MR Safety / The New MR ACR QC Manual
R Price1*, (1) Vanderbilt Medical Center, Nashville, TNSA-D-Salon CD-2 Saturday 4:00:00 PM - 6:00:00 PM Room: Salon CD
The planned publication date of the revised ACR MRI Quality Control Manual is the first or second quarter of 2014. The manual will be made available in electronic form on the ACR website. The website will include a link to frequently asked questions (FAQs) as well as planned annual updates to the manual. The required performance parameters identified in the 2004 version of the manual have for the most part not changed. An exception is that the previously required test for RF “cross-talk” has been removed and is now listed as optional. As part of the revised annual performance evaluation the qualified medical physicist/MR scientist must: (1) repeat and verify the weekly technologist’s QC measurements, (2) perform the scans required for accreditation submission and evaluate those measurements with respect to the criteria specified in the most recent version of ACR Phantom Test Guidance Document, and (3) assess the site’s MRI safety program as recommended by the “ACR Guidance Document for Safe MR Practices: 2013” (Kanal E, et al JMRI 2013; 37:501-530). The safety assessment should include a review of written policies, signage and safety training. The revised manual also includes the description and suggested use of the ACR “Small Phantom” for extremity or other special-purpose MRI systems that may not be able to accommodate the original large phantom.
The revised manual includes alternate test procedures for both SNR and magnetic field homogeneity as described in the National Electrical Manufacturers Association (NEMA) publications and in AAPM Report 100. The alternate methods include both a single-image method and a two-image method for SNR assessment in addition to the original method recommended in the 2004 ACR manual. Alternate test methods for magnetic field homogeneity include the “phase-map” method and the “bandwidth-difference” method (Chen HH, et al Medical Physics 2006; 33:4299-4306). The bandwidth-difference method can be used in systems that do not provide access to either phase images or spectroscopy.
Not included in the revised manual is a specific method for testing multi-element array coils or for testing parallel imaging with acceleration. The current manual recommendation is that the maximum SNR be measured for each individual coil element in a manner similar to surface coil SNR assessment. It is anticipated that when the most appropriate method for testing multi-element arrays has been identified and approved, the method will be incorporated into the manual by means of the annual update. All discussed revisions should be considered to be preliminary until final approval has been granted by the American College of Radiology.
1. Identify changes in the Technologist’s Section
2. Review recommendations for the required annual site safety program assessment
3. Review the revised set of tests for annual performance testing
4. Present details of the alternate tests for SNR and field homogeneity
- 87-22893-326454-102529.pdf (R Price)