviews, and 3) assessed experiences of how the adoption of technology changes work and work processes over time by using repeated surveys. Informants in interviews (n = 25) and surveys (n = 90) were home care professionals, who also described the perspectives of older people and informal caregivers. The conceptual models framing the study were adapted from the Technology Acceptance Model and DirVA PROVE-IT. RESULTS There were 80 technology pilots, in which variety of technologies were followed in home care. Familiarity with, commitment to and understanding of technology benefits were considered to be requirements for the technology to be used. The adoption of technology provided new skills and information about older people's wellbeing, realisation of treatment and new possibilities in home care. It developed new procedures to focus on older people's needs and motivated professionals by gained concrete aid. It enabled them to leave out some concrete procedures as unnecessary. On the other hand, there were also pessimistic and negative experiences when technology use provided nothing new or did not change anything. CONCLUSIONS The adoption of technology is dependent on the technology and its integration into the prevailing service practice. When they both work, it is possible to leave out unnecessary procedures in care, allocate resources and save time. It is possible to be aware of older people's safety and how they cope at home, find new ways to get involved in older people's lives, gain insight, and make changes at work. Continuous on-site training, modifications in service practices and communication throughout organisations is needed.
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Affiliation(s)
- Minna Anttila
- Finnish Institute for Health and Welfare, Helsinki, Finland.
| | - Juha Koivisto
- Finnish Institute for Health and Welfare, Helsinki, Finland
| | | | - Heidi Anttila
- Finnish Institute for Health and Welfare, Helsinki, Finland
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Kaihlanen AM, Laukka E, Nadav J, Närvänen J, Saukkonen P, Koivisto J, Heponiemi T. The effects of digitalisation on health and social care work: a qualitative descriptive study of the perceptions of professionals and managers. BMC Health Serv Res 2023; 23:714. [PMID: 37386423 DOI: 10.1186/s12913-023-09730-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 06/21/2023] [Indexed: 07/01/2023] Open
Abstract
BACKGROUND Today, digitalisation is strongly present in health and social care, and it increasingly affects the organisation of work, work requirements, tasks and tools. Due to the constant change in work, up-to-date knowledge is needed about these micro-level effects of digitalisation and how professionals experience the effects in their work. Furthermore, even though managers play a key role in implementing new digital services, their perceptions of the effects of digitalisation and whether they match the views of professionals remain unknown. This study examined how health and social care professionals and managers perceive the effects of digitalisation on the work of professionals. METHODS We used a qualitative approach and conducted eight semi-structured focus group interviews with health and social care professionals (n = 30) and 21 individual interviews with managers in 2020 in four health centres in Finland. The qualitative content analysis included both an inductive and a deductive approach. RESULTS Digitalisation was perceived to have changed professionals' 1) workload and pace, 2) the field and nature of work, 3) work community communication and interaction, and 4) information flow and security. Both professionals and managers identified effects such as accelerated work, reduction in workload, constant learning of technical skills, complicated work due to vulnerable information systems, and reduction in face-to-face encounters. However, managers did not bring up all the effects that professionals considered important, such as the creation of new work tasks, increased and duplicated work, or insufficient time to get acquainted with the systems. CONCLUSIONS The findings suggest that some of the effects of digitalisation on professionals' work and changes in the workplace may receive too little or no recognition from managers. This increases the risk that the potential negative effects may be overlooked and that managers will adopt systems that do not support the work of professionals. To reach a common understanding of the effects of digitalisation, continuous discussions between employees and different management levels are required. This contributes to professionals' well-being and adaptation to changes, as well as the provision of quality health and social services.
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Affiliation(s)
- Anu-Marja Kaihlanen
- Finnish Institute for Health and Welfare, PO Box 30, 00271, Helsinki, Finland.
| | - Elina Laukka
- Research Unit of Nursing Science and Health Management, University of Oulu, 90230, Oulu, Finland
| | - Janna Nadav
- Finnish Institute for Health and Welfare, PO Box 30, 00271, Helsinki, Finland
| | - Johanna Närvänen
- Department of Health and Social Management, University of Eastern Finland, Kuopio, Finland
| | - Petra Saukkonen
- Finnish Institute for Health and Welfare, PO Box 30, 00271, Helsinki, Finland
| | - Juha Koivisto
- Finnish Institute for Health and Welfare, PO Box 30, 00271, Helsinki, Finland
| | - Tarja Heponiemi
- Finnish Institute for Health and Welfare, PO Box 30, 00271, Helsinki, Finland
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Söderqvist S, Sivonen V, Koivisto J, Aarnisalo A, Sinkkonen ST. Spread of the intracochlear electrical field: Implications for assessing electrode array location in cochlear implantation. Hear Res 2023; 434:108790. [PMID: 37196460 DOI: 10.1016/j.heares.2023.108790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/03/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
The electrode-generated intracochlear electrical field (EF) spreads widely along the scala tympani surrounded by poorly-conducting tissue and it can be measured with monopolar transimpedance matrix (TIMmp). Bipolar TIM (TIMbp) allows estimations of local potential differences. With TIMmp, the correct alignment of the electrode array can be assessed, and TIMbp may be useful in more subtle evaluations of the electrode array's intracochlear location. In this temporal bone study, we investigated the effect of the cross-sectional scala area (SA) and the electrode-medial-wall distance (EMWD) on both TIMmp and TIMbp using three types of electrode arrays. Also, multiple linear regressions based on the TIMmp and TIMbp measurements were used to estimate the SA and EMWD. Six cadaver temporal bones were consecutively implanted with a lateral-wall electrode array (Slim Straight) and with two different precurved perimodiolar electrode arrays (Contour Advance and Slim Modiolar) for variation in EMWD. The bones were imaged with cone-beam computed tomography with simultaneous TIMmp and TIMbp measurements. The results from imaging and EF measurements were compared. SA increased from apical to basal direction (r = 0.96, p < 0.001). Intracochlear EF peak negatively correlated with SA (r = -0.55, p < 0.001) irrespective of the EMWD. The rate of the EF decay did not correlate with SA but it was faster in the proximity of the medial wall than in more lateral positions (r = 0.35, p < 0.001). For a linear comparison between the EF decaying proportionally to squared distance and anatomic dimensions, a square root of inverse TIMbp was applied and found to be affected by both SA and EMWD (r = 0.44 and r = 0.49, p < 0.001 for both). A regression model confirmed that together TIMmp and TIMbp can be used to estimate both SA and EMWD (R2 = 0.47 and R2 = 0.44, respectively, p < 0.001 for both). In TIMmp, EF peaks grow from basal to apical direction and EF decay is steeper in the proximity of the medial wall than in more lateral positions. Local potentials measured via TIMbp correlate with both SA and EMWD. Altogether, TIMmp and TIMbp can be used to assess the intracochlear and intrascalar position of the electrode array, and they may reduce the need for intra- and postoperative imaging in the future.
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Affiliation(s)
- Samuel Söderqvist
- Department of Otorhinolaryngology - Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Kasarmikatu 11-13, Helsinki 00130, Finland.
| | - Ville Sivonen
- Department of Otorhinolaryngology - Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Kasarmikatu 11-13, Helsinki 00130, Finland
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Antti Aarnisalo
- Department of Otorhinolaryngology - Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Kasarmikatu 11-13, Helsinki 00130, Finland
| | - Saku T Sinkkonen
- Department of Otorhinolaryngology - Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Kasarmikatu 11-13, Helsinki 00130, Finland
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Heikkinen AK, Rissanen V, Aarnisalo AA, Nyman K, Sinkkonen ST, Koivisto J. Assessment of subjective image quality, contrast to noise ratio and modulation transfer function in the middle ear using a novel full body cone beam computed tomography device. BMC Med Imaging 2023; 23:51. [PMID: 37038130 PMCID: PMC10084678 DOI: 10.1186/s12880-023-00996-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 03/14/2023] [Indexed: 04/12/2023] Open
Abstract
BACKGROUND Multi slice computed tomography (MSCT) is the most common used method in middle ear imaging. However, MSCT lacks the ability to distinguish the ossicular chain microstructures in detail resulting in poorer diagnostic outcomes. Novel cone beam computed tomography (CBCT) devices' image resolution is, on the other hand, better than MSCT resolution. The aim of this study was to optimize imaging parameters of a novel full body CBCT device to obtain optimal contrast to noise ratio (CNR) with low effective dose, and to optimize its clinical usability. METHODS Imaging of five anonymous excised human cadaver temporal bones, the acquisition of the effective doses and the CNR measurements were performed for images acquired on using Planmed XFI® full body CBCT device (Planmed Oy, Helsinki, Finland) with a voxel size of 75 µm. All images acquired from the specimens using 10 different imaging protocols varying from their tube current exposure time product (mAs) and tube voltage (kVp) were analyzed for eight anatomical landmarks and evaluated by three evaluators. RESULTS With the exception of protocol with 90 kVp 100 mAs, all other protocols used are competent to image the finest structures. With a moderate effective dose (86.5 µSv), protocol with 90 kV 450 mAs was chosen the best protocol used in this study. A significant correlation between CNR and clinical image quality of the protocols was observed in linear regression model. Using the optimized imaging parameters, we were able to distinguish even the most delicate middle ear structures in 2D images and produce accurate 3D reconstructions. CONCLUSIONS In this ex vivo experiment, the new Planmed XFI® full body CBCT device produced excellent 2D resolution and easily created 3D reconstructions in middle ear imaging with moderate effective doses. This device would be suitable for middle ear diagnostics and for e.g., preoperative planning. Furthermore, the results of this study can be used to optimize the effective dose by selecting appropriate exposure parameters depending on the diagnostic task.
