Factors affecting decreasing radiation dose for mammography in North Carolina after 2002: an analysis of Food and Drug Administration annual surveys.

RATIONALE AND OBJECTIVES: We sought to determine which factors affected the decrease in average glandular dose recorded at the annual U.S. Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 2002 through 2005. MATERIALS AND METHODS: Average glandular dose, half-value layer, kVp, equipment age, processing speed, and system speed for every mammography unit in the state were collected by Food and Drug Administration-trained state inspectors. A mixed-effect model was used to evaluate the changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant decrease in average glandular dose in North Carolina since 2002. Factors that were statistically significantly associated with this effect were changes in kVp, equipment age, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has decreased in North Carolina after 2002. This change is probably at least partially due to the cumulative effect of direct intervention by mammography consultants and statewide educational seminars on mammography quality control.

Factors affecting increasing radiation dose for mammography in North Carolina from 1997 through 2001: an analysis of Food and Drug Administration annual surveys.

RATIONALE AND OBJECTIVES: To determine which factors affected the increase in average glandular dose recorded at the annual US Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 1997 to 2001. MATERIALS AND METHODS: Average glandular dose, HVL, kVp, ambient light, luminance, equipment age, processing speed, and system speed for every mammography unit at all facilities in the state were collected by state inspectors. A mixed-effect model was used to assess the average changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant increase in the average glandular dose in North Carolina in 1999, 2000, and 2001 when compared with the baseline year of 1997. Factors that were statistically significantly linked to this effect were changes in kVp, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has recently increased in North Carolina. This change is likely caused by changes in screen-film products and processing techniques.