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NEW JERSEY CT DOSE PROJECT UPDATE. New Jersey Medical Physicist Meeting March 9, 2006 Web version with summary of meeting outcomes. November 2004 Meeting Outcomes. A standardized method for calculating and reporting CT dose should be used.
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NEW JERSEY CT DOSE PROJECT UPDATE New Jersey Medical Physicist Meeting March 9, 2006 Web version with summary of meeting outcomes
November2004 MeetingOutcomes • A standardized method for calculating and reporting CT dose should be used. • ACR’s 2002 CT Accreditation Program’s method and set up procedures for calculating CT dose should be used. • BRH to develop a form to report CT dose. • CT dose should be calculated and reported for Adult Head, Adult Abdomen and Pediatric Abdomen. • Patient scan protocols should be used.
Meeting Outcomes • NJ should apply ACR’s CTDI(w) reference values as its reference levels for CTDI(vol). • This will account for pitch from helical scanning • Facilities will be encouraged to submit CT doses to the BRH. • BRH will collect and analyze CT dose data and report results to medical physicists.
Why is Monitoring CT Dose Important? • Some data suggest that CT procedures account for 16% of all radiologic procedures performed, but contribute 65% of the dose delivered to patients.
Analysis of CT Dose Data • Demographic Information: • Data includes CT doses collected from December 2004 to February 2006. • A total of 396 CT Doses were collected on 141 CT scanners. (About 40% of all registered CT scanners)
CTDI Doses (mGy) By Procedure Type AAPM May 2005 recommendation to use 80th percentile
Observations and Discussion • Highest percentage to exceed the Reference Value is Adult Head. • Why? Is ACR’s reference value set too low or are values for adult abdomen and pediatric abdomen set too high? ALARA? Both? • High percentage of Pediatric Abdomen CT doses exceed Reference Value and greater variation of doses among CT types. • Suggests a need for better evaluation of patient scan protocols. (N.J.A.C. 7:28-22.10(a) Item #12)
Pediatric Scan Protocol • Is ALARA practiced? • Scan Protocols between adult abdomen and pediatric abdomen vary greatly depending on CT Slice type. • CTDI(w) for single slice and 64 slice CT scanners for pediatric abdomen are higher than for adult abdomen. • No significant change in the mean scan protocol between adult abdomen and pediatric abdomen for 64 Slice CT Scanners. • CAN DOSE BE LOWER?
Revisions to New Jersey CT Dose Report • The following were added to the report: • Field for facility name. • Field to enter procedures not performed. • Auto calculation field for pitch. • Area to enter recommendations for dose and patient protocol. • Requirement for facilities to implement corrective action if recommendations are made. • Pediatric patient is defined. • Physicists are encourages to use this form since it provides data that is not currently on ACR’s form (Examples: CT slice type, review pitch and requirement to reduce high doses).
What’s Next • Implement revised NJ CT Dose Report form. • Continue tracking CT doses. • Investigate facilities that have a CTDI(vol) dose that exceed ACR’s CTDI(w) Reference Value. • Continue to update medical physicists on findings and issues involving CT. • Physicists to notify the Bureau of issues relating to CT.
What a Difference 15 Months Makes?The only available dose data that could be reported in November 2004: Doses calculated and reported by various methods (ex. MSAD and Various CTDI)
Establishment of Project Goals To reduce CTDI(vol) dose in all three procedures by 15% by 2008.
How Can This Be Accomplished? • Ensure the practice of ALARA by: • Reviewing patient scan protocol to ensure the lowest CTDI(W) dose possible is used and if possible a greater use of pitch so that CTDI(vol) is lower than CTDI(w) while maintaining acceptable image quality. • Establishing a committee of physicists and radiologists to examine dose and imaging quality and identify a “suggested” scan protocol that would result in the lowest patient dose while maintain acceptable image quality. Bureau to publish this protocol to facilities.
Major 2006 Meeting Outcomes • For all three procedures, New Jersey’s mean CTDI(vol) doses are below ACR’s CTDI(w) reference values. • Facilities experiencing difficulties staying below ACR’s reference value for Adult Head. • New Jersey’s CT Dose Report is updated to provide better statistical analysis. • Committee established to optimize dose and image quality for certain CT scanners.