328 research outputs found

    Characterisation and State Estimation of Magnetic Soft Continuum Robots

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    Minimally invasive surgery has become more popular as it leads to less bleeding, scarring, pain, and shorter recovery time. However, this has come with counter-intuitive devices and steep surgeon learning curves. Magnetically actuated Soft Continuum Robots (SCR) have the potential to replace these devices, providing high dexterity together with the ability to conform to complex environments and safe human interactions without the cognitive burden for the clinician. Despite considerable progress in the past decade in their development, several challenges still plague SCR hindering their full realisation. This thesis aims at improving magnetically actuated SCR by addressing some of these challenges, such as material characterisation and modelling, and sensing feedback and localisation. Material characterisation for SCR is essential for understanding their behaviour and designing effective modelling and simulation strategies. In this work, the material properties of commonly employed materials in magnetically actuated SCR, such as elastic modulus, hyper-elastic model parameters, and magnetic moment were determined. Additionally, the effect these parameters have on modelling and simulating these devices was investigated. Due to the nature of magnetic actuation, localisation is of utmost importance to ensure accurate control and delivery of functionality. As such, two localisation strategies for magnetically actuated SCR were developed, one capable of estimating the full 6 degrees of freedom (DOFs) pose without any prior pose information, and another capable of accurately tracking the full 6-DOFs in real-time with positional errors lower than 4~mm. These will contribute to the development of autonomous navigation and closed-loop control of magnetically actuated SCR

    The Association Between Antihypertensive Drug Use and Risk of Cancer Death in Finland

