Did the Monthly QC Suite not complete?

The Monthly QC Suite workflow performs the following tasks:

[] Remove the collimator from each detector.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC point source and then tune Detector 1.

[] Retract the AQC point source.

[] Rotate Detector 2 to top-dead-center.

[] Extend the AQC point source and then tune Detector 2.

[] Retract the AQC point source.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC Point Source and acquire an Intrinsic Calibration Flood on both detectors (200 million counts on each head), followed by an Intrinsic Verification Flood on both detectors (10 million counts on each head).

[] Retract the AQC point source.

[] Install the collimators that were previously removed.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC line source, and then extend the AQC MHR Sleeve overtop the line source.

[] Acquire either a Head Alignment Calibration or Verification Tomo (120 views, First View by 25k counts on Detector 1). The time needed to acquire 25k counts during the first view on Detector 1 will be the time each remaining view is acquired.

[] Retract the AQC MHR Sleeve from overtop the line source, then retract the line source.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC line source.

[] Acquire Extrinsic Sweep Verification Flood (66 views on Det 1, and upon completion, 66 views on Det 2). When started as part of the Monthly QC Suite, the system acquires 160k counts on Detector 1, and then acquires each of the 132 views for that same amount of time.

Everything works as expected with the Monthly QC Suite until the AQC Line Source is 18 months past its Reference Date (180 days remaining until scheduled source replenishment) and then mysteriously the Monthly QC Suite no longer completes by 5 AM. When that occurs, most users immediately assume something is wrong with their scanner, but that’s usually not the case. Here’s why…

NOTE: The “scheduled” completion time for AQC procedures is configured via Options > Configuration > MI Acquisition Settings. It is a common practice to setup AQC procedure to complete at 5 AM each morning.

The above scenario with the Monthly QC Suite not completing occurs because the gadolinium rod source has decayed from 10 milli-curies (when it was installed) to 2 milli-curies (18 months later); and as a result, 12 hours or more are need for the combination of the Head Alignment and the Extrinsic Sweep. Be advised that the Head Alignment must complete before the “scheduled” completion time for the Extrinsic Sweep, otherwise the Extrinsic Sweep will not start until the next day, i.e., the next time 5 AM rolls around. This is a common reason for users arriving the morning after starting the Monthly QC Suite and finding it has not completed.

Siemens recommends replacing the AQC line source every 24 months. Therefore, once the AQC Line Source is 18 months past its Reference Date, customers should either:

[A] Start the Monthly QC Suite earlier in the day each month. However, as the gadolinium rod source continues to decay, the QC Suite will need to be started earlier and earlier each following month.

[B] Setup the Monthly QC Suite to run over the weekend. This is the most common workaround. However, many systems are used for patient scanning over the weekend, so this option might be impractical in some situations.

[C] Run each portion of the required monthly QC as a separate protocol, instead of running the Monthly QC Suite workflow,

The Monthly QC Suite workflow was created so all the required Nuclear Medicine QC can be accomplished using a single protocol. However, users are not required to utilize it. In fact, users without Auto Collimator Change (ACC) and Auto Quality Control) (AQC) cannot use it.

The Monthly QC requirements are listed in each system’s Operators Manual. While It is imperative that each test is performed monthly, users are free to use whatever workflows they desire.

- - Tuning can be performed separately.
  - Intrinsic Calibration can be performed separately,
  - Head Alignment 180 can be performed separately.

Tuning and Intrinsic Calibration could be performed one day, and then the Head Alignment 180 performed on another day, That would prevent the scanner from being unable to scan patients for a prolonged period.

Did the Monthly QC Suite not complete?

The Monthly QC Suite workflow performs the following tasks:

[] Remove the collimator from each detector.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC point source and then tune Detector 1.

[] Retract the AQC point source.

[] Rotate Detector 2 to top-dead-center.

[] Extend the AQC point source and then tune Detector 2.

[] Retract the AQC point source.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC Point Source and acquire an Intrinsic Calibration Flood on both detectors (200 million counts on each head), followed by an Intrinsic Verification Flood on both detectors (10 million counts on each head).

[] Retract the AQC point source.

[] Install the collimators that were previously removed.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC line source, and then extend the AQC MHR Sleeve overtop the line source.

[] Acquire either a Head Alignment Calibration or Verification Tomo (120 views, First View by 25k counts on Detector 1). The time needed to acquire 25k counts during the first view on Detector 1 will be the time each remaining view is acquired.

[] Retract the AQC MHR Sleeve from overtop the line source, then retract the line source.

[] Rotate Detector 1 to top-dead-center.

[] Extend the AQC line source.

[] Acquire Extrinsic Sweep Verification Flood (66 views on Det 1, and upon completion, 66 views on Det 2). When started as part of the Monthly QC Suite, the system acquires 160k counts on Detector 1, and then acquires each of the 132 views for that same amount of time.

NOTE: The “scheduled” completion time for AQC procedures is configured via Options > Configuration > MI Acquisition Settings. It is a common practice to setup AQC procedure to complete at 5 AM each morning.

Siemens recommends replacing the AQC line source every 24 months. Therefore, once the AQC Line Source is 18 months past its Reference Date, customers should either:

[A] Start the Monthly QC Suite earlier in the day each month. However, as the gadolinium rod source continues to decay, the QC Suite will need to be started earlier and earlier each following month.

[B] Setup the Monthly QC Suite to run over the weekend. This is the most common workaround. However, many systems are used for patient scanning over the weekend, so this option might be impractical in some situations.

[C] Run each portion of the required monthly QC as a separate protocol, instead of running the Monthly QC Suite workflow,

The Monthly QC Suite workflow was created so all the required Nuclear Medicine QC can be accomplished using a single protocol. However, users are not required to utilize it. In fact, users without Auto Collimator Change (ACC) and Auto Quality Control) (AQC) cannot use it.

The Monthly QC requirements are listed in each system’s Operators Manual. While It is imperative that each test is performed monthly, users are free to use whatever workflows they desire.

Tuning can be performed separately.

Intrinsic Calibration can be performed separately,

Head Alignment 180 can be performed separately.

Tuning and Intrinsic Calibration could be performed one day, and then the Head Alignment 180 performed on another day, That would prevent the scanner from being unable to scan patients for a prolonged period.