Improving Health Through Medical Physics

ACR Accreditation: Frequently Asked Questions for Medical Physicists

Dustin A. Gress, MS | Reston, VA

AAPM Newsletter — Volume 44 No. 4 — July | August 2019

In each issue of this newsletter, I'll present frequently asked questions (FAQs) or other information of particular importance for medical physicists. You may also check out the ACR's accreditation web site portal for more FAQs, accreditation application information, and QC forms.

Last November, the ACR released its 2018 Digital Mammography QC Manual with 2D and Digital Breast Tomosynthesis. Below is a single but important FAQ that corrects a typographical error in the manual. As always, our current and FDA-approved FAQs can be found on the ACR Digital Mammography QC Manual Resources web page, where you can also find updated Microsoft Excel forms for technologist and medical physicist QC (free to download), and recordings and slides from webinars pertaining to the manual. Please contact us, if you have questions.

Q. While performing SNR during my survey I noticed a discrepancy in the manual. On page 170, the Performance Criteria and Corrective Actions section states that "The SNR must be ≥40.0 for the 4.0 cm phantom in the DBT mode." However, the Precautions and Caveats section also states, "It is recognized that the SNR is not strictly defined for DBT images." Which is correct?
A. The ACR recognizes that this is a typographical error in the manual, and it will be corrected in a revision. The SNR Performance Criteria and Corrective Actions should state, "The SNR must be ≥40.0 for the 4.0 cm phantom in the 2D Contact mode." For DBT, the SNR is not strictly defined.

On Friday, May 31, Michael Simanowith, MD, ACR's director of registries, sent an email to selected Dose Index Registry (DIR) participants. I share it with my AAPM colleagues below because I believe medical physicists can provide value to their imaging clinics by assisting with the upcoming change in how the DIR will be receiving and processing dose index data. Our FAQs on the NEMA XR-29 Standard can be found here.

Dear DIR Participant,
Thank you for your ongoing participation in the American College of Radiology's (ACR) Dose Index Registry (DIR). Your participation in the registry not only affects quality improvement at your own facility, but also establishes benchmarks that other facilities use for performance comparison and ultimately to reduce unnecessary patient radiation exposure across all participant sites.

When we launched the DIR in 2011 few CT scanners were capable of generating Radiation Dose Structured Reports (RDSRs). Therefore, we accepted exams directly from a RDSR as well as from secondary capture images (without RDSR). In the years since the registry launch, and with the implementation of the XR-29 standard on CT scanners, most scanners submitting DIR data are now capable of producing RDSRs. In addition, the secondary capture method has proven to be less effective than RDSR in terms of data quality, information processing time, and resource support requirements. In response to the industry technology changes, and to the overall limitations of secondary capture, we would like to transition DIR support to RDSR submission only. Consequently, we are requesting that all sites shift submission of all of their registry data to the RDSR format as soon as possible.

Your site is one of several identified as sending secondary capture images without RDSRs in the past three months. As such, we ask that you switch over to RDSR transmission by September 3, 2019. Though we would prefer to receive the RDSR message exclusively, we can accept an accompanying secondary capture (it will not be processed) in the event your system mandates sending both.

The continued success of the Dose Index Registry and the resulting improvement in radiological quality is dependent on active participation by sites such as yours. We realize that making this change may result in modifications to your processes/systems with potential effort required by you. ACR thanks you in advance for your willingness to consider this change. If you have barriers to sending the RDSR we will be more than happy to work with you in an attempt to overcome these issues. Please contact the National Radiology Data Registry support team for assistance.

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