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    Verenpainelääkkeet on hyvin yleisesti käytetty lääkeryhmä. Niihin kuuluu useita lääkeaineita, jotka toimivat eri vaikutusmekanismeilla. Vaikutusmekanismin mukaan ne jaetaan viiteen pääryhmään: angiotensiinia konvertoivan entsyymin (ACE) estäjiin, angiotensiinireseptorin (ATR) salpaajiin, beetasalpaajiin, kalsiumkanavan salpaajiin ja diureetteihin. Nimestään huolimatta verenpainelääkkeitä käytetään verenpainetaudin lisäksi myös sepelvaltimotaudin ja sydämen vajaatoiminnan hoidossa. Furosemidia, joka kuuluu diureetteihin, käytetään lähinnä turvotusten ja sydämen vajaatoiminnan hoidossa. Koska verenpainelääkkeet ovat paljon käytettyjä, on hyvä tietää niiden vaikutuksesta myös mahdollisiin muihin sairauksiin kuten syöpiin. Joillakin verenpainelääkkeillä saattaa olla vaikutusta myös syöpäsoluihin vaikutusmekanisminsa kautta. Eräiden tutkimusten mukaan reniini-angiotensiini-aldosteronijärjestelmään (RAA) vaikuttavilla lääkkeillä saattaa olla vaikutusta syöpäsolujen kasvuun ja syövän ennusteeseen esimerkiksi eturauhassyövässä. Tulokset ovat kuitenkin ristiriitaisia. Tämän väitöskirjan tarkoitus on arvioida verenpainelääkkeiden käytön ja syöpäkuoleman välistä riskiä eturauhassyöpä-, uroteelisyöpä-, rintasyöpä- ja munasarjasyöpäpotilailla. Tutkimusaineisto muodostettiin keräämällä Suomen Syöpärekisteristä tiedot syöpädiagnooseista, jotka tehtiin Suomessa vuosina 1995–2013 ja aineistoon yhdistettiin tiedot reseptilääkkeiden käytöstä Kelan lääkekorvaustietokannasta. Lääkeostoja arvioitiin ennen ja jälkeen syöpädiagnoosin ja myös käytön voimakkuutta arvioitiin laskemalla vuosikohtainen suositeltu päiväannos (DDD) jokaiselle osallistujalle. Riskitiheyssuhteet (HRs) ja luottamusvälit (95 % CIs) syöpäkuolemalle laskettiin Cox- regressiolla. Syöpädiagnoosia edeltävään verenpainelääkkeiden käyttöön huomioitiin kaikki ostot vuoden 1995 ja syöpädiagnoosin välillä. Diagnoosin jälkeistä käyttöä arvioitaessa käytettiin aikariippuvaa analyysiä kuolemattomuusharhan minimoimiseksi. Riskiyhteyksien annosriippuvuutta arvioitiin käytön intensiteetin mukaan. Jokaiselle verenpainelääkeryhmälle luotiin oma muuttuja ja ne lisättiin samaan analyysimalliin yhtäaikaisen käytön mallintamiseksi. Analyysissa vakioitiin useita potentiaalisia sekoittavia tekijöitä kuten primaarivaiheen hoito, syövän levinneisyys, liitännäissairaudet ja statiinien sekä diabeteslääkkeiden samanaikainen käyttö. Eturauhassyöpäpotilailla ATR-salpaajien käyttö oli yhteydessä pienempään syöpäkuoleman riskiin. Riskin alenema oli annosriippuvainen sekä ennen että jälkeen diagnoosin. Riskinalenema oli nähtävissä vielä viisi vuotta käytön jälkeenkin. Sen sijaan beetasalpaajien käyttö oli yhteydessä suurentuneeseen eturauhassyöpäkuoleman riskiin ennen ja jälkeen diagnoosin. Samaan tapaan ATR-salpaajien käyttö oli annosriippuvaisesti yhteydessä myös pienempään rakkosyöpäkuoleman riskiin. Rintasyövässäkin ATR- salpaajien ja lisäksi myös beetasalpaajien ja kalsiumkanavan salpaajien käyttö oli annosriippuvaisesti yhteydessä alentuneeseen rintasyöpäkuoleman riskiin. Munasarjasyövässä ainoastaan ACE-estäjien käyttö oli yhteydessä alentuneeseen syöpäkuoleman riskiin mutta vain pitkän yli 10 vuoden seuranta-ajan yhteydessä. ATR-salpaajien käyttö toisin kuin muiden verenpainelääkkeiden käyttö oli yhteydessä alentuneeseen syöpäkuoleman riskiin useassa eri syöpätyypissä. Kaikissa näissä syövissä yhteys oli annosriippuvainen mikä tukee kausaalista yhteyttä. AT-reseptorin lääkkeellinen salpaaminen saattaa siis vaikuttaa syövän ennusteeseen. Samanlaisia tuloksia ei kuitenkaan havaittu ACE-estäjillä, vaikka nekin vaikuttavat RAA-järjestelmään eri mekanismilla. RAA-järjestelmän rooli syövän kasvussa vaatii lisätutkimuksia.Antihypertensive drugs (anti-HT drugs) are very commonly used drugs. They include several different drug molecules with different mechanisms of action. Based on their mechanism of action, they can be categorized into five main groups: angiotensin converting enzyme (ACE) inhibitors, angiotensin-receptor (ATR) blockers, beta-blockers, calcium-channel blockers, and diuretics. These drugs are used in also other conditions than hypertension such as in the treatment of coronary artery disease and heart failure; the loop diuretic compound, furosemide, is mainly used in the treatment of oedema. Since antihypertensive drugs are so widely prescribed, it would be important to know whether they would affect also other diseases; one can speculate that the mechanism of action of some antihypertensive drug groups may have relevance in non-cardiovascular diseases e.g., cancer. Although there are some indications that the drugs affecting the renin-angiotensin aldosterone (RAA) system (ACE-inhibitors and ATR- blockers) might affect cancer cell growth and improve prognosis of some cancer types, like prostate cancer, the published results have been conflicting. The purpose of this thesis is to evaluate the association between antihypertensive drug use in general as well as subdivided according to the drugs’ mechanism of action and the risk of cancer death from prostate (PCa), urothelial (UC), breast (BCa) and ovarian (OC) cancer. The study was conducted by obtaining the information on cancer diagnoses from The Finnish Cancer Registry during 1995-2013 and combining this with information on drug purchases from the national prescription database. Drug use was evaluated separately before and after cancer diagnosis as well as the amount of use by calculating drug-specific Defined Daily Dose (DDD) for each participant. Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the risk of cancer death after the diagnosis of each cancer type. Anti-HT drug use before diagnosis was analysed as a time-fixed variable taking into account the duration and cumulative dose of use occurring between 1995 and the year of cancer diagnosis. Post-diagnostic use was analyzed as a time-dependent variable to minimize immortal time bias. Time-dependent variables were formed by updating medication user status as well as estimating the cumulative amount, duration, and intensity of use separately for each follow-up year after the cancer diagnosis. Dose dependence was evaluated by stratifying medication users by tertiles of DDD amount, duration and intensity of use based on the level reached on each follow-up year. The simultaneous use of multiple anti-HT drug groups was modelled by forming separate time-dependent variables for use of each drug group with these variables included in a Cox- regression model. The long- term association between anti-HT drug use and the risk of cancer death was investigated in lag time analyses where the exposure was lagged forward in the follow-up time and analyzing medication use that occurred before that event. Analyses were adjusted for several confounders such as primary treatment, tumor extent, comorbidities, and simultaneous use of other drugs like statins and antidiabetic medication. In prostate cancer, the use of ATR-blockers was associated with a decreased risk of cancer death. The risk decrease was dose-dependent and concerned usage both before and after diagnosis. The risk decrease remained for five years after usage. In contrast, use of beta-blockers was associated with an increased PCa death risk with both pre-and post-diagnostic use. Similarly, the post-diagnostic use of ATR-blockers was dose-dependently associated with a reduced risk of cancer death also in bladder (BC) cancer. In BCa, ATR-blockers but also beta-blockers and calcium-channel blockers displayed a dose-dependent association with a reduced BCa death risk in post-diagnostic use. In ovarian cancer, ACE-inhibitors were associated with a decreased cancer death risk but only with very long follow-up periods exceeding 10 years. ATR-blockers, unlike any other anti-HT drug group, were associated with decreased risk of cancer death in PCa, BC and BCa and furthermore in these three cancer types, the risk decrease was dose-dependent. This indicates that the association was causal. RAA- inhibition may confer benefits in preventing the progression of cancer. However, similar results were not observed for ACE-inhibitors even though they also inhibit RAA-system but in a different way. The role of the RAA- system in cancer progression warrants further study. In BCa, decreased risk associations were observed for multiple anti-HT drug groups after cancer diagnosis. This suggests that the control of hypertension may be more important in this cancer type than any given mechanism of action. However, ATR-blockers were the only drug group also in this cancer type in which the pre-diagnostic use was associated with a decreased BCa death risk and furthermore in a dose-dependent manner. In conclusion, the use of ATR-blockers is associated with improved cancer-specific survival in multiple cancer types. ATR- blockers differ in this regard from all other anti-HT drug groups, even ACE-inhibitors. Our studies suggest a possible prognostic role of ATR- inhibition in cancer. It would be enlightening to clarify the underlying biological mechanisms to explain why the blockade of the ATR- receptor can exert this potential anti-cancer effect

