2015 BFY II Abstract Detail Page
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||Teaching about the Gamma Camera and Ultrasound Imaging
||Instructional modules on applications of physics in medicine are being developed. The target audience consists of students who have had an introductory undergraduate physics course. This poster will describe active learning approaches to teaching the principles of the gamma camera and ultrasound imaging.
The gamma camera (or scintillation camera) is one of the most important nuclear imaging devices used in a hospital. A radiopharmaceutical is introduced into a patient, which becomes concentrated in an organ or tumor. The gamma camera is placed over the patient. Gamma rays emitted from the radionuclide pass through an array of lead tubes and hit a scintillator crystal to produce flashes of light at different positions. The flashes are detected by an array of PMTs and an image based on the positions of the flashes is constructed using fast electronics. The distribution of gamma emitters in the body is useful for diagnosing disease.
Since a real gamma camera is not feasible in the undergraduate classroom, we have developed two types of optical apparatus that teach the main principles. To understand the collimator, LEDS mimic gamma emitters in the body, and the photons pass through an array of tubes. To determine the positions of the gamma emitters, a second apparatus uses fluorescent plastic in lieu of the scintillation crystal, acrylic rods that mimic the PMTs, and a photodetector to measure the intensity. The position of the laser is calculated with a centroid algorithm.
To teach the principles of ultrasound imaging, we use a sound head, pulse generator, variable gain amplifier, digital oscilloscope, and Matlab software. Students gain proficiency with the oscilloscope while learning to read the echoes produced by the front and back surfaces of an object. To understand how a B-scan is constructed from a series of A-scans, an object is placed on a linear translation stage, and the signals are reconstructed in Matlab. Students can vary the algorithm to understand the effects upon the image. By using an array of sewing pins as the object, students can understand the effects of varying speeds of sound in an object (ex. to mimic a cyst embedded in an organ) and axial and lateral resolution.
Loyola University Maryland
Alex Spiro, Loyola University Maryland
Ronald F. Vogel, Loyola University Maryland
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