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Affiliation(s)
- Anssi-Kalle Heikkinen
- Department of Otorhinolaryngology-Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
| | - Valtteri Rissanen
- Department of Otorhinolaryngology-Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Antti A Aarnisalo
- Department of Otorhinolaryngology-Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Kristofer Nyman
- Radiology, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Saku T Sinkkonen
- Department of Otorhinolaryngology-Head and Neck Surgery and Tauno Palva Laboratory, Head and Neck Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
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Söderqvist S, Sivonen V, Aarnisalo A, Karppi H, Sinkkonen ST, Koivisto J. OPTIMISING THE PARAMETERS OF COCHLEAR IMPLANT IMAGING WITH CONE-BEAM COMPUTED TOMOGRAPHY. Radiat Prot Dosimetry 2023; 199:462-470. [PMID: 36789742 PMCID: PMC10077498 DOI: 10.1093/rpd/ncad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/22/2022] [Accepted: 01/15/2023] [Indexed: 06/18/2023]
Abstract
With computed tomography (CT), the delicate structures of the inner ear may be hard to visualise, which a cochlear implant (CI) electrode array can further complicate. The usefulness of a novel cone-beam CT device in CI recipient's inner ear imaging was evaluated and the exposure parameters were optimised to attain adequate clinical image quality at the lowest effective dose (ED). Six temporal bones were implanted with a Cochlear Slim Straight electrode array and imaged with six different imaging protocols. Contrast-to-noise ratio was calculated for each imaging protocol, and three observers evaluated independently the image quality of each imaging protocol and temporal bone. The overall image quality of the inner ear structures did not differ between the imaging protocols and the most relevant inner ear structures of CI recipient's inner ear can be visualised with a low ED. To visualise the most delicate structures in the inner ear, imaging protocols with higher radiation exposure may be required.
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Affiliation(s)
| | - Ville Sivonen
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Antti Aarnisalo
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | | | - Saku T Sinkkonen
- Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Tauno Palva Laboratory, Department of Otorhinolaryngology—Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital, Helsinki, Finland
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
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Charuakkra A, Mahasantipiya P, Lehtinen A, Koivisto J, Järnstedt J. Comparison of subjective image analysis and effective dose between low-dose cone-beam computed tomography machines. Dentomaxillofac Radiol 2023; 52:20220176. [PMID: 36168973 PMCID: PMC9974239 DOI: 10.1259/dmfr.20220176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/02/2022] [Accepted: 09/20/2022] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVES To compare the cone-beam computed tomography (CBCT) image quality and effective dose between low-dose scanning and standard manufacturer-recommended protocols among different CBCT units. METHODS Three human-equivalent phantoms were scanned using the ultra-low-dose (ULD), low dose (LD), and standard dose (STD) modes of ProMax 3D Mid (Planmeca Oy, Helsinki, Finland) and Orthophos SL (Sirona, Bensheim, German) for the CBCT images. The quality of the dental anatomical images was assessed by four experienced oral and maxillofacial radiologists using a 5-point Likert scale. OnDemand3D (Cybermed Co., Seoul, Korea) was used as the third-party software for viewing. The percentage of absolute agreement was calculated to determine intra- and interrater agreements among the observers. The effective doses for all CBCT scanning protocols were also calculated. RESULTS The STD protocol yielded a higher image quality than did the ULD and LD protocols in both ProMax 3D Mid and Orthophos SL. The ULD and LD protocols demonstrated an "acceptable-to-good" sense of visual perception of the CBCT images. The visibility scores significantly differed between the ULD and LD and the STD protocols in ProMax 3D Mid and Orthophos SL, except for the 120-kVp setting in ProMax 3D Mid. The average intra- and interrater agreement scores ranged from 0.63 to 0.89 and from 0.44 to 0.76, respectively. The ULD and LD protocols reduced the radiation dose sixfold compared with the STD protocol. CONCLUSIONS High-tube-voltage protocols could remarkably reduce the imaging dose without degrading the image quality. Specifically, ULD and LD CBCT protocols may be adopted as routine practice for diagnosis and treatment planning.
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Affiliation(s)
- Arnon Charuakkra
- Division of Oral and Maxillofacial Radiology, Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Phattaranant Mahasantipiya
- Division of Oral and Maxillofacial Radiology, Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Antti Lehtinen
- Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Jorma Järnstedt
- Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
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Miranda-Valdez IY, Viitanen L, Intyre JM, Puisto A, Koivisto J, Alava M. Predicting effect of fibers on thermal gelation of methylcellulose using Bayesian optimization. Carbohydr Polym 2022; 298:119921. [DOI: 10.1016/j.carbpol.2022.119921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 11/29/2022]
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DeNunzio G, Evans T, Beebe ME, Browning J, Koivisto J. Craniocervical Junction Visualization and Radiation Dose Consideration Utilizing Cone Beam Computed Tomography for Upper Cervical Chiropractic Clinical Application a Literature Review. Dose Response 2022; 20:15593258221107515. [PMID: 35719850 PMCID: PMC9201332 DOI: 10.1177/15593258221107515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives To highlight the detail obtained on a Cone Beam Computed Tomography (CBCT) scan of the craniocervical junction and its usefulness to Chiropractors who specialize in the upper cervical spine. A review of the dose considerations to patients vs radiography in a chiropractic clinical setting and to review the effective radiation dose to the patient. Methods A review of studies discussing cervical biomechanics, neurovascular structures, and abnormal radiographic findings, was discussed in relation to chiropractic clinical relevance. Further studies were evaluated demonstrating radiation dose to the patient from radiographs compared to CBCT. Results Incidental and abnormal findings of the craniocervical junction were shown to have superior visualization with CBCT compared to radiography. The radiation dose to the patient for similar imaging protocols to the craniocervical junction and cervical spine was equal or less utilizing CBCT when compared to radiographs. Conclusions The use of CBCT for visualization of the craniocervical junction and cervical spine in the chiropractic clinical setting allows for adjunctive visualization of the osseous structures which is germane to clinical protocol. Further with CBCT the effective dose to the patient is equal or less than similar imaging protocols utilizing radiographs to evaluate the craniocervical junction.
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Affiliation(s)
- Greg DeNunzio
- Sweere Center for Clinical Biomechanics and Applied Ergonomics, Northwestern Health Sciences University, Bloomington, MI, USA
| | - Tyler Evans
- Private Practice, Arete Chiropractic, Portsmouth, NH, USA
| | - Mychal E Beebe
- Private Practice, Arete Chiropractic, Portsmouth, NH, USA
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Nadav J, Kaihlanen AM, Kujala S, Laukka E, Hilama P, Koivisto J, Keskimäki I, Heponiemi T. How to Implement Digital Services in a Way That They Integrate Into Routine Work: Qualitative Interview Study Among Health and Social Care Professionals. J Med Internet Res 2021; 23:e31668. [PMID: 34855610 PMCID: PMC8686404 DOI: 10.2196/31668] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/11/2021] [Accepted: 10/21/2021] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Although the COVID-19 pandemic has significantly boosted the implementation of digital services worldwide, it has become increasingly important to understand how these solutions are integrated into professionals' routine work. Professionals who are using the services are key influencers in the success of implementations. To ensure successful implementations, it is important to understand the multiprofessional perspective, especially because implementations are likely to increase even more. OBJECTIVE The aim of this study is to examine health and social care professionals' experiences of digital service implementations and to identify factors that support successful implementations and should be considered in the future to ensure that the services are integrated into professionals' routine work. METHODS A qualitative approach was used, in which 8 focus group interviews were conducted with 30 health and social care professionals from 4 different health centers in Finland. Data were analyzed using qualitative content analysis. The resulting categories were organized under the components of normalization process theory. RESULTS Our results suggested 14 practices that should be considered when implementing new digital services into routine work. To get professionals to understand and make sense of the new service, (1) the communication related to the implementation should be comprehensive and continuous and (2) the implementation process should be consistent. (3) A justification for the service being implemented should also be given. The best way to engage the professionals with the service is (4) to give them opportunities to influence and (5) to make sure that they have a positive attitude toward the service. To enact the new service into professionals' routine work, it is important that (6) the organization take a supportive approach by providing support from several easy and efficient sources. The professionals should also have (7) enough time to become familiar with the service, and they should have (8) enough know-how about the service. The training should be (9) targeted individually according to skills and work tasks, and (10) it should be diverse. The impact of the implementation on the professionals' work should be evaluated. The service (11) should be easy to use, and (12) usage monitoring should happen. An opportunity (13) to give feedback on the service should also be offered. Moreover, (14) the service should support professionals' work tasks. CONCLUSIONS We introduce 14 practices for organizations and service providers on how to ensure sustainable implementation of new digital services and the smooth integration into routine work. It is important to pay more attention to comprehensive and continuing communication. Organizations should conduct a competence assessment before training in order to ensure proper alignment. Follow-ups to the implementation process should be performed to guarantee sustainability of the service. Our findings from a forerunner country of digitalization can be useful for countries that are beginning their service digitalization or further developing their digital services.
