Registration accuracy of the optical navigation system for image-guided surgery

Abstract. During the last decades, image-guided surgery has been a vastly growing method during medical operations. It provides a new opportunity to perform surgical operations with higher accuracy and reliability than before. In image-guided surgery, a navigation system is used to track the instrument’s location and orientation during the surgery. These navigation systems can track the instrument in many ways, the most common of which are optical tracking, mechanical tracking, and electromagnetic tracking. Usually, the navigation systems are used primarily in surgical operations located in the head and spine area. For this reason, it is essential to know the registration accuracy and thus the navigational accuracy of the navigation system, and how different registration methods might affect them. In this research, the registration accuracy of the optical navigation system is investigated by using a head phantom whose coordinate values of holes in the surface are measured during the navigation after different registration scenarios. Reference points are determined using computed tomography images taken from the head phantom. The absolute differences of the measured points to the corresponding reference points are calculated and the results are illustrated using bar graphs and three-dimensional point clouds. MATLAB is used to analyze and present the results. Results show that registration accuracy and thus also navigation accuracy are primarily affected by how the first three registration points are determined for the navigation system at the beginning of the registration. This should be considered in future applications where the navigation system is used in image-guided surgery.Kuvaohjatun kirurgian optisen navigointilaitteen rekisteröintitarkkuus. Tiivistelmä. Viimeisten vuosikymmenien aikana kuvaohjattu kirurgia on yleistynyt laajalti lääketieteellisten toimenpiteiden aikana ja se tarjoaa entistä paremman mahdollisuuden tarkkaan ja luotettavaan hoitoon. Kuvaohjatussa kirurgiassa navigointilaitteisto seuraa käytetyn instrumentin paikkaa ja orientaatiota operaation aikana. Navigointilaitteistoilla on erilaisia toimintaperiaatteita, joiden perusteella ne seuraavat instrumenttia. Yleisimmin käytetyt navigointilaitteistot perustuvat optiseen, mekaaniseen, tai sähkömagneettiseen seurantaan. Yleensä kuvaohjattua kirurgiaa käytetään pään ja selkärangan alueen kirurgisissa operaatioissa, joten on erittäin tärkeää, että navigointilaitteiston rekisteröinti- ja siten myös navigointitarkkuus tunnetaan, sekä erilaisten rekisteröintitapojen mahdolliset vaikutukset kyseisiin tarkkuuksiin. Tässä tutkimuksessa optisen navigointilaitteen rekisteröintitarkkuutta tutkitaan päämallin avulla, jonka pintaan luotujen reikien koordinaattiarvot mitataan navigointitilanteessa erilaisten rekisteröintitapojen jälkeen. Referenssipisteet kyseisille mittauspisteille määritetään päämallin tietokonetomografiakuvista. Mitattujen pisteiden, sekä vastaavien referenssipisteiden väliset absoluuttiset erot lasketaan ja tulokset esitetään palkkikuvaajien, sekä kolmiulotteisten pistepilvien avulla käyttäen apuna MATLAB-ohjelmistoa. Tulokset osoittavat, että rekisteröintitarkkuuteen ja siten navigointitarkkuuteen vaikuttaa eniten rekisteröintitilanteen alussa määritettävien kolmen ensimmäisen rekisteröintipisteen sijainti ja tämä tuleekin ottaa huomioon jatkossa tilanteissa, joissa navigointilaitetta käytetään kuvaohjatussa kirurgiassa

Painettujen johtimien venymän mittaus 3D-pinnalta

Tiivistelmä. Työn tavoitteena on löytää painettujen johtimien venymien mittaukseen soveltuvia menetelmiä, joiden avulla syntyvien venymien arvot pystytään mittaamaan mahdollisimman tarkasti ja luotettavasti myös 3D-tilanteissa. Aiemmin käytössä olleiden menetelmien avulla venymiä on pystytty tarkastelemaan pääasiallisesti 2D-tilanteissa. Työssä on käytetty apuna aiempien aiheeseen liittyvien tutkimusten tuloksia ja kirjallisuutta. Useita erilaisia menetelmiä löydettiin, joiden avulla venymien mittauksen voisi toteuttaa. Suurin osa näistä menetelmistä kuitenkin oli soveltumattomia johtimien venymien mittaukseen johtuen pääasiassa niiden koosta tai mittatarkkuudesta. Lupaavin menetelmä pohjautuu digitaalisen kuvakorrelaation ja valokenttäkameran yhteiskäyttöön, jonka avulla syntyneitä 3D-muodonmuutoksia voidaan tarkastella koko kappaleen alueella.Strain measurement of printed conductors from a 3D surface. Abstract. The aim of this bachelor’s thesis is to find suitable methods for measuring the strains of printed conductors, which can be measured as accurately and reliably as possible in 3D situations. Previously used methods have been able to examine strains mainly in 2D situations. The results of researches and literature have been used in this work. A lot of different methods were found to make strain measurements possible. However, most of these methods were unsuitable for measuring the strains of the conductors due to their size or dimensional accuracy. The most promising method is based on the combination of digital image correlation and light field camera, which can be used to measure 3D deformations in the desired area

