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MITA Dose Check Initiative

MITA Dose Check Initiative. Goals of the initiative Enhance dose awareness (CTDI/DLP) Help to avoid excessive radiation events Provide data to sites for QA MITA has published the standard (XR-25)* Manufacturers worked to ensure Uniformity Speed of implementation Breadth of deployment.

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MITA Dose Check Initiative

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  1. MITA Dose Check Initiative • Goals of the initiative • Enhance dose awareness (CTDI/DLP) • Help to avoid excessive radiation events • Provide data to sites for QA • MITA has published the standard (XR-25)* Manufacturers worked to ensure • Uniformity • Speed of implementation • Breadth of deployment *Available at: http://www.nema.org/stds/xr25.cfm

  2. Dose Notification • Pop-up message • Notifies technologist that dose for the current scan will exceed a certain value • Tech may proceed but must confirm or adjust scan parameters • System records audit trail • Predicted dose, Notification value, Date/time, diagnostic reason, etc. • Clinical sites set values that will trigger a notification • Can set DLP and/or CTDIvol values for each scan elemente.g. head without contrast • Defined by the clinical site for their patient population

  3. Dose Alert • Pop-up message • Alerts technologist: cumulative dose will exceed a certain value of • CTDIvol per patient location for the current study • DLP for the current study • Tech may proceed but must confirm or adjust scan parameters • If the tech confirms, must input • Their name • Password (if configured) • System records audit trail • Operator name, Predicted dose, Alert value, Date/time, Diagnostic reason, etc. • Clinical sites set values that will trigger an alert • Can set DLP and/or CTDIvol values • System must allow at least one global value • System tracks accumulated CTDIvol at each patient location & accumulated DLP • System checks predicted accumulated dose indices when protocols are saved & when scans are confirmed

  4. Notification vs Alert

  5. Phased Rollout of Dose Check • Initially on one platform from each manufacturer • During 2011 and 2012 • Ported to other scanner platforms • Installed base (similarly configured platforms) • Follow a strict FDA Quality Systems Regulation • Design • Implementation • Testing

  6. Next Steps for Dose Check • Sites need to establish • Notification and Alert values • Part of larger dose control effort • Protocol review • Dose review • Dose Check and subsequent audit review • Accreditation • Training

  7. How to set the Values? • Alert values • FDA sent a letter to manufacturers on 8Nov2010 Therefore, the default Alert value* will be 1 Gy CTDIvol *configurable by site

  8. How to set the Values? • Notification values • Linked to DRLs? • Linked to local regulation?

  9. Implementation in the Member Countries of the EU Examples of Reference Dose Values for different Members of the EU, the regulating bodies and year when they were published • Germany, Bundesamt für Strahlenschutz (BfS), Jun 22, 2010 • Switzerland, Bundesamt fuer Gesundheit (BAG), Apr 1, 2010 • France, Societe Francaise de Radiologie (SFR), 2004 • UK Department of Health, Ionizing Radiation Regulations, 2000 • Norway, Norwegian Radiation Protection Authority (NRPA), 2007 Reference dose values are different in each country, e.g. * For comparison ** Pass/Fail criteria

  10. How to set the Values? • Notification values • Linked to DRLs? • Linked to local regulation? • Site specific?

  11. US Weight Distribution Downloaded from CalorieLab http://calorielab.com/news/2010/06/28/fattest-states-2010/

  12. How to set the Values? • Notification values • Linked to DRLs? • Linked to local regulation? • Site specific? • How often should they be tripped?

  13. Possible procedure • For a given protocol • Site ensures reasonable • Image Quality • Dose settings • Site reviews typical dose values for their patient population • Analyze dose distribution • Determine how often the notifications should occur • Set the standard deviation accordingly

  14. as a conversation starter…. Distribution of Dose for Notification Value ± 1.282 ± 1.644 How often to notify? 10% 5% NOTE: Fabricated distribution of 50 abdominal patients

  15. How to set the Values? • Notification values on manufacturer protocols • National dose index registry will help determine • DRLs • Population based notification levels • Want to ship scanners with Dose Check “On” by default • Don’t have site dose index distributions • Can’t use stdev approach

  16. Manufacturer Protocols • Fixed offset from nominal protocol CTDIvol • Most conservative is 1x • Will not realistically accommodate the patient spectrum • Trigger unnecessary notifications, reducing the effectiveness of the feature • Proposing 1.25x • Allows for some variation in patients • Does not inhibit sites from setting their own values • (give example, abdomen, head)

  17. as a conversation starter…. Distribution of Dose for Notification Value 1.25x 1.25x NOTE: Fabricated distribution of 50 abdominal and head patients

  18. Manufacturer Protocols • Another possibility • ACR reference values for • Adult abdomen • Adult head • Pediatric abdomen • Use 1.25x for • All other protocols

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