Implementation And Optimization Of Magnetic Particle Imaging System

Magnetic Particle Imaging(MPI)is a new tracer imaging technology.It uses the nonlinear magnetization characteristics of magnetic nano particle tracers in zero magnetic field to visualize the tracer concentration in the measured object,so as to detect the spatial distribution of magnetic nano particle tracers.The detected signal intensity is proportional to the concentration of magnetic nano particles,which is characterized by high sensitivity.The reconstruction of high-precision,high-quality,and high spatial resolution MPI images has great practical significance and is also one of the current problems.And currently,most MPI devices are designed in a closed manner.In order to achieve larger and deeper detection areas,the device volume is generally large,lacks flexibility,and is difficult to move.In order for MPI to achieve higher accuracy and quality images,and for devices to be flexible in movement,this article proposes two design schemes for devices,namely the development and implementation of a large open MPI scanning system and a small handheld MPI detection device.The design methods of both devices are based on the research of magnetic nanoparticles,the principle of signal acquisition and the principle of spatial resolution.Image reconstruction based on system matrix is an important component of MPI reconstruction and an indispensable part of optimizing MPI.This article uses non negative least squares algorithm for image reconstruction to optimize MPI devices.A large open MPI scanning system and a small handheld MPI detection device were used to compare and analyze the image reconstruction time using two experimental platforms: workstations and portable devices.For the experimental results and analysis,the spatial resolution of the image scanned by the large open MPI scanning system is 8mm,which is about 4 times the original resolution.After image reconstruction,it can reach about 2mm,basically restoring the sample size and achieving optimization.The large-scale open MPI scanning system provides the possibility to solve various clinical problems that are difficult to implement.In the examination of deep intracranial hemorrhage,traditional imaging methods are difficult to achieve continuous intracranial blood flow imaging.However,if it is installed in an ICU hospital bed,it can monitor the patient’s intracranial blood flow status continuously and continuously for 24 hours,without the need to move the patient to the CT/MRI examination room;In terms of surgical assistance,using it instead of radioactive X-ray for DSA imaging will directly eliminate the long-term radiation side effects of imaging on both doctors and patients during interventional surgery.This huge technological innovation will undoubtedly bring good news to the rehabilitation of patients and even the development of clinical medicine.On the basis of this,a small handheld MPI detection device achieves accurate positioning and detection of sentinel lymph nodes,shortest and best time detection,minimum concentration detection of tracer required for experiments,and comparison detection with traditional methods.It also reconstructs the image of the detected sentinel lymph nodes,accurately restoring the size of the lymph nodes themselves,and ultimately achieves mobile scanning,expanding the scanning area,making the experiment flexible.Finally,by presenting and analyzing the results of two types of devices,the accuracy of a large open MPI scanning system and the feasibility and effectiveness of a small handheld MPI detection device were verified,proving that MPI has high temporal and spatial resolution advantages and will inevitably have high application prospects in future medical detection.