Dose Course Book

OF: small fields

Parallel to beam axis

Perpendicular to beam axis

Organic scintillator

(W1 Standard Imaging)

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

Relative difference normalized to EFD OF

Exradin W1 Cal. A

Exradin W1 Cal. B

Exradin W1 Cal. C

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

-5.0%

-4.0%

-3.0%

-2.0%

-1.0%

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)

Pinpoint

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

OF are referred to a 10 x 10 cm

field size.

be used.

These results show that the CRL and gain

depend on field size and orientation of the

scintillator.