Magnetic resonance imaging is a major advancement in the diagnostic imaging field. Most patients can tolerate an MRI however, there are some who are unable to complete a lengthy scan while lying completely still without sedatives or anesthesia. Non-MRI healthcare providers are trained to use equipment that is “unsafe” in the MRI suite due to the strong magnetic field. Staff who are not fully knowledgeable and trained in MRI safety measures can endanger staff and patients. The purpose of this study was to determine the knowledge level of non-MRI healthcare providers regarding safety risks associated with MRI and to determine their level of satisfaction regarding the MRI safety training they received. This study concluded that non-MRI healthcare providers are knowledgeable about most of the safety hazards. They are satisfied with annual training but would like more in-depth material added to their current learning modules.

Deep brain stimulation (DBS) improves the quality of life for patients suffering from neurological disorders such as Parkinson’s disease and, more recently, psychiatric/cognitive disorders such as depression and addiction. This treatment option involves the implantation of an implantable pulse generator (or neurostimulator) and leads (or electrodes) implanted deep within the human brain. Magnetic resonance imaging (MRI) is a powerful diagnostic tool that offers superior soft tissue contrast and is routinely used in clinics for neuroimaging applications. MRI is advantageous in DBS pre-surgical planning as precise lead placement within the brain is essential for optimal treatment outcomes. DBS patients can also benefit from post-surgery MRI, and studies have shown that DBS patients are more likely to require MRI within 5-10 years post-surgery. However, imaging DBS patients is restricted by substantial safety concerns that arise from localized electric charge accumulation along the implanted device during resonant radiofrequency (RF) excitation, which can potentially lead to tissue heating and bodily damage. With the technological advancement of ultra-high field (UHF) MRI systems and a growing DBS patient population, DBS MRI safety will become increasingly problematic in the future and needs to be addressed. Parallel RF transmission (pTx) is a promising technology that utilizes multiple transmit channels to generate a desired electromagnetic profile during MRI RF excitation. Several proof-of-concept studies successfully demonstrated its efficacy in creating a "safe mode" of imaging that minimizes the localized RF heating effects. However, pTx MRI systems are not easily accessible and are often custom-built and integrated onto existing MRI systems. Consequently, it adds system characterization and verification complexity to the DBS MRI safety problem. System channel count is also an important consideration as implementation costs can be very high, and the impact of system transmit channel count remains unexplored. Furthermore, in practice, DBS patients with motor-related disorders will impact the pTx MRI system’s ability to precisely generate these safe mode electromagnetic profiles. Commercial DBS devices (i.e., the neurostimulator and leads) are manufactured with fixed dimensions, and the caring surgeon typically manages the surgical orientation of the implanted DBS device and leads. Therefore, lead trajectories can vary hospital-to-hospital. As a result, standard phantoms, i.e., the ASTM International Standard, used in safety verification experiments may not be suitable for DBS MRI applications. To advance DBS patient safety in MRI, this thesis studied the implant heating effects of pTx system uncertainty, system channel count, patient motion on a novel pTx MRI research platform and its associated safe mode of imaging. It developed a new anthropomorphic heterogeneous phantom to improve safety verification experiments. / Dissertation / Doctor of Philosophy (PhD)

Identification of risks ahead of MRI examinations is identified as a cumbersome and time-consuming process at the Linköping University Hospital radiology clinic. The hospital staff often have to search through large amounts of unstructured patient data to find information about implants. Word embeddings has been identified as a possible tool to speed up this process. The purpose of this thesis is to evaluate this method, and that is done by training a Word2Vec model on patient journal data and analyzing the close neighbours of key search words by calculating cosine similarity. The 50 closest neighbours of each search words are categorized and annotated as relevant to the task of identifying risk patients ahead of MRI examinations or not. 10 search words were explored, leading to a total of 500 terms being annotated. In total, 14 different categories were observed in the result and out of these 8 were considered relevant. Out of the 500 terms, 340 (68%) were considered relevant. In addition, 48 implant models could be observed which are particularly interesting because if a patient have an implant, hospital staff needs to determine it’s exact model and the MRI conditions of that model. Overall these findings points towards a positive answer for the aim of the thesis, although further developments are needed.

