Exam 2 Review

12345678910111213141516171819202122232425262728
Across
  1. 1. method used by the computer to filter out bad beats
  2. 4. allows for only the PMTs in the immediate vicinity of the event to contribute to the position location
  3. 5. mode that caps out the potential counts at 255 in a pixel
  4. 10. is a correction that is done by creating a linearity correction map by imaging precise linear phantoms & measuring the amount of displacement to produce straight lines in the image
  5. 12. creates a time activity curve
  6. 17. _____ smoothing used with dynamic(perfusion) image sets; weighted averaging occurs by looking at the frame before and after the frame to be altered and the frame being smoothed is given twice the weight
  7. 18. occurs when imaging too high an activity such that the pulses leaving the amplifier occur so rapidly that multiple pulses are handled as a single event and are rejected by the PHA
  8. 19. camera's ability to stop gamma rays and collect counts
  9. 20. _____ activity is the main loss of contrast in planar nuclear medicine
  10. 21. used to improve the spatial resolution of small organs, such as the heart or thyroid
  11. 22. a dynamic sequence of images viewed in a continuous loop
  12. 23. mode that equals 16 bits of information (2 bytes); takes up 2X the memory requirements
  13. 26. occurs when counts in each pixel in the image matrix are compared and lowest count pixel is used as a reference and the counts in the higher counting pixels are lowered
  14. 27. of the camera is placed inside the matrix
  15. 28. uniform shading between all count levels
Down
  1. 2. mode where a digital image is built in the computer's memory as the signals are received
  2. 3. method that assigns gray scale to pixel display suppressing high count pixels while increasing number of shades of gray to the lower count pixels
  3. 6. is done by collecting a high number of counts and setting up slightly different energy windows for each pixel in the matrix
  4. 7. a shading that enhances differences in the high count pixels
  5. 8. _____ smoothing is readjusting pixel count by looking at its 8 nearest neighbors; reduces image noise from low count values in individual pixels
  6. 9. statistical variations in the number of counts in the pixels that create the image
  7. 11. can occur in the camera display from spatial distortion and energy variation
  8. 13. method of increasing the camera's sensitivity by stopping the signal collection at the PMT anode after most of the scintillation photons have been registered
  9. 14. analyzed by PHA; determines if energy is counted or not (fit in the window)
  10. 15. occurs when a high count pixel is selected and the counts in the other pixels are increased
  11. 16. the camera's ability to clearly see detail; seeing objects as two separate objects
  12. 24. used in bkg subtraction when the ROI drawn is smaller than the ROI drawn around the organ of interest
  13. 25. mode that allows you to reformat a flow study by shortening the acquisition times of the individual frames that might have been collected over too long of a time interval