Question

How to assess nonuniformity in a gamma camera? Do you need the collimator for this? List four common causes of nonuniformity and how to correct them.

Answer 1

To assess nonuniformity in a gamma camera, perform a nonuniformity correction test with a uniform radioactive source and analyze pixel values. Common causes of nonuniformity are crystal defects, collimator misalignment, detector aging, and nonuniform flood source.

Step-by-step explanation:

To assess nonuniformity in a gamma camera, you need to perform a nonuniformity correction test. This can be done by acquiring an image of a uniform radioactive source and analyzing the pixel values across the image. The collimator, which is a device used to shape the radiation field, is usually used during the test to ensure uniformity.

Four common causes of nonuniformity in a gamma camera are:

1. Gamma camera crystal defects: These can be corrected by replacing the defective crystal or calibrating the system to compensate for the nonuniformity.
2. Collimator misalignment: This can be corrected by adjusting the collimator position or realigning it.
3. Detector aging: This can be corrected by performing regular calibrations, adjusting gain, or replacing the detector if necessary.
4. Nonuniform flood source: The flood source used for calibration should have a uniform distribution of radioactivity to avoid nonuniformity.