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Design Case Studies

Design Case Studies. Multidetector Brain Scanning System Development. Problem: given point source response, how can one improve net spatial sensitivity of a device? Pre-CAT scanning and other current technologies. Detector Point source response.

Jeffrey
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Design Case Studies

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  1. Design Case Studies

  2. Multidetector Brain Scanning System Development • Problem: given point source response, how can one improve net spatial sensitivity of a device? • Pre-CAT scanning and other current technologies

  3. Detector Point source response Lead collimator cross section & detector are on the left on this diagram, iso-response profiles are to the right

  4. Problem Statement "Given one or more focusing collimators (and related electronics), develop a brain scanning system that shows increased sensitivity compared to a rectilinear scan using a single detector, and which gives a cross sectional image of the brain more suited for surgical planning than rectilinear scans."

  5. Solution 1: Multicrystal Tomographic Scanner Schematic of early tomographic scanner, U.S. Patent Number 3,591,806, eight detectors arranged in a circle with a common intercept point.

  6. Solution 2: Mutually Orthogonal Multicrystal Tomographic Scanner Mutually orthogonal schematic arrangement – one quadrant of a 12-detector system with 4 sets of three mutually orthogonal detectors

  7. TRIZ principle 5 • "combining in space homogenous objects destined for contiguous operations " • Both systems worked, one was patented, both formed the basis for other technologies (see reference patents.)

  8. Testing of Anesthetists: Hypotheses • A challenging protocol may be developed using a simulator that tests anesthetists' skills at maintaining patient homeostasis within limits, and • An analytical technique may be demonstrated that will suggest that "skill level" may be inferred from the data collected from the simulator.

  9. Simulation Method • Inform examinee who the patient is (Stan, normal young male) • Operation type: low anterior bowel resection • SOP please … • Inform re stage of surgery… • Start!

  10. And we are off…

  11. The protocol (“Stable Anesthesia”) • Induction  Intubation (epi) Maintenance •  Incision (epi) Fluid loss(~ 3L)  •  Maintenance  Ischemia & Desaturation ( & lung changes) •  Maintenance  Emergence •  Extubation ( adequacy)

  12. Trained Physician Results:

  13. Novice Results:

  14. Conclusion: • The human patient simulator may be used as a testing device to do inter-individual comparison of anesthetist response to simulated stresses during anesthetic procedures. • A simple measure of competency of intervention may be derived by a “time out of range” measure … • King, P.H., Pierce, D., Higgins, M., Beattie, C., Waitman, L. C. “A Proposed Method for the Measurement of Anesthetist Care Variability”, Journal of Clinical Monitoring and Computing, 16 (2): 121-125, 2000.

  15. Apnea Detection System A means of monitoring patients for potential respiratory depression needs to be found, such that the patient in a step-down unit may be better monitored than just with simple periodic visits by hospital personnel.

  16. A partial solution included the following items: • CO2 monitoring -too low a CO2 level, or no waveform (apnea) as detected by a commercial unit … Sampling was achieved with a single capillary tube placed near the patient's nostrils. The units used had an alarm level that could be set manually; the alarm signal could be accessed for use in other devices. • An autodialing motion detection alarm system was modified and connected to the capnometer. The system would then dial the charge a nurses' beeper when the system alarmed. The beeper was unique to the patient being monitored. • The basic system had to be modified with an on/off switch that could be activated when the patient was talking (seen as a high respiration rate) or eating. • A special cannula had to be obtained to sample air from both nostrils and from near the mouth. This was necessary for patients who mouth breathed due to snoring and/or stuffy noses.

  17. Cancer Clinic Charting While charting the pathway of patients through a screening clinic (breast cancer screening) a means had to be found to display not only the process but also the patient perception of the process.

  18. Cancer clinic diagnosis/discharge/follow-up section

  19. EKG Analysis Techniques • 2 -3 hours of ekg sampled at 1000 samples/sec – analyze & report on 10-20 averaged ekgs at multiple points in time (mouse, implanted transmitter) • Desire r-r interval analysis also • Desire arrhythmia analysis

  20. Alternatives considered: • Access + Excel + Visual Basic • IDL and Visual C • PV-Wave & C • MATLAB & Visual C++ + Excel + Visual Basic • Others’ approaches, ease of use?

  21. Current solution: • Initial developmental work done in Excel with visual basic (debug & test) • Migration to MATLAB as soon as feasible • Currently in use

  22. EKG Analysis Module Given the mandate to do so, design an introductory freshman module (1 credit hour) to allow students potentially interested in your department to sample what they might experience in their remaining three years should they elect your department's major.

  23. Electrocardiogram Capture and Analysis • data analysis techniques in electrocardiography, • medical and engineering nomenclature, • engineering and engineering applied to medicine, • technologies involved in cardiology and electrocardiography, • and societal ramifications of heart-related research

  24. Basics: • EKG lectures, basic ekg recognition • Student ekg sampled, analyzed with Excel (for R- wave analysis & HR determination) • Same ekg analyzed with MATLAB • http://vubme.vuse.vanderbilt.edu/King/ekg2000.htm for layout, etc.

  25. Choosing the Correct Plastic Material The purpose of the test is to provide rough insight into whether plastic materials subjected to stress are compatible with common cleaning substances. The materials being considered are Valox, Zytel, Cycoloy, and Thermocomp.

  26. Test dogbones of material: • Kleen-Aseptic • Sporicidin • Cidex+ • Aldiced • Virex 256 • Wescodyn • Acetone • Bleach • Isopropyl alcohol.

  27. Testing - • Tensile tests • Flex tests • Time/exposure tests • Inspect visually • Test to failure

  28. Similar tests & procedures • Materials tests for autoclaving • Choosing the right cleaning material …

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