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Affiliation(s)
- Janna Nadav
- Finnish Institution for Health and Welfare, Helsinki, Finland.,Department of Health and Social Care Systems, Tampere, Finland
| | | | | | | | - Pirjo Hilama
- South Savo Social and Health Care Authority, Mikkeli, Finland
| | - Juha Koivisto
- Finnish Institution for Health and Welfare, Helsinki, Finland
| | - Ilmo Keskimäki
- Finnish Institution for Health and Welfare, Helsinki, Finland.,Department of Health and Social Care Systems, Tampere, Finland
| | - Tarja Heponiemi
- Finnish Institution for Health and Welfare, Helsinki, Finland
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Minnema J, Wolff J, Koivisto J, Lucka F, Batenburg KJ, Forouzanfar T, van Eijnatten M. Comparison of convolutional neural network training strategies for cone-beam CT image segmentation. Comput Methods Programs Biomed 2021; 207:106192. [PMID: 34062493 DOI: 10.1016/j.cmpb.2021.106192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 05/11/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Over the past decade, convolutional neural networks (CNNs) have revolutionized the field of medical image segmentation. Prompted by the developments in computational resources and the availability of large datasets, a wide variety of different two-dimensional (2D) and three-dimensional (3D) CNN training strategies have been proposed. However, a systematic comparison of the impact of these strategies on the image segmentation performance is still lacking. Therefore, this study aimed to compare eight different CNN training strategies, namely 2D (axial, sagittal and coronal slices), 2.5D (3 and 5 adjacent slices), majority voting, randomly oriented 2D cross-sections and 3D patches. METHODS These eight strategies were used to train a U-Net and an MS-D network for the segmentation of simulated cone-beam computed tomography (CBCT) images comprising randomly-placed non-overlapping cylinders and experimental CBCT images of anthropomorphic phantom heads. The resulting segmentation performances were quantitatively compared by calculating Dice similarity coefficients. In addition, all segmented and gold standard experimental CBCT images were converted into virtual 3D models and compared using orientation-based surface comparisons. RESULTS The CNN training strategy that generally resulted in the best performances on both simulated and experimental CBCT images was majority voting. When employing 2D training strategies, the segmentation performance can be optimized by training on image slices that are perpendicular to the predominant orientation of the anatomical structure of interest. Such spatial features should be taken into account when choosing or developing novel CNN training strategies for medical image segmentation. CONCLUSIONS The results of this study will help clinicians and engineers to choose the most-suited CNN training strategy for CBCT image segmentation.
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Affiliation(s)
- Jordi Minnema
- Department of Oral and Maxillofacial Surgery/Pathology, 3D Innovationlab, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam 1081 HV, theNetherlands.
| | - Jan Wolff
- Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT, Am Schleusengraben 13, Hamburg 21029, Germany; Department of Oral and Maxillofacial Surgery, Division for Regenerative Orofacial Medicine, University Hospital Hamburg-Eppendorf, Hamburg 20246, Germany; Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, DK-8000 Aarhus C, Denmark
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki 20560, Finland
| | - Felix Lucka
- Centrum Wiskunde & Informatica (CWI), Amsterdam 1090 GB, the Netherlands; University College London, London WC1E 6BT, United Kingdom
| | | | - Tymour Forouzanfar
- Department of Oral and Maxillofacial Surgery/Pathology, 3D Innovationlab, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam 1081 HV, theNetherlands
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Tainio O, Sohrabi F, Janarek N, Koivisto J, Puisto A, Viitanen L, Timonen JVI, Alava M. Correction: Chlamydomonas reinhardtii swimming in the Plateau borders of 2D foams. Soft Matter 2021; 17:6675. [PMID: 34180932 DOI: 10.1039/d1sm90118d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Correction for 'Chlamydomonas reinhardtii swimming in the Plateau borders of 2D foams' by Oskar Tainio et al., Soft Matter, 2021, 17, 145-152, DOI: 10.1039/D0SM01206H.
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Affiliation(s)
- Oskar Tainio
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
| | - Fereshteh Sohrabi
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
| | - Nikodem Janarek
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland. and Department of Physics and Astronomy, University College London, UK
| | - Juha Koivisto
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
| | - Antti Puisto
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
| | - Leevi Viitanen
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
| | | | - Mikko Alava
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
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Minnema J, van Eijnatten M, der Sarkissian H, Doyle S, Koivisto J, Wolff J, Forouzanfar T, Lucka F, Batenburg KJ. Efficient high cone-angle artifact reduction in circular cone-beam CT using deep learning with geometry-aware dimension reduction. Phys Med Biol 2021; 66. [PMID: 34107467 DOI: 10.1088/1361-6560/ac09a1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 06/09/2021] [Indexed: 11/11/2022]
Abstract
High cone-angle artifacts (HCAAs) appear frequently in circular cone-beam computed tomography (CBCT) images and can heavily affect diagnosis and treatment planning. To reduce HCAAs in CBCT scans, we propose a novel deep learning approach that reduces the three-dimensional (3D) nature of HCAAs to two-dimensional (2D) problems in an efficient way. Specifically, we exploit the relationship between HCAAs and the rotational scanning geometry by training a convolutional neural network (CNN) using image slices that were radially sampled from CBCT scans. We evaluated this novel approach using a dataset of input CBCT scans affected by HCAAs and high-quality artifact-free target CBCT scans. Two different CNN architectures were employed, namely U-Net and a mixed-scale dense CNN (MS-D Net). The artifact reduction performance of the proposed approach was compared to that of a Cartesian slice-based artifact reduction deep learning approach in which a CNN was trained to remove the HCAAs from Cartesian slices. In addition, all processed CBCT scans were segmented to investigate the impact of HCAAs reduction on the quality of CBCT image segmentation. We demonstrate that the proposed deep learning approach with geometry-aware dimension reduction greatly reduces HCAAs in CBCT scans and outperforms the Cartesian slice-based deep learning approach. Moreover, the proposed artifact reduction approach markedly improves the accuracy of the subsequent segmentation task compared to the Cartesian slice-based workflow.
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Affiliation(s)
- Jordi Minnema
- Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Department of Oral and Maxillofacial Surgery/Pathology, 3D Innovationlab, Amsterdam Movement Sciences, 1081 HV Amsterdam, The Netherlands
| | - Maureen van Eijnatten
- Medical Image Analysis Group, Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.,Centrum Wiskunde & Informatica (CWI), 1090 GB Amsterdam, The Netherlands
| | | | - Shannon Doyle
- Centrum Wiskunde & Informatica (CWI), 1090 GB Amsterdam, The Netherlands
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Gustaf Hällsströmin katu 2, FI-00560, Helsinki, Finland
| | - Jan Wolff
- Department of Oral and Maxillofacial Surgery, Division for Regenerative Orofacial Medicine, University Hospital Hamburg-Eppendorf, D-20246 Hamburg, Germany.,Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT, Am Schleusengraben 13, D-21029 Hamburg, Germany.,Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, DK-8000 Aarhus C, Denmark
| | - Tymour Forouzanfar
- Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Department of Oral and Maxillofacial Surgery/Pathology, 3D Innovationlab, Amsterdam Movement Sciences, 1081 HV Amsterdam, The Netherlands
| | - Felix Lucka
- Centrum Wiskunde & Informatica (CWI), 1090 GB Amsterdam, The Netherlands.,Centre for Medical Image Computing, University College London, WC1E 6BT London, United Kingdom
| | - Kees Joost Batenburg
- Centrum Wiskunde & Informatica (CWI), 1090 GB Amsterdam, The Netherlands.,Leiden Institute of Advanced Computer Science (LIACS), Leiden University, 2333 CA Leiden, The Netherlands
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Koivisto J, van Eijnatten M, Ludlow J, Kiljunen T, Shi X, Wolff J. Comparative dosimetry of radiography device, MSCT device and two CBCT devices in the elbow region. J Appl Clin Med Phys 2021; 22:128-138. [PMID: 33811787 PMCID: PMC8130242 DOI: 10.1002/acm2.13245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 12/27/2022] Open
Abstract
The aim of the study was to estimate and to compare effective doses in the elbow region resulting from four different x-ray imaging modalities. Absorbed organ doses were measured using 11 metal oxide field effect transistor (MOSFET) dosimeters that were placed in a custom-made anthropomorphic elbow RANDO phantom. Examinations were performed using Shimadzu FH-21 HR radiography device, Siemens Sensation Open 24-slice MSCT-device, NewTom 5G CBCT device, and Planmed Verity CBCT device, and the effective doses were calculated according to ICRP 103 recommendations. The effective dose for the conventional radiographic device was 1.5 µSv. The effective dose for the NewTom 5G CBCT ranged between 2.0 and 6.7 µSv, for the Planmed Verity CBCT device 2.6 µSv and for the Siemens Sensation MSCT device 37.4 µSv. Compared with conventional 2D radiography, this study demonstrated a 1.4-4.6 fold increase in effective dose for CBCT and 25-fold dose for standard MSCT protocols. When compared with 3D CBCT protocols, the study showed a 6-19 fold increase in effective dose using a standard MSCT protocol. CBCT devices offer a feasible low-dose alternative for elbow 3D imaging when compared to MSCT.
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Affiliation(s)
- Juha Koivisto
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Maureen van Eijnatten
- Department of Oral and Maxillofacial Surgery/Oral PathologyVU University Medical CenterAmsterdamThe Netherlands
| | - John Ludlow
- University of North CarolinaAdams School of DentistryChapel HillNCUSA
| | | | - Xie‐Qi Shi
- Section of Oral Maxillofacial RadiologyDepartment of Clinical DentistryFaculty of Medicine and DentistryUniversity of BergenBergenNorway
| | - Jan Wolff
- Department of Oral Maxillofacial SurgeryUniversity Medical Center Hamburg‐EppendorfHamburgGermany
- Division of Regenerative Orofacial MedicineHamburgGermany
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Tainio O, Sohrabi F, Janarek N, Koivisto J, Puisto A, Viitanen L, Timonen JVI, Alava M. Chlamydomonas reinhardtii swimming in the Plateau borders of 2D foams. Soft Matter 2021; 17:145-152. [PMID: 33155584 DOI: 10.1039/d0sm01206h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Unicellular Chlamydomonas reinhardtii micro-algae cells were inserted into a quasi-2D Hele-Shaw chamber filled with saponin foam. The movement of the algae along the bubble borders was then manipulated and tracked. These self-propelled particles generate flow and stresses in their surrounding matter. In addition, the algae possess the capability of exerting forces that alter bubble boundaries while maintaining an imminent phototactic movement. We find that by controlling the gas fraction of the foam we can change the interaction of the algae and bubbles. Specifically, our data expose three distinct swimming regimes for the algae with respect to the level of confinement due to the Plateau border cross-section: unlimited bulk, transition, and overdamped regimes. At the transition regime we find the speed of the algae to be modeled by a simple force balance equation emerging from the shear inside the Plateau border. Thus, we have shown that it is possible to create an algae-friendly foam while controlling the algae motion. This opens doors to multiple applications where the flow of nutrients, oxygen and recirculation of living organisms is essential.
