Dose Course 2018_Flipping book

Organic scintillator (W1 Standard Imaging)

OF: small fields

Perpendicular to beam axis

Parallel to beam axis

Figure 1. Calibration plate with the scintillator in the maximum fiber configuration (left) and minimum fiber configuration (right).

5.0%

The calibration methodology proposed by the manufacturer is not appropriate for measuring output factors for small fields. Calibration using smaller fields and the detector axis parallel to beam axis should be used. These results show that the CRL and gain depend on field size and orientation of the scintillator.

4.0%

3.0%

2.0%

1.0%

Exradin W1 Cal. A Exradin W1 Cal. B Exradin W1 Cal. C Pinpoint

0.0%

-1.0%

-2.0%

-3.0%

-4.0%

Relative difference normalized to EFD OF

-5.0%

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 Side of equivalent square field size at isocenter (cm)

Relative differences of OF normalized to EFD-3G OF.

OF are referred to a 10 x 10 cm 2 field size.