<p>Magnetic Resonance Imaging, MRI, is a diagnostic tool in progress which has been available at major hospitals since the mid eighties. Today almost all hospitals world wide may depict the human body with their own MRI scanner. MRI is dependent on a uniform magnetic field inside the scanner tunnel and Radio frequent (RF) waves used for excitation of the magnetic dipole moments in the body. These properties along with the magnetic field surrounding the scanner are associated with dangerous effects - when interacting with medical implants made of metals. These dangerous effects are twisting forces or torques, heating and translational forces respectively. A database containing information about known implants behaviour regarding these effects among with earlier documentation and information concerning MRI patient safety at Karolinska hospital, Huddinge was constructed.</p><p>Also a phantom used for heating effect measurements was constructed and heating effect measurements were performed at a SPC4129 locking titanium Peritoneal Dialysis (PD) catheter adapter and a Deep Brain Stimulator (DBS) in order to test the phantom and confirm the theory about RF induced heating on medical implants. Evidence for heating effects caused by the implants was found.</p><p>A torque measurement apparatus was constructed and measurements were performed. All measurements where performed in order to investigate the functionality of the apparatus and also the theory behind dangerous magnetically induced torques (twisting movements). Substantial torque were measured on the ferromagnetic device used for the test.</p><p>The heating phantom and torque measurement apparatus is slightly modified models of those proposed by ASTM (American Society for Testing and Materials).</p>

Magnetic Resonance Imaging, MRI, is a diagnostic tool in progress which has been available at major hospitals since the mid eighties. Today almost all hospitals world wide may depict the human body with their own MRI scanner. MRI is dependent on a uniform magnetic field inside the scanner tunnel and Radio frequent (RF) waves used for excitation of the magnetic dipole moments in the body. These properties along with the magnetic field surrounding the scanner are associated with dangerous effects - when interacting with medical implants made of metals. These dangerous effects are twisting forces or torques, heating and translational forces respectively. A database containing information about known implants behaviour regarding these effects among with earlier documentation and information concerning MRI patient safety at Karolinska hospital, Huddinge was constructed. Also a phantom used for heating effect measurements was constructed and heating effect measurements were performed at a SPC4129 locking titanium Peritoneal Dialysis (PD) catheter adapter and a Deep Brain Stimulator (DBS) in order to test the phantom and confirm the theory about RF induced heating on medical implants. Evidence for heating effects caused by the implants was found. A torque measurement apparatus was constructed and measurements were performed. All measurements where performed in order to investigate the functionality of the apparatus and also the theory behind dangerous magnetically induced torques (twisting movements). Substantial torque were measured on the ferromagnetic device used for the test. The heating phantom and torque measurement apparatus is slightly modified models of those proposed by ASTM (American Society for Testing and Materials).

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Background: MRI- safety education is an important aspect from a work environment perspective and patient perspective, to avoid harmful and deadly accidents. Aim: The aim of the study was at two hospitals investigate if the radiographers feels that the MRI safety education is enough to work safe in MRI environment. The study’s aim was also to investigate in what form MRI-safety is preformed and see if there is a difference between hospital A and B. The study was addressed to radiographers who works with MRI and radiographers who works with other modalities. This study also investigates if radiographers knows about guidelines for other staff who works regularly at MRI and if the radiographers feel that this education is enough. Method: The study is an empirical quantitative inquiry study with qualitative analysis. The inquiry was own constructed to answer the study´s aims. Forty radiographers from two hospitals ware included. Results: The results showed 53% of the participants have not attended any education about MRI-safety through their current employer. 65 % of the participants who attended education claimed the education was enough for them to work in a MRI-safe way. 52% of the participants experience that other workmen’s/clinicians don’t have enough education to create an MRI safe environment. A significant different in form of education was found in web education that were more frequent at hospital B. Conclusion: The results shows that majority of the participant haven’t had any safety education from their current employer. However, the ones who did found it to be enough to work in an MRI-safe way. The participants comments showed that MR-safety education always a current subject in need of repetition and development. / Bakgrund: Magnetisk Resonanstomografi (MR)- säkerhetsutbildning är en viktig aspekt ur både arbetsmiljösynpunkt och ur patientperspektiv för att undvika skadliga och dödliga olyckor. Syfte: Studien syftade till att på två sjukhus undersöka om röntgensjuksköterskorna upplever att utbildningen är tillräcklig för att arbeta säkert i MR-miljö. Studien syftade också till att undersöka på vilket sätt säkerhetsutbildning inom MR sker samt jämföra skillnaden mellan sjukhus A och B. Studien riktade sig till röntgensjuksköterskor som arbetar med MR, samt övriga röntgensjuksköterskor på röntgenavdelningen. I studien undersöktes även om röntgensjuksköterskorna känner till om det finns riktlinjer för annan personal/sjukvårdspersonal som vistas i MR-miljö samt om röntgensjuksköterskan upplever den utbildningen som tillräcklig. Metod: En empirisk kvantitativ enkätstudie med inslag av kvalitativ analys. Enkätfrågorna egenkonstruerades för att besvara studiens syften. Fyrtio röntgensjuksköterskor från två sjukhus inkluderades. Resultat: Resultatet visade att 53% av deltagarna inte genomgått någon MR-säkerhetsutbildning via nuvarande arbetsgivare. Av deltagarna som hade genomgått en sådan utbildning uppgav 65% att den var tillräcklig för att arbeta MR-säkert. I studien upplevde 52% att övrig personal/sjukvårdspersonal inte var tillräckligt utbildad för att skapa en säker MR-miljö. En signifikant skillnad mellan sjukhusen visades vid utbildningsform webbutbildning som var mer förekommande på sjukhus B.  Slutsats: Resultatet av studien visade att majoriteten av deltagarna inte hade genomgått någon MR-säkerhetsutbildning via nuvarande arbetsgivare, däremot upplevde de som hade gjort det att utbildningen var tillräcklig för att kunna arbeta MR-säkert. Deltagarnas egna synpunkter visar att MR-säkerhetsutbildning är något som ständigt är aktuellt och alltid behöver upprepas samt uppdateras.

