Labs
| (Labs 1-3 included with scanner purchase) | |
| Lab1: Introduction to Medical Imaging 3D Localization In this lab, students will make geometric measurements of the 3D positions of fiducial markers embedded in a cylindrical phantom. Measurements are made from 2 orthogonal radiographic projections, as well as from a CT reconstructed 3D image.Students can compare and contrast the two imaging modalities and calculation approaches. If performed correctly, students should determine the marker positions which are in close agreement using a pair of 2D, and 3D images. |
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| This exercise will introduce the students to the user interface of the DeskCAT™ scanner, and allow them to explore the different navigational and measurement tools that the software offers both for 2D projections and for 3D reconstructions. Students will determine the geometric positions of fiducial markers in 3D space, and will also learn how to adjust window and level to improve visibility of targets in an image. | |
| Lab 2: System Linearity In this lab, students will develop an experiment to assess the linearity of the DeskCAT™ scanner performance. Students are given a water-filled jar and concentrated dye, and must acquire a data-set of phantoms with linearly increasing optical attenuation coefficients. By measuring the overall thickness of the jar, students must also assess the accuracy of the reconstructed attenuation coefficients from their knowledge of photon attenuation laws. If performed correctly, students should acquire a linear trend and accurate reconstructions to within 10%. Students must identify sources of error and offer suggestions to reduce the experimental error. |
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| This exercise will illustrate the importance of an imaging system’s accuracy on its suitability as a quantitative diagnostic tool. Alternatively, if imaging systems provide non-linear outputs, students will see that the potential still exists in such systems, as long as the non-linearity is well-characterized with calibration techniques and stable. | |
| Lab 3: Spatial Resolution and Modulation Transfer Function (MTF) In this lab, the student will assess the spatial resolution of the DeskCAT™ scanner at 2 levels: The spatial resolution of a single 2D projection radiographic “raw” image, and the spatial resolution of a 3D CT reconstructed image. Students will acquire images of a test bar pattern with a series of “picket fence” line thicknesses. By measuring the contrast of line pairs, students can plot pixel intensity (i.e. modulation) vs spatial frequency to estimate the shape of the modulation transfer function. |
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| Future Advanced labs DRAFT (Available Summer 2012): (Additional Labs 4, 5 and 6 available for purchase as a package of 3) |
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| Lab 4: Point Spread Function (PSF) and Shift-Invariance In this lab, a more mathematical technique is used to determine the modulation transfer function. A “half moon” phantom is used and pixel profiles are measured across the contrasted edge. Using Fourier methods, the MTF is calculated and plotted. Results are compared with the outcome of Experiment 3 for on-axis and off-axis locations in the image. |
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| Lab 5: Contrast to Noise Ratio (CNR) In this lab, student learns the importance of contrast and imaging dose. A lower dose image is simulated by adding Gaussian noise to the projection images of a “finger” phantom. For high noise (i.e. low dose) conditions, the ability to resolve low contrast objects is progressively impaired as noise is enhanced. This is an important topic in view of the “Image Gently” movement in medical diagnostic imaging. |
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| Lab 6: Faulty Detectors and Missing Projections In this lab, students learn that CT images are not a perfect rendition of the anatomy. The transmission of photons is measured by real detectors with inherent noise and faults. Software is used to “knock out” user-selected camera pixels or entire images and the students observe artifacts in the reconstructed CT images. |
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| Future Super-Advanced Labs DRAFT (Available Fall 2012): (Additional Labs 7, 8 and 9 available for purchase as a package of 3) |
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| Lab 7: Contrast in Dual Energy CT | |
| Lab 8: SPECT Imaging (Nuclear Medicine) | |
| Lab 9: IMRT Simulation (Radiation Oncology) | |
