Quality Management 2017

A NALYZE

11. Control charts building: Individual value

Type of drifts to detect

Control charts

Part 1 :

Introduction to SPC

Ex.: wrong adjustment of linac’s parameters, errors during measurement…

Large and Fast

Individual value / Moving Range Indi idual value /

( I -MR)

Part 2 :

Patient number

Diff. mes/calc. (%)

Essential concepts to start with SPC

Example of a measurement logbook EWMA - Exponentially Weighted Moving Average -

Ex.: drift of the detector’s dose response

Small and slow

Part 3 :

Patient number Diff. mes/calc. (%)

SPC in practice

Patient #

1

2

3

4

5

Beam #

1

1,00% -1,80% 1,68% -1,07% 3,20%

2

2,02% -1,27% -1,15% -0,55% 3,58%

Part 4

3

0,20% 2,10% 2,83% -0,52% 5,49%

Conclusion

4

2,11% -2,06 % 0,64% -

3,68%

5

4,61% 0,78% -0,39% -

-

03/10/17

26

4