Computer Lab Exercises For Medical Imaging Using Simurad

In this paper we present a series of computer lab exercises for an undergraduate Medical Imaging course using a newly developed computer simulation software – SimuRad, which has been designed to help students better understand the underlying math, physics and engineering principles of medical imaging. This paper includes the discussions on the architecture of the SimuRad software, the design of the computer lab series, preliminary assessment from student groups, and subsequent improvement and deployment plans. The development and deployment of this software is partially supported by an NSF CCLI grant. Introduction “Medical Imaging” is an important subject in most bio-medical and bio-engineering curricula. It is a multi-discipline subject involving studies in biology, physics, mathematics, electrical engineering, and computer science. A comprehensive medical imaging course may cover fundamental science and engineering principles (e.g. atomic and nuclear physics, Fourier analysis and reconstruction, and computer assisted tomography), medical imaging modalities (e.g. x-ray radiography, x-ray CT, nuclear medicine gamma imaging, magnetic resonance imaging, and ultrasound imaging), and clinical imaging practices (e.g. image analysis, visualization, instrumentation, and radiological protection) 1,2 . Although it has been a typically a graduate level course in most of the radiology, medical physics, biomedical engineering, and computer engineering programs 3 , it has also been frequently offered to undergraduate students as a required or elective course. In order to offer this as an introductory undergraduate course, it is necessary to emphasize conceptual learning through lab exercises 4,5 . In this paper we present a series of computer lab exercises based on a newly developed computer simulation software – SimuRad 6 , which can help students better understand the underlying science and engineering principles of medical imaging. SimuRad is an interactive software which implements numerical algorithms to simulate physical and biological processes in most common medical imaging modalities. The software contains expandable modules, each to support a series lab exercises related to a particular modality. Currently implemented modules include math fundamentals, computed tomography (CT), x-ray physics, nuclear magnetic resonance (NMR), image enhancement and analysis. With these modules, seven computer lab exercises have been designed. Lab 1, Convolution and Fourier Transform (math preparation) Lab 2, Projection and Projection Slice Theorem (tomography) Lab 3, Frequency domain reconstruction – number of projects, interpolation methods (xray CT, MRI) Lab 4, Filtered back projection – number of projections, filters, noise (x-ray CT) Lab 5, X-ray attenuation coefficient and survival probability (x-ray) Lab 6, NMR signals – precessions, relaxation, basic sequences (MRI) Lab 7, Brain activation detection in fMRI (image analysis) P ge 15304.2 These computer lab exercises have been adopted in the Introduction to Medical Imaging course instructed by the author at StevensInstitute of Technology for several semesters. This paper reports on the designs of these lab exercises using SimuRad, together with preliminary assessment results from student groups, and subsequent improvement and deployment plans. Descriptions of the computer lab exercises Lab 1. User generates different signals by selecting multiple simple waveforms, e.g. sine, square. The amplitude, frequency and phase of each simple waveform are specified by the user. Then Fourier Transform is performed and the frequency response is displayed for each generated signal. User is instructed to try a sequence of parameter sets to observe the changes of frequency responses corresponding to changes in signals. User then selects a filter. Convolution of a signal with the filter is implemented through multiplication in frequency domain, which is to demonstrate the concept that filtering is a process of frequency selective attenuation or amplification. 0 50 100 150 200 250 300 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 0 50 100 150 200 250 300 0 20 40 60 80 0 50 100 150 200 250 300 -500 -400 -300 -200 -100 0 Figure 1. Samples of student works on frequency component analysis in 1D waveforms. Lab 2. User first creates simple 2D objects from isolated points, simple shapes (rectangle, circle, ellipse etc.), and observes their projection (radon) domain presentations. The number and angle of projections are specified by the user. A phantom template is also provided so that user can manipulate the components to created different phantom objects for projection tests. User then use the phantom object to validate projection slice theorem. The process is to take one projection at user specified angle, then display this projection signal, the 1D FFT of this projection, as well as the corresponding slice of the 2D DFT of the phantom image. The user can observe the consistency of these two FFT results at any selected projection angle.