Life history of Megamelus scutellaris with description of immature stages (Hemiptera: Delphacidae)

The five immature stages of Megamelus scutellaris Berg (Hemiptera: Delphacidae) are described and illustrated. The main characters that distinguish the various stages are body size, number of tarsomeres and tibial spines, color, and number of teeth on the metatibial spur. New biological data based on laboratory rearing and field observations show that M. scutellaris can carry out its biological cycle successfully on water hyacinth, Eichhornia crassipes (Martius) Solms Laubach (Pontederiaceae). Mating occurs close to the water level and one to four eggs per scar are laid in apical portion of petiole and pseudolaminae. Ovipositional scars are recognized by three parallel marks. In addition, the efficient rearing in captivity, the high survivorship registered, and overwintering on only water hyacinth suggest M. scutellaris as a potential biocontrol agent of this invasive aquatic weed.Facultad de Ciencias Naturales y Muse

Measurements of muon flux in the Pyh\"asalmi underground laboratory

The cosmic-ray induced muon flux was measured at several depths in the Pyh\"asalmi mine (Finland) using a plastic scintillator telescope mounted on a trailer. The flux was determined at four different depths underground at 400 m (980 m.w.e), at 660 m (1900 m.w.e), at 990 m (2810 m.w.e) and at 1390 m (3960 m.w.e) with the trailer, and also at the ground surface. In addition, previously measured fluxes from depths of 90 m (210 m.w.e) and 210 m (420 m.w.e) are shown. A relation was obtained for the underground muon flux as a function of the depth. The measured flux follows well the general behaviour and is consistent with results determined in other underground laboratories.Comment: 8 pages, 2 figures. Submitted to Nuclear Instrum. Methods

Effectiveness of a workshop-based intervention to reduce bullying and violence at work: A 2-year quasi-experimental intervention study

INTRODUCTION: Bullying and violence at work are associated with reduced wellbeing of the victims, but few evidence-based interventions are available to prevent these offensive behaviours. We developed and examined the effectiveness of an intervention aimed at prevention of bullying and violence at work through modifications in psychosocial work environment. METHODS: In accordance with pre-published protocol, employees and supervisors of 12 work units in 3 cities (intervention group A: n = 315; intervention group B: n = 271) received a workshop-based intervention on organizational practices to prevent bullying and violence, including supervisor support, supervisor justice, workplace social capital, and psychological safety and were compared to a reference group (n = 2310) which did not receive the intervention. Latent change score modelling (LCSM) was used to estimate between- and within-individual differences in changes of organizational practices and prevalence of bullying and violence from baseline (2020) to follow-up (2022). RESULTS: No direct or indirect effects of intervention were observed. Of the potential mediator variables, supervisor support (B = 0.04; 95% confidence interval 0.006, 0.07) and supervisor justice (0.04; 0.01, 0.08) improved in the intervention group B between the measurements and compared to control group, but the result was not replicated in intervention group A. No changes were observed between the measurement points in bullying or violence at work. CONCLUSIONS: No intervention effects on bullying and violence at work were observed. It may be worthwhile to develop the intervention further to focus more on supervisor and co-worker relationships and on psychosocial resources of work team

Life history of Megamelus scutellaris with description of immature stages (Hemiptera: Delphacidae)

The five immature stages of Megamelus scutellaris Berg (Hemiptera: Delphacidae) are described and illustrated. The main characters that distinguish the various stages are body size, number of tarsomeres and tibial spines, color, and number of teeth on the metatibial spur. New biological data based on laboratory rearing and field observations show that M. scutellaris can carry out its biological cycle successfully on water hyacinth, Eichhornia crassipes (Martius) Solms Laubach (Pontederiaceae). Mating occurs close to the water level and one to four eggs per scar are laid in apical portion of petiole and pseudolaminae. Ovipositional scars are recognized by three parallel marks. In addition, the efficient rearing in captivity, the high survivorship registered, and overwintering on only water hyacinth suggest M. scutellaris as a potential biocontrol agent of this invasive aquatic weed.Facultad de Ciencias Naturales y Muse