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Affiliation(s)
- Oskar Tainio
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland.
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15
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Rinkinen O, Viitanen L, Mac Intyre JR, Koivisto J, Puisto A, Alava M. Vibration controlled foam yielding. Soft Matter 2020; 16:9028-9034. [PMID: 32842140 DOI: 10.1039/d0sm00439a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In rheological terms, foams are time independent yield stress fluids, displaying properties of both solid and liquid materials. Here we measure the propagation of a 2D dry foam in a radially symmetric Hele-Shaw cell forcing local yielding. The yield rate is manipulated by mechanical vibration with frequencies from 0 to 150 Hz. The flow speed is then extracted from the video stream and analyzed using digital image correlation software. The data are modeled analytically by a Guzman-Arrhenius type of energy landscape where the local yielding of foam correlates with the number of oscillations, i.e. attempts to cross the energy barrier. The model is confirmed in an auxiliary experiment where the vibrated foam stays in its flowing state at the same small driving pressures, where the flow of the unvibrated foam ceases. We conclude that the yield stress behaviour of foams under an external perturbation can be summarized using a simple energy landscape model. The vibration affects the films causing the stress to occasionally and locally exceed the yield threshold. This, thus, prevents the foam from jamming as in a static configuration even when the global driving is below the yield point of the foam.
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Affiliation(s)
- Oona Rinkinen
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
| | - Leevi Viitanen
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
| | - Jonatan R Mac Intyre
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
| | - Juha Koivisto
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
| | - Antti Puisto
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
| | - Mikko Alava
- Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland.
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16
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Mäkinen T, Koivisto J, Pääkkönen E, Ketoja JA, Alava MJ. Crossover from mean-field compression to collective phenomena in low-density foam-formed fiber material. Soft Matter 2020; 16:6819-6825. [PMID: 32632431 DOI: 10.1039/d0sm00286k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We study the compression of low-weight foam-formed materials made out of wood fibers. Initially the stress-strain behavior follows mean-field like response, related to the buckling of fiber segments as dictated by the random three-dimensional geometry. Our Acoustic Emission (AE) measurements correlate with the predicted number of segment bucklings for increasing strain. However, the experiments reveal a transition to collective phenomena as the strain increases sufficiently. This is also seen in the gradual failure of the theory to account for the stress-strain curves. The collective avalanches exhibit scale-free features both as regards the AE energy distribution and the AE waiting time distributions with both exponents having values close to 2. In cyclic compression tests, significant increases in the accumulated acoustic energy are found only when the compression exceeds the displacement of the previous cycle, which further confirms other sources of acoustic events than fiber bending.
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Affiliation(s)
- Tero Mäkinen
- Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Espoo, Finland.
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17
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Inkinen J, Ahonen M, Iakovleva E, Karppinen P, Mielonen E, Mäkinen R, Mannonen K, Koivisto J. Contamination detection by optical measurements in a real-life environment: A hospital case study. J Biophotonics 2020; 13:e201960069. [PMID: 31613045 PMCID: PMC7065611 DOI: 10.1002/jbio.201960069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/30/2019] [Accepted: 10/06/2019] [Indexed: 05/05/2023]
Abstract
Organic dirt on touch surfaces can be biological contaminants (microbes) or nutrients for those but is often invisible by the human eye causing challenges for evaluating the need for cleaning. Using hyperspectral scanning algorithm, touch surface cleanliness monitoring by optical imaging was studied in a real-life hospital environment. As the highlight, a human eye invisible stain from a dirty chair armrest was revealed manually with algorithms including threshold levels for intensity and clustering analysis with two excitation lights (green and red) and one bandpass filter (wavelength λ = 500 nm). The same result was confirmed by automatic k-means clustering analysis from the entire dirty data of visible light (red, green and blue) and filters 420 to 720 nm with 20 nm increments. Overall, the collected touch surface samples (N = 156) indicated the need for cleaning in some locations by the high culturable bacteria and adenosine triphosphate counts despite the lack of visible dirt. Examples of such locations were toilet door lock knobs and busy registration desk armchairs. Thus, the studied optical imaging system utilizing the safe visible light area shows a promising method for touch surface cleanliness evaluation in real-life environments.
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Affiliation(s)
- Jenni Inkinen
- Aalto University, School of Science, Department of Applied PhysicsComplex Systems and MaterialsAaltoFinland
| | - Merja Ahonen
- Satakunta University of Applied Sciences, Faculty of TechnologyWANDER Nordic Water and Materials InstituteRaumaFinland
| | - Evgenia Iakovleva
- Aalto University, School of Science, Department of Applied PhysicsComplex Systems and MaterialsAaltoFinland
| | - Pasi Karppinen
- Aalto University, School of Science, Department of Applied PhysicsComplex Systems and MaterialsAaltoFinland
| | - Eelis Mielonen
- Aalto University, School of Science, Department of Applied PhysicsComplex Systems and MaterialsAaltoFinland
| | - Riika Mäkinen
- Satakunta University of Applied Sciences, Faculty of TechnologyWANDER Nordic Water and Materials InstituteRaumaFinland
| | - Katriina Mannonen
- Satakunta University of Applied Sciences, Faculty of TechnologyWANDER Nordic Water and Materials InstituteRaumaFinland
| | - Juha Koivisto
- Aalto University, School of Science, Department of Applied PhysicsComplex Systems and MaterialsAaltoFinland
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Benchimol D, Koivisto J, Kadesjö N, Shi XQ. Effective dose reduction using collimation function in digital panoramic radiography and possible clinical implications in dentistry. Dentomaxillofac Radiol 2018; 47:20180007. [PMID: 29722543 PMCID: PMC6196069 DOI: 10.1259/dmfr.20180007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/27/2018] [Accepted: 04/30/2018] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES: The primary aim was to evaluate the effective dose for a full size panoramic image and nine different panoramic protocols using collimation. The secondary aim was to estimate possible reduction of effective dose in clinical situations. METHODS Effective dose, according to International Commission on Radiological Protection 2007 was determined for a full size panoramic image and nine different panoramic protocols applying collimation on an anthropomorphic Rando phantom, using metal-oxide semiconductor field-effect transistor dosemeters. The collimation protocols were chosen based on common diagnostic questions. 10 exposures were made for each protocol using a Planmeca ProMax® 2D (Helsinki, Finland). The mean effective doses were calculated according to clinical default exposure settings and compared for all protocols. A retrospective analysis of 252 referrals to a specialist clinic in dentomaxillofacial radiology assessed usability and dose reduction applying nine different collimation protocols, based on possible collimation of panoramic images. Dose reduction was calculated applying collimation feature in comparison to constant use of full size panoramic imaging. Referrals were categorized according to indication for radiographic examination. RESULTS: Effective dose of a full size panoramic radiograph was 17.6 µSv at 8 mA and 66 kV. The dose reduction for the collimated images compared to a full size panoramic radiograph ranged from 4.5 to 86.9%. Potential total dose reduction in the studied sample was 35% if collimation feature had been applied. In four out of five of the referrals, collimation was possible and in 61% of the referrals the indication for radiographic examination was restricted to the dental alveolar region, reducing the dose by 40.3% compared with a full size panoramic image. CONCLUSIONS: Since the effective dose may be reduced without losing diagnostic information in the area of interest, collimation feature of panoramic imaging should be routinely applied when the diagnostic task allows.
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Affiliation(s)
- Daniel Benchimol
- Section of Oral Diagnostics and Surgery, Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Juha Koivisto
- Department of Oral and Maxillofacial Surgery, VU University Medical Center, Amsterdam, The Netherlands
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19
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Koivisto J, van Eijnatten M, Kiljunen T, Shi XQ, Wolff J. Effective Radiation Dose in the Wrist Resulting from a Radiographic Device, Two CBCT Devices and One MSCT Device: A Comparative Study. Radiat Prot Dosimetry 2018; 179:58-68. [PMID: 29040707 DOI: 10.1093/rpd/ncx210] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
The objective of the present study was to assess and compare the effective doses in the wrist region resulting from conventional radiography device, multislice computed tomography (MSCT) device and two cone beam computed tomography (CBCT) devices using MOSFET dosemeters and a custom made anthropomorphic RANDO phantom according to the ICRP 103 recommendation. The effective dose for the conventional radiography was 1.0 μSv. The effective doses for the NewTom 5 G CBCT ranged between 0.7 μSv and 1.6 μSv, for the Planmed Verity CBCT 2.4 μSv and for the MSCT 8.6 μSv. When compared with the effective dose for AP- and LAT projections of a conventional radiographic device, this study showed an 8.6-fold effective dose for standard MSCT protocol and between 0.7 and 2.4-fold effective dose for standard CBCT protocols. When compared to the MSCT device, the CBCT devices offer a 3D view of the wrist at significantly lower effective doses.
