The regulations state that while in automatic decompression override status, mammography equipment must provide "maintenance of compression" after completion of an exposure or in case of a power interruption. What degree of compression and for how long must it be maintained?
The intent of this requirement is that systems in override status allow the continuation of compression so that it is not released in a manner likely to cause patient injury. The facility should evaluate system use in their clinical setting. The concerns for non-interventional procedures relate to the stability and balance of the patient and the potential falling hazard resulting from unexpected release. Although interventional mammography is not covered under current regulations, these procedures add the concern of uncontrolled needle withdrawal and attendant tissue damage and we recommend that these units be tested against the same requirement.
Non-interventional units that were not designed to provide automatic release after the completion of an exposure or upon power interruption also are not covered under this requirement. However, we recommend that such units be tested to assure that they meet their design intent.
In each context, the degree of compression maintenance and the time for which it needs to be applied should be assessed with regard to the likely potential for patient injury. Any problems identified by the physicist should be evaluated together with other responsible facility personnel and should be based on the use of the system in their specific clinical setting.