Immunohistochemical Expression of Somatostatin Receptor Subtypes in a Panel of Neuroendocrine Neoplasias

Neuroendocrine neoplasias (NENs) are known to express somatostatin receptors (SSTRs) 1-5, which are G-protein-coupled cell membrane receptors. Somatostatin receptor imaging and therapy utilizes the SSTR expression. Synthetic somatostatin analogs with radioligands are used to detect primary tumors, metastases, and recurrent disease. Receptor analogs are also used for treating NENs. Furthermore, commercially available SSTR antibodies can be used for the immunohistochemical (IHC) detection of SSTRs. We investigated different SSTR antibody clones applying diverse IHC protocol settings to identify reliable clones and feasible protocols for NENs. A tissue microarray including NENs from 12 different primary sites were stained. Only UMB clones were able to localize SSTR on the cell membranes of NENs. SSTR2 (UMB1) emerged as the most common subtype followed by SSTR5 (UMB4) and SSTR1 (UMB7). SSTR3 (UMB5) expression was mainly cytoplasmic. Yet, SSTR4 expression was weak and located primarily in the cytoplasm. Thus, appropriate IHC protocols, including proper positive and negative controls, represent requirements for high-quality NEN diagnostics and for planning personalized therapy.Peer reviewe

Probing sporadic and familial Alzheimer's disease using induced pluripotent stem cells.

Our understanding of Alzheimer's disease pathogenesis is currently limited by difficulties in obtaining live neurons from patients and the inability to model the sporadic form of the disease. It may be possible to overcome these challenges by reprogramming primary cells from patients into induced pluripotent stem cells (iPSCs). Here we reprogrammed primary fibroblasts from two patients with familial Alzheimer's disease, both caused by a duplication of the amyloid-β precursor protein gene (APP; termed APP(Dp)), two with sporadic Alzheimer's disease (termed sAD1, sAD2) and two non-demented control individuals into iPSC lines. Neurons from differentiated cultures were purified with fluorescence-activated cell sorting and characterized. Purified cultures contained more than 90% neurons, clustered with fetal brain messenger RNA samples by microarray criteria, and could form functional synaptic contacts. Virtually all cells exhibited normal electrophysiological activity. Relative to controls, iPSC-derived, purified neurons from the two APP(Dp) patients and patient sAD2 exhibited significantly higher levels of the pathological markers amyloid-β(1-40), phospho-tau(Thr 231) and active glycogen synthase kinase-3β (aGSK-3β). Neurons from APP(Dp) and sAD2 patients also accumulated large RAB5-positive early endosomes compared to controls. Treatment of purified neurons with β-secretase inhibitors, but not γ-secretase inhibitors, caused significant reductions in phospho-Tau(Thr 231) and aGSK-3β levels. These results suggest a direct relationship between APP proteolytic processing, but not amyloid-β, in GSK-3β activation and tau phosphorylation in human neurons. Additionally, we observed that neurons with the genome of one sAD patient exhibited the phenotypes seen in familial Alzheimer's disease samples. More generally, we demonstrate that iPSC technology can be used to observe phenotypes relevant to Alzheimer's disease, even though it can take decades for overt disease to manifest in patients

Unified incremental nonlinear controller for the transition control of a hybrid dual-axis tilting rotor quad-plane

Overactuated Tilt Rotor Unmanned Aerial Vehicles are renowned for exceptional wind resistance and a broad operational range, which poses complex control challenges due to non-affine dynamics. Traditional solutions employ multi-state switched logic controllers for transitions. Our study introduces a novel unified incremental nonlinear controller for overactuated dual-axis tilting rotor quad-planes, seamlessly managing pitch, roll, and physical actuator commands. The control allocation problem is addressed using a SQP iterative optimization algorithm, well-suited for nonlinear actuator effectiveness in thrust vectoring vehicles. The controller design integrates desired roll and pitch angle inputs. These desired attitude angles are autonomously managed by the controller and then conveyed to the vehicle during slow airspeed phases, when the vehicle maintains its 6 DOF. We incorporate an AoA protection logic to prevent wing stall and a yaw rate reference model for coordinated turns. Flight tests confirm the controller's effectiveness in transitioning from hovering to forward flight, achieving desired vertical and lateral accelerations, and reverting to hovering