As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants. Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can be calculated as , where σ is electrical conductivity of the medium in units of , |E| is the magnitude of the applied electric field in units of , and ρ is the density of the medium in units of . For continuous, uniform power deposition this can be measured experimentally as a rise in temperature over time (∆T/t), where c is the specific heat capacity of the medium in units of. To understand the SAR induced in-vivo, a phantom (Figure 2.10) is used to conduct in-vitro experiments, as it provides a controllable and repeatable experimental setup. In order to experiment in the phantom, an understanding of the background SAR distribution and in turn the exposure field distribution of the phantom is required as per the ASTMF2182-09 standard [2]. In this work, the background SAR distribution of an ASTM standard torso phantom is measured and studied via fiber optic thermometry. The measurements are compared with an electromagnetic model simulated via FDTD, demonstrating agreement between 10-25%. A custom exposure and data collection setup (including oscilloscope, function generator, RF amplifier, directional coupler, and Neoptix Omniflex Fiber Optic Thermometry system) was integrated and automated using NI LabView. The purpose of this thesis is to map the field distribution in a torso phantom under RF exposure from a 64 MHz MRI RF Birdcage, compare the results to an electromagnetic simulation, and finally conclude the accuracy of this method for field measurements in a standard torso phantom. Understanding the capabilities and accuracy of the fiber optic thermometry method will ultimately allow researchers to successfully apply this method to monitor background fields in their respective experimental setups (related to MRI implant heating) and understand its limitations.

L’Imagerie par Résonance Magnétique (IRM) est une technique d’imagerie de référence pour réaliser des diagnostics médicaux. Pour des patients implantés avec des dispositifs médicaux actifs, l’IRM peut engendrer des risques qui doivent être étudiés et minimisés. En effet, ces dispositifs sont constitués en partie de matériaux conducteurs et/ou magnétiques qui interagissent avec l’environnement électromagnétique d’une IRM. Lorsque ces dispositifs ont des câbles, une des interactions les plus problématiques est l’induction d’énergie dans ses câbles qui peut entrainer des stimulations, des dysfonctionnements ou des brûlures. Le premier objectif de cette thèse est de développer des outils pour étudier et quantifier ces interactions électromagnétiques d’une IRM sur un câble. Pour cela, des capteurs innovants compatibles IRM ont été développés pour mesurer la tension induite sur un câble, aux bornes de l’électronique d’entrée d’un dispositif médical actif. Des bancs de tests ont également été mis en place pour simuler les champs électromagnétiques d’une IRM. Le second objectif de cette thèse est de concevoir des câbles innovants qui réduisent au maximum ses interactions électromagnétiques avec une IRM. Nous avons réalisé un câble constitué d’un fil conducteur qui limite l’énergie induite par l’IRM grâce à son bobinage variable. Nous avons réalisé un deuxième câble avec un conducteur de fine épaisseur et des ruptures d’impédances sur sa longueur / Magnetic Resonance Imaging (MRI) is an established imaging technique for medical diagnostics but could expose patients with active medical devices to risks that need to be studied and minimized. In fact, these devices encompass conductive and/or magnetic materials which interact with the electromagnetic field of the MRI. When these devices contain leads, MRI induced energy within the lead is considered to be one of the most problematic interaction as it can lead to stimulations, malfunction or burns. The first goal of this thesis is to create tools to study and quantify the electromagnetic interactions between an MRI and a lead. This has led to the design of novel MRI compatible sensors that measure induced voltage within leads connected active medical device entry terminals. Experimental MRI set-ups were also developed to simulate the MRI’s electromagnetic field. The second goal of this thesis is to design new leads that are minimally affected by the MRI’s electromagnetic field. Two proofs of concept were achieved. On the one hand, a lead capable of reducing MRI induced energy thanks to its winding was made. On the second hand, a second lead with a thin conductor and impedance mismatches along its length was created

