Computer Based Quality Control in Digital Imaging

Current radiation protection guidelines call for reviewing clinical practices to ensure that patient doses are kept to levels that are as low as reasonably achievable. Objectives: The purpose of this study was to demonstrate the capacity of a computer-based program to manage a quality review for digital panoramic imaging.   Methods: A commercially available image management software package (Romexis™ Planmeca, Inc) was used to perform an annual review of panoramic practices within a dental school setting. Results: The total number of panoramic images made during the academic year 2007 was 14,388. Retake errors and mean exposure values are given in the table below.

Age Group	Retake Percentage	Dose Area  Product mGy *cm2	Kilovoltage	Milliamperage	Exposure Time (seconds)
2 - 12	5.5	102.09	65.25	8.70	14.65
13 -17	4.5	140.85	65.95	9.20	15.69
18 - 30	2.5	163.72	66.39	9.96	15.92
31 - 59	3.7	166.96	66.52	10.11	15.90
60 -103	6.6	160.21	66.29	9.77	15.91

For the clinic population as a whole a retake rate of 4.2% was determined. More retake errors were found in children, elderly and special needs patients. The most common retake error was patient movement. The rate of repeated examinations was found to approach 10%.  Comparing exposure doses of our current digital system to our previous film based system; reduction in exposure dose was calculated to be 80%.  Conclusions: Image management software can be used to calculate population exposures and to manage a quality assurance program.  Retake errors in this present study were found to be within acceptable ranges, however, it is concluded that exposure reductions can be achieved by improved management of repeat examinations.   A change in software controls will be instituted that will alert the ordering clinician that an examination is a repeat request requiring further clinical justification and recommending collimation  to a specific region of interest.