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BEGINNER LAB EXERCISES± Lab 0: Introduction to DeskCATIn this lab, students will scan a simple 3D object (i.e. a mouse phantom) tobecome familiar with the DeskCAT scanner procedures and software interface.This will help students become oriented with the operations of a CT scannerand associated software for data capture, image reconstruction, and 3D imagedisplay.This exercise will introduce the students to the user interface of the DeskCATscanner, explain the concept of a reference versus data scan, and allow them toexplore the different navigational and visualization tools that the software offersfor both 2D projections and 3D reconstructions.± Lab 1: Introduction to Medical Imaging – 3D LocalizationIn this lab, students will make geometric measurements of the 3D positions offiducial markers embedded in a cylindrical phantom. Measurements are madefrom 2 orthogonal radiographic (camera) projections, as well as from a CTreconstructed 3D image. Students can compare and contrast the two imagingmodalities with calculations of coordinates by each approach. By the end of thelab, students should find that the marker positions are in close agreement usingan orthogonal pair of 2D radiographic images and the full 3D CT image.This exercise will further introduce the students to the user interface of theDeskCAT scanner. Students will determine the geometric positions of fiducialmarkers in 3D space, and will also learn how to adjust window and level toimprove visibility of targets in an image.± Lab 2: System LinearityIn this lab, students will perform an experiment to assess the linearity of theDeskCAT scanner performance. Students are given a water-filled jar andconcentrated black dye solution. They must acquire a data-set of scans withincreasing optical attenuation coefficients. By the end of the lab, students shouldobserve a linear trend and accurate reconstructions to within 10%, with resultsdepending on the concentration of the dye. Students must identify sources oferror and offer suggestions to reduce the experimental error.This exercise will illustrate the importance of an imaging system’s linearity on itssuitability as a quantitative tool.± Lab 3: Spatial Resolution and Modulation Transfer Function (MTF)In this lab, the student will assess the spatial resolution of the DeskCATscanner at 2 levels: The spatial resolution of a single 2D projection radiographicimage, and the spatial resolution of a 3D CT reconstructed image. Studentswill acquire images of a test bar pattern with a series of “picket fence” linethicknesses. By measuring the contrast of line pairs, students plot pixel intensity(or modulation) vs. spatial frequency to estimate the shape of the modulationtransfer function (MTF).This exercise will introduce students to the concept of MTF, its practicalimplications and demonstrate one method of measuring it.© 2012 Modus Medical Devices Inc. Version 1.1 Modus Medical Devices Inc. reserves the right to make changes without notice and shall not be liable for any errors or omissions contained in this document.