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"Penyakit ginjal kronis (PGK) merupakan salah satu penyakit dengan tingkat kematian terbanyak di dunia. Oleh karena itu, diperlukan metode diagnosis yang cekatan dan akurat agar dapat ditangani dalam waktu secepatnya. Magnetic Particle Imaging (MPI) adalah metode pencitraan non-invasif baru yang sedang berkembang. MPI bekerja dengan menggunakan medan magnet untuk memindai, mengeksitasi dan mendeteksi sinyal tracer, yang berupa superparamagnetic iron oxide nanoparticle (SPION), yang sebelumnya telah diinjeksikan ke dalam subjek. Dibandingkan dengan modalitas lain seperti Computed Tomography (CT), tracer MPI tidak radioaktif dan tidak diproses oleh ginjal, sehingga lebih aman untuk diagnosis atau pemantauan PGK. Tujuan dari penelitian tesis ini adalah untuk menyimulasikan alat MPI dengan bidang field-free point (FFP) dan mendemonstrasikan rekonstruksi citra MPI 1D dari sinyal output simulasi. Hal tersebut dilakukan dengan membuat model 3 dimensi sesuai dengan parameter yang telah ditentukan oleh hasil studi literatur dan melakukan simulasi dengan tracer pada lokasi-lokasi berbeda dalam field of view, lalu mengolah data menggunakan dua metode signal processing yaitu metode system matrix (SM) dan metode X-Space. Hasil dari penelitian adalah model 3D mampu menyimulasikan kinerja MPI dengan cukup baik, dengan hasil rekonstruksi dengan metode SM mempunyai error rata-rata 42,66% dan skor Structural Similarity Index Measure (SSIM) 0,346 karena jumlah sampel yang sedikit. Namun, sinyal output tidak dapat digunakan untuk rekonstruksi X-Space oleh karena bentuk FFP yang terlalu landai, meskipun berdasarkan pemodelan matematis, metode rekonstruksi X-Space memiliki tingkat akurasi yang sangat tinggi dengan waktu rekonstruksi yang cepat, dengan resolusi 2 mm dan skor SSIM 0,861. Melalui penelitian ini, didapat bahwa meskipun tidak dapat menggunakan metode X-Space, model MPI yang dibuat mampu digunakan untuk menyimulasikan kinerja MPI FFP 1D dengan akurasi yang cukup baik agar dapat menghasilkan citra melalui metode rekonstruksi system matrix.

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Chronic kidney disease (CKD) is one of the deadliest diseases in the world. Therefore, there is a constant search for an accurate and fast method to diagnose CKD so treatment can begin as fast as possible. Magnetic Particle Imaging (MPI) is an emerging non-invasive imaging method that is currently being developed for medical use. MPI uses a combination of varying magnetic fields to scan and detect magnetic signals from its tracers, named superparamagnetic iron oxide nanoparticles (SPIONs), which are injected into the subject beforehand. Compared to other imaging modalities like Computed Tomography (CT), MPI’s tracers are not radioactive and are not processed in the kidneys, making it a safer option for diagnosing CKD without worsening its condition. The aim of this thesis is to simulate the mechanisms of a field-free point (FFP) MPI and to reconstruct a 1D image based on the acquired simulated MPI data. This is done by making a 3-dimensional model of an MPI device based on parameters gathered via literature research and simulating MPI scans with tracers located in various points inside the field of view. The gathered data are then processed by two methods, the system matrix (SM)-based reconstruction and the X-Space reconstruction. The results of this research are that the 3D model can simulate the mechanisms of MPI properly, with an average error of 42.66% and a Structural Similarity Image Measure (SSIM) score of 0.346 using the SM-based reconstruction due to a very limited sample size and an inaccurate tracer model. However, the signals cannot be reconstructed using X-Space methods due to the low gradient of the FFP, despite the X-Space method being a very fast and accurate reconstruction method based on mathematical models, having a 2 mm resolution and an SSIM of 0.861. These findings conclude that despite being unable to use the X-Space reconstruction method, the 1-dimensional FFP MPI model can simulate the mechanics of MPI with enough accuracy to create an image using SM-based reconstruction."

"Magnetite nanoparticles (Fe3O4) are a type of magnetic particle with huge potential for application as a drug carrier due to their excellent superparamagnetic, biocompatible, and easily modified surface properties. One characteristic of nanoparticles is that they can be controlled by studying the evolution of crystal growth. The purpose of this research is to study the evolution of magnetite-crystal growth and determine the crystal growth kinetics using the Ostwald ripening model. Magnetite nanoparticles were synthesized from FeCl3, citrate, urea, and polyethylene glycol using the hydrothermal method at 220oC for times ranging from 1–12 hours. The characterizations using X-ray diffraction (XRD) indicated that the magnetite began to form after 3 hours synthesis. The crystallinity and crystal size of the magnetite increased with the reaction time. The diameter size of the magnetite crystals was in the range of 10–29 nm. The characterizations using a transmission electron microscope (TEM) showed that magnetite nanoparticles had a relatively uniform size and were not agglomerated. The core-shell nanoparticles were obtained after 3 hours synthesis and had a diameter of 60 nm, whereas the irregular-shaped nanoparticles were obtained in 12 hours and had a diameter of 50 nm. The characterizations using a vibrating sample magnetometer (VSM) revealed that magnetite nanoparticles have superparamagnetic properties. The magnetization saturation (Ms) value was proportional to the degree of crystallinity. The magnetite-crystal growth data can be fitted to an Ostwald ripening model with the growth controlled by the dissolution of the surface reaction (n?4)."