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Affiliation(s)
- Juha Koivisto
- Department of Oral and Maxillofacial Surgery, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Maureen van Eijnatten
- Department of Oral and Maxillofacial Surgery, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Timo Kiljunen
- International Docrates Cancer Center, Helsinki, Finland; Saukonpaadenranta 2, FI-00180, Helsinki, Finland
| | - Xie-Qi Shi
- Section of Oral Maxillofacial Radiology, Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Årstadveien 19, 5009 Bergen, Norway
- Sektionen för bild- och funktionsfysik, C2-63Karolinska Universitetssjukhuset, Huddinge, SE-141 86 Stockholm, Sweden
| | - Jan Wolff
- Department of Oral and Maxillofacial Surgery, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
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Abstract
We investigate the coupling between the interstitial medium and granular particles by studying the hopper flow of dry and submerged systems experimentally and numerically. In accordance with earlier studies, we find that the dry hopper empties at a constant rate. However, in the submerged system we observe the surging of the flow rate. We model both systems using the discrete element method, which we couple with computational fluid dynamics in the case of a submerged hopper. We are able to match the simulations and the experiments with good accuracy by fitting the particle-particle contact friction for each system separately. Submerging the hopper changes the particle-particle contact friction from μvacuum = 0.15 to μsub = 0.13, while all the other simulation parameters remain the same.
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Affiliation(s)
- Juha Koivisto
- Department of Applied Physics, Aalto University, Aalto 00067, Finland.
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21
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Koivisto J, van Eijnatten M, Järnstedt J, Holli-Helenius K, Dastidar P, Wolff J. Impact of prone, supine and oblique patient positioning on CBCT image quality, contrast-to-noise ratio and figure of merit value in the maxillofacial region. Dentomaxillofac Radiol 2017; 46:20160418. [PMID: 28306334 DOI: 10.1259/dmfr.20160418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To assess the impact of supine, prone and oblique patient imaging positions on the image quality, contrast-to-noise ratio (CNR) and figure of merit (FOM) value in the maxillofacial region using a CBCT scanner. Furthermore, the CBCT supine images were compared with supine multislice CT (MSCT) images. METHODS One fresh frozen cadaver head was scanned in prone, supine and oblique imaging positions using a mobile CBCT scanner. MSCT images of the head were acquired in a supine position. Two radiologists graded the CBCT and MSCT images at ten different anatomical sites according to their image quality using a six-point scale. The CNR and FOM values were calculated at two different anatomical sites on the CBCT and MSCT images. RESULTS The best image quality was achieved in the prone imaging position for sinus, mandible and maxilla, followed by the supine and oblique imaging positions. 12-mA prone images presented high delineation scores for all anatomical landmarks, except for the ear region (carotid canal), which presented adequate to poor delineation scores for all studied head positions and exposure parameters. The MSCT scanner offered similar image qualities to the 7.5-mA supine images acquired using the mobile CBCT scanner. The prone imaging position offered the best CNR and FOM values on the mobile CBCT scanner. CONCLUSIONS Head positioning has an impact on CBCT image quality. The best CBCT image quality can be achieved using the prone and supine imaging positions. The oblique imaging position offers inadequate image quality except in the sinus region.
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Affiliation(s)
- Juha Koivisto
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
| | - Maureen van Eijnatten
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
| | - Jorma Järnstedt
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Kirsi Holli-Helenius
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Prasun Dastidar
- 2 Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland.,3 University of Tampere, Medical School, Tampere, Finland
| | - Jan Wolff
- 1 Department of Oral and Maxillofacial Surgery/Oral Pathology and 3D Innovation Lab, VU University Medical Center, Amsterdam, Netherlands
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Koivisto J, Durian DJ. Effect of interstitial fluid on the fraction of flow microstates that precede clogging in granular hoppers. Phys Rev E 2017; 95:032904. [PMID: 28415287 DOI: 10.1103/physreve.95.032904] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Indexed: 06/07/2023]
Abstract
We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is slower and the events last longer, we find that the average discharge mass is only slightly reduced for submerged grains. Furthermore, we find that the shape of the distribution remains exponential, implying that clogging is still a Poisson process even for immersed grains. Per Thomas and Durian [Phys. Rev. Lett. 114, 178001 (2015)PRLTAO0031-900710.1103/PhysRevLett.114.178001], this allows for an interpretation of the average discharge mass in terms of the fraction of flow microstates that precede, i.e., that effectively cause, a stable clog to form. Since this fraction is barely altered by water, we conclude that the crucial microscopic variables are the grain positions; grain momenta play only a secondary role in destabilizing weak incipient arches. These insights should aid ongoing efforts to understand the susceptibility of granular hoppers to clogging.
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Affiliation(s)
- Juha Koivisto
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
| | - Douglas J Durian
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
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23
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Koivisto J, Ovaska M, Miksic A, Laurson L, Alava MJ. Predicting sample lifetimes in creep fracture of heterogeneous materials. Phys Rev E 2016; 94:023002. [PMID: 27627383 DOI: 10.1103/physreve.94.023002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Indexed: 11/07/2022]
Abstract
Materials flow-under creep or constant loads-and, finally, fail. The prediction of sample lifetimes is an important and highly challenging problem because of the inherently heterogeneous nature of most materials that results in large sample-to-sample lifetime fluctuations, even under the same conditions. We study creep deformation of paper sheets as one heterogeneous material and thus show how to predict lifetimes of individual samples by exploiting the "universal" features in the sample-inherent creep curves, particularly the passage to an accelerating creep rate. Using simulations of a viscoelastic fiber bundle model, we illustrate how deformation localization controls the shape of the creep curve and thus the degree of lifetime predictability.
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Affiliation(s)
- Juha Koivisto
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, P. O. Box 11100, FIN-00076, Aalto, Espoo, Finland
| | - Markus Ovaska
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, P. O. Box 11100, FIN-00076, Aalto, Espoo, Finland
| | - Amandine Miksic
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, P. O. Box 11100, FIN-00076, Aalto, Espoo, Finland
| | - Lasse Laurson
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, P. O. Box 11100, FIN-00076, Aalto, Espoo, Finland
| | - Mikko J Alava
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, P. O. Box 11100, FIN-00076, Aalto, Espoo, Finland
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24
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Koivisto J, Dalbe MJ, Alava MJ, Santucci S. Path (un)predictability of two interacting cracks in polycarbonate sheets using Digital Image Correlation. Sci Rep 2016; 6:32278. [PMID: 27578388 PMCID: PMC5006083 DOI: 10.1038/srep32278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/05/2016] [Indexed: 11/15/2022] Open
Abstract
Crack propagation is tracked here with Digital Image Correlation analysis in the test case of two cracks propagating in opposite directions in polycarbonate, a material with high ductility and a large Fracture Process Zone (FPZ). Depending on the initial distances between the two crack tips, one may observe different complex crack paths with in particular a regime where the two cracks repel each other prior to being attracted. We show by strain field analysis how this can be understood according to the principle of local symmetry: the propagation is to the direction where the local shear - mode KII in fracture mechanics language - is zero. Thus the interactions exhibited by the cracks arise from symmetry, from the initial geometry, and from the material properties which induce the FPZ. This complexity makes any long-range prediction of the path(s) impossible.
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Affiliation(s)
- J Koivisto
- Aalto University, Department of Applied Physics, PO Box 14100, 00076 Aalto, Finland
| | - M-J Dalbe
- Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, UMR CNRS 5672, Université de Lyon, 69634 Lyon Cedex 07, France.,Institut Lumière Matière, UMR5306 Université de Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France.,Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - M J Alava
- Aalto University, Department of Applied Physics, PO Box 14100, 00076 Aalto, Finland
| | - S Santucci
- Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, UMR CNRS 5672, Université de Lyon, 69634 Lyon Cedex 07, France
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Dalbe MJ, Koivisto J, Vanel L, Miksic A, Ramos O, Alava M, Santucci S. Repulsion and Attraction between a Pair of Cracks in a Plastic Sheet. Phys Rev Lett 2015; 114:205501. [PMID: 26047240 DOI: 10.1103/physrevlett.114.205501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Indexed: 06/04/2023]
Abstract
We study the interaction of two collinear cracks in polymer sheets slowly growing towards each other, when submitted to uniaxial stress at a constant loading velocity. Depending on the sample's geometry-specifically, the initial distances d between the two cracks' axes and L between the cracks' tips-we observe different crack paths with, in particular, a regime where the cracks repel each other prior to being attracted. We show that the angle θ characterizing the amplitude of the repulsion-and specifically its evolution with d-depends strongly on the microscopic behavior of the material. Our results highlight the crucial role of the fracture process zone. At interaction distances larger than the process zone size, crack repulsion is controlled by the microscopic shape of the process zone tip, while at shorter distances, the overall plastic process zone screens the repulsion interaction.
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Affiliation(s)
- Marie-Julie Dalbe
- Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, UMR CNRS 5672, Université de Lyon, 69364 Lyon Cedex 07, France
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Juha Koivisto
- COMP Center of Excellence, Department of Applied Physics, Aalto University, 00076 Aalto, Espoo, Finland
| | - Loïc Vanel
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Amandine Miksic
- COMP Center of Excellence, Department of Applied Physics, Aalto University, 00076 Aalto, Espoo, Finland
| | - Osvanny Ramos
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Mikko Alava
- COMP Center of Excellence, Department of Applied Physics, Aalto University, 00076 Aalto, Espoo, Finland
| | - Stéphane Santucci
- Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, UMR CNRS 5672, Université de Lyon, 69364 Lyon Cedex 07, France
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Zou J, Lähelmä J, Koivisto J, Dhanasingh A, Jolly C, Aarnisalo A, Wolff J, Pyykkö I. Imaging cochlear implantation with round window insertion in human temporal bones and cochlear morphological variation using high-resolution cone beam CT. Acta Otolaryngol 2015; 135:466-72. [PMID: 25675836 PMCID: PMC4487572 DOI: 10.3109/00016489.2014.993090] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Conclusions: The present experimental set-up of high spatial resolution cone-beam computed tomography (CBCT) showed advantages of demonstrating the critical landmarks of the cochlea in identifying the position of intracochlear electrode contacts and has the potential for clinical application in cochlear implant (CI) surgery. Objective: To evaluate a newly developed CBCT system in defining CI electrode array in human temporal bone and cochlear morphological variation. Methods: Standard electrode, flexible tip electrode (Flex28), and an experimental electrode array with 36 contacts from MED-EL were implanted into the cochleae of six human temporal bones through an atraumatic round window membrane insertion. The cochleae were imaged with 900 frames using an experimental set-up based on a CBCT scanner installed with Superior SXR 130-15-0.5 X-ray tube in combination with filtration of copper and aluminum. Results: In all temporal bones, the landmarks of the cochlea, modiolus, osseous spiral lamina, round window niche, and stapes were demonstrated at an average level of 3.4–4.5. The contacts of electrode arrays were clearly shown to locate in the scala tympani. There was a linear correlation between the ‘A’ value and cochlea height, and between the A value and actual electrode insertion length for the first 360° insertion depth.
