TMIST Physics and QC CoreQC Frequency Changes“Gold Status Machines”

ACRIN ECOG Fall Meeting, Oct. 25, 2019

Aili Maki, B.A.Sc, P. Eng.

Good News!

Starting in late November, the frequency and number of TMIST QC tests will be reduced for some mammography and tomosynthesis units.

This reduced frequency is called “Gold Status” and is for stable machines at sites with good compliance to the QC program.

Current TMIST QC Tests and Frequencies

Test Image Type Frequency

SDNR and Uniformity (2D) Processed Mammogram Weekly

TMIST 3D Tomosynthesis volume Weekly

TMIST Synthetic 2D Synthetic 2D Weekly

Monthly Uniformity Tomosynthesis projections/volume Monthly

Annual QC Tests Varies Annual

New TMIST QC Tests and Frequencies for “Gold Status” MachinesTest Image Type Frequency

SDNR and Uniformity (2D) Processed Mammogram Monthly

TMIST 3D Tomosynthesis volume Monthly

TMIST Synthetic 2D Synthetic 2D Monthly

Monthly Uniformity Tomosynthesis projections/volume When needed (trouble shooting)

Annual QC Tests Varies Annual

Qualifying a Machine as “Gold Status”

• TMIST weekly QC promptly and consistently submitted and reviewed for one calendar year

• No TMIST cases imaged on the machine when it is in “Action Required” or “Under Maintenance/On Hold”.

• Allowed exceptions from timely weekly submission and review• When a site requests a machine be put “Under Maintenance/On

Hold”(email/phone TMIST PQC)

• Delays in submission due to network/technical problems • e.g. slow internet transfers causes a test to show up 6 or more hours after image

submitted via TRIAD

Qualifying a Machine as “Gold Status” (cont’d)• Any “Failed” test points are commented on the website and a

passing test image submitted within 2 business days.

• QC performance indicators must be “stable” • No trends up or down for these parameters:

• SDNR

• Dose

• Calc. Slice Height (all groups)

• A “trend” is a steady change upwards or downwards in a plotted value over 3 months or more.

Examples – stable QC for one year

Example – QC Not stable (trend)

Dose dropping steadily over 3 months. Note I have zoomed in y axis (mGy), so the 3 mGy “Fail” limit is not visible

Example – properly documented QC problems, Aug. 26, 27• Comments on test points:

• Aug. 26 – “Test repeated”

• Aug. 27 – “Test done wrong”

• Passing reshoot (Aug. 28) within 2 business days of initial problemCompression paddle at 15 cm, 39 kV chosen.

Example – Bad QC• Site did comment that test was done incorrectly, however……

• Comment dates are the dates the QC reshot, not the date QC processed (Sep 10 and Sep 24)

• Failing QC not redone within 2 business days• Failing QC 1 done Sep 6, reshoot Sep. 10

• Failing QC 2 done Sep 20, reshoot Sep. 24

Wrong technique used (manual and 200 mAs)

How to Maintain Gold Status

Clear communication is key. Our email address is: contact@tmistqc.org

• Let us know every time service comes in and touches the machine –adjustments or software upgrades may result in the need to recalculate QC baselines

• Let us know when the physicist comes in and tests the machine

• Tell us if you are pausing imaging for any reason

Resetting QC Baselines/ Control limits for Gold Status Machine• If baselines need to be reset, email us the service report and physicist’s test

report (if applicable, and when available).

• Submit QC daily or weekly until there are 5 test points to establish the new control limits, then return to submitting QC monthly.

• Likely causes of Baseline shifts:• New generator• New tube• Gain adjustment• AEC adjustment• New detector (need new credentialing images!)

Loss of “Gold Status” (return to Weekly QC)

• If a machine ceases to be “Stable”, it will be put back onto weekly QC• 2 or more “Failed” QC data points with no clear documentation (comments)

on the website and/or without a passing re-shoot within 2 business days.

• Clear and consistent upward or downward trend over 3 months for any parameter with “Fail” (red) limits

• If QC is not submitted and reviewed consistently, the machines will be put back onto weekly QC - either• 2 or more “Overdue QC” emails not due to ACR/TRIAD or PQC Core software

malfunction

• 2 or more “Unreviewed QC” emails for QC when unit not on hold and not due to “late” processing and posting of QC by PQC Core

Regaining “Gold Status”

• Submit all service reports for adjustments made to equipment

• Demonstrate stable QC behavior for 3 months• Any failed test points have an explanation/comment• Passing re-shoot within 2 business days• No trends over the 3 months

• Demonstrate timely submission and review of weekly QC for 3 months• No Overdue QC emails except for ones aligned with monthly QC submission

week, or ones due to ACR/TRIAD or PQCCore software problems• No Un-reviewed QC emails unless due to late processing, or when unit was on

hold.

Gold Status goes live November 25, 2019*

• If you think your machine is ready for Gold Status, email TMIST PQC Core (contact@tmistqc.org) requesting review.

• Whenever PQC Core changes a machine’s status, all persons with active TMIST QC website accounts for that site (who haven’t opted out of emails) will be notified by email.

• If your machine is “Gold Status” but you are more comfortable submitting weekly or suspect a problem, you can submit QC more frequently.

* Estimated date. We will announce “Go Live” on the monthly call