FDA warns of sandbags in MRI suites

ระวัง! เครื่อง MR จะพังเพราะถุงทราย : ถุงทรายที่ใช้ได้ในห้อง MRI ต้องเป็นถุงทรายที่ติดเครื่องหมาย MR Safe หรือ MR Conditional เท่านั้น

Sandbags that contain metal shavings could pose a hazard in MRI suites, according to an alert issued Friday by the U.S. Food and Drug Administration (FDA).

The FDA issued its warning after a report of a case in which healthcare staff placed a sandbag on a patient's groin to help facilitate hemostasis after a femoral artery puncture procedure. As the study began, the sandbag was pulled into the MRI scanner, damaging the system. The patient was not injured in the incident.


Staff had assumed that the sandbag contained only sand, but upon further investigation it was found to contain ferromagnetic shavings and iron pellets. The sandbag was originally purchased for the hospital's physical therapy department and shouldn't have been brought into the MRI suite, according to the FDA.


The FDA suggests that sites purchase only sandbags that are labeled with the MR Safe or MR Conditional icon. Ferromagnetic sandbags should be appropriately labeled as MR Unsafe to ensure that they aren't brought into the MRI suite, and unlabeled sandbags should not be brought into MRI rooms.


In addition, MRI staff should be educated to screen patients for ferromagnetic objects and should remove patients' blankets and sheets to search for objects. Patient records should be checked before MRI scans for recent procedures that may have required the use of a sandbag, and signs should be placed in visible areas outside the MRI room reminding staff to check for ferromagnetic objects.

By AuntMinnie.com staff writers
April 3, 2009


Note :

 MR Conditional icon

MR CONDITIONAL is defined by the ASTM International as an item that has been demonstrated to pose no known hazards in a specified MR environment with specifiedconditions of use. Conditions that may be used to define the specified MR environment include field strength, spatial gradient, RF fields, specific absorption rate (SAR) as well as the potential for additional conditions such as operational conditions for a device. The MR CONDITIONIAL label is used to alert the user that there are certain limitations to the usability of the item, or the testing that was performed. As an example, an item may have been tested for a 1.5-Tesla system, but not a 3-Tesla. Items bearing the MR CONDITIONAL icon should include additional information on the label, as to what the conditionality of use is, such as a gauss-line restriction or SAR level limitation. The icon designated for MR CONDITIONAL marking is a yellow equilateral triangle with a black border and black capital letters “MR” inside.

 MR SAFE icon

MR SAFE as defined by the ASTM International document is applied to an item that poses no known hazards in all MR environments. MR SAFE items would include nonconducting, nonmagnetic items such as a plastic Petri dish. The document further states that an item may be determined to be MR SAFE by providing a scientifically based rationale rather than test data. Unlike the previous FDA’s definition of MR Safe, the new MR SAFE may only be applied if the item is 100% safe, without exception, regardless of MR system field strength or any environmental or extenuating circumstances. The universal icon to be used for all MR SAFE products is a green square with white capital letters “MR”, or, a white square with green border and green capital letters “MR”. Items marked with the green MR SAFE icon may be taken into, used, or placed anywhere within any MR environment without risk or potential harm.



MR UNSAFE as defined by the ASTM International is any item that is a known threat or poses ahazard in all MR environments. An example of an MR UNSAFE item would be a pair of ferromagnetic scissors, or any item constructed of ferrous metals. The MR UNSAFE icon consists of a white circle with red border and diagonal strike through and the capital black letters “MR” inside.

คำสำคัญ (Tags): #mr conditional#mr safe#mr unsafe#sandbags
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