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Affiliation(s)
- Jing Zou
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Tampere, Finland
- Correspondence: Jing Zou MD PhD, Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Medisiinarinkatu 3, 33520 Tampere, Finland. +358 401901307. +358 3 364 1482.
| | | | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
| | | | | | - Antti Aarnisalo
- Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Jan Wolff
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Tampere, Finland
| | - Ilmari Pyykkö
- Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Tampere, Finland
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Koivisto J, Kiljunen T, Kadesjö N, Shi XQ, Wolff J. Effective radiation dose of a MSCT, two CBCT and one conventional radiography device in the ankle region. J Foot Ankle Res 2015; 8:8. [PMID: 25788986 PMCID: PMC4363062 DOI: 10.1186/s13047-015-0067-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/24/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of this study was to assess and compare the effective doses (ICRP 103) in the ankle region of X-ray imaging resulting from a multi slice computed tomography (MSCT) device, two cone beam CT (CBCT) devices and one conventional x-ray device. METHODS Organ dose measurements were performed using 20 metal oxide field effect transistor (MOSFET) dosimeters that were placed in a custom made anthropomorphic RANDO ankle phantom. The following scanners were assessed in this study: Siemens Sensation Open 24-slice MSCT-scanner (120 kVp, 54 mAs), NewTom 5G CBCT scanner (110 kVp, 2.3 - 59 mAs), Planmed Verity CBCT-scanner (90 kVp, 48 mAs), Shimadzu FH-21 HR direct radiography equipment (AP + LAT), (57 kVp, 16 mAs). RESULTS Measurements of the MSCT device resulted in 21.4 μSv effective dose. The effective doses of CBCTs were between 1.9 μSv and 14.3 μSv for NewTom 5G and 6.0 μSv for Planmed Verity. Effective doses for the Shimadzu FH-21 HR conventional radiography were 1.0 μSv (LAT) and 0.5 μSv (AP), respectively. CONCLUSIONS Compared with a conventional 2D radiographic device, this study showed a 14-fold effective dose for standard MSCT and 1.3 -10 fold effective dose for standard CBCT protocols. CBCT devices offers a 3D view of ankle imaging and exhibited lower effective doses compared with MSCT.
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Affiliation(s)
- Juha Koivisto
- />Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Nils Kadesjö
- />Image and Functional Odontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Xie-Qi Shi
- />Image and Functional Odontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Jan Wolff
- />VU University Medical Center, Amsterdam, The Netherlands
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Zou J, Koivisto J, Lähelmä J, Aarnisalo A, Wolff J, Pyykkö I. Imaging Optimization of Temporal Bones With Cochlear Implant Using a High-resolution Cone Beam CT and the Corresponding Effective Dose. Ann Otol Rhinol Laryngol 2014; 124:466-73. [DOI: 10.1177/0003489414565004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective: To evaluate the impact of tube voltage, tube current, pulse number, and magnification factor on the image quality of a novel experimental set-up and the corresponding radiation. Materials and Methods: Six human temporal bones with cochlear implant were imaged using various tube voltages, tube currents, pulse numbers, and magnification. The effect of radiation was evaluated using a metaloxide semiconductor field-effect transistor (MOSFET) dosimeter device on an anthropomorphic RANDO RAN102 male head phantom. A copper and aluminum combination filter was used for hardware filtration. Results: Overall, 900 frames, 11 mA, and 88 kV provided the best image quality. In temporal bones imaged with the optimized parameters, the cochlea, osseous spiral lamina, modiolus, stapes, round window niche, and oval window landmarks were demonstrated with anatomic structures still fully assessable in all parts and acceptable image quality. The most dominant contributor to the effective dose was bone marrow (36%-37 %) followed by brain (34%-36%), remainder tissues (12%), extra-thoracic airways (7%), and oral mucosa (5%). Conclusions: By increasing the number of frames, the image quality of the inner ear details obtained using the novel cone-beam computed tomography improved.
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Affiliation(s)
- Jing Zou
- Hearing and Balance Research Unit, Field of Otolaryngology, School of Medicine, University of Tampere, Tampere, Finland
- Department of Otolaryngology-Head and Neck Surgery, Center for Otolaryngology-Head & Neck Surgery of Chinese PLA, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Juha Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Antti Aarnisalo
- Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Jan Wolff
- Hearing and Balance Research Unit, Field of Otolaryngology, School of Medicine, University of Tampere, Tampere, Finland
- Department of Oral and Maxillofacial Surgery/Oral Pathology, VU University Medical Center, Amsterdam, the Netherlands
| | - Ilmari Pyykkö
- Hearing and Balance Research Unit, Field of Otolaryngology, School of Medicine, University of Tampere, Tampere, Finland
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Vaikkinen A, Shrestha B, Koivisto J, Kostiainen R, Vertes A, Kauppila TJ. Laser ablation atmospheric pressure photoionization mass spectrometry imaging of phytochemicals from sage leaves. Rapid Commun Mass Spectrom 2014; 28:2490-6. [PMID: 25366396 DOI: 10.1002/rcm.7043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/22/2014] [Accepted: 09/03/2014] [Indexed: 05/03/2023]
Abstract
RATIONALE Despite fast advances in ambient mass spectrometry imaging (MSI), the study of neutral and nonpolar compounds directly from biological matrices remains challenging. In this contribution, we explore the feasibility of laser ablation atmospheric pressure photoionization (LAAPPI) for MSI of phytochemicals in sage (Salvia officinalis) leaves. METHODS Sage leaves were studied by LAAPPI-time-of-flight (TOF)-MSI without any sample preparation. Leaf mass spectra were also recorded with laser ablation electrospray ionization (LAESI) mass spectrometry and the spectra were compared with those obtained by LAAPPI. RESULTS Direct probing of the plant tissue by LAAPPI efficiently produced ions from plant metabolites, including neutral and nonpolar terpenes that do not have polar functional groups, as well as oxygenated terpene derivatives. Monoterpenes and monoterpenoids could also be studied from sage by LAESI, but only LAAPPI was able to detect larger nonpolar compounds, such as sesquiterpenes and triterpenoid derivatives, from the leaf matrix. Alternative MSI methods for nonpolar compounds, such as desorption atmospheric pressure photoionization (DAPPI), do not achieve as good spatial resolution as LAAPPI (<400 µm). CONCLUSIONS We show that MSI with LAAPPI is a useful tool for concurrently studying the distribution of polar and nonpolar compounds, such as phytochemicals, directly from complex biological samples, and it can provide information that is not available by other, established methods.
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Affiliation(s)
- Anu Vaikkinen
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5 E), 00014 University of Helsinki, Helsinki, Finland
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Figueiras E, Soto AM, Jesus D, Lehti M, Koivisto J, Parraga JE, Silva-Correia J, Oliveira JM, Reis RL, Kellomäki M, Hyttinen J. Optical projection tomography as a tool for 3D imaging of hydrogels. Biomed Opt Express 2014; 5:3443-9. [PMID: 25360363 PMCID: PMC4206315 DOI: 10.1364/boe.5.003443] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/15/2014] [Accepted: 08/29/2014] [Indexed: 05/22/2023]
Abstract
An Optical Projection Tomography (OPT) system was developed and optimized to image 3D tissue engineered products based in hydrogels. We develop pre-reconstruction algorithms to get the best result from the reconstruction procedure, which include correction of the illumination and determination of sample center of rotation (CoR). Existing methods for CoR determination based on the detection of the maximum variance of reconstructed slices failed, so we develop a new CoR search method based in the detection of the variance sharpest local maximum. We show the capabilities of the system to give quantitative information of different types of hydrogels that may be useful in its characterization.
