Cluster 3 conclusion

Cluster 3 Conclusion

              

          The three quality control tests our group did are linearity, reproducibility and dark noise.  Linearity is to test the accuracy of linear output according to changes in mAs with a fixed kVp and reciprocity between mA and exposure time.  For the first part of the linearity test, although the results show there was a variance in mR/mAs, all the results were well within the acceptable range suggested by SC 35 and HARP act. For the second part of the linearity test, a different combination of mA and time were used to test the linearity of mR/mAs.  Again, the results showed a slightly variation of mR/mAs but they were all within the acceptable range of SC 35 and HARP act. The second quality control test is reproducibility, the test is to check whether the mammo unit and an x-ray unit produce a consistent exposures.  Since the mammo unit did not allow us to alter mAs settings, we used the same technique in all 10 exposures.  The coefficient of radiation from the mammo unit was 0.0053457 and the coefficient of radiation in the x-ray unit is 0.03294. According to SC 35 and HARP act, the coefficient of radiation should not be greater than 0.05 and 0.08 respectively. In a result, our mammo and x-ray units both passed the reproducibility control test. Note that the x-ray unit has a higher coefficient than the mammo unit and that is because the mammo unit was using the same mAs and kVp throughout the ten exposures while a different combination of mAs and kVp was used in the x-ray unit. The last quality control test was dark noise and the purpose is to test the uniformity of the CR processor. The CR reader did not show any artifacts while having a low EI value, which was 10, on the image. The acceptable range of the dark noise test was anything less than 80. Thus, the CR processor passed the test.  Though all the units are functioning properly, quality control tests should be done frequently to ensure the equipments keep up the same level of performance.