Bakgrund: Antalet magnetresonanstomografi (MR)-undersökningar ökar kontinuerligt vilket resulterar i ökat antal fall där annan sjukvårdspersonal, som i denna studie kallad för övrig personal, följer med patienten in i MR-rummet. Eftersom arbetet i en MR-miljö innefattar väldigt starka magnetfält bör all personal som skall vistas i och omkring MR-rummet ha genomgått en MR-säkerhetsutbildning för att förebygga skadliga och potentiellt dödliga olyckor .  Syfte: Denna studie syftar till att undersöka MR-personalens säkerhetsupplevelser när övrig personal är närvarande i MR-miljön, samt om det föreföll skillnader mellan universitetssjukhus och medelstora sjukhus i fyra kategorier: teamsamarbete, säkerhetsklimat, incidentrapportering och utbildning.  Metod: En empirisk kvantitativ enkätstudie som utgick från enkäten SAQ (Safety Attitudes Questionnaire)användes vilken anpassades för att besvara studiens syfte. Enkäten distribuerades till sju universitetssjukhus och sju medelstora sjukhus där målgruppen var röntgensjuksköterskor som arbetade med MR.  Dataanalysen genomfördes med hjälp av statistikprogramvaran SPSS för att kunna bearbeta resultaten.  Resultat:  Röntgensjuksköterskor upplevde en känsla av osäkerhet när övrig personal är närvarande i MR-miljön och att det fanns bristfällig kunskap och utbildning för att upprätthålla ett MR-säkert arbetssätt. Det fanns även signifikant skillnad mellan universitetssjukhus och mellanstora sjukhus avseende efterlevnad av säkerhetsrutiner och riktlinjer samt MR-säkerhetsutbildning bland övrig personal.  Slutsats: Denna studie visade att övrig personal utgör en väsentlig bidragande faktor till ökade risker för MR-relaterade olyckor. Resultaten tyder även på att det finns skillnader i efterlevnad av säkerhetsrutiner och riktlinjer samt MR-säkerhetsutbildning bland övrig personal, där faktorerna i båda fallen visade att universitetssjukhus hade bättre utfall än medelstora sjukhus. / Background: The number of Magnetic Resonance Imaging (MRI) -examinations is constantly increasing and thus the number of cases where other healthcare personnel, referred to as "other personnel" in this study, accompany the patient into the MRI room. Because the MRI-environment includes strong magnetic fields ,all personnel who are to be present in and around the MRI room should have undergone MRI safety training to prevent harmful and potentially fatal accidents. Objectives: This study aim to investigate the safety experiences of MRI personnel when other personnels are present in the MRI environment and explore potential differences between university hospitals and medium-sized hospitals in four categories, teamwork, safety climate, incident rapporting and education .  Methods: A quantitative survey using the adapted Safety Attitudes Questionnaire (SAQ) in order to answer the purpose of the study was conducted. The survey was distributed to seven university hospitals and seven medium-sized hospitals, targeting radiographers working with MRI. Data analysis was performed using the statistical software SPSS to be able to process the results.  Results: Radiographers experienced a sense of uncertainty when other personnels were present in the MRI environment, indicating a lack of knowledge and training to maintain adequate MRI safe working method.There was also a significant difference between university hospitals and medium-sized hospital regarding compliance with safety routines and guidelines as well as MRI safety training amongst other staff.  Conclusion: This study demonstrated that other personnels constitute a significant contributing factor to increased risks of MRI-related accidents. The results also suggest differences in adherence to safety procedures, guidelines, and MR safety training among the other personel, with both factors indicating better outcomes in university hospitals compared to medium-sized hospitals.