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Affiliation(s)
- Edite Figueiras
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - Ana M. Soto
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - Danilo Jesus
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - M. Lehti
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - J. Koivisto
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
- University of Tampere, BioMediTech, Tampere, Finland
| | - J. E. Parraga
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - J. Silva-Correia
- 3Bs- Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Guimarães, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - J. M. Oliveira
- 3Bs- Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Guimarães, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - R. L. Reis
- 3Bs- Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Guimarães, Portugal
- ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - M. Kellomäki
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
| | - J. Hyttinen
- Tampere University of Technology, ELT, BioMediTech, Tampere, Finland
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Koivisto J, Wolff J, Järnstedt J, Dastidar P, Kortesniemi M. Assessment of the effective dose in supine, prone, and oblique positions in the maxillofacial region using a novel combined extremity and maxillofacial cone beam computed tomography scanner. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118:355-62. [DOI: 10.1016/j.oooo.2014.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 04/14/2014] [Accepted: 05/21/2014] [Indexed: 11/27/2022]
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Koivisto J, Schulze D, Wolff J, Rottke D. Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field-effect transistor (MOSFET) dosemeters: a comparative study. Dentomaxillofac Radiol 2014; 43:20140202. [PMID: 25143020 PMCID: PMC4240264 DOI: 10.1259/dmfr.20140202] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/11/2014] [Accepted: 08/19/2014] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The objective of this study was to compare the performance of metal oxide semiconductor field-effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. METHODS Organ and effective dose measurements were performed using 40 TLD and 20 MOSFET dosemeters that were alternately placed in 20 different locations in 1 anthropomorphic RANDO(®) head phantom (the Phantom Laboratory, Salem, NY). The phantom was exposed to four different CBCT default maxillofacial protocols using small (4 × 5 cm) to full face (20 × 17 cm) fields of view (FOVs). RESULTS The TLD effective doses ranged between 7.0 and 158.0 µSv and the MOSFET doses between 6.1 and 175.0 µSv. The MOSFET and TLD effective doses acquired using four different (FOV) protocols were as follows: face maxillofacial (FOV 20 × 17 cm) (MOSFET, 83.4 µSv; TLD, 87.6 µSv; -5%); teeth, upper jaw (FOV, 8.5 × 5.0 cm) (MOSFET, 6.1 µSv; TLD, 7.0 µSv; -14%); tooth, mandible and left molar (FOV, 4 × 5 cm) (MOSFET, 10.3 µSv; TLD, 12.3 µSv; -16%) and teeth, both jaws (FOV, 10 × 10 cm) (MOSFET, 175 µSv; TLD, 158 µSv; +11%). The largest variation in organ and effective dose was recorded in the small FOV protocols. CONCLUSIONS Taking into account the uncertainties of both measurement methods and the results of the statistical analysis, the effective doses acquired using MOSFET dosemeters were found to be in good agreement with those obtained using TLD dosemeters. The MOSFET dosemeters constitute a feasible alternative for TLDs for the effective dose assessment of CBCT devices in the maxillofacial region.
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Affiliation(s)
- J Koivisto
- 1 Department of Physics, University of Helsinki, Helsinki, Finland
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Koivisto J, Kiljunen T, Wolff J, Kortesniemi M. Assessment of effective radiation dose of an extremity CBCT, MSCT and conventional X ray for knee area using MOSFET dosemeters. Radiat Prot Dosimetry 2013; 157:515-524. [PMID: 23825221 DOI: 10.1093/rpd/nct162] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The objective of this study was to assess and compare the organ and effective doses in the knee area resulting from different commercially available multislice computed tomography devices (MSCT), one cone beam computed tomography device (CBCT) and one conventional X-ray radiography device using MOSFET dosemeters and an anthropomorphic RANDO knee phantom. Measurements of the MSCT devices resulted in effective doses ranging between 27 and 48 µSv. The CBCT measurements resulted in an effective dose of 12.6 µSv. The effective doses attained using the conventional radiography device were 1.8 µSv for lateral and 1.2 µSv for anterior-posterior projections. The effective dose resulting from conventional radiography was considerably lower than those recorded for the CBCT and MSCT devices. The MSCT effective dose results were two to four times higher than those measured on the CBCT device. This study demonstrates that CBCT can be regarded as a potential low-dose 3D imaging technique for knee examinations.
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Affiliation(s)
- Juha Koivisto
- Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00560 Helsinki, Finland
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Koivisto J, Kiljunen T, Wolff J, Kortesniemi M. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material. J Radiat Res 2013; 54:943-949. [PMID: 23520268 PMCID: PMC3766287 DOI: 10.1093/jrr/rrt015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/18/2013] [Accepted: 02/05/2013] [Indexed: 06/01/2023]
Abstract
When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure.
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Affiliation(s)
- Juha Koivisto
- Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00560 Helsinki, Finland
| | - Timo Kiljunen
- International Comprehensive Cancer Center Docrates, Saukonpaadenranta 2, FI-00180 Helsinki, Finland
| | - Jan Wolff
- Oral and Maxillofacial Unit, Department of Ortholaryngology, PO Box 2000, University of Tampere, FI-33521 Tampere, Finland
- Medical Imaging Center, Department of Radiology, Tampere University Hospital, Tampere, Finland
| | - Mika Kortesniemi
- HUS Helsinki Medical Imaging Center, University of Helsinki, Haartmaninkatu 4 (POB 340), Helsinki, FI-00029 HUS, Finland
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Koivisto J, Kiljunen T, Tapiovaara M, Wolff J, Kortesniemi M. Assessment of radiation exposure in dental cone-beam computerized tomography with the use of metal-oxide semiconductor field-effect transistor (MOSFET) dosimeters and Monte Carlo simulations. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 114:393-400. [PMID: 22862982 DOI: 10.1016/j.oooo.2012.06.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/28/2012] [Accepted: 06/01/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES The aims of this study were to assess the organ and effective dose (International Commission on Radiological Protection (ICRP) 103) resulting from dental cone-beam computerized tomography (CBCT) imaging using a novel metal-oxide semiconductor field-effect transistor (MOSFET) dosimeter device, and to assess the reliability of the MOSFET measurements by comparing the results with Monte Carlo PCXMC simulations. STUDY DESIGN Organ dose measurements were performed using 20 MOSFET dosimeters that were embedded in the 8 most radiosensitive organs in the maxillofacial and neck area. The dose-area product (DAP) values attained from CBCT scans were used for PCXMC simulations. The acquired MOSFET doses were then compared with the Monte Carlo simulations. RESULTS The effective dose measurements using MOSFET dosimeters yielded, using 0.5-cm steps, a value of 153 μSv and the PCXMC simulations resulted in a value of 136 μSv. CONCLUSIONS The MOSFET dosimeters placed in a head phantom gave results similar to Monte Carlo simulations. Minor vertical changes in the positioning of the phantom had a substantial affect on the overall effective dose. Therefore, the MOSFET dosimeters constitute a feasible method for dose assessment of CBCT units in the maxillofacial region.
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Affiliation(s)
- J Koivisto
- Department of Physics, University of Helsinki, Helsinki, Finland.
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Rosti J, Koivisto J, Laurson L, Alava MJ. Fluctuations and scaling in creep deformation. Phys Rev Lett 2010; 105:100601. [PMID: 20867504 DOI: 10.1103/physrevlett.105.100601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 07/12/2010] [Indexed: 05/29/2023]
Abstract
The spatial fluctuations of deformation are studied in the creep in Andrade's power law and the logarithmic phases, using paper samples. Measurements by the digital image correlation technique show that the relative strength of the strain rate fluctuations increases with time, in both creep regimes. In the Andrade creep phase characterized by a power-law decay of the strain rate ϵt∼t(-θ), with θ≈0.7, the fluctuations obey Δϵt∼t(-γ), with γ≈0.5. The local deformation follows a data collapse appropriate for a phase transition. Similar behavior is found in a crystal plasticity model, with a jamming or yielding transition.
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Affiliation(s)
- Jari Rosti
- Department of Applied Physics, Aalto University, PO Box 14100, Aalto 00076, Finland.
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Hämeri K, Lähde T, Hussein T, Koivisto J, Savolainen K. Facing the key workplace challenge: assessing and preventing exposure to nanoparticles at source. Inhal Toxicol 2010; 21 Suppl 3:17-55. [PMID: 19558229 DOI: 10.3109/08958370903202804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Nanomaterials present new challenges to understanding, predicting, and managing potential health risks in occupational environments. In this study, we characterize the key physical processes related to formation and growth of nanoparticles. The main focus is on various occupational environments, as these are known to be major environments with nanoparticles in indoor air. The protection of people potentially to be exposed to nanoparticles is one of the key issues in terms of risk assessment and prevention. Two of the main protection techniques that are discussed and characterized are ventilation and filtration, which are widely used in practical applications.
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Affiliation(s)
- K Hämeri
- Finnish Institute of Occupational Health, Helsinki, Finland.
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Miksic A, Koivisto J, Mykkänen E, Saarenpää J, Alava M, Mustonen K, Karppinen P, Karppinen T, Hæggström E. Deformation, acoustic emission and ultrasound velocity during fatigue tests on paper. EPJ Web of Conferences 2010. [DOI: 10.1051/epjconf/20100642016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Koivisto J, Illa X, Rosti J, Alava M. Line Creep in Paper Peeling. EPJ Web of Conferences 2010. [DOI: 10.1051/epjconf/20100642010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Hämeri K, Lähde T, Hussein T, Koivisto J, Savolainen K. Facing the key workplace challenge: Assessing and preventing exposure to nanoparticles at source. Inhal Toxicol 2009. [DOI: 10.1080/08958370902942525] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Abstract
The slow motion of a crack line is studied via an experiment in which sheets of paper are split into two halves in a "peel-in-nip" (PIN) geometry under a constant load, in creep. The velocity-force relation is exponential. The dynamics of the fracture line exhibits intermittency, or avalanches, which are studied using acoustic emission. The energy statistics is a power law, with the exponent beta ~ 1.8 +/- 0.1. Both the waiting times between subsequent events and the displacement of the fracture line imply complicated stick-slip dynamics. We discuss the correspondence to tensile PIN tests and other similar experiments on in-plane fracture and the theory of creep for elastic manifolds.
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Affiliation(s)
- J Koivisto
- Helsinki University of Technology, Laboratory of Physics, FIN-02015, HUT, Finland
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42
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Pallesen KJ, Brattico E, Bailey C, Korvenoja A, Koivisto J, Gjedde A, Carlson S. Emotion processing of major, minor, and dissonant chords: a functional magnetic resonance imaging study. Ann N Y Acad Sci 2006; 1060:450-3. [PMID: 16597801 DOI: 10.1196/annals.1360.047] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Musicians and nonmusicians listened to major, minor, and dissonant musical chords while their BOLD brain responses were registered with functional magnetic resonance imaging. In both groups of listeners, minor and dissonant chords, compared with major chords, elicited enhanced responses in several brain areas, including the amygdala, retrosplenial cortex, brain stem, and cerebellum, during passive listening but not during memorization of the chords. The results indicate that (1) neural processing in emotion-related brain areas is activated even by single chords, (2) emotion processing is enhanced in the absence of cognitive requirements, and (3) musicians and nonmusicians do not differ in their neural responses to single musical chords during passive listening.