    Arc-to-line frame registration method for ultrasound and photoacoustic image-guided intraoperative robot-assisted laparoscopic prostatectomy

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    Purpose: To achieve effective robot-assisted laparoscopic prostatectomy, the integration of transrectal ultrasound (TRUS) imaging system which is the most widely used imaging modelity in prostate imaging is essential. However, manual manipulation of the ultrasound transducer during the procedure will significantly interfere with the surgery. Therefore, we propose an image co-registration algorithm based on a photoacoustic marker method, where the ultrasound / photoacoustic (US/PA) images can be registered to the endoscopic camera images to ultimately enable the TRUS transducer to automatically track the surgical instrument Methods: An optimization-based algorithm is proposed to co-register the images from the two different imaging modalities. The principles of light propagation and an uncertainty in PM detection were assumed in this algorithm to improve the stability and accuracy of the algorithm. The algorithm is validated using the previously developed US/PA image-guided system with a da Vinci surgical robot. Results: The target-registration-error (TRE) is measured to evaluate the proposed algorithm. In both simulation and experimental demonstration, the proposed algorithm achieved a sub-centimeter accuracy which is acceptable in practical clinics. The result is also comparable with our previous approach, and the proposed method can be implemented with a normal white light stereo camera and doesn't require highly accurate localization of the PM. Conclusion: The proposed frame registration algorithm enabled a simple yet efficient integration of commercial US/PA imaging system into laparoscopic surgical setting by leveraging the characteristic properties of acoustic wave propagation and laser excitation, contributing to automated US/PA image-guided surgical intervention applications.Comment: 12 pages, 9 figure

