Experiences of daily use of a database for linear accelerator quality

Experiences of daily use of a database for linear accelerator quality control

McGrath N, Stilwell E, Budgell G, Beck J, Aziz T

The Christie NHS Foundation Trust

McGrath N, Stilwell E, Budgell G, Beck J, Aziz TChristie Medical Physics & Engineering

The Christie NHS Foundation TrustManchester

Overview

BackgroundDaily output and QC checks

Linac QC checksProblems and solutions


Problems and solutionsFuture solutions

Conclusions

Background and Purpose• A database has been developed (MS access)

and brought into routine use for daily output checks and quality control (QC) check results

• The need for a database:• Paper-light working


• Paper-light working• Handwriting• Consistency of data recorded

Background and Purpose

• Satellite working:• 16 linear accelerators within

the Christie network • Database has been in use for:


• Database has been in use for:• 18 months for linac QC • 30 months for daily output

checks

Database main menu


Daily output and QC checks

• Check-boxes are ticked to record that the daily QC tests have been done

• Ion chamber/daily check device results entered• Doses are calculated by the database using


• Doses are calculated by the database using stored calibration factors and the pressure from a networked barometer

• An instant green/amber/red tolerance is applied to the results.




• Easy verification of results by a physicist• Saves time• Avoids calculation errors

• Allows remote checking of results between sites


• Displays of monthly results are available

Linac QC

• A form is generated for each linac QC test• Date, time and staff name are automatically

entered• Data boxes are set as compulsory or optional,


• Data boxes are set as compulsory or optional, as required

• Calculations are performed automatically• Results compared with baseline data stored

within the database

Example – Photon Beam Energy


Example – X Ray Field Size


Linac QC

• Tolerances are applied• Can be linac specific if required• Out of tolerance results are flagged as red

• External files can be linked to forms to record data• Graphs of individual MLC leaf positions


• Graphs of individual MLC leaf positions • Shortcuts to work instructions• Shortcuts to QC test schedule spreadsheets

• Opened from the database• Tick off to record that the tests have been completed

Problems and solutions

• Gaining familiarity and coping with change!• Replicating the conveniences of a paper log-

book in an electronic form • Final conclusions from a session


• Final conclusions from a session• Identifying what was carried out during a QC

session• Passing on information between sessions


• Results and final conclusions from a session• QC session has to be concluded with a sign-off form• Tick box indicating that linac is fit for clinical use

• Identifying what was carried out during a QC session• Tick-boxes to show which tests have been performed


• Tick-boxes to show which tests have been performed• Free text box for conclusions and comments

• Passing on information between sessions• Electronic notes system• Checked before the next QC session• Signed and dated when issue has been addressed

QC session sign off


QC Checklists



Electronic Notes System



• A series of search tools has been designed to allow quick and thorough review of data• All occasions of a specified test filtered for

linac and date range• All the tests performed on a linac in a given


• All the tests performed on a linac in a given date range • Results can be directly accessed

• Reports exist to allow all the sign-off forms in a specified date range to be reviewed• Used in monthly QC review meetings

Searching for previous work



Future solutions

• Constantly improving and updating • Extension of the database to include

• Simulator QC• Superficial Unit QC


• Superficial Unit QC• ICRs• Sr checks

Conclusions

• Improved consistency of data recording and results• A number of QC tests have become quicker to carry out• Easier to review results, plot trends and monitor QC

• Can be done remotely across multiple sites• New tests and improvements can be implemented quickly


• New tests and improvements can be implemented quickly• Staff must adhere strictly to correct sign-off and

information transfer procedures• The time and effort required for it’s development has

been well worth it

Acknowledgements

Ted StilwellDatabase creator


Physicists and Engineers who have contributed feedback during the development

Documents

Experiences of daily use of a database for linear accelerator quality