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Affiliation(s)
- Karen Johanne Pallesen
- Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark.
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43
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Abstract
Somatosensory point localization is a clinical test evaluating spatial accuracy of the somatosensory system. Possible effects of the interstimulus interval (ISI) on point localization threshold have not been previously examined. In the present set of experiments the effect of time delay on somatosensory point localization was studied using ISIs of 1, 3, 5, 7, and 9 s, and applying a newly developed computer-controlled application method of a Semmes-Weinstein monofilament. It was found that the point localization threshold was not significantly affected by the ISI length. However, the response time was shorter and response accuracy better at the shorter (1 and 3 s) than at the longer (5, 7, and 9 s) ISIs, suggesting a change in the mechanism underlying point localization decision criteria in ISIs longer than 3 s.
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Affiliation(s)
- Shelley Ylioja
- Neuroscience Unit, Institute of Biomedicine/Physiology, University of Helsinki, Finland
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44
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Vuontela V, Steenari MR, Carlson S, Koivisto J, Fjällberg M, Aronen ET. Audiospatial and visuospatial working memory in 6-13 year old school children. Learn Mem 2003; 10:74-81. [PMID: 12551966 PMCID: PMC196650 DOI: 10.1101/lm.53503] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The neural processes subserving working memory, and brain structures underlying this system, continue to develop during childhood. We investigated the effects of age and gender on audiospatial and visuospatial working memory in a nonclinical sample of school-aged children using n-back tasks. The results showed that auditory and visual working memory performance improves with age, suggesting functional maturation of underlying cognitive processes and brain areas. The gender differences found in the performance of working memory tasks suggest a larger degree of immaturity in boys than girls at the age period of 6-10 yr. The differences observed between the mastering of auditory and visual working memory tasks may indicate that visual working memory reaches functional maturity earlier than the corresponding auditory system.
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Affiliation(s)
- Virve Vuontela
- Institute of Biomedicine/Physiology, FIN-00014 University of Helsinki, Helsinki, Finland
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45
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Meklin T, Husman T, Vepsäläinen A, Vahteristo M, Koivisto J, Halla-Aho J, Hyvärinen A, Moschandreas D, Nevalainen A. Indoor air microbes and respiratory symptoms of children in moisture damaged and reference schools. Indoor Air 2002; 12:175-183. [PMID: 12244747 DOI: 10.1034/j.1600-0668.2002.00169.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microbial indoor air quality and respiratory symptoms of children were studied in 24 schools with visible moisture and mold problems, and in eight non-damaged schools. School buildings of concrete/brick and wooden construction were included. The indoor environment investigations included technical building inspections for visible moisture signs and microbial sampling using six-stage impactor for viable airborne microbes. Children's health information was collected by questionnaires. The effect of moisture damage on concentrations of fungi was clearly seen in buildings of concrete/brick construction, but not in wooden school buildings. Occurrence of Cladosporium, Aspergillus versicolor, Stachybotrys, and actinobacteria showed some indicator value for moisture damage. Presence of moisture damage in school buildings was a significant risk factor for respiratory symptoms in schoolchildren. Association between moisture damage and respiratory symptoms of children was significant for buildings of concrete/brick construction but not for wooden school buildings. The highest symptom prevalence was found during spring seasons, after a long exposure period in damaged schools. The results emphasize the importance of the building frame as a determinant of exposure and symptoms.
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Affiliation(s)
- T Meklin
- National Public Health Institute, Department of Environmental Health, Department of Environmental Sciences, University of Kuopio, Kuopio, Finland.
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Perjéssy A, Meyer P, Rudorf WD, Loos D, Kolehmainen E, Laihia K, Nissinen M, Koivisto J, Kauppinen R. Structural study of ethyl 3-arylcarbamoyl-2,3-diazabicyclo[2.2.1]hept-5-ene-2-carboxylates: conformation and transmission of substituent effects across the diazabicycloheptene ring. J PHYS ORG CHEM 2001. [DOI: 10.1002/poc.436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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47
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Koivisto J, Kolehmainen E, Nikiforov VA, Nissinen M, Linnanto J, Lahtiperä M, Miltsov SA, Karavan VS. A new potential toxaphene congener: synthesis, GC/EI-MS study, crystal structure, NMR analysis, and ab initio calculations of 3-endo,5-endo-dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0(2,6)]heptane. Chemosphere 2001; 44:671-679. [PMID: 11482655 DOI: 10.1016/s0045-6535(00)00336-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new potential toxaphene congener 3-endo,5-endo-dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0(2,6)]heptane 2 has been isolated from reaction mixture obtained by the chlorination of 2-exo, 10,10-trichlorobornane 1. The X-ray structural analysis of 2 revealed an unusual tricyclic structure, where the two chlorine atoms occupying endo-positions are in close spatial proximity with each other and near to the neighbouring CHCl2 group. Further, it revealed that the symmetry of the molecule is distorted. The 1H and 13C NMR spectra of 2 have been assigned by means of 1H, 1H double-quantum filtered correlation spectroscopy (DQF COSY), PFG 1H, 13C HMQC (pulsed field gradient heteronuclear multiple-quantum coherence), 1H, 13C heteronuclear multiple bond correlation (HMBC) experiments, and computer aided 1H NMR spectral analysis. The asymmetry of 2 is also discernible on the 1H NMR parameters. In addition, gas chromatographic (GC) properties and electron impact (EI) mass spectrum of 2 has been studied. Ab initio Hartree-Fock (HF) method with the basis set 6-31G(d) has been used for the optimization of the equilibrium geometry and calculation of total energy for 2. The optimized geometry is in good agreement with the crystal structure. According to the rotation energy profile calculated at the HF/6-31G(d) level, rotation of the chloromethyl and dichloromethyl groups are highly unlikely at the room temperature.
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Affiliation(s)
- J Koivisto
- Department of Chemistry, University of Jyväskylä, Finland.
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Rämä P, Martinkauppi S, Linnankoski I, Koivisto J, Aronen HJ, Carlson S. Working memory of identification of emotional vocal expressions: an fMRI study. Neuroimage 2001; 13:1090-101. [PMID: 11352614 DOI: 10.1006/nimg.2001.0777] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The distribution of brain activation during working memory processing of emotional vocal expressions was studied using functional magnetic resonance imaging (fMRI) in eight female subjects performing n-back tasks with three load levels (0-back, 1-back, and 2-back tasks). The stimuli in the n-back tasks were the Finnish female name [Saara] uttered in an astonished, angry, frightened, commanding, and scornful mode, and the subjects were instructed to memorize the emotional connotation of the stimuli. Subregions in the prefrontal, parietal, and visual association areas were load-dependently activated during the performance of the n-back tasks. The most consistently activated areas in the prefrontal region were detected in the inferior frontal gyrus corresponding to Brodmann's areas (BAs) 44 and 45 and in the middle and superior frontal gyri (BAs 6/8). Activation was also found in the inferior parietal lobe and intraparietal sulcus (BAs 40/7) and visual association areas including the lingual and fusiform gyri. The results suggest that a distributed neuronal network in occipital, parietal, and frontal areas is involved in working memory processing of emotional content of aurally presented information.
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Affiliation(s)
- P Rämä
- Institute of Biomedicine, Department of Physiology, University of Helsinki, Finland
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Chelelgo J, Haverinen U, Vahteristo M, Koivisto J, Husman T, Nevalainen A, Jääskeläinen E. Analysis of moisture findings in the interior spaces of Finnish housing stock. J Air Waste Manag Assoc 2001; 51:69-77. [PMID: 11218427 DOI: 10.1080/10473289.2001.10464245] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A grading system was developed to rate the moisture damage profile of dwellings and to study the relationship between moisture-induced indoor air problems and occupant health. A total of 630 randomly selected houses and apartments, built between 1950 and 1989, were visually inspected. Moisture observations were standardized into three damage levels. Thus, a system to classify the homes into three grades was devised. The two grades of homes associated with the highest levels of damage were graded as index homes. Overall, 51% of the sample had some kind of moisture fault in them and one in every three homes (33%) was classified as an index home. The mean number of damage incidents in the index dwellings varied from 1.4 to 2.6. The mean number of damage incidents in the reference homes was 0.28. Prevalence of index dwellings was significantly higher (p < 0.01) in houses (38%) than in apartments (26%). There was no major difference in the prevalence of index buildings in houses built in any particular decade (30-35%). Moisture was observed in 28% of bathrooms, in 10% of kitchens, and in 17% of other spaces. Indoor relative humidity (RH) levels were low in most homes.
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Affiliation(s)
- J Chelelgo
- National Public Health Institute, Division of Environmental Health, Kuopio, Finland
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Pahlman I, Hermanson T, Hannuniemi A, Koivisto J, Hannikainen P, Ilveskivi P. Three years in force: has the finnish Act on the Status and Rights of Patients materialized? Med Law 1996; 15:591-603. [PMID: 9114701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Finland enacted as the first country in Europe an Act on the Status and Rights of Patients. This report deals with the experiences gained in the course of the implementation of the patient law during the past three years it has been in force. Patients' rights to information and self-determination are considered as the most central matters. Also the right to good care, the status of minor patients and patients' right to privacy protection are important matters. Patient ombudsmen have tried to convey information to the field on the law and the obligations it imposes on health care personnel. The law is considered to already have influenced practical functions within health care. However, there is still much to improve in patients' access to information and in the treatment of patients; the attitudes and the care traditions change slowly. That living wills have become more general is a manifestation of people's willingness to use their right of self-determination even when they are no more able to express their will. Complaints that are processed at the local level are frequent, and each organization has a Patient Ombudsman. The principles of this system of complaints and patient ombudsmen are considered good, but there is much room for improvement.
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