    Comparación de toxicidad y resultados oncológicos de la braquiterapia de baja tasa de dosis frente a la braquiterapia de alta tasa de dosis como método de sobreimpresión en el cáncer de próstata local

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    261 p.Este estudio tiene como objetivo determinar la toxicidad y los resultados oncológicos de aquellos pacientes portadores de un adenocarcinoma de próstata localizado que precisaron entre los años 2001 y 2016 de un tratamiento de sobreimpresión a la radioterapia en el Instituto Oncológico (Onkologikoa), bien sea mediante braquiterapia de baja tasa de dosis (LDR) o braquiterapia de alta alta tasa de dosis (HDR). Para poder comparar ambas modalidades de tratamiento y enfrentarlas, se ha procedido a emparejarlas mediante pareamiento por puntaje de propensión utilizando el PSA pre-tratamiento, el estadio clínico, el Gleason Score y el tratamiento hormonal realizado, obteniendo para el análisis final 204 pacientes de cada cohorte (408 en total). Con una mediana de seguimiento de 8 años para cada cohorte, no se encontraron diferencias significativas en cuanto a resultados oncológicos, pero se concluye que la braquiterapia LDR obtiene peores datos en cuanto a toxicidad genitourinaria tardía

    Augmented reality guidance for robot-assisted laparoscopic surgery

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    The most common treatment for organ confined prostate cancer is radical prostatectomy (RP), where cancerous prostate is incised out. Nowadays, mostly the da Vinci system is used to do robot assisted laparoscopic radical prostatectomy (RALRP), providing improved dexterity and significantly faster patient recovery times. However similar to open surgery, the RALRP has higher numbers of reported positive surgical margins. This is potentially due to a surgeon’s effort to remove the cancer and preserving the healthy tissue, when the cancerous and non-cancerous boundaries are indistinguishable in the endoscope. Therefore, the objective of this thesis is to clearly display these boundaries and tumors, using Augmented/Mixed Reality (AR/MR) technology, utilizing imaging data such as, magnetic resonance imaging and ultrasound (US). The successful intra-operative AR/MR depends on primarily two things. First, the surgically compatible calibration steps, to map the imaging data correctly in camera image. Second, the visualization of the co-located data to give reliable depth of subsurface structures, which is imperative to patient safety. Unlike existing methods, in our first work, we propose a method that performs the required hand-eye and camera calibrations without using external markers during surgery. To further streamline the process, in another work, we use an optimization scheme to combine both the calibrations in a single step. The method allows to register the robotic data to the camera within minutes. Additionally, we presented an evaluation of a full AR system that registers the phantom US to the camera image. Next, we address the well-known problem of occlusion while visualizing the overlayed imaging data. For this, our deep learning-based method segments surgical instruments in the human RALRPs videos without using any labelled data. In our other two works we explore the color and motion parallax as depth cues to provide a reliable depth judgement. The usefulness of these are validated through user studies showing significantly better depth perception when using our methods. In conclusion, this thesis presents multiple methods to make AR/MR guidance feasible for RALRP by addressing two pressing challenges in the field of surgical AR, i.e. surgically compatible calibrations and reliable visualization of the registered data.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

    The value of standardized intra-operative surgical margin assessment during prostate cancer operation

