A beam profile generation algorithm for wedged half-beam blocked asymmetric fields.

Abstract:

:A method is presented to predict beam profiles and outputs for wedged asymmetric fields defined by independent collimator jaws allowing fast generation of beam profiles whilst requiring very little additional data to that already used by most treatment planning systems in generating symmetric field isodoses. Symmetric field data are modified by the use of wedged primary off-centre ratios (POCRS) which are obtained from in air measurements of the largest possible wedged field. Beam hardening occurring within the flattening filter and wedge is taken into account by the use of attenuation coefficients measured under each wedge and used to generate the wedged POCR at depth. A full investigation into the comparison between measured and calculated profiles was performed which demonstrates favourable agreement across the whole of the asymmetric field including the penumbra.

journal_name

Phys Med Biol

authors

Millin AE,Smith CW

doi

10.1088/0031-9155/39/1/004

subject

Has Abstract

pub_date

1994-01-01 00:00:00

pages

63-73

issue

1

eissn

0031-9155

issn

1361-6560

journal_volume

39

pub_type

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