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    One of the main treatment options for localised prostate cancer is radical prostatectomy. Radical prostatectomy is complicated by urinary incontinence and erectile dysfunction in 3-16% and 20-90% of men, respectively. Preservation of the neurovascular bundle adjacent to the prostate can reduce the incidence of these complications. However, nerve-sparing surgery may conversely lead to more frequent positive surgical margins. With intraoperative frozen sections (NeuroSAFE) during radical prostatectomy, the surgical margin of the prostate adjacent to the neurovascular bundle is assessed during the operation. The NeuroSAFE-technique thus may provide nerve-sparing surgery and reduce positive surgical margin involvement. Since the development of this technique by the Martini Klinik, several centres have implemented this procedure. However, the effects of this technique have not been validated in large independent cohorts. From September 2018 onwards, scheduled radical prostatectomies from eight centres in the Netherlands were concentrated in one centre utilising the NeuroSAFE technique. In this thesis, we investigate the implementation and the impact of the NeuroSAFE technique in a high-volume centre in the Netherlands. We provided a detailed description of the NeuroSAFE procedure and clinical decision-making, which will facilitate its use in other hospitals and support comparability between centres. We showed that NeuroSAFE enabled more uni- and bilateral nerve-sparing surgery, while NeuroSAFE had no negative impact on positive surgical margin or oncological outcome at short term. Although we were not able to prospectively compare the functional outcomes with patients undergoing RP without NeuroSAFE, we showed that nerve-sparing surgery improved the erectile function and continence after surgery.<br/

    Talking about sex: erectile dysfunction in the oncology patient

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    : Cancer-related diagnosis and treatments can profoundly affect every aspect of an individual's life. The negative impact on the sexual sphere can manifest with onset or worsening of the most frequent male form of sexual dysfunction, that is the erectile dysfunction (ED), with an estimated incidence ranging from 40 to 100% in patients living with cancer. Cancer and ED are strictly related for many reasons. First, the psychological distress, the so-called 'Damocles syndrome', afflicting cancer patients contributes to ED onset. Second, all cancer therapies can variably lead to sexual dysfunction, even more than the disease itself, having both direct or indirect effects on sexual life. Indeed, alongside pelvic surgery and treatments directly impairing the hypothalamus-pituitary-gonadal axis, the altered personal-body-image frequently experienced by people living with cancer may represent a source of distress contributing to sexual dysfunction. It is undeniable that sexual issues are currently neglected or at least under-considered in the oncological setting, mainly due to the subjective lack of preparation experienced by healthcare professionals and to scant information provided to oncological patients on this topic. To overcome these management problems, a new multidisciplinary medical branch called 'oncosexology' was set up. The aim of this review is to comprehensively evaluate ED as an oncology-related morbidity, giving new light to sexual dysfunction management in the oncological setting

    A Comparison of the Thulium Fiber Laser versus Holmium:YAG Laser Lithotripsy of Upper Urinary Tract Calculi: Preliminary Results of a Randomized Prospective Clinical Trial

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    The Holmium:yttrium-aluminium-garnet (Ho:YAG) laser has become an indispensable tool in Endourology since its introduction in 1995, due to its safe and efficient urinary stone fragmentation capabilities. The Thulium Fiber Laser (TFL), is the latest innovation with early clinical experience suggesting improvements over the Ho:YAG. This prospective, randomized controlled study aims to compare clinical outcomes of Ho:YAG versus TFL lithotripsy for upper urinary tract calculi. Patients undergoing ureteroscopy for renal stones (size 8-20mm, density \u3e600 HU) from a single institution were prospectively recruited. Thirty-eight patients have been recruited (Ho:YAG=20, TFL=18). The laser-on time (p=.330), total operative time (p=.849), total laser energy (p=.745), ablation speed (p=.745) and ablation efficiency (p=.745) were not statistically different between groups. Multiple trends in favor the TFL were documented, including shorter laser-on time and total operative time, improved ablation efficiency and ablation speed. Preliminary results suggest similar outcomes for both technologies. Several parameters are trending in favor of the TFL being more efficient; however, recruitment fulfillment will be necessary to determine if there are significant differences
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